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   427211篇
  免费   34242篇
  国内免费   11481篇
耳鼻咽喉   4520篇
儿科学   11488篇
妇产科学   5069篇
基础医学   35917篇
口腔科学   11584篇
临床医学   42647篇
内科学   74795篇
皮肤病学   5157篇
神经病学   35949篇
特种医学   12267篇
外国民族医学   16篇
外科学   38723篇
综合类   62349篇
现状与发展   36篇
一般理论   32篇
预防医学   45593篇
眼科学   4323篇
药学   34917篇
  520篇
中国医学   34279篇
肿瘤学   12753篇
  2024年   1587篇
  2023年   8739篇
  2022年   15984篇
  2021年   21606篇
  2020年   20643篇
  2019年   19605篇
  2018年   18105篇
  2017年   16546篇
  2016年   15919篇
  2015年   15176篇
  2014年   29228篇
  2013年   31149篇
  2012年   24937篇
  2011年   26925篇
  2010年   21537篇
  2009年   19716篇
  2008年   19104篇
  2007年   18845篇
  2006年   16521篇
  2005年   13746篇
  2004年   11570篇
  2003年   10087篇
  2002年   8163篇
  2001年   6990篇
  2000年   5998篇
  1999年   5006篇
  1998年   4460篇
  1997年   3970篇
  1996年   3409篇
  1995年   3148篇
  1994年   2901篇
  1993年   2501篇
  1992年   2383篇
  1991年   2110篇
  1990年   1744篇
  1989年   1567篇
  1988年   1450篇
  1987年   1315篇
  1986年   1164篇
  1985年   2522篇
  1984年   2685篇
  1983年   1666篇
  1982年   2168篇
  1981年   1562篇
  1980年   1304篇
  1979年   1161篇
  1978年   933篇
  1977年   727篇
  1976年   837篇
  1975年   533篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
COPD机械通气病人下呼吸道感染致病菌分布特点   总被引:1,自引:0,他引:1  
①目的 探讨慢性阻塞性肺病(COPD)病人机械通气后下呼吸道感染致病菌的特点。②方法 取32例COPD并发呼吸衰竭行机械通气病人下呼吸道分泌物做痰细菌学培养,同时做药物敏感试验。③结果 32例病人共分离出菌株76株,阳性率71.7%,其中混合感染10例次。其中革兰阴性杆菌(GNB)58株,占76.3%;阳性球菌10株,占13.2%;真菌8株,占10.5%。常见致病菌以铜绿假单胞菌、鲍曼不动杆菌和肺炎杆菌为主,GNB中铜绿假单胞菌和不动杆菌的耐药率高。④结论 COPD应用机械通气病人下呼吸道感染以革兰阴性杆菌为主,耐药性高。  相似文献   
72.
目的 探讨实时双平面超声心动图的临床应用价值。方法 对 83例受检者进行实时双平面超声 (BP)检查 ,其中男 46例 ,女 3 7例 ,平均年龄 2 0 92± 19 16岁。正常人 10例 ,先天性心脏病 44例 ,心瓣膜病 2 6例 ,其他心脏病变3例。结果 实时双平面超声有助于理解心脏立体解剖 ;能通过有限的声窗获得更多的切面 ,并可显示常规经胸超声不易得到的切面 ;多切面显示心脏瓣膜及其病变 ,有利于获得瓣膜狭窄或关闭不全的最佳观察平面 ;多切面显示房、室间隔缺损 ,便于寻找缺损的最佳显示切面以及与毗邻结构的关系。房、室间隔缺损BP、2DE测值与手术测值均有良好相关性 ;室间隔缺损BP测值与手术测值无显著性差异 ;BP、2DE均有低估房间隔缺损大小的倾向。实时双平面超声能同时显示复杂先心病的多种解剖畸形 ,有利于确定房室连接 ;辨认主、肺动脉。结论 实时双平面超声有其独特的优势 ,可为心血管疾病的准确诊断提供更多的信息。  相似文献   
73.
大学新生心理健康状况的调查研究   总被引:2,自引:0,他引:2  
目的 了解大学新生的心理健康状况 ,探讨提高其心理健康水平的措施。方法 采用大学生人格问卷(UPI) ,以班级为单位 ,在新生正式上课两周以后进行测试。结果 学生一类筛选率 9.2 4 %。UPI关键题选择中 ,以常常失眠占的比例最高 ,想轻生的比例最低 (P <0 .0 5 )。UPI附加题选择中 ,以自身健康方面有问题及有健康或心理卫生方面想要咨询的问题较多 (P <0 .0 5 )。选择“想轻生”的男生的比例略高于女生 ,选择“常常失眠”的女生的比例却明显高于男生 (P <0 .0 5 ) ;选择“常常失眠”、“对任何事情都不感兴趣”和“感觉自己的过去及家庭不幸”的农村学生的比例都高于城市学生 (P <0 .0 5 )。选择“想轻生”和“对任何事情都不感兴趣”的独生子女的比例明显高于非独生子女 ,而选择“自己的过去和家庭是不行的”和“常常失眠”的非独生子女的比例又明显高于独生子女 (P <0 .0 5 )。结论 单亲家庭学生、残疾学生、家庭经济困难学生、独生子女学生是心理问题高危人群  相似文献   
74.
Laparoscopic procedures continue to gain popularity over traditional open procedures for a number of abdominal and pelvic surgeries. With increasing experience, the application of this technique is rising because it provides an alternative, less invasive, approach to various surgical procedures. Herein, we report our experience with adult patients with polycystic kidney disease, requiring bilateral laparoscopic nephrectomy before renal transplantation.  相似文献   
75.
ABSTRACT. Hultcrantz R, Angelin B, Einarsson K, Friman L (Departments of Internal Medicine and Roentgenology, Serafimer Hospital, and Department of Internal Medicine, Huddinge University Hospital, Karolinska Institute, Stockholm, Sweden). Spontaneous regression of Budd-Chiari syndrome (hepatic venous occlusion) in a young female. Acta Med Scand 1987; 221:503–7. A case of occlusion of the hepatic veins in an 18-year-old girl is presented. The onset was sudden with massive ascites and markedly impaired general condition. The diagnosis was based on liver biopsy and angiograms of the caval and hepatic veins as well as of the celiac artery. No predisposing factors could be found. The patient was treated conservatively with laparo-centesis and diuretics. Clear improvement was seen after two weeks, and after four weeks she had no ascites and could be discharged. All liver function tests were then normalized. After three months, all diuretics could be withdrawn, and in the following 11 years she has remained completely recovered. The case illustrates that also widespread thrombi of the hepatic veins may sometimes rapidly dissolve spontaneously, with apparent total reconstitution of hepatic function. This case is unusual since previously reported cases have had high mortality rates and, in surviving cases, operative procedures or large doses of diuretics have been required to control the ascites.  相似文献   
76.
The Low Vision Clinic at the Palmerston North Hospital has now been oerating for 70 years. Over the course of these ten years a number of factors have emerged which can be as readily applied to general ophthalmological practice as to low vision practice. The philosophy of low vision care is one of which all ophthalmologists should be aware and includes factors to be taken into account when dealing with children, people in the workplace, and everyday factors involved in daily living activities, all of which are equally relevant in routine ophthalmological practice. This paper endeavours to share some thoughts on these factors and also discusses means by which the visually handicapped can be helped in areas where specialist low vision services are not readily available.  相似文献   
77.
Secondary prevention of coronary events in coronary artery disease (CAD) patients with aspirin is generally accepted because of ease of administration, predictable safety, and proven efficacy. The use of long-term anticoagulant therapy with heparins, vitamin-K antagonists (VKAs), or thrombin inhibitors is, however, more controversial. During the last 40 years, several trials have been conducted in order to evaluate the role of anticoagulant therapy in patients with CAD as a protection against subsequent death and thrombo-embolic complications. The conducted trials are heterogeneous in many ways, concerning comparative medications, patient populations, endpoints and follow-up, which makes a standardized recommendation on the basis of these studies difficult. This review is an overview of the largest and best studies on this topic and discusses the scientific background for a possible use of VKA or an alternative anticoagulant treatment in CAD patients, looking at both the beneficial effects and the risk of bleeding.  相似文献   
78.
The endotoxin receptor soluble CD14 (sCD14) has been implicated in the 'hygiene hypothesis' suggesting reduced allergic sensitization with bacterial stimulation. However, the relationship between early life sCD14 and allergic diseases is conflicting. We aimed to investigate whether possible risk factors for allergic diseases were associated with sCD14 levels at 2 yr of age. In the nested case-control study of the birth cohort studies 'Environment and Childhood Asthma study in Oslo' 411 children selected with recurrent bronchial obstruction (rBO) (n=241) and no bronchial obstruction (n=170) by 2 yr were investigated with skin prick test and structured parental interview at age 2 yr. Exposure to tobacco smoke, pets and infections was recorded semi-annually by questionnaires (0-2 yr). The sCD14 was analysed from frozen, stored serum by ELISA technique. Regression analyses were performed in all subjects with complete data (n=406, 180 girls), and in girls and in boys separately. Mean sCD14 (ng/ml) was significantly higher among girls 2035 (1973-2096) vs. 1947 (1890-2004) (boys). The sCD14 was significantly reduced among girls exposed to antenatal maternal smoking and with parental asthma, after adjusting for age, parental rhino-conjunctivitis, pet keeping and childhood infections. Recurrent otitis media (OM) increased and common colds significantly decreased sCD14 levels in girls. Boys with atopic dermatitis and rBO had reduced sCD14. Pet exposure was not significantly associated with sCD14. We report novel gender-related effects of sCD14 in early life and suggest that gender, tobacco smoke exposure, age and middle ear disease in particular should be accounted for when assessing the role of sCD14 in childhood allergic diseases.  相似文献   
79.
High cord blood immunoglobulin E (cbIgE) is known to be associated with increased risks of atopic diseases in childhood. The relationship between genetic polymorphisms and high cbIgE has not been well documented. A cross-sectional study was conducted to assess the association between cbIgE and genetic polymorphisms of interleukin (IL)-4 -590C/T, the beta-subunit of the high-affinity receptor for IgE (FcepsilonRI-beta) E237G, lymphotoxin (LT)-alphaNcoI alleles, and tumor necrosis factor (TNF)-alpha -308G/A. A total of 320 mother-neonate pairs were recruited from four maternity hospitals from different locations of Taiwan. Cord blood was obtained and assayed for cbIgE. Polymerase chain reaction followed by restriction fragment length polymorphism was used to assess the genotypes. Three hundred pairs of mothers and neonates were included in the final analysis. Infants with IL-4 -590 C allele were found to have higher risk of elevated cbIgE (> or =0.35 IU/ml, 24.3%) (p = 0.004). After adjusting for gender, birth order, maternal age, and history of allergic disease in maternal and paternal families, odds ratios for CC and CT genotypes were 4.41 and 3.16 (95% confidence interval 0.78-22.67, and 1.66-6.13), respectively, using TT genotype as reference. The genotypes of FcepsilonRI-beta, LT-alpha, and TNF-alpha were not associated with cbIgE before or after the adjustment. Our finding suggested a significant association of cbIgE with genetic polymorphism of IL-4 -590C/T, but not with the genotypes of FcepsilonRI-beta, LT-alpha, and TNF-alpha.  相似文献   
80.
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