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   578篇
  免费   88篇
  国内免费   13篇
耳鼻咽喉   1篇
儿科学   26篇
妇产科学   3篇
基础医学   37篇
口腔科学   15篇
临床医学   69篇
内科学   142篇
皮肤病学   7篇
神经病学   15篇
特种医学   199篇
外科学   18篇
综合类   43篇
预防医学   19篇
眼科学   4篇
药学   48篇
  1篇
肿瘤学   32篇
  2021年   5篇
  2018年   6篇
  2016年   3篇
  2015年   6篇
  2014年   5篇
  2013年   4篇
  2012年   10篇
  2011年   10篇
  2010年   13篇
  2009年   11篇
  2008年   5篇
  2007年   17篇
  2006年   12篇
  2005年   11篇
  2004年   11篇
  2003年   15篇
  2002年   8篇
  2001年   11篇
  2000年   7篇
  1999年   11篇
  1998年   30篇
  1997年   26篇
  1996年   19篇
  1995年   26篇
  1994年   26篇
  1993年   37篇
  1992年   13篇
  1991年   12篇
  1990年   21篇
  1989年   30篇
  1988年   30篇
  1987年   45篇
  1986年   34篇
  1985年   24篇
  1984年   9篇
  1983年   19篇
  1982年   6篇
  1981年   13篇
  1980年   13篇
  1979年   3篇
  1978年   10篇
  1977年   6篇
  1976年   4篇
  1975年   6篇
  1970年   3篇
  1967年   3篇
  1964年   2篇
  1960年   4篇
  1881年   2篇
  1871年   2篇
排序方式: 共有679条查询结果,搜索用时 15 毫秒
1.
The long term recovery of a series of 27 patients who had undergone rupture and repair of an aneurysm of the anterior communicating artery was assessed using a number of neuropsychological measures. Testing took place 12 to 84 months post surgery. On the basis of the results from tests of intellect, memory, and conceptual learning, three subgroups of patients were identified: those with persuasive cognitive defects, those with evidence of residual frontal lobe damage and those who showed no evidence of dysfunction. The occurrence of cerebral vasospasm was the most consistent predictor of long term cognitive deficit.  相似文献   
2.
3.
Ten thrombocytopenic patients (platelets < 10–24 × 10(9)/L) who were refractory to platelet transfusion were investigated for their responsiveness to staphylococcal protein A column therapy. Nine patients had previously been treated with steroids, intravenous immune globulin, and/or other forms of immunosuppressive therapy without improvement in their transfusion response. All patients were receiving multiple platelet transfusions without achieving 1-hour corrected count increments (CCIs) > or = 7500. Eight patients had antibodies that reacted with platelets and were directed against HLA class I antigens, ABO antigens, and/or platelet-specific alloantigens. Plasma (500-2000 mL) from each patient was passed over a protein A silica gel column and then returned to the patient. Patients received from 1 to 14 treatments. A positive response to protein A therapy was defined as at least a doubling of the pretreatment platelet count and/or two successive 10- to 120-minute posttransfusion CCIs > or = 7500. Following plasma treatments, 6 of 10 patients responded with daily platelet counts that averaged 48 +/− 11 × 10(9) per L as compared with counts of 16 +/− 7 × 10(9) per L (p < 0.0005) before treatment. Posttransfusion CCI values determined in four of these patients averaged 2480 +/− 810 and 10,010 +/− 3540 (p < 0.005) before and after treatment, respectively. In contrast, among the four unresponsive patients, platelet counts averaged 10 +/− 9 and 13 +/− 10 × 10(9) per L (p = NS), respectively, while posttransfusion CCIs were 700 +/− 1410 and 1520 +/− 2460 (p = NS), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
4.
Results of clinical, contrast enema (CE), and computed tomographic (CT) examinations in 39 patients with perforated colorectal neoplasms were retrospectively reviewed. Twenty patients were toxemic at initial presentation, but in only four patients was the diagnosis of perforated colorectal neoplasm initially suspected clinically. CE study was performed in 22 patients and enabled the diagnosis of perforated neoplasm in 11 cases, neoplasm alone in eight, and neither neoplasm nor perforation in three. CT was performed in 38 patients and enabled the diagnosis of perforated neoplasm in 36; pericolic phlegmon but no mass lesion was evident in two. In 16 patients, CT also demonstrated metastatic disease. Because of its reliability in establishing the diagnosis and staging the extent of the inflammatory and neoplastic disease, CT is indicated in cases of suspected or proved perforated colorectal neoplasm and in cases in which CE study findings are indeterminate or suggestive of perforated neoplasm.  相似文献   
5.
6.
7.
8.
Synthesis of collagenous proteins by pulmonary type II epithelial cells   总被引:2,自引:0,他引:2  
We have investigated the production of collagenous proteins by primary cultures of rat lung epithelial cells (type II pneumocytes). Three major bacterial collagenase-sensitive chains were synthesized and secreted into the medium between 12 and 36 h of culture. Two of the chains comigrated on sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis (SDS-PAGE) with radiolabeled type IV procollagen (PC) chains isolated from adult rat lung (Mr = 185,000 and 170,000 after reduction) and were coprecipitated with monospecific antibodies to type IV collagen. Cyanogen bromide (CNBr) peptide maps of the chromatographically purified chains were identical to maps of rat lung type IV PC, and confirmed the identity of these chains as pro alpha 1(IV) and pro alpha 2(IV). Type IV PC was the major high molecular weight collagen in the cell layer, and a fraction of the newly synthesized type IV PC was selectively deposited on the substratum together with newly synthesized fibronectin. Type II cells also secreted a low molecular weight, non-disulfide-bonded, collagenase-sensitive protein (Mr = 19,000, collagen standards; Mr = 26,000, globular standards). The protein coeluted with type IV PC from DEAE-cellulose but was resolved from native type IV on CM-cellulose. The protein was not precipitated with polyclonal antibodies to type IV collagen or rat surfactant apoprotein. These studies further demonstrate the heterogeneity of collagenous macro-molecules synthesized by lung epithelial cells in vitro. We suggest that interactions between pneumocyte-derived fibronectin and type IV procollagen contribute to the formation of the epithelial basement membrane and to the attachment of these cells in normal or injured lung.  相似文献   
9.
10.
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