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   3432466篇
  免费   250880篇
  国内免费   9211篇
耳鼻咽喉   46437篇
儿科学   113220篇
妇产科学   95734篇
基础医学   481885篇
口腔科学   94764篇
临床医学   314698篇
内科学   673770篇
皮肤病学   81392篇
神经病学   282412篇
特种医学   130788篇
外国民族医学   1111篇
外科学   512413篇
综合类   74081篇
现状与发展   7篇
一般理论   1334篇
预防医学   267590篇
眼科学   77710篇
药学   248380篇
  8篇
中国医学   7252篇
肿瘤学   187571篇
  2019年   27444篇
  2018年   38490篇
  2017年   29550篇
  2016年   33956篇
  2015年   38249篇
  2014年   53292篇
  2013年   80004篇
  2012年   106768篇
  2011年   113239篇
  2010年   67846篇
  2009年   64765篇
  2008年   105259篇
  2007年   111675篇
  2006年   113516篇
  2005年   109243篇
  2004年   104759篇
  2003年   101025篇
  2002年   97599篇
  2001年   165406篇
  2000年   169461篇
  1999年   142504篇
  1998年   41218篇
  1997年   36703篇
  1996年   36720篇
  1995年   35510篇
  1994年   32432篇
  1993年   30346篇
  1992年   110020篇
  1991年   105616篇
  1990年   102334篇
  1989年   98581篇
  1988年   90433篇
  1987年   88588篇
  1986年   82985篇
  1985年   79412篇
  1984年   59550篇
  1983年   50473篇
  1982年   30178篇
  1981年   26902篇
  1979年   52638篇
  1978年   37254篇
  1977年   31391篇
  1976年   29250篇
  1975年   30833篇
  1974年   36725篇
  1973年   35111篇
  1972年   32988篇
  1971年   30510篇
  1970年   28352篇
  1969年   26995篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Summary Cytosine arabinsodie (ara-C) and etoposide (VP-16) display synergy in the laboratory. Twenty-six patients participated in a phase I study of high-dose ara-C in combination with VP-16. The dose of VP-16 was held constant at 50 mg/m2 as an intermittent infusion over 33 h; escalating doses of ara-C were given as infusions during hours 9–12 and 21–24. Myelosuppression was the dose-limiting toxicity and occurred with doses considerably less than those expected from studies of the two drugs as single agents. The suggested initial doses for phase II trials with this schedule are 750 mg/m2×2 doses of ara-C and 50 mg/m2 of VP-16. Nonhematologic toxicity was minimal; therefore, further dose escalation is feasible in patients in whom myelosuppression is acceptable.Supported in part by grants from the National Cancer Institute (CA-12197 and CA-09422) and the American Cancer Society CF-85-182  相似文献   
992.
A 50-year-old woman with bilateral inflammatory breast cancer (T4, N1b, M1, Stage IV) underwent right extended radical mastectomy and left modified radical mastectomy following pre-operative administration of carcinostatics (ADM, 5-FU) and irradiation. However, tumor recurrence was observed at the skin and right pleural cavity after the operation. Adriamycin-containing combination chemotherapy and radiation therapy were performed, but no significant response was obtained. CDDP was then administered intravenously at a daily dose of 62.5 mg/m2 at intervals of 60 days. The pleural effusion disappeared and the extent of skin metastasis was reduced, resulting in partial response which lasted for 90 days. The serum CEA level decreased from 13.1 ng/ml to 2.3 ng/ml. As the side effects of this therapy, slight nausea, vomiting and general fatigue were observed. This result suggested that CDDP is an effective drug for inflammatory breast cancer.  相似文献   
993.
Platelet antibodies in systemic lupus erythematosus   总被引:2,自引:0,他引:2  
In systemic lupus erythematosus (SLE), the precise cause of the thrombocytopenia is unknown. Since platelet associated IgG is increased in many patients, it has been suggested that the destruction of platelets might be dependent on specific antibodies. In nine patients with SLE, platelet associated immunoglobulins were found together with free serum antibody which bound to platelets from all normal subjects. Using an immunoblotting technique with membrane proteins from normal platelets incubated with patient sera, target antigens were localized on a band of mol wt 108,000 in two cases (B. and N.) and on a band of mol wt 66,000 in a third (M.). When the same technique was applied to autologous platelets of patient N., autoantibody binding to the protein of mol wt 108,000 was demonstrated. The antigenic determinants were not removed from the platelets by enzyme treatment or by disulphide bond reduction, and were localized in the cytoplasmic fraction of the platelets.  相似文献   
994.
995.
996.
We investigated the effects of imaging and display conditions on the detectability of low-contrast objects in digital subtraction angiographic (DSA) images. The test images were produced by superimposition of low-contrast objects on a uniform noisy background obtained with a DSA system. We employed 18-alternative forced-choice (18-AFC) experiments and predictions based on statistical decision theory to study the dependence of the threshold contrasts of the test objects on the object size, incident x-ray exposure, display window width, and display medium. The results indicated that the threshold contrast decreased with increasing object size, and that the detectability of an object of a given size increased with increasing incident x-ray exposure and decreasing width of the display window. We found that the signal-to-noise ratio (SNR) obtained from the perceived statistical decision theory model, which includes the observer's internal noise, can accurately predict the detectability of low-contrast objects in DSA images. The threshold SNR corresponding to 50% correct detection in the 18-AFC experiments had a constant value of 3.8, in agreement with results reported previously for screen-film systems. The theoretical model will be useful for prediction of the performance of a DSA system based on its physical characteristics, and for evaluation of the tradeoff between patient exposure and diagnostic accuracy for a given DSA unit.  相似文献   
997.
998.
999.
1000.
The family physician should follow the small premature infant in the neonatal intensive care center and review the baby's problems and risk factors. In the office, special attention is required in monitoring the infant. Proper hospital and office care greatly improve the prognosis.  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