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   134062篇
  免费   10541篇
  国内免费   5984篇
耳鼻咽喉   1766篇
儿科学   1477篇
妇产科学   1986篇
基础医学   19547篇
口腔科学   2721篇
临床医学   15483篇
内科学   22157篇
皮肤病学   2753篇
神经病学   8260篇
特种医学   5867篇
外国民族医学   53篇
外科学   15682篇
综合类   10973篇
现状与发展   22篇
一般理论   36篇
预防医学   7718篇
眼科学   4164篇
药学   13037篇
  67篇
中国医学   4708篇
肿瘤学   12110篇
  2024年   285篇
  2023年   1617篇
  2022年   4404篇
  2021年   6004篇
  2020年   3933篇
  2019年   4071篇
  2018年   4614篇
  2017年   3680篇
  2016年   4258篇
  2015年   6143篇
  2014年   7516篇
  2013年   7355篇
  2012年   11062篇
  2011年   11020篇
  2010年   6625篇
  2009年   5284篇
  2008年   7489篇
  2007年   7028篇
  2006年   6737篇
  2005年   6273篇
  2004年   4690篇
  2003年   4138篇
  2002年   3451篇
  2001年   3137篇
  2000年   3021篇
  1999年   2949篇
  1998年   1644篇
  1997年   1508篇
  1996年   1158篇
  1995年   1074篇
  1994年   910篇
  1993年   610篇
  1992年   920篇
  1991年   811篇
  1990年   751篇
  1989年   667篇
  1988年   615篇
  1987年   547篇
  1986年   425篇
  1985年   375篇
  1984年   249篇
  1983年   196篇
  1982年   97篇
  1981年   109篇
  1980年   70篇
  1979年   144篇
  1978年   90篇
  1975年   61篇
  1974年   87篇
  1973年   69篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
本研究拟探讨染料木黄酮对前列腺癌细胞LNCaP和CWR22RV1的增殖、迁移和侵袭能力的影响。一、材料与方法1.材料:前列腺癌细胞株LNCaP和CWR22RV1(中国科学院上海生命科学研究院);Genistein(天津科瑞泰科技有限公司);RPMI 1640、胎牛血清(FBS)、胰蛋白酶(美国Gibco公司);E-钙黏蛋白(E-cadherin)、N-钙黏蛋白(N-cadherin)、波形蛋白(Vimentin,Abcam公司);聚氰基丙烯酸正丁酯(BCA)试剂盒、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)上样缓冲液(×5)及蛋白质印迹法(Western blot)试剂盒(上海市碧云天生物公司);2.实验方法:采用噻唑蓝(MTT)实验、划痕实验和Transwell实验检测Genistein对细胞增殖、迁移及侵袭能力的影响。采用Western blot检测E-cadherin、N-cadherin、Vimentin、CD44和Oct-4的表达水平。  相似文献   
42.
43.
44.
A typical time series in functional magnetic resonance imaging (fMRI) exhibits autocorrelation, that is, the samples of the time series are dependent. In addition, temporal filtering, one of the crucial steps in preprocessing of functional magnetic resonance images, induces its own autocorrelation. While performing connectivity analysis in fMRI, the impact of the autocorrelation is largely ignored. Recently, autocorrelation has been addressed by variance correction approaches, which are sensitive to the sampling rate. In this article, we aim to investigate the impact of the sampling rate on the variance correction approaches. Toward this end, we first derived a generalized expression for the variance of the sample Pearson correlation coefficient (SPCC) in terms of the sampling rate and the filter cutoff frequency, in addition to the autocorrelation and cross‐covariance functions of the time series. Through simulations, we illustrated the importance of the variance correction for a fixed sampling rate. Using the real resting state fMRI data sets, we demonstrated that the data sets with higher sampling rates were more prone to false positives, in agreement with the existing empirical reports. We further demonstrated with single subject results that for the data sets with higher sampling rates, the variance correction strategy restored the integrity of true connectivity.  相似文献   
45.
46.
47.
48.
49.
Ferroptosis is an iron-dependent novel cell death pathway. Deferoxamine, a ferroptosis inhibitor, has been reported to promote spinal cord injury repair. It has yet to be clarified whether ferroptosis inhibition represents the mechanism of action of Deferoxamine on spinal cord injury recovery. A rat model of Deferoxamine at thoracic 10 segment was established using a modified Allen's method. Ninety 8-week-old female Wistar rats were used. Rats in the Deferoxamine group were intraperitoneally injected with 100 mg/kg Deferoxamine 30 minutes before injury. Simultaneously, the Sham and Deferoxamine groups served as controls. Drug administration was conducted for 7 consecutive days. The results were as follows:(1) Electron microscopy revealed shrunken mitochondria in the spinal cord injury group.(2) The Basso, Beattie and Bresnahan locomotor rating score showed that recovery of the hindlimb was remarkably better in the Deferoxamine group than in the spinal cord injury group.(3) The iron concentration was lower in the Deferoxamine group than in the spinal cord injury group after injury.(4) Western blot assay revealed that, compared with the spinal cord injury group, GPX4, xCT, and glutathione expression was markedly increased in the Deferoxamine group.(5) Real-time polymerase chain reaction revealed that, compared with the Deferoxamine group, mRNA levels of ferroptosis-related genes Acyl-CoA synthetase family member 2(ACSF2) and iron-responsive element-binding protein 2(IREB2) were up-regulated in the Deferoxamine group.(6) Deferoxamine increased survival of neurons and inhibited gliosis. These findings confirm that Deferoxamine can repair spinal cord injury by inhibiting ferroptosis. Targeting ferroptosis is therefore a promising therapeutic approach for spinal cord injury.  相似文献   
50.
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