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   8695篇
  免费   790篇
  国内免费   50篇
耳鼻咽喉   70篇
儿科学   311篇
妇产科学   272篇
基础医学   1076篇
口腔科学   377篇
临床医学   781篇
内科学   1675篇
皮肤病学   111篇
神经病学   1023篇
特种医学   517篇
外科学   1160篇
综合类   140篇
一般理论   9篇
预防医学   902篇
眼科学   163篇
药学   566篇
中国医学   5篇
肿瘤学   377篇
  2022年   77篇
  2021年   153篇
  2020年   113篇
  2019年   135篇
  2018年   135篇
  2017年   120篇
  2016年   131篇
  2015年   145篇
  2014年   205篇
  2013年   303篇
  2012年   365篇
  2011年   393篇
  2010年   218篇
  2009年   269篇
  2008年   371篇
  2007年   436篇
  2006年   379篇
  2005年   400篇
  2004年   363篇
  2003年   354篇
  2002年   337篇
  2001年   271篇
  2000年   283篇
  1999年   271篇
  1998年   121篇
  1997年   98篇
  1996年   105篇
  1995年   113篇
  1994年   84篇
  1993年   91篇
  1992年   199篇
  1991年   175篇
  1990年   164篇
  1989年   125篇
  1988年   142篇
  1987年   144篇
  1986年   159篇
  1985年   144篇
  1984年   134篇
  1983年   95篇
  1982年   73篇
  1980年   60篇
  1979年   94篇
  1978年   71篇
  1975年   64篇
  1974年   70篇
  1973年   58篇
  1972年   60篇
  1969年   59篇
  1968年   56篇
排序方式: 共有9535条查询结果,搜索用时 15 毫秒
51.
Staphylococcus aureus enterotoxin B (SEB) was added to explants of fetal human intestine in organ culture or administered into the lumen of fetal small intestine prior to culture. Both routes produced a massive increase in lamina propria T cells expressing Vβ33, and to a lesser extent, those expressing Vβ5 and Vβ12. SEB-activated lamina propria T cells produced interleukin-2 and interferon-Y and T cell activation was accompanied by tissue damage, which was inhibited by FK506.  相似文献   
52.
Prominent in T cells and natural killer cells, CD2 binding protein 1 (CD2BP1) plays an important role in CD2-mediated adhesion and signal transduction. In the current study, we investigated CD2 and PSTPIP (proline, serine, threonine phosphatase interacting protein, murine homologue of CD2BP1) interactions in purified mouse splenic T cells. PSTPIP associated with CD2 in both resting and activated T cells. Following various stimuli, such as concanavalin A, anti-TCRbeta, anti-CD3epsilon, anti-CD3epsilon/phorbol myristate acetate (PMA), IL-2, or PMA/ionomycin, PSTPIP and CD2 expression, as well as their association, increased in a time-dependent fashion. While PSTPIP expression and CD2 expression were comparable across most groups, the PSTPIP-CD2 association stimulated by anti-CD3epsilon alone was significantly greater than with other stimuli. Stimulation by anti-CD3epsilon plus anti-CD28 induced even greater PSTPIP-CD2 association than anti-CD3epsilon treatment alone, indicating that CD28 initiated signals are involved in regulating this interaction. There was no direct association between CD3epsilon or CD28 and PSTPIP. Tyrosine phosphorylated PSTPIP bound poorly to CD2 compared to dephosphorylated PSTPIP, and protein tyrosine phosphatase was shown to affect both phosphorylation of PSTPIP and the CD2-PSTPIP association. In addition to CD2, PSTPIP associated with CD4, CD8, CD54, and CD62L. CD2 and CD4 ligation reciprocally regulated their association with PSTPIP. These findings indicate that T cell activation, particularly through the CD3 and CD28 signal transduction pathways, regulates PSTPIP-CD2 interactions. PSTPIP likely has additional broader effects through interactions with CD4, CD8, CD54, and CD62L, and this may influence T cell responses to antigen.  相似文献   
53.
54.
55.
56.
57.
Marketing of an intravaginal ring that releases a progestagen at low dosage willbegin in 1985. The device is a silicone rubber toroidal ring 55.6 mm in diameter. Its active constituent is 5 mg of levonorgestrel, with an in vivo release rate of 20 mcg/day. The device is left in the vagina for 3 months, at which point a new ring is fitted. The device largely acts locally on the genital tract, altering cervical mucus so that it is relatively inpenetrable to sperm. Over 50% of cycles in device acceptors are ovulatory; 19% have inadequate luteal function and 29% are anovulatory. In a social acceptability study involving 27 ring users, all participants asserted at the 8 week follow up that the ring was the best method they had used and indicated an interest in continuing to use the device. Over 50% cited health reasons for this choice. The ring was viewed as less invasive than the IUD and more convenient than the diaphragm. The greatest criticism of the ring resulted from changed menstrual patterns; in most cases, however, it was the unexpectedness of the change rather than the change itself that concerned the user. Clinical trials have suggisted that the ring is viable in terms of its safety, efficacy, and overall acceptability. The pregnancy rate in 5500 woman-months of experinence stands at 3%, and there has been no evidence of an increased incidence of actopic pregnancy. Although 20% of women experienced expulsion of the device, only 2% discontinued use for thes reason. The continuation rate of 60% after 1 year's use compares favorably with other methods of hormonal contraception.  相似文献   
58.
An 11.8-year median follow-up evaluation of 42 "ideal" patients who had chemonucleolysis was obtained by examination, questionnaire, and roentgenograms. The excellent and good rating of this group was 81%, as compared to the total of 135 patients previously evaluated at 42 months and showing 85.2%. No complications were noted. Disc space rewidening, after initial narrowing, was observed in eight patients and 26% of all discs injected. While all who showed rewidening had excellent results, widening was not necessary to achieve an excellent rating. Marked narrowing and sclerosis of intervertebral margins were seen in many excellent and good clinical results. Chemonucleolysis represents a viable option as definitive treatment for a herniated nucleus pulposus in carefully selected patients.  相似文献   
59.
Maternal and Child Health Journal - The article “Factor Structure and Equivalence of Maternal Resources for Care in Bangladesh, Vietnam, and Ethiopia”, written by Sulochana Basnet,...  相似文献   
60.
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