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   4787篇
  免费   301篇
  国内免费   15篇
耳鼻咽喉   76篇
儿科学   118篇
妇产科学   109篇
基础医学   974篇
口腔科学   120篇
临床医学   389篇
内科学   735篇
皮肤病学   101篇
神经病学   483篇
特种医学   155篇
外科学   513篇
综合类   19篇
预防医学   399篇
眼科学   97篇
药学   576篇
中国医学   31篇
肿瘤学   208篇
  2023年   47篇
  2022年   53篇
  2021年   97篇
  2020年   70篇
  2019年   135篇
  2018年   239篇
  2017年   199篇
  2016年   233篇
  2015年   198篇
  2014年   250篇
  2013年   460篇
  2012年   551篇
  2011年   589篇
  2010年   351篇
  2009年   155篇
  2008年   107篇
  2007年   102篇
  2006年   82篇
  2005年   49篇
  2004年   28篇
  2003年   29篇
  2002年   20篇
  2001年   43篇
  2000年   46篇
  1999年   48篇
  1998年   31篇
  1997年   33篇
  1996年   30篇
  1995年   35篇
  1994年   30篇
  1993年   19篇
  1992年   25篇
  1991年   20篇
  1990年   26篇
  1989年   21篇
  1988年   29篇
  1987年   17篇
  1985年   22篇
  1984年   33篇
  1983年   28篇
  1982年   33篇
  1981年   28篇
  1980年   24篇
  1979年   25篇
  1978年   25篇
  1977年   18篇
  1976年   24篇
  1975年   21篇
  1973年   16篇
  1971年   17篇
排序方式: 共有5103条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
 The case report of a 61 year-old man with AML M2 FAB, t(1; 13; 14) and zygomycotic mesenterial thromboangiitis is presented. Two induction cycles of chemotherapy were administered due to primary drug resistance. They were complicated by pneumonia, colonic pseudo-obstruction and perforation with peritonitis. The patient died on the 40th day of therapy, 4 days after undergoing palliative surgery. Zygomycotic thromboangiitis, which very probably contributed to the intestinal perforation, was confirmed morphologically at necropsy. The novel complex chromosomal translocation t(1; 13; 14) (q31; q32; q24) and the problems connected with the diagnosis of invasive fungal infections are discussed. Received: 26 January 1996 / Accepted: 12 June 1996  相似文献   
5.
Summary.  Two vaccinia virus (VV) strains, WR and Praha, were selected for a study undertaken to determine whether the virus-encoded interferon-γ receptor (IFN-γR) plays any role in virus virulence. Both of the viruses expressed the B8R gene coding for IFN-γR in infected cell cultures. The nucleotide sequence of the Praha virus B8R gene was determined, and, when compared with the published sequence of the WR virus, it only displayed one silent nucleotide substitution. Mutants of the WR and Praha viruses with deleted B8R gene were constructed. In rabbits, skin lesions produced by the WR B8R-deleted mutants were smaller and tended to disappear earlier than those caused by wild-type WR virus. Similar results were obtained with both independently prepared WR B8R-deleted mutants. These data strongly suggested that the product of B8R gene did play a role in virus virulence. A similar comparison of the wild-type Praha virus and its mutant could not be done because of the very low virulence of the parental virus for rabbits. Received March 13, 2000 Accepted August 16, 2000  相似文献   
6.
7.
The intestinal epithelium of third-stage larvae and adults of Cystidicoloides ephemeridarum from haemocoel of mayflies and stomach of brown trout was studied by electron microscopy and cytochemistry. In section, the intestine of both stages is composed of a single layer of about ten undifferentiated intestinal cells in a ring. A labyrinth of deep invaginations is present in the basal region of each cell. The apical surface is modified into well developed, regularly arranged microvilli. These, together with numerous organelles engaged in metabolism and a well defined gut lumen filled with unidentifiable material suggest that the intestine may function in digestion and absorption during both stages. The adults seem to feed upon the semifluid content of the stomach of brown trout. Fortuitous oral infection with undetermined bacteria in vitro led to degenerative changes in the intestinal tissue and probably caused death of the infected specimens. Up to 75% of the cell volume in the L3 is occupied by glycogen deposits. In the adults, a minor portion of glycogen, together with lipid droplets, has been observed. The adults are considered to rely more on aerobic metabolism, whereas anaerobic metabolism (glycolysis) may prevail in L3.  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