首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1790篇
  免费   17篇
  国内免费   44篇
教育   1399篇
科学研究   186篇
体育   125篇
综合类   123篇
信息传播   18篇
  2023年   2篇
  2022年   5篇
  2021年   23篇
  2020年   16篇
  2019年   17篇
  2018年   13篇
  2017年   18篇
  2016年   14篇
  2015年   21篇
  2014年   103篇
  2013年   99篇
  2012年   95篇
  2011年   118篇
  2010年   86篇
  2009年   96篇
  2008年   121篇
  2007年   122篇
  2006年   158篇
  2005年   126篇
  2004年   104篇
  2003年   103篇
  2002年   104篇
  2001年   73篇
  2000年   62篇
  1999年   41篇
  1998年   14篇
  1997年   17篇
  1996年   18篇
  1995年   14篇
  1994年   18篇
  1993年   8篇
  1992年   9篇
  1991年   4篇
  1990年   5篇
  1989年   2篇
  1986年   1篇
  1984年   1篇
排序方式: 共有1851条查询结果,搜索用时 31 毫秒
1.
Proteins are major functional units that are tightly connected to form complex and dynamic networks.These networks enable cells and organisms to operate properly and respond efficiently to environmental cues.Over the past decades,many biochemical methods have been developed to search for protein-binding partners in order to understand how protein networks are constructed and connected.At the same time,rapid development in proteomics and mass spectrometry(MS)techniques makes it possible to identify interacting proteins and build comprehensive protein-protein interaction networks.The resulting interactomes and networks have proven informative in the investigation of biological functions,such as in the field of DNA damage repair.In recent years,a number of proteins involved in DNA damage response and DNA repair pathways have been uncovered with MS-based protein-protein interaction studies.As the technologies for enriching associated proteins and MS become more sophisticated,the studies of protein-protein interactions are entering a new era.In this review,we summarize the strategies and recent developments for exploring protein-protein interaction.In addition,we discuss the application of these tools in the investigation of protein-protein interaction networks involved in DNA damage response and DNA repair.  相似文献   
2.
目的:研究CHOP及GRP78与复发性GBM的相关性。方法:采用Western blot检测CHOP及GRP78在初发及复发GBM组织中的表达;Real-time PCR检测GRP78在初发以及复发GBM组织中的表达。结果:CHOP及GRP78在初发GBM中表达上调,而在经过原发性肿瘤切除后接受放疗和替莫唑胺化疗的复发性GBM中增加尤为显著。结论:CHOP及GRP78在GBM发病机制中起重要作用,该分子有望成为GMB潜在的诊断及预后评估标志物。  相似文献   
3.
Numerous national reports have identified the importance of significantly improving pathways that begin with Latinx students enrolling in 2-year institutions and ultimately completing baccalaureate degrees in STEM fields at 4-year institutions. Many programs using multiple interventions have been designed, implemented, and studied to achieve this goal. To synthesize what has been learned from studies of these programs, this article presents a systematic review of published studies of programs designed to support Latinx student success in 2-year institutions and successful transfer to 4-year institutions, particularly for STEM majors. A total of 49 quantitative, 9 qualitative, and 16 mixed-methods studies published as reports, articles, or dissertations since 1980 were identified that met the criteria for the review. Studies covered a wide range of interventions, including mentoring, counseling, advising, study groups, tutoring, scholarships, orientations, career services, undergraduate research, articulation agreements, and transfer programs. Individually, these studies report positive influences on student success outcomes, including 2- and 4-year graduation, transfer to a 4-year institution, retention, and success in individual courses. However, the number of qualifying studies was surprisingly small, considering the importance of improving success of Latinx students and the length of time during which the problem has been repeatedly emphasized. Few interventions have been undertaken from explicitly assets-based perspectives or theoretical frameworks. The lack of explicit frameworks underlying interventions—combined with a sole/primary focus on students—suggests many interventions were approached from a deficit-based perspective. Further, the study found no pattern of replication studies that might confirm effectiveness of potentially promising interventions. Based on our analysis of evaluations presented in the studies, it does not appear that the research community has developed agreed-upon methods to evaluate commonly agreed-upon outcomes. Finally, no intervention has been sufficiently supported that widespread implementation could be recommended.  相似文献   
4.
Practical independent research projects (IRPs) are a feature of school science in a number of countries. To assess the impact of IRPs on students, a systematic review of the literature was undertaken. Thirty-nine papers met the review inclusion criteria, reporting on work from twelve countries. The review indicates that IRPs are often associated with wider initiatives such as authentic science, problem-based learning, and project-based learning. There is considerable variability in the nature of IRP work in relation to focus, models of provision, assessment, the involvement of external partners such as universities and employers, and funding, and this diversity affects judgements on the quality of the evidence base on impact. The majority of the research reviewed explored areas such as conceptual understanding, motivation to study science once it is no longer compulsory and attitudes to science, and the development of practical skills. Benefits were identified in relation to the learning of science ideas, affective responses to science, views of pursuing careers involving science, and development of a range of skills. Studies focusing on traditionally under-represented groups indicated that such students felt more positive about science as a result of undertaking IRPs. The review findings indicate that further work is needed to enhance the quality of the available evidence, to consider the ways in which IRPs can be validly assessed, to explore more fully the potential benefits for traditionally under-represented groups, and to explore more fully the potential longer-term benefits of participation in IRPs at high school level.  相似文献   
5.
This study examined the effects of reading interventions from single‐case design studies for students with and at‐risk of emotional and behavioral disorders in grades K–12 using a quantitative synthesis. Seventeen studies met the selection criteria of having one more dependent variables meeting what works clearinghouse (WWC) design standards with or without reservations. Although students’ reading performance significantly improved from baseline to intervention phases (p < 0.001), the overall weighted average effect size was weak (Tau‐U = 0.58, 95% confidence interval = [0.54, 0.63]; d = 0.29); smaller effects were found on reading comprehension. Interventions were less effective for students in secondary grades, students with a comorbid disability, and students in substantially separate settings. While no studies meeting the selection criteria were conducted in inclusive settings, the teacher provided interventions were more effective than those provided by researchers suggesting the importance of the student–teacher relationship for reading instruction. Study limitations, areas for future research, and implications for school practices are discussed.  相似文献   
6.
While written and audio feedback have been well-examined by researchers, video feedback has received less attention. This review establishes the current state of research into video feedback encompassing three formats: talking head, screencast and combination screencast. Existing research shows that video feedback has a high level of acceptability amongst both staff and students and may help strengthen student-marker relationships; however, the impact of video feedback on student learning outcomes is yet to be determined. In addition, current evidence is drawn largely from small-scale studies and self-reported data susceptible to the novelty effect. While video feedback appears to be a promising alternative to traditional written feedback for its relative relational richness, the medium continues to be primarily used for information transmission rather than dialogue. Further research is needed to establish how the medium of video influences the feedback process, its potential to facilitate dialogue and its effects on student learning.  相似文献   
7.
Rutile-type fluorides have been proven to be active components in the context of emerging antiferr-omagnetic devices. However, controlled synthesis of low-dimensional, in particular two-dimensional (2D), fluorides in a predictable and deterministic manner remains unrealized because of a lack of efficient anisotropic control, which impedes their further development in reduced dimensions. We report here that altered passivation of {110} growing facets can direct the synthesis of rutile-type fluoride nanocrystals into well-defined zero-dimensional (0D) particulates, one-dimensional (1D) rods and 2D sheets in a colloidal approach. The obtained nanocrystals show positive exchange bias and enhanced magnetic transition temperature from the coexistence of long-range antiferromagnetic order and disordered surface spins, making them strong alternatives for flexible magnetic devices and sensors.  相似文献   
8.
This systematic review is built on the seminal work by the New London Group in 1996. Few endeavours have synthesized findings of empirical studies pertaining to the effects and challenges of multiliteracies practices in various schooling and geographical contexts. Through a five-point Likert scale and a deductive and inductive thematic analysis, we conducted a systematic review of 66 multiliteracies articles from the ProQuest® database. These studies were empirical, qualitative/mixed-method, and ranged from 2006 to 2015. Findings show a burgeoning number of multiliteracies studies occurring in 15 countries, with Canada being the most prominently involved. Our evaluation of the reviewed studies was generally favourable with strengths identified in researchers’ articulation of pertinent theoretical frameworks and connections to existent literature. Our findings refer to insufficient information of data collection and data analysis in a certain number of papers. We also elaborate on major affordances, challenges, and oversights of the multiliteracies practices as reported by the reviewed studies and discuss implications for future multiliteracies research, policies on literacy education, and teacher education in diverse contexts.  相似文献   
9.
为使教育评估结果更具科学性、准确性,文章探讨了教育评估过程中数据汇总合成的处理方法,包含指标群体评判结果的汇总处理、评估指标属性值的规范化处理和多指标数据的合成处理等方面,并结合实例具体介绍了合成的具体做法。  相似文献   
10.
Beginning with two important meta-analyses by Hattie and Timperley (2007) and Shute (2008), the relationship between teacher feedback and student self-perception has received more attention. One way students enact a self-perception is by reflectively writing about their participation within a particular field of study. The current review analyzes how teacher feedback facilitates and supports the formation of self-perception made visible in students’ reflective writing. The following electronic databases were searched up to February 2018: CINAHL, Academic Search Complete, PsycINFO, ERIC, ProQuest Dissertations and Theses, and Google Scholar. Five themes in total were constructed. These themes indicate contexts when feedback might lead to students reflecting through writing on a self-perception. Features of feedback that most likely promote this kind of reflection can be described as: content situated, dialogic, and empathic. As a secondary category of themes, feedback should position students as: fluid and/or vulnerable.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号