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   82754篇
  免费   8165篇
  国内免费   183篇
耳鼻咽喉   1180篇
儿科学   2488篇
妇产科学   1787篇
基础医学   11836篇
口腔科学   2003篇
临床医学   10170篇
内科学   14585篇
皮肤病学   1295篇
神经病学   6730篇
特种医学   2784篇
外国民族医学   10篇
外科学   11404篇
综合类   1664篇
一般理论   67篇
预防医学   9476篇
眼科学   1853篇
药学   6750篇
  1篇
中国医学   77篇
肿瘤学   4942篇
  2021年   1112篇
  2020年   738篇
  2019年   1118篇
  2018年   1391篇
  2017年   1001篇
  2016年   1093篇
  2015年   1238篇
  2014年   1634篇
  2013年   2564篇
  2012年   3465篇
  2011年   3744篇
  2010年   1984篇
  2009年   1910篇
  2008年   3224篇
  2007年   3558篇
  2006年   3414篇
  2005年   3476篇
  2004年   3247篇
  2003年   3022篇
  2002年   2955篇
  2001年   2713篇
  2000年   2828篇
  1999年   2502篇
  1998年   1074篇
  1997年   878篇
  1996年   865篇
  1995年   779篇
  1994年   806篇
  1993年   739篇
  1992年   2092篇
  1991年   2018篇
  1990年   1893篇
  1989年   1860篇
  1988年   1769篇
  1987年   1774篇
  1986年   1680篇
  1985年   1665篇
  1984年   1386篇
  1983年   1256篇
  1982年   838篇
  1981年   715篇
  1979年   1213篇
  1978年   872篇
  1977年   759篇
  1976年   718篇
  1975年   715篇
  1974年   859篇
  1973年   752篇
  1972年   733篇
  1971年   640篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Choristomas, masses of normal tissues in aberrant locations, contain smooth muscle fibers and fibrous tissues. We describe the MR imaging features of two choristomas located in the internal auditory canals and arising from the facial and vestibulocochlear nerves. Both lesions enhanced with contrast material. In one case, enhancement was seen in the geniculate ganglion and greater superficial petrosal nerve. In the other, a medial component enhanced less than the lateral component did.  相似文献   
3.
Herpes zoster probably occurs more often than generally thought. Since it produces a radicular distribution of pain, it should be included in the differential diagnosis of radiculopathy. A case is presented in which evaluating the radicular low back pain before the characteristic rash appears was misleading. Careful history-taking concerning the exact nature of the pain and sensory changes is needed to differentiate between zoster and radiculopathy, if no rash is evident.  相似文献   
4.
. Neutrophil-mediated tissue damage has been implicated in the pathogenesis of diarrhoea-associated haemolytic uraemic syndrome (D+ HUS). This study evaluates priming and activation of the neutrophil oxidative burst in D+ HUS using chemiluminescent techniques. Peripheral blood neutrophils from 11 children with acute D+ HUS were examined. No difference was found in the oxidative burst of neutrophils from patients and controls. Serum elastase levels were measured in 8 patients and found to be significantly elevated. Although elastase results suggest neutrophil activation, chemiluminescence studies do not confirm this in the peripheral blood neutrophil. This does not support a significant role for circulating agents in priming and activating the peripheral blood neutrophil. Received August 17, 1995; received in revised form and accepted November 27, 1995  相似文献   
5.
OBJECTIVES: The incidence of bacterial microleakage, pulp inflammation and necrosis associated with dentine etching treatments prior to restoration are not known. Consequently, to resolve some of the controversy surrounding the effects and importance of vital dentine etching, the authors investigated these factors. METHODS: 110 standardised class V cavities were cut into buccal dentine, without exposing the pulp of teeth scheduled for extraction for orthodontic reasons. Cavities were either left unetched, or etched with the non-equivalent treatments of phosphoric acid gel for 60s or Ethylenediaminetetraacetic acid (EDTA) for 30s, prior to placement of composite resin. Teeth were collected and pulp responses were evaluated according to ISO guidelines, using pathohistomorphometric analysis and ANOVA statistics. RESULTS: Etching was found to be correlated to bacterial microleakage (p=0.0001) and tertiary dentine formation (p=0.0023). Bacterial microleakage was correlated to inflammatory activity (p=0.0001). The frequency of bacterial microleakage was: no etching (65%), EDTA (51%) and phosphoric acid (PA) (20%). SIGNIFICANCE: Vital dentine etching treatment is of extreme importance for the placement of RC to minimise bacterial microleakage. PA etching proved to be more effective at preventing bacterial microleakage than non-etching, and etching with EDTA.  相似文献   
6.
Maya families from Guatemala migrated to the United States in record numbers from the late 1970s to the early 1990s. Births to Maya immigrant women have created a sizable number of Maya American children. The height and sitting height of 5 to 12 years children (n = 431) were measured in 1999 and 2000. Leg length was estimated and the sitting height ratio was calculated. These data were compared with a sample of Maya children living in Guatemala measured in 1998 (n = 1,347). Maya American children are currently 11.54 cm taller and 6.83 cm longer‐legged, on average, than Maya children living in Guatemala. Consequently, the Maya Americans have a significantly lower average sitting height ratio (i.e., relatively longer legs in proportion to length of the head and trunk) than do the Maya in Guatemala. These results add support to the hypothesis that both the height and body proportions of human populations are sensitive indicators of the quality of the environment for growth. Am. J. Hum. Biol. 14:753–761, 2002. © 2002 Wiley‐Liss, Inc.  相似文献   
7.
8.
Horner's syndrome or oculosympathetic paralysis is not an uncommon finding in patients with head and neck neoplasms. While in most cases the syndrome is easily established at the bedside, it can be confirmed and topographically defined as a central, preganglionic, or postganglionic lesion through sequential pharmacologic testing. The importance of such localization lies in differentiating neoplasia vs. a benign condition as the cause of the syndrome. Such variants as congenital Horner's, an alternating Horner's, and a pseudo-Horner's syndrome are discussed in regard to their differential features.  相似文献   
9.
10.
Peripheral arterial thromboembolism and thrombosis of arterial grafts continue to threaten viability of extremities. Percutaneous intra-arterial thrombolysis (IAT) and angiodilatation have afforded limb salvage in some of these patients. Proper patient selection appears to be the hallmark of success with IAT. During a recent three-year period, we used IAT in 32 extremities in 28 patients who had acute arterial insufficiency. Before IAT, 16 extremities were painful at rest, and 16 had incapacitating claudication. The overall success rate was 38%, but some degree of thrombolysis occurred in 88%. Limb salvage was achieved in 27 of 32 extremities (84%). Only five of 17 limbs (29%) with arterial graft thrombosis required no operation or an operation of lesser magnitude than predicted before IAT. Of six extremities with native arterial embolism, four (67%) were completely cleared with IAT. Major complications occurred in eight cases (25%), with two IAT-related deaths (6%). This study suggests that IAT is best reserved for individuals with acute limb ischemia caused by arterial embolus, those whose degree of ischemia would tolerate a 24-hour trial of IAT, and those whose femoral or tibial runoff is not likely to require remedial operation.  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