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   37085篇
  免费   3583篇
  国内免费   25篇
  2023年   152篇
  2022年   387篇
  2021年   847篇
  2020年   453篇
  2019年   601篇
  2018年   704篇
  2017年   580篇
  2016年   1039篇
  2015年   1748篇
  2014年   1866篇
  2013年   2207篇
  2012年   2880篇
  2011年   2927篇
  2010年   1767篇
  2009年   1492篇
  2008年   2222篇
  2007年   2183篇
  2006年   2129篇
  2005年   1840篇
  2004年   1883篇
  2003年   1633篇
  2002年   1631篇
  2001年   448篇
  2000年   391篇
  1999年   436篇
  1998年   396篇
  1997年   269篇
  1996年   268篇
  1995年   253篇
  1994年   226篇
  1993年   215篇
  1992年   257篇
  1991年   286篇
  1990年   228篇
  1989年   234篇
  1988年   217篇
  1987年   186篇
  1986年   189篇
  1985年   184篇
  1984年   180篇
  1983年   180篇
  1982年   171篇
  1981年   179篇
  1980年   143篇
  1979年   159篇
  1977年   122篇
  1976年   115篇
  1975年   123篇
  1974年   140篇
  1973年   114篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
M Green  P M Loewenstein 《Cell》1987,51(5):795-802
Bovine papillomavirus type 1 contains the smallest known oncogene (ORF E5), encoding a hydrophobic 44 amino acid protein. To study the biochemical functions of the E5 oncoprotein, we have chemically synthesized it and several deletion mutant peptides. We demonstrate induction of cellular DNA synthesis in growth-arrested cells by microinjection of E5 oncoprotein. This activity can be broken down into two functionally distinguishable domains. Remarkably, the first domain, which alone is sufficient to induce cellular DNA synthesis, contains only the C-terminal 13 amino acids. This is the smallest known protein fragment that can autonomously activate cellular DNA synthesis. The second domain is the hydrophobic middle region, which by itself fails to induce cellular DNA synthesis but confers a 1000-fold increase in specific activity. The N-terminal one-third of the molecule is dispensable for induction of DNA synthesis.  相似文献   
3.
4.
5.
For decades, the bio-duck sound has been recorded in the Southern Ocean, but the animal producing it has remained a mystery. Heard mainly during austral winter in the Southern Ocean, this ubiquitous sound has been recorded in Antarctic waters and contemporaneously off the Australian west coast. Here, we present conclusive evidence that the bio-duck sound is produced by Antarctic minke whales (Balaenoptera bonaerensis). We analysed data from multi-sensor acoustic recording tags that included intense bio-duck sounds as well as singular downsweeps that have previously been attributed to this species. This finding allows the interpretation of a wealth of long-term acoustic recordings for this previously acoustically concealed species, which will improve our understanding of the distribution, abundance and behaviour of Antarctic minke whales. This is critical information for a species that inhabits a difficult to access sea-ice environment that is changing rapidly in some regions and has been the subject of contentious lethal sampling efforts and ongoing international legal action.  相似文献   
6.
7.
8.
Metabolism is recognized as an important driver of cancer progression and other complex diseases, but global metabolite profiling remains a challenge. Protein expression profiling is often a poor proxy since existing pathway enrichment models provide an incomplete mapping between the proteome and metabolism. To overcome these gaps, we introduce multiomic metabolic enrichment network analysis (MOMENTA), an integrative multiomic data analysis framework for more accurately deducing metabolic pathway changes from proteomics data alone in a gene set analysis context by leveraging protein interaction networks to extend annotated metabolic models. We apply MOMENTA to proteomic data from diverse cancer cell lines and human tumors to demonstrate its utility at revealing variation in metabolic pathway activity across cancer types, which we verify using independent metabolomics measurements. The novel metabolic networks we uncover in breast cancer and other tumors are linked to clinical outcomes, underscoring the pathophysiological relevance of the findings.  相似文献   
9.
Connective tissue growth factor (CTGF/CCN2) is overexpressed in diabetes. Diabetic rats possess myocardial and cardiomyocyte hypertrophy. In a recent report, Wang and colleagues (Am J Physiol Cell Physiol. 2009 Jul 22. [Epub ahead of print]) show that CCN2 directly mediates cardiomyocyte hypertrophy as well as that induced by high glucose and fatty acid. CCN2 acted via the TrkA receptor. These data are the subject of this commentary, and emphasize that CCN2 may be an excellent target for therapy in diabetes.  相似文献   
10.
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