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   4133篇
  免费   347篇
  国内免费   14篇
耳鼻咽喉   79篇
儿科学   114篇
妇产科学   81篇
基础医学   528篇
口腔科学   62篇
临床医学   479篇
内科学   732篇
皮肤病学   161篇
神经病学   334篇
特种医学   294篇
外科学   541篇
综合类   99篇
一般理论   4篇
预防医学   412篇
眼科学   59篇
药学   270篇
中国医学   12篇
肿瘤学   233篇
  2021年   58篇
  2020年   31篇
  2019年   52篇
  2018年   69篇
  2017年   54篇
  2016年   51篇
  2015年   72篇
  2014年   81篇
  2013年   148篇
  2012年   193篇
  2011年   199篇
  2010年   131篇
  2009年   125篇
  2008年   169篇
  2007年   164篇
  2006年   171篇
  2005年   173篇
  2004年   158篇
  2003年   132篇
  2002年   141篇
  2001年   118篇
  2000年   108篇
  1999年   104篇
  1998年   60篇
  1997年   77篇
  1996年   62篇
  1995年   48篇
  1994年   40篇
  1993年   45篇
  1992年   93篇
  1991年   71篇
  1990年   111篇
  1989年   98篇
  1988年   95篇
  1987年   91篇
  1986年   96篇
  1985年   87篇
  1984年   72篇
  1983年   44篇
  1982年   40篇
  1981年   40篇
  1980年   28篇
  1979年   41篇
  1978年   32篇
  1977年   36篇
  1976年   37篇
  1975年   30篇
  1973年   32篇
  1971年   28篇
  1970年   29篇
排序方式: 共有4494条查询结果,搜索用时 0 毫秒
1.
2.
Osteomalacia and bone disease arising from aluminum   总被引:2,自引:0,他引:2  
  相似文献   
3.
4.
Two examples of localized primary amyloid tumor of the breast are presented, including one patient with metachronous bilateral lesions. Our findings and review of the literature indicate that this rare lesion occurs predominantly in elderly females and can be mammographically and clinically confused with carcinoma. Fine-needle aspiration biopsy can be a useful procedure to make a preliminary diagnosis. Congo red staining with prior potassium permanganate incubation confirmed the AL type of amyloid in our two cases; this might be the predominant type in the localized form involving the breast. Immunofluorescence studies demonstrated IgA, with kappa and lambda light-chain deposition within the amyloid foci in one case, and intracytoplasmic IgG with both light chains within plasma cells and amyloid deposits of the second case. Ultrastructural examination of one of the cases showed characteristic findings of straight, nonbranching fibrils of 4-9 nm, diagnostic of amyloid. From our findings and a review of the literature, we conclude that amyloid tumors of the breast can occur in three separate settings: secondary amyloidosis, systemic or multiple myeloma associated amyloidosis, and as a localized primary type having a benign course.  相似文献   
5.
FLP 62064 [N-(4-methoxyphenyl)-1-phenyl-1H-pyrazole-3-amine] is a dual inhibitor of prostaglandin synthetase and 5-lipoxygenase. The compound had anti-inflammatory activity in vivo in a number of models. It inhibited peritoneal inflammation induced by immune-complex when given locally. When applied to the skin, FPL 62064 inhibited UV irradiation-induced erythema and PGE2 formation in the guinea pig and also oedema formation and eicosanoid production in the mouse ear produced by arachidonic acid. Co-injected with arachidonic acid in rabbit skin, FPL 62064 inhibited oedema and eicosanoid formation.  相似文献   
6.
Expression of tau protein in non-neuronal cells can result in a redistribution of the microtubule cytoskeleton into thick bundles of tau-containing microtubules (Lewis et al.: Nature 342:498-505, 1989; Kanai et al.: J Cell Biol 109:1173-1184, 1989). We reconstituted microtubule bundles using purified tubulin and tau in order to study the assembly of these structures. Taxol-stabilized tubulin polymers were incubated with various concentrations of recombinant human tau and examined by electron microscopy. With increasing concentrations of tau 3 (tau isoform containing three microtubule binding domains) or tau 4 (isoform containing four microtubule binding domains) the microtubules changed orientation from a random distribution to loosely and tightly packed parallel arrays and then to thick cables. In contrast, tau 4L, the tau isoform containing four microtubule binding domains plus a 58-amino acid insert near the N-terminus, showed minimal bundling activity. tau 4-induced bundling could be inhibited by the addition of 0.5 M NaCl or 0.4 mM estramustine phosphate, conditions which are known to inhibit tau binding to microtubules. A tau construct that contained only the microtubule binding domains plus 19 amino acids to the C-terminus was fully capable of bundling microtubules. Phosphorylation of tau 3 with cAMP-dependent protein kinase had no effect on its ability to induce microtubule bundling. These results indicate that tau protein is directly capable of bundling microtubules in vitro, and suggests that different tau isoforms differ in their ability to bundle microtubule filaments.  相似文献   
7.
8.
9.
10.
Thirty six patients were admitted to hospital as a result of Salmonella virchow infection during an outbreak of food poisoning in Essex in 1984. Out of 12 patients with evidence of bloodstream invasion, one third presented primarily with meningism and attention is drawn to this unusual clinical picture.  相似文献   
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