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   30727篇
  免费   2101篇
  国内免费   65篇
耳鼻咽喉   220篇
儿科学   1001篇
妇产科学   880篇
基础医学   3895篇
口腔科学   593篇
临床医学   4476篇
内科学   5108篇
皮肤病学   315篇
神经病学   3138篇
特种医学   779篇
外科学   3439篇
综合类   395篇
一般理论   36篇
预防医学   4065篇
眼科学   485篇
药学   1735篇
中国医学   31篇
肿瘤学   2302篇
  2023年   162篇
  2022年   236篇
  2021年   514篇
  2020年   355篇
  2019年   539篇
  2018年   660篇
  2017年   484篇
  2016年   566篇
  2015年   645篇
  2014年   935篇
  2013年   1350篇
  2012年   1993篇
  2011年   2151篇
  2010年   1114篇
  2009年   1009篇
  2008年   1847篇
  2007年   1989篇
  2006年   1891篇
  2005年   1830篇
  2004年   1841篇
  2003年   1695篇
  2002年   1686篇
  2001年   496篇
  2000年   445篇
  1999年   457篇
  1998年   356篇
  1997年   306篇
  1996年   216篇
  1995年   262篇
  1994年   225篇
  1993年   179篇
  1992年   336篇
  1991年   325篇
  1990年   278篇
  1989年   288篇
  1988年   257篇
  1987年   301篇
  1986年   242篇
  1985年   242篇
  1984年   200篇
  1983年   172篇
  1982年   132篇
  1981年   133篇
  1980年   94篇
  1979年   151篇
  1978年   111篇
  1977年   98篇
  1974年   86篇
  1973年   91篇
  1972年   88篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
21.
22.
23.
24.
The anti-granulocyte activity of serum from patients with B-cell chronic lymphocytic leukaemia (CLL) and other lymphoproliferative disorders was investigated. Granulocyte-binding IgG was measured in 34 patients with CLL, 13 patients with hairy cell leukaemia, one patient with prolymphocytic leukaemia, two patients with Sézary cell leukaemia, and seven patients with chronic T-cell lymphocytosis who had a predominance of circulating large granular lymphocytes. Anti-granulocyte activity was absent in CLL and its variants, but present in the majority of granulocytopenic patients with chronic T-cell lymphocytosis. In one of these patients, granulocytopenia was associated with complement-activating IgG granulocyte antibody. Thus, antibody-mediated granulocyte injury appears to be an unusual occurrence in chronic lymphocytic leukaemia, but is a frequent complication of chronic T-cell lymphocytosis.  相似文献   
25.
26.
Arsenic pollution has become increasingly severe. It occurs as the result of geological processes and different human activities. Arsenic toxicity at the respiratory level occurs mainly by inhalation of products of coal combustion. The aim of this study was to evaluate sodium arsenite (As3+) toxicity in murine alveolar macrophages (AMs) in vitro and its association with the alterations in cell metabolism.

No changes in viability, apoptosis or cell area were detected in AMs treated with As3+ concentrations up to 2 μM for 24–96 h. A marked decrease in these end-points was observed for As3+ concentrations ranging from 2.5 μM to 10 μM.

Regarding the dynamics of the endo-exocytic process triggered by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell incorporation, no variations were detected for As3+ concentrations lower than 2 μM while higher concentrations markedly modified this response.

MTT specific activity, as a measure of cell metabolic activity, was not modified irrespective of the As3+ concentration assayed. However, nitroblue tetrazolium (NBT) specific activity, as a measure of superoxide anion generation, is responsive but only to low As3+ doses.

Although this study focuses on lung macrophages, the effects of As3+ described herein may also apply to the response of macrophages residing in other organs.

Arsenite modifies the metabolic and the oxidative status of AMs in vitro. When macrophages are in an As3+ rich medium, they exhibit a reduction in respiratory burst levels and lose their intrinsic capacity to respond to toxicants.  相似文献   

27.
Castleman disease is a rare disorder characterized by lymphoid hyperplasia which rarely manifests in children. We present 2 cases which highlight both histologic variants of this disease, and provide suggestions regarding workup and treatment with the goal of making practitioners aware of Castleman disease in the differential diagnosis of a child presenting with vague symptoms.  相似文献   
28.
29.
30.
To determine whether polymorphisms of platelet surface glycoprotein associated with arterial thrombosis are risk factors for branch retinal vein occlusion. A case-control study in which 69 patients with branch retinal vein occlusion and 147 controls who attended the eye clinic for nonvascular complications participated. DNA was extracted from whole blood and analyzed for genotyping of platelet glycoprotein polymorphisms by polymerase chain reactions and specific restricted enzymes. No relationship was found between the four platelet glycoprotein polymorphisms i.e. GPIa C807T, VNTR and Kozak of glycoprotein Ibalpha, the HPA-1 of glycoprotein IIIa and the occurrence of branch retinal vein occlusion. The HPA-2 polymorphism was found in 18 out 60 (30%) patients with branch retinal vein occlusion in comparison with 27 out 142 (19%) of controls, with an estimated odds ratio of 1.8 (95% confidence interval, 0.91-3.65). The four platelet glycoprotein polymorphisms are not risk factors for branch retinal vein occlusion and therefore it seems unnecessary to screen those patients for it. A larger study is required, however, to determine whether HPA-2 is a novel risk factor for branch retinal vein occlusion.  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