全文获取类型
收费全文 | 572篇 |
免费 | 37篇 |
国内免费 | 48篇 |
专业分类
教育 | 149篇 |
科学研究 | 347篇 |
体育 | 24篇 |
综合类 | 13篇 |
文化理论 | 1篇 |
信息传播 | 123篇 |
出版年
2023年 | 15篇 |
2022年 | 22篇 |
2021年 | 34篇 |
2020年 | 34篇 |
2019年 | 34篇 |
2018年 | 45篇 |
2017年 | 26篇 |
2016年 | 16篇 |
2015年 | 36篇 |
2014年 | 45篇 |
2013年 | 43篇 |
2012年 | 34篇 |
2011年 | 41篇 |
2010年 | 29篇 |
2009年 | 32篇 |
2008年 | 23篇 |
2007年 | 27篇 |
2006年 | 15篇 |
2005年 | 13篇 |
2004年 | 24篇 |
2003年 | 26篇 |
2002年 | 8篇 |
2001年 | 10篇 |
2000年 | 10篇 |
1999年 | 9篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 2篇 |
排序方式: 共有657条查询结果,搜索用时 31 毫秒
91.
Corey Jones Emily Graybill Brian Barger Andrew T. Roach 《Psychology in the schools》2020,57(6):923-936
Through this study we compared different informants and different behavior screening tools that are available to screen for behavioral and emotional risk. We examined screening results from 100 students from a high school with a high achiever's magnet program in the Southeastern United States (school demographics: 71% female and 79% black, non-Hispanic). This school conducted behavior screening using both teacher-report via the Student Risk Screening Scale, Internalizing/Externalizing (SRSS-IE) and student report via the Strengths and Difficulties Questionnaire (SDQ). Nonparametric correlation tests were conducted between the SRSS-IE and SDQ externalizing and internalizing scores. Generalized linear regression models were created based on the data (demographics, internalizing, and externalizing scores on both screening tools) to model the two count outcomes (office discipline referrals [ODRs] and absences). Diagnostic accuracy metrics were generated from the scores on both the SRSS-IE and SDQ with the outcome measures (ODRs and absences). Externalizing scores on both screening tools had statistically significant low correlations. The ODR model contained two predictors: externalizing score on the SRSS-IE and internalizing score on the SDQ, while the absence model contained grade and the externalizing score on the SDQ. The highest accuracy and agreement values were seen between students with elevated risks on both screening measures and ODRs. The results confirmed that teacher and student reporting, as well as different screening tools, will result in some different students being identified. The choice of informant and screening tools should be dependent on the needs and resources of the school. 相似文献
92.
93.
王巍 《哈尔滨体育学院学报》2010,28(3)
采用文献资料、访谈等研究方法,对我国乒乓球专利项目现状进行探讨,并针对这些专利存在的问题进行了分析。结果发现:现阶段我国乒乓球专利项目的创新研究少;同类专利的重复性研究较多;专利转化效果差、实用性差,并针对这些问题提出了相应的建议。 相似文献
94.
95.
96.
从网络效应出发,探究信息通信技术使创新空间分布趋向均衡的理论机制.利用长三角城市群面板数据构建门限回归模型,检验在不同互联网普及程度下各类创新主体对城市创新产出贡献的门限效应.研究发现:长三角城市群内,创新主体位于互联网普及程度高的城市对创新产出具有更高的边际贡献,互联网普及率13.67%和38.98%分别为创新主体边际贡献门限效应的两个临界点,达到38.98%后大学、外资企业、消费者的创新效率达到最大化,而政府干预作用相对降低;早期阶段,中心城市率先达到互联网普及的临界点,但随后互联网基础设施的快速发展消弭了城市间互联网"接入鸿沟",大部分城市突破了互联网普及的门限条件,互联网快速普及促进创新空间分布趋向均衡,为摆脱极化陷阱创造了条件.据此从城市群层面对实施创新驱动发展和协调区域平衡发展战略提出建议:关注中心城市的创新发展,集中突破核心关键技术创新;以数字经济发展为契机,优化调整创新空间分布;推动协同建设新一代信息基础设施,在更大地理范围内将创新主体纳入网络效应作用机制. 相似文献
97.
《Research Policy》2023,52(3):104696
How does patent scope influence licensing propensity of inventions? Prior studies have often been confined to specific industries or settings, and their results have been mixed with studies showing a positive, a negative, or even no significant relationship. Also, while some have explored moderating factors that might influence the patent scope-licensing relationship, a systematic investigation of the heterogeneous effects of patent scope on licensing at the invention level has not been undertaken. This study combines a broad sample of publicly reported patent licensing agreements and a novel methodology that captures an exogenous variation in patent scope to re-investigate the relationship between patent scope and licensing and to explore key invention and inventor characteristics that could influence this relationship. The results show that narrowed patent scope leads to a substantial decline in licensing propensity of inventions and that the effect is stronger for high-quality, science-based, and novel inventions as well as for inventions generated by small inventors. 相似文献
98.
《Research Policy》2023,52(2):104670
Encouraging disclosure is important for the patent system, yet the technical information in patent applications is often inadequate. We use algorithms from computational linguistics to quantify the effectiveness of disclosure in patent applications. Relying on the expectation that universities have more ability and incentive to disclose their inventions than corporations, we analyze 64 linguistic measures of patent applications, and show that university patents are more readable by 0.4 SD of a synthetic measure of readability. Results are robust to controlling for non-disclosure-related invention heterogeneity. The linguistic metrics are evaluated by a panel of “expert” student engineers and further examined by USPTO 112(a) – lack of disclosure – rejection. The ability to quantify disclosure opens new research paths and potentially facilitates improvement of disclosure. 相似文献
99.
纤维素分解菌的分离、筛选及其环境适应性初步研究 总被引:14,自引:0,他引:14
以滤纸平板和羧甲基纤维素钠培养基为基础培养基,从采集的样品中筛选出具有分解纤维素能力的38株菌株。采用纤维素刚果红培养基进行粗选,得到10株透明圈较大的菌株。将这10株菌株进行液体发酵培养,测定其酶活力,得到4株分解纤维素能力较强的菌株。对这4株菌株进行碳源、温度、pH值的适应性研究。结果发现,真菌3和真菌6的适应性都比较好。 相似文献
100.
The paper applies a novel methodology to US and EPO patent data to assess how often the “general grace period” exception is used in the USA and the likely impact of international patent regulations that almost invariably deny such use on the pace of new disclosures in academia. Comparisons of average publication delays of European academic inventors show that the grace period accelerates knowledge communication and that variations are likely to depend on a lack of harmonisation of international legal systems, transaction costs and the presence of a firm among patent assignees. 相似文献