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   34262篇
  免费   2866篇
  国内免费   1831篇
  2023年   332篇
  2022年   382篇
  2021年   1576篇
  2020年   1032篇
  2019年   1248篇
  2018年   1223篇
  2017年   863篇
  2016年   1324篇
  2015年   2022篇
  2014年   2363篇
  2013年   2547篇
  2012年   3082篇
  2011年   2762篇
  2010年   1718篇
  2009年   1428篇
  2008年   1661篇
  2007年   1513篇
  2006年   1350篇
  2005年   1141篇
  2004年   1019篇
  2003年   864篇
  2002年   743篇
  2001年   680篇
  2000年   681篇
  1999年   660篇
  1998年   387篇
  1997年   335篇
  1996年   351篇
  1995年   333篇
  1994年   325篇
  1993年   217篇
  1992年   351篇
  1991年   270篇
  1990年   305篇
  1989年   257篇
  1988年   189篇
  1987年   170篇
  1986年   152篇
  1985年   134篇
  1984年   121篇
  1983年   95篇
  1982年   77篇
  1981年   60篇
  1980年   45篇
  1979年   74篇
  1978年   54篇
  1977年   52篇
  1975年   59篇
  1974年   47篇
  1973年   50篇
排序方式: 共有10000条查询结果,搜索用时 406 毫秒
991.
992.
The use of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) is limited in drug discovery and cardiac disease mechanism studies due to cell immaturity. Micro-scaled grooves can promote the maturation of cardiomyocytes by aligning them in order, but the mechanism of cardiomyocytes alignment has not been studied. From the level of calcium activity, gene expression and cell morphology, we verified that the W20H5 grooves can effectively promote the maturation of cardiomyocytes. The transient receptor potential channels (TRP channels) also play an important role in the maturation and development of cardiomyocytes. These findings support the engineered hPSC-CMs as a powerful model to study cardiac disease mechanism and partly mimic the myocardial morphological development. The important role of the TRP channels in the maturation and development of myocardium is first revealed.  相似文献   
993.
A novel pH-activatable fluorescent probe, 1-(propan-2-yl)-9H-pyrido[3,4-b]indole-3-carboxylic acid ( L-1 ), based on β-carboline derivatives, has been developed, which displays significant fluorescent response toward pH variation with high selectivity, good photo-stability and favorable pKa value. Moreover, L-1 can dynamically monitor the release of protons during ester hydrolysis reaction in consistent with enzymatic kinetics manner.  相似文献   
994.
Lizard beetles (Erotylidae, Languriinae, Languriini) are known as stem borers of plants and contain agricultural pests and endangered species, but their species–host plant associations have been poorly documented. Here we investigated the larval host plants of two species of the genus Tetraphala Strum, T. collaris (Crotch) and Tetraphala sp. occurring in Taiwan. Females of T. collaris excavated living leafstalks and stems of the herbaceous dicot, Sambucus chinensis (Adoxaceae) using their mandibles for oviposition. We observed the eggs and early-instar larvae inside and nearby oviposition holes and late-instar larvae inside stems, suggesting that T. collaris uses living leafstalks and stems of S. chinensis as oviposition substrate and the larvae tunnel into stems with feeding on the tissues. Similarly, females of Tetraphala sp. excavated living leafstalks of the fern, Pteris wallichiana (Pteridaceae) using their mandibles for oviposition. We observed the eggs and early-instar larvae inside and nearby oviposition holes. When reared in laboratory, a larva reached adulthood inside the leafstalk. These results indicated that Tetraphala sp. uses living leafstalks of Pt. wallichiana as oviposition substrate and the larvae complete their development within. This study revealed that the genus Tetraphala contains both fern- and dicot-users during larval period. Further study is needed to clarify the evolutionary process of host plant use of languriines. Additionally, the host plant list of Languriini is provided.  相似文献   
995.
996.
997.
998.
Wang  Yuhan  Wang  Dianhong  Zhang  Xiangli  Huang  Tianye  Zhao  Xiang  Zeng  Shuwen 《Plasmonics (Norwell, Mass.)》2021,16(2):463-469
Plasmonics - By introducing the sub-wavelength grating (SWG) waveguide in the long-range surface phonon resonance (LRSPhR) device, a mid-infrared Fano resonance is formed due to the coupling...  相似文献   
999.
Huang  Wei  Cao  Yu  Chen  Chenyang  Wu  Xi  Sheng  Zhe  Li  Anying 《Journal of molecular histology》2021,52(4):767-780
Journal of Molecular Histology - Myocardial infarction (MI) is a great threat to patients all over the word. MicroRNAs (miRNAs) are a group of non-coding RNAs and can regulate initiation and...  相似文献   
1000.
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