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   2183篇
  免费   260篇
  国内免费   8篇
耳鼻咽喉   15篇
儿科学   70篇
妇产科学   50篇
基础医学   347篇
口腔科学   21篇
临床医学   221篇
内科学   461篇
皮肤病学   22篇
神经病学   185篇
特种医学   50篇
外科学   245篇
综合类   39篇
一般理论   9篇
预防医学   162篇
眼科学   87篇
药学   229篇
中国医学   1篇
肿瘤学   237篇
  2021年   34篇
  2020年   26篇
  2019年   31篇
  2018年   28篇
  2017年   37篇
  2016年   40篇
  2015年   40篇
  2014年   55篇
  2013年   59篇
  2012年   116篇
  2011年   111篇
  2010年   62篇
  2009年   52篇
  2008年   112篇
  2007年   125篇
  2006年   116篇
  2005年   120篇
  2004年   105篇
  2003年   101篇
  2002年   79篇
  2001年   78篇
  2000年   81篇
  1999年   74篇
  1998年   25篇
  1997年   28篇
  1996年   23篇
  1995年   24篇
  1994年   24篇
  1993年   16篇
  1992年   54篇
  1991年   39篇
  1990年   41篇
  1989年   31篇
  1988年   33篇
  1987年   35篇
  1986年   26篇
  1985年   29篇
  1984年   28篇
  1983年   23篇
  1981年   16篇
  1979年   24篇
  1978年   15篇
  1977年   15篇
  1976年   20篇
  1975年   20篇
  1974年   19篇
  1972年   14篇
  1970年   13篇
  1968年   16篇
  1967年   15篇
排序方式: 共有2451条查询结果,搜索用时 15 毫秒
91.
92.
93.
The standard surgical approach to nonleaking iliac aneurysms found at repair of a leaking abdominal aortic aneurysm is to minimize the operative risk by repairing the abdominal aorta only. This means that the bypassed iliac aneurysms may have to be repaired later. As this population of patients are usually elderly with coexisting medical problems, interventional radiology is being used to embolize these aneurysms, thus avoiding the morbidity and mortality associated with further general anesthesia and surgery. Various materials and stents have been reported to be effective in the treatment of iliac aneurysms. We report the successful use of endoluminal fibrin tissue glue (Beriplast) to treat two large iliac aneurysms in a patient who had had a previous abdominal aortic aneurysm repair. We discuss the technique involved and the reasons why we used tissue glue in this patient.  相似文献   
94.
95.
96.
It has been hypothesized that complement inhibitors expressed on the surface of tumor cells prevent effective immune-mediated clearance. Whereas there are in vitro data to support this hypothesis, the species-selective activity of complement inhibitors has been a hindrance to investigating the role of membrane-bound complement inhibitors in rodent models of human cancer. The CD59-positive LAN-1 human neuroblastoma cell line was significantly more sensitive to lysis by rat complement than by human complement, illustrating the species selectivity of endogenously expressed complement inhibitors. Transfection of LAN-1 cells with rat CD59, an inhibitor of the terminal cytolytic membrane attack complex, effectively protected the cells from lysis by rat complement in vitro. When LAN-1 cells stably expressing rat CD59 were inoculated into immune-deficient rats, the onset of tumor growth and the rate of tumor growth were significantly enhanced compared with those of control-transfected LAN-1 cells. These data show directly that the expression of a complement inhibitor on a tumor cell promotes tumor growth. Flow cytometric analysis revealed that the endogenous expression of decay-accelerating factor (DAF), an inhibitor of complement activation, was up-regulated on the surface of cells after in vivo growth. Of further interest, higher levels of DAF were present on CD59-transfected cells than on control-transfected cells derived from tumors. Increased DAF expression correlated with decreased complement deposition on the tumor cell surface. These results show that expression of complement inhibitors on a tumor cell has functional consequences with regard to complement deposition in vivo and indicate that CD59 can indirectly effect complement activation and C3 deposition in vivo via a link between CD59 and DAF expression.  相似文献   
97.
1. Atherosclerotic cardiovascular disease is still the leading cause of death in Western countries. Oxygen free radicals are considered to be intimately involved in the development of atherosclerosis. Anti-oxidants may help to protect mammalian cells from the damage induced by these reactive oxygen species. Many reports have indicated that anti-oxidants used in the treatment or prevention of disease could modify the levels of superoxide dismutase (SOD). However, the effects of long-term anti-oxidant treatment on the levels of SOD in smooth muscle cells (SMC) is still unclear. In the present study, the effects of the lipophilic anti-oxidant trilinolein on the activity and gene expression of SOD in SMC were evaluated. 2. After 2 days incubation with 0.1 micromol/L trilinolein, the activity and mRNA levels of SOD were increased in rat aortic SMC (A7r5), but there was no significant change in these parameters with a higher concentration of 1 micromol/L trilinolein. 3. In contrast, after 7 days incubation with trilinolein, both the activity and mRNA levels of SOD were lowered in a dose-dependent manner. 4. These data emphasize the importance of choosing an optimal dosage for supplementation with anti-oxidants in humans for the scavenging of oxygen free radicals.  相似文献   
98.
99.
100.
Background: Traditional Chinese medicines often contain 'chuanwu' and 'caowu', the roots of certain Aconitum species which are thought to have an anti-inflammatory effect in many conditions. Excessive amounts of these materials, which contain diterpene alkaloids particularly aconitine, can produce toxic effects and occasional fatalities.
Aims: This study was conducted to document the adverse effects related to these herbal medicines which resulted in hospital admission and to determine the outcome in these patients.
Methods: A retrospective survey was conducted of patients admitted to the Prince of Wales Hospital, Hong Kong with suspected adverse effects from Chinese herbal medicines containing chuanwu or caowu over a two year period from 1989 to 1991.
Results: Eight patients were identified with features of mild to moderate intoxication including nausea and vomiting, paraesthesiae or numbness in the mouth and extremities, hypotension and ventricular extrasystoles. The management of aconitine poisoning is essentially supportive and in-hospital observation with ECG monitoring should be continued for at least 24 hours because of the risk of cardiovascular collapse and ventricular arrhythmias. The medical profession and general public should be alerted to the potential toxicity of these herbs and their usage should be controlled by legislation in Hong Kong as it is in some other countries. (Aust NZ J Med 1993; 23: 268–271.)  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