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   102673篇
  免费   7535篇
  国内免费   376篇
耳鼻咽喉   1129篇
儿科学   2557篇
妇产科学   1652篇
基础医学   14489篇
口腔科学   2193篇
临床医学   10490篇
内科学   21739篇
皮肤病学   1799篇
神经病学   10945篇
特种医学   4264篇
外国民族医学   6篇
外科学   14656篇
综合类   1252篇
一般理论   73篇
预防医学   7923篇
眼科学   1723篇
药学   6910篇
中国医学   111篇
肿瘤学   6673篇
  2023年   573篇
  2022年   1088篇
  2021年   2145篇
  2020年   1323篇
  2019年   1973篇
  2018年   2427篇
  2017年   1792篇
  2016年   2139篇
  2015年   2480篇
  2014年   3273篇
  2013年   4303篇
  2012年   6664篇
  2011年   6714篇
  2010年   3964篇
  2009年   3616篇
  2008年   5929篇
  2007年   6431篇
  2006年   5962篇
  2005年   5904篇
  2004年   5517篇
  2003年   4926篇
  2002年   4887篇
  2001年   1875篇
  2000年   1791篇
  1999年   1664篇
  1998年   1219篇
  1997年   1002篇
  1996年   812篇
  1995年   821篇
  1994年   700篇
  1993年   636篇
  1992年   1155篇
  1991年   1070篇
  1990年   1012篇
  1989年   972篇
  1988年   864篇
  1987年   810篇
  1986年   832篇
  1985年   827篇
  1984年   669篇
  1983年   578篇
  1982年   552篇
  1981年   453篇
  1980年   394篇
  1979年   515篇
  1978年   407篇
  1977年   367篇
  1975年   329篇
  1974年   355篇
  1973年   344篇
排序方式: 共有10000条查询结果,搜索用时 13 毫秒
81.
The neurosteroid allopregnanolone may increase feeding by altering food palatability; however, it may also increase feeding by reducing anxiety (neophobia). Moreover, it is unclear whether this induced hyperphagia is selective to safe, palatable foods only. Male rats were injected with allopregnanolone 20 min prior to behavioral testing. The taste reactivity test was used to examine possible shifts in the palatability of a 0.3 M sucrose solution. A lickometer was used to monitor intake and licking of either a sucrose or sucrose-quinine solution. Sucrose palatability was not enhanced; however, allopregnanolone significantly increased sucrose intake and licking on Test Day 1 when the solution was novel, but not on Test Day 2 when the solution was familiar. Sucrose-quinine intake was not enhanced. Allopregnanolone-induced hyperphagia is not a result of altered sucrose palatability, but rather reflects a reduction in the neophobia elicited by a novel solution; an effect that further seems to be selective to safe, palatable foods.  相似文献   
82.
Immortalized cell lines offer significant logistical advantages over primary cells when used for in-vitro studies. Immortalized cells may, however, exhibit important differences relative to their primary cell counterparts. In this study, microarrays were used to make a genome-wide comparison between primary human umbilical vein endothelial cells (HUVECs) and EA.hy926, an immortalized HUVEC cell line, in their baseline properties and in their response to inhibition of the mevalonate pathway with an inhibitor of hydroxy methylglutaryl-coenzyme A reductase (statin). HUVECs and EA.hy926 were incubated with control medium, atorvastatin, mevalonate, or a combination of atorvastatin and mevalonate for 24 h. Gene expression profiles were obtained in duplicates using Affymetrix Human Genome U133A 2.0 arrays (Santa Clara, California, USA). Probe-sets were selected according to the following criteria: a twofold or greater increase/decrease in atorvastatin-treated cells compared with untreated cells; a twofold or greater reversal of the effect of atorvastatin by combined treatment with atorvastatin and mevalonate; no significant change in gene expression in cells treated with mevalonate alone compared with untreated cells. Most genes that were expressed by untreated HUVECs, were also expressed by untreated EA.hy926 cells. EA.hy926 cells, however, constitutively expressed a large number of additional genes, many of which were related to cell cycle control and apoptosis. Atorvastatin induced differential expression (> or = twofold) of 103 genes in HUVECs (10 up, 93 down) and 466 genes in EA.hy926 cells (198 up, 268 down). Applying the above selection criteria, thrombomodulin and tissue plasminogen activator were up-regulated in both cell types, whereas, connective tissue growth factor, thrombospondin-1, and cysteine-rich angiogenic inducer 61 were down-regulated. In conclusion, EA.hy926 cells retain most of the characteristics of endothelial cells under baseline conditions as well as after treatment with atorvastatin. It is necessary, however, to carefully select and validate changes in genes that are the focus of studies when using EA.hy926 cells. While this cell line is highly useful in studies on some genes, including genes encoding molecules involved in regulating thrombohemorrhagic homeostasis, they appear to be less suited for studies focused on other genes, particularly those involved in the regulation of cell proliferation and apoptosis.  相似文献   
83.
84.
85.
Synkinesias secondary to nerve lesions and aberrant re-innervation are well-known phenomena especially after lesions of the facial nerve. Synkinesias can successfully be treated with botulinum toxin A (BTx A). Synkinesias of the cremaster muscle have not been described or treated to date. We present the case of a 62-year-old man who developed synkinesias of both cremaster muscles after extensive laparatomy for esophageal cancer. Treatment of synkinesias with various oral medications had been unsuccessful. Electromyography-guided injections of BTx A in both cremaster muscles (15 MU on the right and 10 on the left) led to significant symptom relief for an average of 8 weeks. We present the case including pre- and posttreatment video clips.  相似文献   
86.
87.
Severe burns and scalds are still frequent. If the burn victim is a child, it should ideally be taken care of in a pediatric burn center, where both the burn and child-related needs are specifically met. The goals of burn care are to preserve life, to preserve function, to limit physical and psychological sequelae and to provide social reintegration. The system of burn care essentially consists of adequate initial resuscitation followed by early surgery aimed at rapid and definitive wound closure. Vigorous nutritional support as well as early rehabilitation and continuous psychosocial care are of paramount importance. The paper summarizes the essentials of pediatric burn care (burn surgery excluded).  相似文献   
88.
89.
90.
A 73-year-old woman was studied after admission for anteriorwall ST-segment elevation myocardial infarction. Transthoracicechocardiography (GE Vingmed, Vivid 7, Horten, Norway)  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