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   236974篇
  免费   12636篇
  国内免费   1997篇
耳鼻咽喉   3161篇
儿科学   6558篇
妇产科学   6420篇
基础医学   33305篇
口腔科学   8630篇
临床医学   17578篇
内科学   50362篇
皮肤病学   5424篇
神经病学   17914篇
特种医学   7093篇
外国民族医学   3篇
外科学   33390篇
综合类   5818篇
一般理论   83篇
预防医学   18533篇
眼科学   5341篇
药学   17392篇
中国医学   1310篇
肿瘤学   13292篇
  2023年   1162篇
  2022年   1854篇
  2021年   4416篇
  2020年   2421篇
  2019年   4233篇
  2018年   6139篇
  2017年   4013篇
  2016年   4043篇
  2015年   4500篇
  2014年   5901篇
  2013年   7963篇
  2012年   12714篇
  2011年   13623篇
  2010年   7436篇
  2009年   5913篇
  2008年   11165篇
  2007年   11612篇
  2006年   10970篇
  2005年   10414篇
  2004年   9381篇
  2003年   8736篇
  2002年   8090篇
  2001年   8867篇
  2000年   9457篇
  1999年   7333篇
  1998年   2600篇
  1997年   1945篇
  1996年   1443篇
  1995年   1347篇
  1994年   1175篇
  1992年   4269篇
  1991年   4230篇
  1990年   3918篇
  1989年   3851篇
  1988年   3724篇
  1987年   3507篇
  1986年   3356篇
  1985年   3216篇
  1984年   2280篇
  1983年   2003篇
  1982年   1149篇
  1979年   2035篇
  1978年   1328篇
  1975年   1291篇
  1974年   1459篇
  1973年   1502篇
  1972年   1435篇
  1971年   1316篇
  1970年   1201篇
  1969年   1185篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
1.
2.
3.
4.
The present study aimed at measuring seropositivities for infection by Ascaris suum and Toxocara canis using the excretory/secretory (E/S) antigens from Ascaris suum (AES) and Toxocara canis (TES) within an indigenous population. In addition, quantification of cytokine expressions in peripheral blood cells was determined. A total of 50 Warao indigenous were included; of which 43 were adults and seven children. In adults, 44.1% were seropositive for both parasites; whereas children had only seropositivity to one or the other helminth. For ascariosis, the percentage of AES seropositivity in adults and children was high; 23.3% and 57.1%, respectively. While that for toxocariosis, the percentage of TES seropositivity in adults and children was low; 9.3% and 14.3%, respectively. The percentage of seronegativity was comparable for AES and TES antigens in adults (27.9%) and children (28.6%). When positive sera were analyzed by Western blotting technique using AES antigens; three bands of 97.2, 193.6 and 200.2 kDas were mostly recognized. When the TES antigens were used, nine major bands were mostly identified; 47.4, 52.2, 84.9, 98.2, 119.1, 131.3, 175.6, 184.4 and 193.6 kDas. Stool examinations showed that Blastocystis hominis, Hymenolepis nana and Entamoeba coli were the most commonly observed intestinal parasites. Quantification of cytokines IFN-γ, IL-2, IL-6, TGF-β, TNF-α, IL-10 and IL-4 expressions showed that there was only a significant increased expression of IL-4 in indigenous with TES seropositivity (p < 0.002). Ascaris and Toxocara seropositivity was prevalent among Warao indigenous.  相似文献   
5.
6.
Chlorpyrifos is the most used insecticide in Argentina. Cnesterodon decemmaculatus is a widely distributed, endemic fish from Neotropical America. It attains high densities in the shallow water assemblages of Argentina and Brazil. The aim of this study was to assess the acute toxicity of chlorpyrifos to C. decemmaculatus. The mean 96-h LC50 of three independent determinations was 105.3 (±?3.1) μg/L. Sublethal effects were observed. Swimming behavioral changes at each chlorpyrifos exposure concentration were reported. C. decemmaculatus represents a good model for ecotoxicological risk assessment.  相似文献   
7.
8.
9.

Background

Since recent reports have shown that (-)-Epigallocatechin-3-gallate (EGCG) could be used for treating proliferative and inflammatory disorders, we explored its use for the management of corneal chemical burns.

Materials and methods

Initially, EGCG was assayed on the rabbit corneal epithelial cell line RCE1(5T5) to establish the best testing conditions, and to avoid unwanted outcomes in the experimental animals. Then, we studied its effects on cell proliferation, cell cycle progression and cell differentiation. Afterwards, we instilled EGCG in experimental grade II corneal alkali burns in mice, three times a day up to 21 days, and evaluated by slit lamp examination and histological sections of corneal epithelial, corneal endothelial and stromal edema, as well as the presence of inflammatory cells and neovascularization.

Results

EGCG reduced cell growth and led to a decline in the proportion of proliferative cells in a concentration dependent manner. At 10 μM, EGCG promoted cell differentiation, an effect not related with apoptosis or cytotoxicity. When 10 μM EGCG was instilled in corneal alkali burns in mice three times a day up to 21 days, EGCG significantly reduced corneal opacity and neovascularization. The improved clinical appearance of the cornea was associated to a controlled epithelial growth; epithelial morphology was similar to that observed in normal epithelium and contrasted with the hyperproliferative, desquamating epithelium observed in control burn wounds. EGCG reduced corneal, stromal and endothelial edema, and wound inflammation.

Conclusion

This work constitutes the first evidence for the use of EGCG in the acute phase of a corneal alkali burn, representing a possible novel alternative to improve patient outcomes as an add-on therapy.  相似文献   
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