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   5828篇
  免费   405篇
  国内免费   21篇
耳鼻咽喉   84篇
儿科学   112篇
妇产科学   121篇
基础医学   765篇
口腔科学   146篇
临床医学   599篇
内科学   1012篇
皮肤病学   86篇
神经病学   541篇
特种医学   256篇
外科学   739篇
综合类   88篇
一般理论   4篇
预防医学   689篇
眼科学   108篇
药学   371篇
中国医学   5篇
肿瘤学   528篇
  2023年   32篇
  2022年   66篇
  2021年   140篇
  2020年   70篇
  2019年   131篇
  2018年   147篇
  2017年   122篇
  2016年   93篇
  2015年   106篇
  2014年   178篇
  2013年   278篇
  2012年   468篇
  2011年   521篇
  2010年   250篇
  2009年   210篇
  2008年   380篇
  2007年   399篇
  2006年   374篇
  2005年   369篇
  2004年   325篇
  2003年   294篇
  2002年   292篇
  2001年   68篇
  2000年   51篇
  1999年   61篇
  1998年   59篇
  1997年   32篇
  1996年   34篇
  1995年   38篇
  1994年   42篇
  1993年   45篇
  1992年   31篇
  1991年   26篇
  1990年   20篇
  1989年   24篇
  1987年   19篇
  1986年   29篇
  1985年   15篇
  1984年   22篇
  1983年   23篇
  1982年   27篇
  1981年   31篇
  1980年   40篇
  1979年   18篇
  1978年   21篇
  1977年   20篇
  1976年   21篇
  1975年   16篇
  1974年   16篇
  1971年   14篇
排序方式: 共有6254条查询结果,搜索用时 15 毫秒
1.
2.
Monoclonal antibodies against human and bovine 2′:3′-cyclic nucleotide 3′-phosphodiesterase (CNPase) were generated by fusing FOX-NY myeloma cells with spleen cells from RBF/Dn mice previously immunized with the purified brain antigens. The enzyme isolated from bovine brain was quite basic, with an isoelectric point of 9.71 and both the bovine and human enzymes consisted of a closely spaced doublet at approximately 44 and 46 kDa on SDS-PAGE. Six monoclonals were identified as strongly recognizing the enzyme on both ELISA plates and on immunoblots of whole brain protein. Four monoclonals very weakly cross-reacted with guinea pig myelin basic protein. In contrast with two previous reports, some of our monoclonal antibodies did immunostain 2 or 3 protein bands in peripheral nerve, two bands closely corresponding to those immunostained in central nervous system (CNS) myelin, the Wolfgram protein fraction and in acetone powders of whole brain. Each of the 6 monoclonals reacting strongly on immunoblots recognized the enzyme in from 2 to 5 of the species examined (human, bovine, rat, mouse and rabbit). In addition, all 6 monoclonals that immunostained the enzyme in whole brain, myelin and Wolfgram protein immunoblots recognized both CNP1 (44 kDa) and CNP2 (46 kDa). The two closely spaced protein bands observed on SDS-PAGE and previously stained on immunoblots of CNS CNPase using polyvalent rabbit anti-bovine CNPase antisera, and now different monoclonal antibodies, appear to be immunologically related and to contain highly conserved sequences.  相似文献   
3.
4.
5.
The brains of pathogen-free autoimmune MRL/lpr, NZBWF1 and NZB mice were examined for central nervous system (CNS) inflammation in premoribund 8-week-old animals and at ages when active systemic lupus erythematosus (SLE) was present. CNS inflammation was observed only in MRL/lpr mice. Immunohistochemical studies of brains from young MRL/lpr mice found that infiltrates were composed primarily of CD4+ cells. Older MRL/lpr mice (22 and 26 weeks of age) had CD4+ cells predominantly, but CD8+ and B220+ cells were also present. Perivascular leakage of IgG was a prominent and unexpected finding in the MRL/lpr model. Congenic MRL/+ mice with late-onset autoimmunity had no inflammatory cells in brain tissue, and there was no perivascular staining with IgG or albumin. Our findings suggest that MRL/lpr mice are a useful model for studies of lupus-associated CNS inflammatory disease, and perivascular leakage may be a primary mechanism for entry of IgG into the brain.  相似文献   
6.
7.
Impaired recall for early items (primacy) and late items (recency) on word list recall tests are seen in Alzheimer's disease (AD). We compared conventional scoring on the Telephone Instrument for Cognitive Status (TICS) recall list with scorings based on retention-weighted recall (RWR: each item weighted by its serial position) in older adults participating in a community-based aging study. Subjects with mild AD (N=18) did not differ from those without dementia (N=231) with respect to recency (46% vs. 59%, p = 0.2), but had impaired primacy (2% vs. 39%, p < .001) on word recall on the TICS. RWR scoring improved the effect size (1.52 SD) compared to conventional scoring (1.08 SD). With a fixed sensitivity of 85%, specificity was lower using conventional scoring (56%) than RWR (76%) scoring. Our findings suggest that optimized RWR scoring of word list free recall can improve detection of mild AD compared to conventional scoring.  相似文献   
8.
9.
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