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   3526篇
  免费   280篇
  国内免费   3篇
  2023年   19篇
  2022年   33篇
  2021年   81篇
  2020年   47篇
  2019年   70篇
  2018年   55篇
  2017年   49篇
  2016年   93篇
  2015年   146篇
  2014年   183篇
  2013年   210篇
  2012年   230篇
  2011年   186篇
  2010年   122篇
  2009年   111篇
  2008年   174篇
  2007年   164篇
  2006年   136篇
  2005年   129篇
  2004年   127篇
  2003年   99篇
  2002年   123篇
  2001年   78篇
  2000年   42篇
  1999年   39篇
  1998年   40篇
  1997年   33篇
  1996年   28篇
  1995年   28篇
  1994年   26篇
  1993年   23篇
  1992年   47篇
  1991年   40篇
  1990年   31篇
  1989年   33篇
  1988年   38篇
  1987年   46篇
  1986年   45篇
  1985年   41篇
  1984年   38篇
  1983年   32篇
  1982年   39篇
  1980年   22篇
  1978年   29篇
  1977年   22篇
  1976年   25篇
  1974年   31篇
  1973年   24篇
  1971年   22篇
  1969年   19篇
排序方式: 共有3809条查询结果,搜索用时 15 毫秒
1.
2.
Five cases of coincident salmonellosis and ulcerative colitis are described. In three the diagnostic combination was recognized late. If corticosteroid therapy is given for the colitis once the combination is recognized, then simultaneous systemic antibiotic cover is advisable. One of the five patients died during corticosteroid therapy alone with salmonella septicaemia due to a usually non-invasive organism.  相似文献   
3.
Closed circuit TV has proved to be a valuable aid for many patients with partial sight and a new device for magnification of printed material has been developed. This is in the form of a small camera, guided over the page by the subject's hand and incorporating a roller drive for a scanning mechanism. The scanning head fits into the hand easily; it is linked to an electronic TV receiver in the form of a mosaic. Tracking the scanner manually operates a flow of the display to the left, with new material emerging from the right of the screen. The present paper outlines an evaluation of the device under different conditions with patients.  相似文献   
4.
5.
Readouts that define the physiological distributions of drugs in tissues are an unmet challenge and at best imprecise, but are needed in order to understand both the pharmacokinetic and pharmacodynamic properties associated with efficacy. Here we demonstrate that it is feasible to follow the in vivo transport of unlabeled drugs within specific organ and tissue compartments on a platform that applies MALDI imaging mass spectrometry to tissue sections characterized with high definition histology. We have tracked and quantified the distribution of an inhaled reference compound, tiotropium, within the lungs of dosed rats, using systematic point by point MS and MS/MS sampling at 200 µm intervals. By comparing drug ion distribution patterns in adjacent tissue sections, we observed that within 15 min following exposure, tiotropium parent MS ions (mass-to-charge; m/z 392.1) and fragmented daughter MS/MS ions (m/z 170.1 and 152.1) were dispersed in a concentration gradient (80 fmol-5 pmol) away from the central airways into the lung parenchyma and pleura. These drug levels agreed well with amounts detected in lung compartments by chemical extraction. Moreover, the simultaneous global definition of molecular ion signatures localized within 2-D tissue space provides accurate assignment of ion identities within histological landmarks, providing context to dynamic biological processes occurring at sites of drug presence. Our results highlight an important emerging technology allowing specific high resolution identification of unlabeled drugs at sites of in vivo uptake and retention.  相似文献   
6.
Catalytic activities of lingual lipase were investigated by enzyme histochemistry in post-mortem tongues from male rats. Sections of fresh-frozen or formalin-calcium fixed tissue were incubated with naphthol-AS-nonanoate and α-naphthyl acetate substrate mixtures. The effects of pH level, sodium taurocholate activator and E600 inhibitor were also examined. The use of cryostat sections of tissues fixed in formalin-calcium and of nonanoate substrate within the range of pH 4.4–6.4, were optimal for localizing maximum reaction product, captured by Fast Blue BB, in acini and demilunes of the posterior deep and superficial lingual glands respectively. The reaction product corresponded with the distribution of secretory granules and failed to develop when taurocholate was omitted from the incubation medium. Similarly localized E600-resistant reaction product occurred with the acetate substrate and hexazotized New Fuchsin at pH 7.4, in the absence of taurocholate. Lipase and conventional esterase activities appear to be superimposed in posterior lingual glands of rat. The ability of their acini and demilunes to hydrolyse nonanoate substrate at an acidic pH optimum, when activated by sodium taurocholate, seems attributable to lipase destined for secretion into saliva – hence convenient for routine histochemical identification of the enzyme.  相似文献   
7.
8.
The development of the highly sensitive cytochemical bioassay for ACTH has permitted the measurement of plasma ACTH levels during the insulin hypoglycaemia test (I.H.T.) in patients treated with corticosteroids and corticotrophin. The ACTH, corticosteroid, and growth hormone (GH) responses in the I.H.T. were measured in three groups of 12 rheumatoid arthritis patients. One group was receiving long-term corticotrophin treatment, the second was undergoing long-term corticosteroid treatment, and the third had never received systemic hormone therapy. The increments in plasma ACTH, corticosteroids, and GH were diminished in the corticosteroid-treated group, as were increments in plasma GH and ACTH in the corticotrophin-treated group; but in this group the corticosteroid increment was normal. Examination of the area under the curve of the ACTH response showed that the total amount of ACTH secreted was normal though the rate of secretion was reduced. In the corticosteroid-treated group both rate and total secretion were diminished.  相似文献   
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