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   1001篇
  免费   141篇
  国内免费   10篇
耳鼻咽喉   15篇
儿科学   93篇
妇产科学   13篇
基础医学   133篇
口腔科学   39篇
临床医学   146篇
内科学   218篇
皮肤病学   9篇
神经病学   38篇
特种医学   161篇
外科学   128篇
综合类   34篇
预防医学   42篇
眼科学   1篇
药学   21篇
中国医学   5篇
肿瘤学   56篇
  2022年   3篇
  2021年   11篇
  2020年   6篇
  2019年   6篇
  2018年   37篇
  2017年   42篇
  2016年   37篇
  2015年   35篇
  2014年   36篇
  2013年   62篇
  2012年   28篇
  2011年   24篇
  2010年   59篇
  2009年   53篇
  2008年   29篇
  2007年   27篇
  2006年   21篇
  2005年   17篇
  2004年   11篇
  2003年   16篇
  2002年   12篇
  2001年   20篇
  2000年   9篇
  1999年   7篇
  1998年   59篇
  1997年   53篇
  1996年   55篇
  1995年   49篇
  1994年   29篇
  1993年   41篇
  1992年   20篇
  1991年   18篇
  1990年   22篇
  1989年   18篇
  1988年   24篇
  1987年   21篇
  1986年   18篇
  1985年   10篇
  1984年   13篇
  1983年   17篇
  1982年   3篇
  1981年   16篇
  1980年   9篇
  1979年   3篇
  1978年   3篇
  1977年   18篇
  1976年   11篇
  1975年   5篇
  1973年   2篇
  1971年   2篇
排序方式: 共有1152条查询结果,搜索用时 0 毫秒
31.
Chronic stress and depression have adverse consequences on many organ systems, including the skeleton, but the mechanisms underlying stress‐induced bone loss remain unclear. Here we demonstrate that neuropeptide Y (NPY), centrally and peripherally, plays a critical role in protecting against stress‐induced bone loss. Mice lacking the anxiolytic factor NPY exhibit more anxious behavior and elevated corticosterone levels. Additionally, following a 6‐week restraint, or cold‐stress protocol, Npy‐null mice exhibit three‐fold greater bone loss compared to wild‐type mice, owing to suppression of osteoblast activity. This stress‐protective NPY pathway acts specifically through Y2 receptors. Centrally, Y2 receptors suppress corticotropin‐releasing factor expression and inhibit activation of noradrenergic neurons in the paraventricular nucleus. In the periphery, they act to control noradrenaline release from sympathetic neurons. Specific deletion of arcuate Y2 receptors recapitulates the Npy‐null stress response, coincident with elevated serum noradrenaline. Importantly, specific reintroduction of NPY solely in noradrenergic neurons of otherwise Npy‐null mice blocks the increase in circulating noradrenaline and the stress‐induced bone loss. Thus, NPY protects against excessive stress‐induced bone loss, through Y2 receptor‐mediated modulation of central and peripheral noradrenergic neurons. © 2014 American Society for Bone and Mineral Research.  相似文献   
32.
33.
34.
Cytomegalovirus is the single most important pathogen in clinical transplantation. Although much progress has been made in our understanding of the molecular biology and epidemiology of CMV infection and in our ability to diagnosis and treat CMV disease, it remains a major cause of morbidity but is no longer a major cause of mortality after liver transplantation. Risk factors for CMV disease after liver transplantation include donor and recipient serologic status, the use of antilymphocyte therapy, and retransplantation. CMV disease occurs early after transplantation, and the most frequent site of disease is the hepatic allograft. We have treated 79 patients with intravenous ganciclovir, with ultimate control of disease achieved in 69 patients (87.3%). Preliminary results using intravenous immunoglobulin and oral acyclovir for CMV prophylaxis in high-risk patients have been encouraging. In addition to producing clinical syndromes, CMV may have direct immunologic effects and is a marker of the net state of immunosuppression.  相似文献   
35.
36.
37.
38.
A new serological test, diffusion in gel-enzyme-linked immunosorbent assay (DIG-ELISA) was developed and compared with the microscopic agglutination test (MAT) for the serological diagnosis of leptospirosis. The results suggest that DIG-ELISA is a viable alternative to the MAT because of its simplicity, sensitivity, versatility and potential for standardisation.  相似文献   
39.
40.
ObjectiveTo investigate the potentials of the root bark of Annona (A.) senegalensis in the control of seizure and related hypnotic and motor incoordination effects in mice using experimental models.MethodsThe methanol extract (ME) of the root bark of A. senegalensis was studied in mice using pentylenetetrazole (PTZ) induced convulsions, phenobarbitone induced sleeping time and motor coordination test on rota-rod performance. Acute toxicity and lethality (LD50) test as well as phytochemical analysis were also carried out.ResultsThe extract (200, 400, 800 mg/kg) exhibited a non-dose dependent significant (P <0.05) delay in the onset of both tonic and clonic phases of seizure induced by PTZ (60 mg/kg, s.c.) as well as offered a 100% protection (200 mg/kg) in mice from PTZ induced seizures. The extract significantly (P <0.05) decreased the latency and increased the duration of phenobarbitone induced sleeping time. At 200 mg/kg, the extract exhibited a significant (P <0.05) motor incoordination. The acute toxicity test revealed an oral LD50 of 1 296 mg/kg, while the phytochemical studies showed the presence of alkaloids, resins, glycosides, carbohydrate, reducing sugar, flavonoids, terpenoids, saponins and tannins.ConclusionThe extract of A. senegalensis possessed anticonvulsant activity with pronounced hypnotic and muscle relaxant effects.  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