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   41717篇
  免费   3091篇
  国内免费   6篇
  2023年   196篇
  2022年   174篇
  2021年   635篇
  2020年   487篇
  2019年   525篇
  2018年   1282篇
  2017年   1089篇
  2016年   1304篇
  2015年   1884篇
  2014年   1878篇
  2013年   2562篇
  2012年   3026篇
  2011年   2862篇
  2010年   1808篇
  2009年   1550篇
  2008年   2323篇
  2007年   2271篇
  2006年   2216篇
  2005年   1944篇
  2004年   1910篇
  2003年   1726篇
  2002年   1603篇
  2001年   865篇
  2000年   795篇
  1999年   728篇
  1998年   424篇
  1997年   322篇
  1996年   297篇
  1995年   305篇
  1994年   249篇
  1993年   233篇
  1992年   421篇
  1991年   420篇
  1990年   353篇
  1989年   318篇
  1988年   300篇
  1987年   261篇
  1986年   253篇
  1985年   250篇
  1984年   200篇
  1983年   156篇
  1982年   139篇
  1981年   170篇
  1980年   139篇
  1979年   189篇
  1978年   159篇
  1977年   136篇
  1976年   140篇
  1975年   127篇
  1974年   130篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Changes in quality of blood units containing one and a half or double amounts of glucose, stored at +4 degrees C for three weeks were analysed. An experimental preservative containing glucose and fructose (1 : 1) was also used. No other additives (purine or purine-nucleoside) were applied. A standard CPD preservative of the National Inst. of Haematology and Blood Transfusion was used as control. The pH, plasma free haemoglobin, K+ content, red blood cell (RBC) ATP and 2,3-DPG content, and RBC fragility index were determined in each sample. Increase of glucose concentration, the addition of fructose had a beneficial effect on blood pH, and on plasma free haemoglobin and K+ concentration. 150% glucose improved the 2,3-DPG maintenance in stored blood.  相似文献   
82.
83.
Mycolactone, a lipid-like toxin, is the major virulence factor of Mycobacterium ulcerans, the etiological agent of Buruli ulcer. Its involvement in lesion development has been widely described in early stages of the disease, through its cytotoxic and immunosuppressive activities, but less is known about later stages. Here, we revisit the role of mycolactone in disease outcome and provide the first demonstration of the pro-inflammatory potential of this toxin. We found that the mycolactone-containing mycobacterial extracellular vesicles produced by M. ulcerans induced the production of IL-1β, a potent pro-inflammatory cytokine, in a TLR2-dependent manner, targeting NLRP3/1 inflammasomes. We show our data to be relevant in a physiological context. The in vivo injection of these mycolactone-containing vesicles induced a strong local inflammatory response and tissue damage, which were prevented by corticosteroids. Finally, several soluble pro-inflammatory factors, including IL-1β, were detected in infected tissues from mice and Buruli ulcer patients. Our results revisit Buruli ulcer pathophysiology by providing new insight, thus paving the way for the development of new therapeutic strategies taking the pro-inflammatory potential of mycolactone into account.  相似文献   
84.
85.
86.
The cellular retinoic acid binding protein is thought to be involved in the retinoic-acid-mediated signal transduction pathway. We have isolated the mouse cellular retinoic acid binding protein cDNA from an embryonal-carcinoma-derived cell line by using differential cDNA cloning strategies. In situ hybridization on sections of mouse embryos of various developmental stages indicated that the cellular retinoic acid binding protein gene, which we localized on mouse chromosome 9, is preferentially expressed in a subpopulation of neurectodermal cells. This restricted expression pattern suggests an important role for cellular retinoic acid binding protein in murine neurogenesis.  相似文献   
87.
88.
89.
R Adány  L Muszbek 《Histochemistry》1989,91(2):169-174
As spontaneous abortion is a frequent finding in females with Factor XIII (FXIII) deficiency it has been presumed that this clotting factor is essential to normal pregnancy. FXIII subunit a (FXIII A) has been demonstrated in the homogenate of human uterus, but no information on its cellular distribution has been published, so far. In the present study first FXIII A was detected in paraformaldehyde-fixed, paraffin-embedded sections of human uterus by immunoperoxidase technique. Cells containing FXIII A were localized between collagen fibrils stained by Picrosirius Red F3B in the connective tissue. To characterize them the immunofluorescent detection of FXIII A was combined by the visualization of different marker antigens of monocytes and macrophages recognized by Leu-M3, RFD7, anti-HLA-DR and DAKO-anti-macrophage monoclonal antibodies on frozen sections. The coexpression of FXIII A with monocyte and macrophage differentiation marker antigens clearly proves that cells containing FXIII A in the uterus are monocyte-derived tissue macrophages. The results well agree with our previous findings demonstrating FXIII A in human monocytes and different types of macrophages. On the basis of these results, the presence of FXIII A does not seem to be a specificity of the uterus but a characteristic of monocyte/macrophage cell line including tissue macrophages, in general.  相似文献   
90.
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