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   14534篇
  免费   28篇
  国内免费   5篇
教育   11161篇
科学研究   1455篇
各国文化   32篇
体育   567篇
综合类   13篇
文化理论   428篇
信息传播   911篇
  2022年   35篇
  2021年   49篇
  2020年   60篇
  2019年   109篇
  2018年   2273篇
  2017年   2184篇
  2016年   1658篇
  2015年   179篇
  2014年   201篇
  2013年   657篇
  2012年   307篇
  2011年   768篇
  2010年   909篇
  2009年   488篇
  2008年   708篇
  2007年   1221篇
  2006年   124篇
  2005年   474篇
  2004年   531篇
  2003年   469篇
  2002年   222篇
  2001年   92篇
  2000年   74篇
  1999年   36篇
  1998年   23篇
  1997年   36篇
  1996年   31篇
  1995年   31篇
  1994年   29篇
  1993年   33篇
  1992年   24篇
  1991年   39篇
  1990年   19篇
  1989年   35篇
  1987年   18篇
  1986年   14篇
  1985年   19篇
  1984年   18篇
  1983年   21篇
  1982年   27篇
  1981年   16篇
  1980年   20篇
  1979年   18篇
  1978年   19篇
  1977年   20篇
  1976年   14篇
  1974年   21篇
  1973年   21篇
  1968年   14篇
  1967年   15篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
105.
106.
107.
Soybean accounts for more than half of the global production of oilseed and more than a quarter of the protein used globally for human food and animal feed. Soybean domestication involved parallel increases in seed size and oil content, and a concomitant decrease in protein content. However, science has not yet discovered whether these effects were due to selective pressure on a single gene or multiple genes. Here, re-sequencing data from >800 genotypes revealed a strong selection during soybean domestication on GmSWEET10a. The selection of GmSWEET10a conferred simultaneous increases in soybean-seed size and oil content as well as a reduction in the protein content. The result was validated using both near-isogenic lines carrying substitution of haplotype chromosomal segments and transgenic soybeans. Moreover, GmSWEET10b was found to be functionally redundant with its homologue GmSWEET10a and to be undergoing selection in current breeding, leading the the elite allele GmSWEET10b, a potential target for present-day soybean breeding. Both GmSWEET10a and GmSWEET10b were shown to transport sucrose and hexose, contributing to sugar allocation from seed coat to embryo, which consequently determines oil and protein contents and seed size in soybean. We conclude that past selection of optimal GmSWEET10a alleles drove the initial domestication of multiple soybean-seed traits and that targeted selection of the elite allele GmSWEET10b may further improve the yield and seed quality of modern soybean cultivars.  相似文献   
108.
109.
ABSTRACT

With increasing demand for improved medical equipment and healthcare, next-generation biomedical engineers need strong design skills. Equipping biomedical engineering students with tools for idea generation and development can increase student design success. Design Heuristics are an ideation tool developed through empirical studies of product designs. While identified in the mechanical engineering space, Design Heuristics may be applicable in biomedical engineering design. In our study, we implemented a Design Heuristics session during upper-level undergraduate and first-year graduate biomedical engineering design courses. We examined the applicability of Design Heuristics within individual and team concept generation contexts. The findings demonstrated that biomedical engineering students were able to use Design Heuristics to generate multiple concepts, and that initial concepts produced using Design Heuristics were carried over into final team design. The results support the applicability of Design Heuristics to student idea generation in biomedical engineering design.  相似文献   
110.
ABSTRACT

This research adapted the Life Skills Scale for Sport (LSSS) into Portuguese and provided evidence for its construct validity. Study 1 included four translators and five academics who developed a Portuguese version of the LSSS (P-LSSS). During this study, evidence for the content and substantive aspects of construct validity was provided using an expert panel and 25 sports participants. Study 2 included 413 participants that completed the P-LSSS. Within this study, evidence for the structural aspect of construct validity was provided via factor analyses. Study 3 included 134 participants who completed the P-LSSS and a measure of motivation. This study provided evidence for the external aspect of construct validity, with results showing more self-determined motivation had positive relationships with participant’s life skills development. Overall, our findings provided evidence for the construct validity of P-LSSS scores. Researchers and practitioners can use the P-LSSS to assess life skills development within sports participants.  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