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   1278663篇
  免费   97801篇
  国内免费   1989篇
耳鼻咽喉   18423篇
儿科学   44349篇
妇产科学   35008篇
基础医学   182162篇
口腔科学   33585篇
临床医学   111242篇
内科学   258205篇
皮肤病学   28020篇
神经病学   100356篇
特种医学   51198篇
外国民族医学   660篇
外科学   196374篇
综合类   27048篇
现状与发展   1篇
一般理论   377篇
预防医学   95714篇
眼科学   27912篇
药学   94761篇
  2篇
中国医学   2422篇
肿瘤学   70634篇
  2018年   13131篇
  2017年   9962篇
  2016年   10896篇
  2015年   12369篇
  2014年   17162篇
  2013年   26208篇
  2012年   36016篇
  2011年   38050篇
  2010年   22798篇
  2009年   21806篇
  2008年   36633篇
  2007年   39243篇
  2006年   39498篇
  2005年   38437篇
  2004年   37589篇
  2003年   36443篇
  2002年   35793篇
  2001年   63987篇
  2000年   66494篇
  1999年   56407篇
  1998年   15128篇
  1997年   13753篇
  1996年   14195篇
  1995年   13452篇
  1994年   12765篇
  1993年   11790篇
  1992年   44554篇
  1991年   43464篇
  1990年   42216篇
  1989年   40111篇
  1988年   36894篇
  1987年   36234篇
  1986年   33618篇
  1985年   32278篇
  1984年   24136篇
  1983年   20268篇
  1982年   11723篇
  1981年   10691篇
  1980年   9515篇
  1979年   21341篇
  1978年   14821篇
  1977年   12532篇
  1976年   11693篇
  1975年   12623篇
  1974年   14661篇
  1973年   14117篇
  1972年   12944篇
  1971年   11729篇
  1970年   11050篇
  1969年   10024篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
In a study of 66 patients with systemic lupus erythematosus (SLE) and 80 controls it was found that the presence of two deficiency (null) alleles of C4 had a significant effect on mean C4 concentrations in serum. In six controls who each had two C4 null alleles the mean C4 concentration in serum was 56% lower than in 43 controls without C4 null alleles; the nadir of the C4 concentration in four patients with SLE with two null alleles was also lower by a mean of 55% than in 32 patients who did not have null alleles. Reduced production of C4 allotypes in subjects with two null alleles may be an important determinant of total C4 concentration in patients with SLE. For optimal interpretation of C4 concentrations in SLE, C4 allotyping appears to be indicated, particularly to identify patients who have two null alleles of C4.  相似文献   
992.
993.
994.
Plasma D-dimer (DD) and thrombin--antithrombin III complex (TAT) were measured with ELISAs in 99 patients investigated by 102 ventilation--perfusion lung scintigraphy because of suspected pulmonary embolism. High-probability lung scan was associated with increased DD (more than 500 ng/ml) and TAT (more than 4.1 ng/ml) levels (sensitivity of 100 and 70%, respectively). The corresponding figures of specificity were 81 and 42%. In the 56 patients with low-probability or indeterminate probability scans, 31 (55%) had DD concentrations of less than 500 ng/ml. These preliminary data suggest that a plasma DD concentration of less than 500 ng/ml might rule out the diagnosis of pulmonary embolism in suspected patients with an inconclusive lung scanning.  相似文献   
995.
J N Harvey  M E Denyer    P DaCosta 《Gut》1989,30(5):691-694
We describe a patient with extensive ischaemic necrosis of the ileum as a result of elastic vascular sclerosis (EVS). A 2 cm carcinoid tumour was located nearby with microscopic evidence of spread to regional lymph nodes. Severe intestinal ischaemia caused by carcinoid associated EVS may be the presenting feature of small carcinoid tumours resulting in their early diagnosis.  相似文献   
996.
997.
998.
Patients suffering from pain due to osteoarthritis of the hip and knee participated in a double-blind placebo controlled trial using daily Codetron home care units for 6 weeks over the tibial, saphenous, popliteal and sciatic nerves, and tender points. Seventy-four percent of patients in the real Codetron (Group A) and 28% of the patients in sham Codetron (Group B) improved their pain level more than 25% as measured by visual analogue scale. The difference in pain improvement in the two groups was statistically significant (p less than 0.02 using Fisher's exact probability ratio). Other functional parameters proved to be insensitive to change in this study. This is highly suggestive of beneficial effect of nonhabituating Codetron as a complementary modality in the therapy of chronic pain conditions such as osteoarthritis.  相似文献   
999.
Sexual victimization is a singularly traumatic event. At times, however, the implicit danger of the trauma experience itself gets exaggerated. For the victim the more lasting damage frequently stems from how he or she was treated by friends, family, health care providers, and public authorities following the incident. Treating the victimized patient as quickly and sensitively as possible is essential to minimizing the potential for further victimization. The Emergency Department at Boston City Hospital is frequently the site for the acute management of sexual assault victims. The Victim Care Service is designed to prevent secondary traumatization of such victims. The five-phase program and the fundamental assumptions upon which the phases are based are presented.  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