全文获取类型
收费全文 | 9000篇 |
免费 | 596篇 |
国内免费 | 127篇 |
专业分类
教育 | 3833篇 |
科学研究 | 2790篇 |
各国文化 | 20篇 |
体育 | 1994篇 |
综合类 | 698篇 |
文化理论 | 10篇 |
信息传播 | 378篇 |
出版年
2024年 | 4篇 |
2023年 | 52篇 |
2022年 | 158篇 |
2021年 | 251篇 |
2020年 | 285篇 |
2019年 | 279篇 |
2018年 | 290篇 |
2017年 | 272篇 |
2016年 | 400篇 |
2015年 | 330篇 |
2014年 | 515篇 |
2013年 | 965篇 |
2012年 | 787篇 |
2011年 | 831篇 |
2010年 | 551篇 |
2009年 | 524篇 |
2008年 | 556篇 |
2007年 | 561篇 |
2006年 | 540篇 |
2005年 | 402篇 |
2004年 | 301篇 |
2003年 | 236篇 |
2002年 | 177篇 |
2001年 | 149篇 |
2000年 | 98篇 |
1999年 | 61篇 |
1998年 | 29篇 |
1997年 | 33篇 |
1996年 | 20篇 |
1995年 | 17篇 |
1994年 | 10篇 |
1993年 | 11篇 |
1992年 | 11篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1957年 | 2篇 |
排序方式: 共有9723条查询结果,搜索用时 15 毫秒
31.
This study examined the heterogeneity in the co-developmental trajectories of reading and math performance (i.e., parallel changes in the initial scores and growth patterns) and identified the number, size and shape of the co-developmental trajectory across elementary and middle schools. In addition, this investigation focused on how an early childhood dysregulation profile (DP; indexed by a high co-occurrence of emotional, behavior, and attention problems) was associated with distinct co-developmental trajectories of reading and math performance. Specifically, we examined whether early childhood DP level can predict (a) membership assignment into each distinct co-development group and (b) variability in initial scores and changes in growth with each distinct co-development group. Participants were 784 academically at-risk students (47 % girls) predominantly from low socioeconomic status families who were recruited in first grade (Mean age = 6.57 years) and followed annually through the final year of middle school (ninth grade). Results revealed two distinct co-developmental trajectories of reading and math performance, including (a) a lower initial reading (higher increasing) and higher initial math (lower increasing) class (85.3 %) and (b) a lower initial math (higher increasing) and higher initial reading (lower increasing) class (14.7 %). Our results provided evidence for the compensatory pattern of co-developmental trajectories, indicating initial lower skills grow at a faster rate than the initial high. Further, early childhood DP was not associated with the membership assignment for these two distinct classes, which means that regardless of children’s early DP level, they have equal chances to be assigned to each of the classes. However, children with higher parent and teacher-reported DP in first grade demonstrated lower initial scores and a slower improvement rate in both classes after controlling for kindergarten literacy skills, gender, ethnicity, intelligence, socioeconomic status, and grade retention. Our study findings demonstrated (a) substantial heterogeneity in the co-developmental trajectories of reading and math performance across elementary and middle school ages; and (b) the importance of promoting self-regulation beginning in early childhood, especially for academically at-risk children in families facing economic challenges. 相似文献
32.
“双一流”建设的一项重要任务就是要加快一流教师队伍建设。在梳理了高校教师绩效评价制度发展历程的基础上,发现当前大多高校教师绩效评价存在评价导向不统一、评价标准不协调、评价主体行政化、反馈机制不畅通等问题。因此,高校教师绩效评价要体现战略导向,树立以人为本的理念,扩大评价的参与度和参与面,创新评价的方式方法,打造高素质的教师队伍,为一流大学建设目标的实现奠定夯实的人力资本基础。 相似文献
33.
随着团体健美操在各种场合的表演,其创编与训练引起了人们的关注。因此,本文就团体健美操的创编与训练作一探析。 相似文献
34.
In recent years, fault detection and isolation(FDI) technologies have been developing rapidly.Among them the observer-based fault detection andisolation technology for nonlinear systems are the mostattractive research areas, and lots of promising resultscan be found in survey papers[1]. Generally, thereare several kinds of strategies for observer-based FDIin nonlinearsystems such as unknown inputs observer-based FDI[2], and adaptive observer-based FDI[3]. Insome cases, fault accommodation… 相似文献
35.
Great efforts have been made to resolve the serious environmental pollution and inevitable declining of energy resources. A review of Chinese fuel reserves and engine technology showed that compressed natural gas (CNG)/diesel dual fuel engine (DFE) was one of the best solutions for the above problems at present. In order to study and improve the emission performance of CNG/diesel DFE, an emission model for DFE based on radial basis function (RBF) neural network was developed which was a black-box input-output training data model not require priori knowledge. The RBF centers and the connected weights could be selected automatically according to the distribution of the training data in input-output space and the given approximating error. Studies showed that the predicted results accorded well with the experimental data over a large range of operating conditions from low load to high load. The developed emissions model based on the RBF neural network could be used to successfully predict and optimize the emissions performance of DFE. And the effect of the DFE main performance parameters, such as rotation speed, load, pilot quantity and injection timing, were also predicted by means of this model. In resume, an emission prediction model for CNG/diesel DFE based on RBF neural network was built for analyzing the effect of the main performance parameters on the CO, NOx emissions of DFE. The predicted results agreed quite well with the traditional emissions model, which indicated that the model had certain application value, although it still has some limitations, because of its high dependence on the quantity of the experimental sample data. 相似文献
36.
图书馆知识管理的内容和实施策略 总被引:2,自引:0,他引:2
安月玲 《河北职业技术学院学报》2004,4(4):69-70
知识管理是图书馆面临的一个新课题。阐述图书馆知识管理的内容,并提出图书馆知识管理的实施策略。 相似文献
37.
企业绩效评价指标体系中存在的问题及改进建议 总被引:5,自引:0,他引:5
彭晓洁 《商丘职业技术学院学报》2006,5(4):24-25
企业绩效评价就是按照企业目标设计相应的评价指标体系,对企业一定经营期间的经营业绩做出客观、公正和准确的综合判断。通过分析我国现行企业绩效评价指标体系中存在的问题,提出了相应的改进建议。 相似文献
38.
We presented a numerical examination of the effect of microtexturing negative rings’ structure on the tribological performance of parallel bearing couples’ cell. Three mcirotexturing rings, which are circle, square and ellipse, were chosen and the analysis model were established. We used the Reynolds equation coupled with finite difference method and successive over relaxation Gauss-Seidel iterative method to solve the Newtonian flow’s hydrodynamics within a bearing couple. The effect of texture density and radius ratio (thickness) of the microtexturing rings were investigated on the tribological performance under the similar operating conditions. The numerical simulation reveals that: 1) The microtexturing rings’ structure can homogenize the local pressure much uniformly within the bearing cell. 2) The tribological performance is determined mainly by the microtexturing rings’ geometry and texture density, and the thickness of the rings’ structure can help to change the quantitative values. 3) The square and circle rings’s microtexturing surface can slightly improve the frictional performance with the bearing cells’ gap, while the ellipse ring’s surface may decrease the frictional performance. 4) The ellipse rings’ microtexturing surface can achieve the minimum spacing gap but the maximum friction coefficient of the bearing couple, and then the circle and square rings’ structure take the second and third place, respectively 相似文献
39.
Amongst the extensive research conducted about girls’ lack of interest in STEM subjects, an issue that is frequently examined is the learning of mathematics. This research investigates the gender gap in mathematics among Italian students based on performance levels, using standardised large-scale data from INVALSI tests. We performed a quantile regression to better understand the differences along the entire score distribution. A latent class model was then estimated to identify groups of students with similar performance levels, taking into account the gender covariate. The results indicate that boys are already ahead from primary education and that there is a general decrease in the performance as students progress through the education stages. 相似文献
40.
构建科学合理的评价方式,通过评价更好地了解学生的学习,并以评价改进教学,成为近来教育教学中非常值得关注的话题。表现性评价运用于小学数学教学中,能更好地了解学生的数学理解水平并有效改进教学。以“两位数减一位数退位减法”为例,制定了算理理解的水平框架并设计了表现性任务,对学生的算理理解水平和学习过程进行了测评。最后,合理应用表现性评价框架及测评,有针对性地进行了教学设计,有效促进了学生对算理的理解水平。 相似文献