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   4917篇
  免费   417篇
  国内免费   36篇
耳鼻咽喉   42篇
儿科学   129篇
妇产科学   60篇
基础医学   560篇
口腔科学   160篇
临床医学   444篇
内科学   1298篇
皮肤病学   55篇
神经病学   449篇
特种医学   209篇
外科学   784篇
综合类   101篇
一般理论   1篇
预防医学   270篇
眼科学   103篇
药学   326篇
中国医学   20篇
肿瘤学   359篇
  2021年   53篇
  2019年   47篇
  2018年   64篇
  2017年   70篇
  2016年   66篇
  2015年   65篇
  2014年   114篇
  2013年   152篇
  2012年   175篇
  2011年   197篇
  2010年   124篇
  2009年   130篇
  2008年   214篇
  2007年   191篇
  2006年   183篇
  2005年   179篇
  2004年   146篇
  2003年   151篇
  2002年   144篇
  2001年   187篇
  2000年   177篇
  1999年   165篇
  1998年   83篇
  1997年   73篇
  1996年   58篇
  1995年   55篇
  1994年   41篇
  1993年   47篇
  1992年   145篇
  1991年   138篇
  1990年   135篇
  1989年   143篇
  1988年   128篇
  1987年   115篇
  1986年   111篇
  1985年   96篇
  1984年   64篇
  1983年   49篇
  1982年   44篇
  1981年   47篇
  1980年   39篇
  1979年   67篇
  1978年   61篇
  1977年   39篇
  1976年   40篇
  1974年   37篇
  1973年   49篇
  1972年   43篇
  1970年   42篇
  1966年   36篇
排序方式: 共有5370条查询结果,搜索用时 15 毫秒
81.
Male research subjects were administered placebo and three doses of d-amphetamine (5, 10 and 20 mg/70 kg) in a laboratory situation which provided both aggressive and non-aggressive response options. The non-aggressive response was button pressing maintained by presentation of points exchangeable for money at the end of the session. The aggressive response was button pressing on a separate manipulanda which ostensibly subtracted points from a fictitious partner. Aggressive responding was elicited by subtracting points from the research subjects which was attributed to the fictitious partner. d-Amphetamine increased both aggressive and non-aggressive responding, particularly at 5 and 10 mg/70 kg. At the highest dose (20 mg/70 kg), aggressive responding decreased to levels similar to those observed during placebo sessions, while monetary reinforced responding remained elevated.  相似文献   
82.
1. When care is taken to produce a peritonitis, which in itself is almost uniformly fatal, drainage of the thoracic duct in dogs has no favorable influence upon the course or result of the peritonitis. 2. Under the conditions of my experiments the thoracic duct did not serve in any important way as a drainage tract for bacterial contamination of the peritoneal cavity.  相似文献   
83.
84.
This study compares different immunosuppressive regimens in the treatment of the lupus-like nephritis of NZB/W mice. Groups of 5-month-old female NZB/W mice were given azathioprine, cyclophosphamide and methylprednisolone in all one-, two- and three-drug regimens, each drug in the relatively low dose of 1.5 mg/kg/day. Treatment for 3 months with one or two drugs resulted in modest suppression of NZB/W disease. Mice receiving all three drugs had significantly less proteinuria, lower titers of anti-DNA antibody and less severe, histologically evident renal involvement than mice treated with one or two drugs. Survival at 1 year was 10% for untreated controls, 44% for one-drug-treated, 37% for two-drug-treated and 86% for the three-drug-treated mice. The survival for the three-drug regimen was significantly longer than any other group (P < 0.01). The three-drug regimen was synergistic, since mice treated with each drug at three times the dose had significantly more proteinuria after 3 months of treatment and lowered 1 year survival (33%). The beneficial effects of triple-drug therapy were attained without increased toxicity. This study represents the first controlled evaluation of single versus combination therapy in a model of autoimmune disease. Based on these results, a controlled evaluation of triple-drug therapy in human systemic lupus erythematosus appears warranted.  相似文献   
85.
Thirty-seven patients with criteria for systemic lupus erythematosus (SLE) and 18 normal controls were studied for their spontaneous background IgM antibody plaque-forming cell number to specific chemical haptens. Active SLE patients had significantly more plaque-forming cells in their peripheral blood to a total of five chemical determinants than did patients with inactive disease or controls. This increased number of plaque forming-cells correlated with depressed serum C3 levels by Spearman rank-order analysis. The finding of elevated numbers of spontaneous IgM plaque-forming cells to defined chemical haptens supports the concept that active SLE demonstrates a generalized increase in B-cell activity toward a variety of antigens.  相似文献   
86.
目的研究早期清创缝合后不预防性地使用抗生素对创口的影响。方法我科自2004年1月至2005年6月有选择性地对50例皮肤软组织挫裂伤进行了急诊清创缝合,术后未给予抗生素,并连续观察伤口的变化。结果本组所有伤口均未发生感染。结论早期清创及规范的清创缝合术后可以不必预防性地使用抗生素。  相似文献   
87.
BACKGROUND: Endothelial damage, such as that associated with balloon angioplasty or preparation of veins for bypass grafts, results in intimal hyperplasia. Growth factors and cytokines that modulate endothelial cell functions through various intracellular signaling pathways mediate rapid endothelial repair, which may prevent or reduce restenosis. Here we investigated the effect of mechanical injury of endothelial cells on the mitogen-activated kinase signaling pathways, extracellular-signal-regulated kinases (ERKs), C-Jun N-terminal kinase (JNK/SAPK), and p38. METHODS: Confluent human umbilical vein endothelial cells or bovine aortic endothelial cells were wounded with a razor blade; mitogen-activated kinase activation was monitored by immunoblotting with antibodies to active ERK, JNK/SAPK, or p38. RESULTS: Wounding of human umbilical vein endothelial cell or bovine aortic endothelial cell monolayers resulted in rapid (5-minute) activation of ERK-1 and -2, which was abolished by monoclonal antibody to basic fibroblast growth factor (FGF-2). This antibody or an inhibitor of ERK activation, PD98059, also blocked endothelial cell migration after the wounding. Thus FGF-2-induced ERK activation mediates the endothelial response to wounding. CONCLUSIONS: ERK-1 and -2 are activated by FGF-2 released from endothelial cells in response to injury. Therapeutic strategies aimed at reducing FGF-2-induced intimal hyperplasia should preserve ERK activation in endothelial cells while abolishing it in smooth muscle cells.  相似文献   
88.
The effects of daily injections of thymosin, bovine fraction V, on the natural history of NZB and NZB/NZW F1 mice were investigated. With the use of several dose schedules, no significant differences were discovered in treated versus control groups when survival, autoantibodies, and mitogen responsiveness were compared. These results provide further evidence that thymosin may have little or no role in the treatment of the autoimmune disease of New Zealand mice. More encouraging research in thymic extracts and their measurement is necessary before clinical trials in SLE are considered.  相似文献   
89.
On the occasion of his 100th birthday this letter is to pay tribute to Swiss psychiatrist and psychopharmacologist Roland Kuhn (1912–2005), who established the antidepressant effects of imipramine starting in 1956. Since until now only monoaminergic-based antidepressants such as this substance found their way into psychopharmacological therapy, one can say that Kuhn established the lead antidepressant substance and has hence fundamentally changed clinical psychiatry and care for the mentally ill.  相似文献   
90.
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