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   1306篇
  免费   129篇
  国内免费   17篇
耳鼻咽喉   5篇
儿科学   85篇
妇产科学   34篇
基础医学   173篇
口腔科学   23篇
临床医学   133篇
内科学   236篇
皮肤病学   26篇
神经病学   113篇
特种医学   59篇
外科学   204篇
综合类   51篇
预防医学   165篇
眼科学   10篇
药学   83篇
中国医学   4篇
肿瘤学   48篇
  2022年   6篇
  2021年   20篇
  2020年   7篇
  2019年   19篇
  2018年   24篇
  2017年   31篇
  2016年   18篇
  2015年   34篇
  2014年   44篇
  2013年   44篇
  2012年   77篇
  2011年   46篇
  2010年   40篇
  2009年   54篇
  2008年   52篇
  2007年   59篇
  2006年   47篇
  2005年   62篇
  2004年   31篇
  2003年   33篇
  2002年   40篇
  2001年   57篇
  2000年   51篇
  1999年   37篇
  1998年   45篇
  1997年   41篇
  1996年   21篇
  1995年   30篇
  1994年   23篇
  1993年   26篇
  1992年   25篇
  1991年   22篇
  1990年   15篇
  1989年   25篇
  1988年   12篇
  1987年   19篇
  1986年   18篇
  1985年   18篇
  1984年   12篇
  1983年   13篇
  1982年   12篇
  1981年   14篇
  1980年   9篇
  1979年   9篇
  1976年   8篇
  1975年   6篇
  1972年   8篇
  1971年   8篇
  1967年   9篇
  1965年   7篇
排序方式: 共有1452条查询结果,搜索用时 31 毫秒
991.
992.
993.
994.
AIMS: To assess the effect on health visitor action of providing community health visitors with information on all injury attendances in children under 5 attending an accident and emergency (A&E) department and of providing additional information about each injury. METHODS: Children under 5 years attending the A&E department at Queen's Medical Centre, Nottingham between October 1998 and April 1999 were studied, using a randomised controlled trial with a 2x2 factorial design. All attendances or selected attendances (all children under 1, burns and scalds, poisonings, head injuries, and repeat attendances in preceding six months) were notified. Provision of standard (diagnosis, circumstances surrounding injury, and disposal) or additional information (standard information plus place of injury, number of A&E attendances for injury in previous year, and any information recorded about safety equipment) was noted. RESULTS: Many notifications (56%) do not result in any action. Health visitors were nearly twice as likely to take action of some kind and three times as likely to undertake a home visit on receipt of notifications for selected attendances than on those for all attendances. A greater number of actions per notification were taken on receipt of information about selected attendances. Providing additional information had little effect on the action taken. CONCLUSIONS: A selective policy for notifying community health visitors of child injury attendances at A&E results in a greater proportion of attendances in which the health visitor takes action and in a greater number of actions per attendance being taken. The utility of notifying all injury attendances is questionable, as many do not result in any action.  相似文献   
995.
Immune-mediated mechanisms are involved in the pathogenesis of cardiomyopathies. In this study, we investigate which pattern of immune response (Th1 or Th2) lies behind these diseases by analysing the basic cytokines secreted from PHA-cultured T lymphocytes and determining what differences, if any, exist between dilated cardiomyopathy (DMC) and hypertrophic cardiomyopathy (HCM). Two groups of patients were studied: 10 patients with DCM and 10 patients with HCM. Age- and sex-matched healthy individuals were used as controls. PHA-cultured T lymphocytes in the presence or absence of different myocardial antigen (MA) concentrations were measured. Interleukine-2 (IL-2), Interleukine-6 (IL-6) and Interferon-γ (IFN-γ) levels were measured in culture supernatants by an ELISA method. At the same time, delayed-type hypereactivity (DTH) against the same antigenic preparation was measured by the leukocyte migration inhibitory index technique. Patients were subdivided into DTH-positive and DTH-negative and re-examined for IL-2 cytokine expression. IL-6 levels were found to increase both in the presence and in the absence of MA in the patient groups compared to the controls. IL-2 levels were decreased in both groups, in an antigen dose-related manner. Anergic patients showed a further reduction in IL-2 levels for both groups of patients. IFN-γ remained unaffected in the patient groups. Almost half of the patients exhibited anergy to the DTH reaction against MA. We conclude that, upon antigenic stimulation, the initially mounted immune response (increased IL-6) is somehow blocked/switched off in patients, resulting in an immunologic tolerance/unresponsiveness to MA (IL-2 decreased, IFN-γ unchanged). Finally, increased IL-6 could lead to a perpetuation of immunologic injury through the release of oxygen-free radicals with a cytotoxic effect on the myocardium. We hypothesize an antigen-related, defective macrophage-Th1 cell reaction, which accounts for the differences in the IL-2 profile between the DCM and HCM groups, that might cause local immune responses to lead to immunosuppression (immune tolerance effect), thus contributing to the pathogenesis of cardiomyopathies.  相似文献   
996.
997.
Tubular basement membrane immune deposits (TBMID) are rare in renal allografts and usually have been found in association with immune complex mediated glomerular injury. We report an association between TBMID and BK polyomavirus nephropathy (BKN). We reviewed clinical data and results of allograft biopsies of 30 patients with BKN (16 with and 14 without TBMID). TBMID were detected by immunofluorescence or electron microscopy. Initial and follow-up biopsies were assessed for degree of interstitial inflammation and fibrosis and severity of viral infection, and were correlated with patients' clinical data. Biopsies initially diagnostic for BKN with TBMID, compared to BKN biopsies without deposits, demonstrated more severe interstitial inflammation and fibrosis, and greater numbers of virally infected cells. Similar findings were present in follow-up biopsies. Utilizing three different antibodies directed against viral epitopes, viral antigens could not be detected within TBMID. Thirty percent of patients with TBMID and 70% without deposits had follow-up biopsies, in which virus could not be detected immunohistochemically. Treatment for all included decreasing immunosuppression, cidofovir and/or leflunomide. Clinical data correlated well with histological findings. We conclude that a significant proportion of patients with BKN show TBMID on kidney biopsy. The prognostic significance of this finding remains to be elucidated.  相似文献   
998.
999.
1000.
Neoadjuvant Targeted Molecular Therapy in the setting of localized and locally advanced renal cell carcinoma has emerged as a strategy to render primary renal tumors amenable to planned surgical resection in settings where radical resection or nephron-sparing surgery was not thought to be safe or feasible. Presurgical tumor reduction has been demonstrated in a number of studies including a recently published randomized double-blind placebo-controlled study, and an expanding body of literature suggests benefit in select patients. Nonetheless, most reports are small phase II clinical trials or retrospective reports. Thus, large randomized clinical trial data are not present to support this approach, and guidelines for use of presurgical therapy have not been promulgated. The advent of immunomodulation through checkpoint inhibition represents an exciting horizon for neoadjuvant strategies. This article reviews the current status and future prospects of neoadjuvant therapy in nonmetastatic renal cell carcinoma.  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