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   1006773篇
  免费   78268篇
  国内免费   3390篇
耳鼻咽喉   13044篇
儿科学   34571篇
妇产科学   28551篇
基础医学   146464篇
口腔科学   27877篇
临床医学   91665篇
内科学   194743篇
皮肤病学   23005篇
神经病学   79515篇
特种医学   38768篇
外国民族医学   308篇
外科学   150707篇
综合类   26004篇
现状与发展   2篇
一般理论   386篇
预防医学   78827篇
眼科学   22877篇
药学   73368篇
  11篇
中国医学   3061篇
肿瘤学   54677篇
  2018年   11008篇
  2017年   8665篇
  2016年   9771篇
  2015年   11130篇
  2014年   15060篇
  2013年   22669篇
  2012年   29834篇
  2011年   31750篇
  2010年   19136篇
  2009年   17977篇
  2008年   29410篇
  2007年   31022篇
  2006年   31491篇
  2005年   30155篇
  2004年   29346篇
  2003年   28322篇
  2002年   27300篇
  2001年   47323篇
  2000年   48323篇
  1999年   40473篇
  1998年   11303篇
  1997年   10227篇
  1996年   10240篇
  1995年   9836篇
  1994年   9146篇
  1993年   8522篇
  1992年   32292篇
  1991年   31508篇
  1990年   31044篇
  1989年   29904篇
  1988年   27187篇
  1987年   27354篇
  1986年   25447篇
  1985年   24615篇
  1984年   18405篇
  1983年   15521篇
  1982年   9289篇
  1981年   8381篇
  1979年   16862篇
  1978年   12217篇
  1977年   10315篇
  1976年   9754篇
  1975年   10178篇
  1974年   12319篇
  1973年   11844篇
  1972年   10885篇
  1971年   10114篇
  1970年   9376篇
  1969年   8724篇
  1968年   8106篇
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
991.
992.
Lyme arthritis     
Evanescent arthralgias and myalgias are common early symptoms of Lyme disease. Transient, intermittent episodes of monoarticular, oligoarticular, or sometimes migratory polyarticular arthritis, lasting weeks to months, with disease-free intervals, are frequently observed in untreated patients with erythema chronicum migrans. A minority of patients develop chronic joint involvement, most commonly affecting the knee. Antibiotic therapy given during erythema chronicum migrans is often protective with regard to late joint manifestations. In chronic Lyme arthritis, however, the response to antibiotics is variable.  相似文献   
993.
994.
995.
This study was conducted to determine if lower steroid secretion by the small white follicles in incubating turkey hens contributes to lower circulating steroid concentrations during this time. Turkey hens were grouped as either laying or incubating. Serum samples and the ovarian small white follicles (SWF; 2-7 mm diameter) were collected from each hen. The SWF were pooled for each group and their cells were dispersed by trypsin digestion. Serum-luteinizing hormone (LH), progesterone (P), testosterone (T), and estradiol (E) concentrations were lower and serum prolactin concentration was higher during incubation than during egg laying. SWF cells from incubating hens secreted more P and T and less E in response to ovine luteinizing hormone (oLH) than did similar cell suspensions from laying hens. The incubating hens' SWF cells' capacity to secrete E but not their capacity to secrete P or T in vitro is consistent with the observed circulating levels. It is hypothesized that lower levels of circulating LH and/or higher levels of prolactin found in incubating hens may have a depressing effect on aromatase activity and/or an up-regulating effect on LH-induced P and T secretion by the SWF cells.  相似文献   
996.
Forty-six patients with cholangitis were randomized to receive therapy with mezlocillin sodium (24 patients) or a combination of ampicillin sodium--gentamicin sulfate (22 patients). The biliary concentration of mezlocillin was 112 times higher than that of ampicillin and 778 times higher than that of gentamicin. The ratio of the concentration in serum or bile over the minimum inhibitory concentration against aerobic gram-negative bacilli (therapeutic index) was higher for mezlocillin than for either ampicillin or gentamicin. Twenty (83%) of 24 patients were cured following mezlocillin therapy compared with 9 (41%) of 22 patients after ampicillin-gentamicin therapy. The 3 patients with superinfection were in the ampicillin-gentamicin arm of the study. Fewer toxic or adverse effects occurred in association with mezlocillin treatment than with ampicillin-gentamicin treatment. Mezlocillin therapy was more effective, less toxic, and less expensive than treatment with ampicillin and gentamicin for patients with cholangitis.  相似文献   
997.
There is evidence that leukocyte contaminating red blood cells and platelet concentrates are responsible for refractoriness to platelet transfusions. The efficacy of a cotton-wool filter to remove leukocytes from red blood cells has been documented previously. The present study was designed to evaluate whether the cotton-wool filters can effectively remove leukocytes from platelet concentrates. Sixty pools of random-donor platelets and single-donor plateletpheresis products were filtered through a cotton-wool filter. The efficacy of filtration was determined by measuring the absolute numbers of leukocytes and platelets and subpopulations of mononuclear cells. The average platelet loss was 8% per pool of random platelets and 10% per plateletpheresis product. The average leukocyte removal was 99% from a pool of random platelets and plateletpheresis concentrates collected by CS-3000 and 90% from plateletpheresis concentrates harvested by single-stage COBE/IBM-2997. The filtration removed 100% of granulocytes, 95% of monocytes, 90% of B-lymphocytes, and 85% of T-lymphocytes. We conclude that filtration through a cotton-wool filter is an efficient and cost-effective method for preparation of leukocyte-poor platelets.  相似文献   
998.
999.
This article reviews the utility of noninvasive echocardiography in the detection of early cardiac transplant rejection before and after the use of cyclosporine. It addresses the use of Doppler and two-dimensional echocardiography in the routine cardiac evaluation of the heart-transplant patient, including the use of two-dimensional echocardiography in guiding the endomyocardial biopsy procedure.  相似文献   
1000.
A giant aneurysm of the right common iliac artery presenting with an arteriovenous fistula (AVF) between the iliac artery and iliac vein and deep venous thrombosis of the right lower extremity is reported. The clinical signs and the radiologic and surgical management of the condition are discussed. In addition a brief review of the literature is given.  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