全文获取类型
收费全文 | 20389篇 |
免费 | 1176篇 |
国内免费 | 194篇 |
专业分类
耳鼻咽喉 | 134篇 |
儿科学 | 1175篇 |
妇产科学 | 297篇 |
基础医学 | 2468篇 |
口腔科学 | 351篇 |
临床医学 | 1238篇 |
内科学 | 3510篇 |
皮肤病学 | 402篇 |
神经病学 | 1298篇 |
特种医学 | 774篇 |
外国民族医学 | 5篇 |
外科学 | 2783篇 |
综合类 | 799篇 |
一般理论 | 1篇 |
预防医学 | 1419篇 |
眼科学 | 1075篇 |
药学 | 2029篇 |
5篇 | |
中国医学 | 307篇 |
肿瘤学 | 1689篇 |
出版年
2022年 | 272篇 |
2021年 | 410篇 |
2020年 | 277篇 |
2019年 | 307篇 |
2018年 | 370篇 |
2017年 | 294篇 |
2016年 | 367篇 |
2015年 | 415篇 |
2014年 | 592篇 |
2013年 | 779篇 |
2012年 | 1113篇 |
2011年 | 1132篇 |
2010年 | 673篇 |
2009年 | 545篇 |
2008年 | 937篇 |
2007年 | 950篇 |
2006年 | 882篇 |
2005年 | 844篇 |
2004年 | 759篇 |
2003年 | 760篇 |
2002年 | 707篇 |
2001年 | 617篇 |
2000年 | 637篇 |
1999年 | 573篇 |
1998年 | 250篇 |
1997年 | 232篇 |
1996年 | 204篇 |
1995年 | 191篇 |
1994年 | 155篇 |
1993年 | 166篇 |
1992年 | 363篇 |
1991年 | 390篇 |
1990年 | 351篇 |
1989年 | 397篇 |
1988年 | 300篇 |
1987年 | 316篇 |
1986年 | 254篇 |
1985年 | 272篇 |
1984年 | 232篇 |
1983年 | 208篇 |
1982年 | 130篇 |
1981年 | 118篇 |
1979年 | 190篇 |
1978年 | 130篇 |
1977年 | 116篇 |
1975年 | 134篇 |
1974年 | 143篇 |
1973年 | 136篇 |
1972年 | 123篇 |
1971年 | 142篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
23.
Pawan Kumar Dhruva Rao Deborah Clements Michael M. Davies Jared Torkington 《Surgical endoscopy》2007,21(6):1036
We present our comments on the above article. 相似文献
24.
25.
26.
为阐明IL-1对粒系细胞和红系细胞的作用,我们通过对小鼠骨髓及外周血的研究探讨了IL-1对粒系和红系造血细胞的调节作用.结果表明:IL-1单剂量腹腔注射后第7天红系造血细胞明显减少,外周血网织红细胞在第8天显著下降.在5~10万U/kg剂量范围内IL-1明显促进粒系细胞的增殖.应用流式细胞仪对DNA分析显示IL-1并不引起全骨髓细胞DNA的变化,但大体积细胞在注射IL-1后第3天S期细胞明显增多.我们的结果表明IL-1抑制红系造血细胞的分化增殖,在适当的剂量范围内促进粒系细胞的增殖和分化成熟.其作用的分子基础是诱导造血细胞的细胞周期变化. 相似文献
27.
Changes in carbohydrate metabolism were studied in midgut gland, muscle, and gill tissues of marine prawn Penaeus indicus exposed to a sublethal concentration (0.3 ppm) of phosphamidon. A significant decrease in glycogen and pyruvate and an increase in lactate content were observed in all phosphamidon-exposed prawn tissues after 96 hr. An increase in phosphorylase a and aldolase activity levels suggested the increased formation of triose sugars during phosphamidon toxicity. LDH activity was considerably decreased and an increment in lactate content was observed which indicates reduced mobilization of pyruvate into the citric acid cycle. Glucose-6-phosphate dehydrogenase activity was considerably increased, suggesting the enhanced oxidation of glucose in the hexose monophosphate shunt pathway. Krebs cycle enzymes such as NAD-isocitrate dehydrogenase, succinate dehydrogenase, and malate dehydrogenase were found to be decreased, suggesting the impairment in mitochondrial oxidative metabolism due to the acute toxic impact of phosphamidon. Cytochrome-c oxidase and Mg2+ ATPase activity levels were also decreased considerably, suggesting impaired energy synthesis and breakdown during phosphamidon toxicity, as a result of reduced oxidation of glucose aerobically. The increase in acid and alkaline phosphatase activities indicates the enhanced breakdown of phosphate to release energy in view of inhibiton or impairment in the ATPase system during phosphamidon-induced stress. These results suggest that phosphamidon has a profound effect on the oxidative metabolism of prawn which results in the triggering of compensatory metabolic pathways for survivability. 相似文献
28.
29.
氟烷吸入麻醉引起c—fos基因在中枢神经系统的表达与分布 总被引:8,自引:2,他引:6
研究氟烷吸入麻醉在中枢神经系统作用部位。应用c-fos基因免疫组织化学方法。SD大鼠在吸入氟烷浓度为0.75%.1。5%和2%麻醉1h后,Fos阳性神经元主要分布于端脑;梨状皮层,杏仁核簇,伏核,外侧隔核,终纹麻核、海马CAI区,海马回嗅觉小岛; 相似文献
30.
Differentiation of pancreatic epithelial progenitor cells into hepatocytes following transplantation into rat liver
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Mariana D. Dabeva Seong-Gyu Hwang Srinivasa Rao G. Vasa Ethel Hurston Phyllis M. Novikoff Douglas C. Hixson Sanjeev Gupta David A. Shafritz 《Proceedings of the National Academy of Sciences of the United States of America》1997,94(14):7356-7361
The ability to identify, isolate, and transplant progenitor cells from solid tissues would greatly facilitate the treatment of diseases currently requiring whole organ transplantation. In this study, cell fractions enriched in candidate epithelial progenitor cells from the rat pancreas were isolated and transplanted into the liver of an inbred strain of Fischer rats. Using a dipeptidyl dipeptidase IV genetic marker system to follow the fate of transplanted cells in conjunction with albumin gene expression, we provide conclusive evidence that, after transplantation to the liver, epithelial progenitor cells from the pancreas differentiate into hepatocytes, express liver-specific proteins, and become fully integrated into the liver parenchymal structure. These studies demonstrate the presence of multipotent progenitor cells in the adult pancreas and establish a role for the liver microenvironment in the terminal differentiation of epithelial cells of foregut origin. They further suggest that such progenitor cells might be useful in studies of organ repopulation following acute or chronic liver injury. 相似文献