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   4980篇
  免费   420篇
  国内免费   2篇
  2024年   2篇
  2023年   24篇
  2022年   69篇
  2021年   135篇
  2020年   69篇
  2019年   103篇
  2018年   94篇
  2017年   96篇
  2016年   173篇
  2015年   285篇
  2014年   310篇
  2013年   384篇
  2012年   464篇
  2011年   470篇
  2010年   276篇
  2009年   263篇
  2008年   365篇
  2007年   332篇
  2006年   319篇
  2005年   278篇
  2004年   243篇
  2003年   221篇
  2002年   184篇
  2001年   24篇
  2000年   17篇
  1999年   30篇
  1998年   33篇
  1997年   23篇
  1996年   29篇
  1995年   10篇
  1994年   6篇
  1993年   9篇
  1992年   4篇
  1991年   8篇
  1990年   10篇
  1989年   4篇
  1988年   8篇
  1987年   2篇
  1985年   2篇
  1984年   1篇
  1983年   1篇
  1982年   6篇
  1981年   2篇
  1980年   4篇
  1979年   2篇
  1978年   2篇
  1977年   2篇
  1976年   1篇
  1974年   2篇
  1968年   1篇
排序方式: 共有5402条查询结果,搜索用时 15 毫秒
91.
92.
Normal enteric nervous system (ENS) development relies on numerous factors, including appropriate migration, proliferation, differentiation, and maturation of neural crest (NC) derivatives. Incomplete rostral to caudal migration of enteric neural crest-derived progenitors (ENPs) down the gut is at least partially responsible for the absence of enteric ganglia that is a hallmark feature of Hirschsprung disease (HSCR). The thought that ganglia proximal to aganglionosis are normal has guided surgical procedures for HSCR patients. However, chronic gastrointestinal dysfunction suffered by a subset of patients after surgery as well as studies in HSCR mouse models suggest that aberrant NC segregation and differentiation may be occurring in ganglionated regions of the intestine. Studies in mouse models that possess enteric ganglia throughout the length of the intestine (non-HSCR) have also found that certain genetic alterations affect neural crest lineage balance and interestingly many of these mutants also have functional gastrointestinal (GI) defects. It is possible that many GI disorders can be explained in part by imbalances in NC-derived lineages. Here we review studies evaluating ENS defects in HSCR and non-HSCR mouse models, concluding with clinical implications while highlighting areas requiring further study.  相似文献   
93.
Melissa L. Caldwell 《Ethnos》2013,78(3):295-319
In this article I consider how Muscovites cultivate and express nationalist sentiments through their food choices. During the last ten years of the post-socialist transition, Russian consumers have encountered an expanding and increasingly transnational commodity market. Locally produced elements of Russian cuisine both compete with and imitate foreign food products. In response to perceptions that foreign cultures are displacing or subsuming local cultural forms, Russian officials have launched a 'Buy Russian' campaign. Domestic food producers, store clerks, and customers collaborate to classify foods and other products as either 'Ours'(Nash) or 'Not Ours' (Ne nash) and describe local goods as superior to foreign goods in terms of taste, quality, and healthfulness. In their own narratives about consumption choices, Muscovites echo these nationalist themes by explicitly linking their personal food experiences with broader political issues. Drawing from ethnographic fieldwork on foodpractices in Moscow(1995-2001), I suggest that consumption strategies mediate Muscovites' experiences with growing nationalist sentiments in the context of a globalizing Russia.  相似文献   
94.
We have adapted a bacterial CRISPR RNA/Cas9 system to precisely engineer the Drosophila genome and report that Cas9-mediated genomic modifications are efficiently transmitted through the germline. This RNA-guided Cas9 system can be rapidly programmed to generate targeted alleles for probing gene function in Drosophila.  相似文献   
95.
The mosquito innate immune response is able to clear the majority of Plasmodium parasites. This immune clearance is controlled by a number of regulatory molecules including serine protease inhibitors (serpins). To determine whether such molecules could represent a novel target for a malaria transmission-blocking vaccine, we vaccinated mice with Anopheles gambiae serpin-2. Antibodies against Anopheles gambiae serpin-2 significantly reduced the infection of a heterologous Anopheles species (Anopheles stephensi) by Plasmodium berghei, however this effect was not observed with Plasmodium falciparum. Therefore, this approach of targeting regulatory molecules of the mosquito immune system may represent a novel approach to transmission-blocking malaria vaccines.  相似文献   
96.
97.
98.
Aplysinopsins are tryptophan-derived natural products that have been isolated from a variety of marine organisms and have been shown to possess a range of biological activities. In vitro receptor binding assays showed that of the 12 serotonin receptor subtypes, analogues showed a high affinity for the 5-HT2B and 5-HT2C receptor subtypes, with selectivity for 5-HT2B over 5-HT2C. While no conclusions could be drawn about the number and position of N-methylations, bromination at C-4 and C-5 of the indole ring resulted in greater binding affinities, with Ki’s as low as 35 nM. This data, combined with previous knowledge of the CNS activity of aplysinopsin analogs, suggested that these compounds may have potential as leads for antidepressant drugs. Compounds 3c, 3u, and 3x were evaluated in the chick anxiety–depression model to assess their in vivo efficacy. Compound 3c showed a modest antidepressant effect at a dose of 30 nM/kg in the animal model.  相似文献   
99.
100.
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