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   16395篇
  免费   943篇
  国内免费   220篇
耳鼻咽喉   88篇
儿科学   166篇
妇产科学   71篇
基础医学   1173篇
口腔科学   187篇
临床医学   1596篇
内科学   1095篇
皮肤病学   117篇
神经病学   658篇
特种医学   428篇
外国民族医学   1篇
外科学   778篇
综合类   2927篇
预防医学   3488篇
眼科学   70篇
药学   3723篇
  12篇
中国医学   652篇
肿瘤学   328篇
  2024年   14篇
  2023年   159篇
  2022年   335篇
  2021年   413篇
  2020年   398篇
  2019年   346篇
  2018年   372篇
  2017年   327篇
  2016年   397篇
  2015年   483篇
  2014年   1321篇
  2013年   1468篇
  2012年   1619篇
  2011年   1618篇
  2010年   1335篇
  2009年   1044篇
  2008年   916篇
  2007年   904篇
  2006年   685篇
  2005年   592篇
  2004年   408篇
  2003年   336篇
  2002年   255篇
  2001年   227篇
  2000年   204篇
  1999年   170篇
  1998年   146篇
  1997年   116篇
  1996年   113篇
  1995年   77篇
  1994年   78篇
  1993年   59篇
  1992年   58篇
  1991年   64篇
  1990年   41篇
  1989年   56篇
  1988年   45篇
  1987年   39篇
  1986年   38篇
  1985年   44篇
  1984年   32篇
  1983年   15篇
  1982年   21篇
  1980年   18篇
  1979年   18篇
  1978年   14篇
  1977年   14篇
  1974年   14篇
  1973年   23篇
  1971年   12篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
基于人文理念的护理质量例会实践与体会   总被引:1,自引:0,他引:1  
建立以人文理念为核心的护理质量分析例会制度,每月召开门诊护士长、护士组长、护士代表例会,分析、讲评门诊护理服务中存在的问题,并提出改进方案,持续改进门诊护理服务质量。  相似文献   
22.
The accuracy of 2D phase contrast (PC) magnetic resonance angiography (MRA) depends on the alignment between the vessels and the imaging plane. PC MRA imaging of blood flow is challenging when the flow in several vessels is to be evaluated with one acquisition. For this purpose, semi-automatic determination of the plane most perpendicular to several vessels is proposed based on centerlines extracted from 3D MRA. Arterial centerlines are extracted from 3D MRA based on iterative estimation-prediction, multi-scale analysis of image moments, and a second-order shape model. The optimal plane is determined by minimizing misalignment between its normal vector and the centerlines’ tangent vectors. The method was evaluated on a phantom and on 35 patients, by seeking the optimal plane for cerebral blood flow quantification simultaneously in internal carotids and vertebral arteries. In the phantom, difference of orientation and of height between known and calculated planes was 1.2° and 2.5 mm, respectively. In the patients, all but one centerline were correctly extracted and the misalignment of the plane was within 12° per artery. Semi-automatic centerline extraction simplifies and automates determination of the plane orthogonal to one vessel, thereby permitting automatic simultaneous minimization of the misalignment with several vessels in PC MRA.  相似文献   
23.
Vasopressin (AVP) receptor binding within hypothalamic sites was compared between cycling and lactating female golden hamsters. The density of AVP receptor binding was analyzed by quantitative autoradiography within the ventrolateral hypothalamus and dorsomedial hypothalamic nucleus. Lactation was correlated with a disappearance of AVP receptor binding within the ventrolateral hypothalamus. In contrast, lactation was associated with a two- to three-fold increase in the density of AVP receptor binding within the dorsomedial hypothalamic nucleus. These results suggest that AVP receptor binding within the ventrolateral hypothalamus is responsive to gonadal hormones in female golden hamsters. However, the increase in binding observed within the dorsomedial hypothalamus may be related to other neurobiological changes associated with lactation.  相似文献   
24.
An advanced analysis of the mechanical properties of bone should include information about the microarchitecture of cancellous bone in addition to its density. It has recently been shown that high-resolution quantitative computed tomography and magnetic resonance imaging have the potential to assess such information in a noninvasive way in patients. Both techniques, however, lack sufficient spatial resolution to image the individual trabeculae with true precision. In this work, a new parameter, Ridge number density (RND), is introduced. RND is a measure for the trabecular number, which can be extracted directly from high-resolution three-dimensional (3D) images of patients. We applied the RND technique to a test group of nine healthy, postmenopausal women measured repetitively with a high-resolution 3D peripheral quantitative computed tomography (3D-pQCT) system with 165 × 165 × 165 μm3 voxel size. Simultaneously with the RND determination, the trabecular bone density (TBD) was also assessed in the same volume of interest. The examination site was the distal radius. The intersubject variability of the measured test group was 10.5% for RND and 26.3% for TBD. The root mean square error between first and second examinations (midterm reproducibility) was 1.6% and 1.1%, respectively. RND is determined independently from TBD and pertains to the structure of the cancellous bone. As such, it might add crucial information in cases where bone mass or bone density measurements alone give ambigous results.  相似文献   
25.
为探讨无名异接骨冲剂加速骨折愈合的作用机理,选用55只新西兰大白兔,随机选择5只作为正常组;另50只在无菌条件下造成双桡骨标准骨折模型。将50只骨折兔随机平均分为实验组和对照组,实验组用无名异接骨冲剂每天4g/kg溶于20ml蒸馏水中分早晚两次灌胃;对照组用20ml蒸馏水灌胃。于骨折后第1,2,3,4及5周用断颈法每次每组处死5只兔,取骨痂进行抗骨形态发生蛋白(BMP)单克隆抗体免疫组化染色,并用CMIAS型图像分析仪对BMP含量进行定量分析。结果发现:实验组骨折局部BMP含量明显高于正常组(P<0.01);第1,2周实验组明显高于对照组(P<0.01);实验组BMP高峰出现在第2周,而对照组出现在第3周。认为,无名异接骨冲剂能促进成骨细胞合成BMP,使BMP峰值提前,从而加速骨折愈合。  相似文献   
26.
Percentages of extremely concordant and extremely discordant sib pairs are calculated that maximize the power to detect a quantitative trait locus (QTL) under a variety of circumstances using the EDAC test. We assume a large fixed number of randomly sampled sib pairs, such as one would hope to find in the large twin registries, and limited resources to genotype a certain number of selected sib pairs. Our aim is to investigate whether optimal selection can be achieved when prior knowledge concerning the QTL gene action, QTL allele frequency, QTL effect size, and background (residual) sib correlation is limited or absent. To this end we calculate the best selection percentages for a large number of models, which differ in QTL gene action allele frequency, background correlation, and QTL effect size. By averaging these percentages over gene action, over allele frequency, over gene action, and over allele frequencies, we arrive at general recommendations concerning selection percentages. The soundness of these recommendations is subsequently in a number of test cases.  相似文献   
27.
医院综合效益评价案例分析   总被引:2,自引:0,他引:2  
运用层次分析法建立了医院综合效益评价指标体系,开发了医院综合效益九型评价图,用于显著评价结果。在此基础上进行了3个案例的评价分析。论述了通过对西南地区27所医院综合效益4年多的追踪分析所发现的共性问题,并提出了相应的管理对策。  相似文献   
28.
The morphological changes produced in the thyroid glands of albino rats following radiation with a 904 nm infrared laser were studied. Two different levels of radiation were applied: 46.8 J/cm2 and 140.4 J/cm2. Evaluation of the changes in the densities of the epithelial, colloidal and follicular volumes and of the activation index revealed that the laser beam produced changes in the thyroid parenchyma. It was observed that there was a direct relationship between the severity of the lesion and the radiation energy applied.  相似文献   
29.
目的探讨颈椎病的有效防治措施。方法对本院康复医学专科收治的420例颈椎病进行分析。结果本病多在40岁左右发病,起病缓慢,呈反复发作难以彻底治愈。结论颈椎病是中老年多发病.影响着健康和生活质量。发挥医疗卫牛保健网功能,积极采用适官技术,能有效控制病情。恢复生理功能和生活、工作能力。  相似文献   
30.
僵蚕抗凝活性及其成分的分析   总被引:7,自引:1,他引:6  
目的对僵蚕不同部位抗凝活性及其主要成分的含量进行测定 ,为僵蚕的质量控制和用药提供依据。方法用凝血酶时间 (TT)和经典化学方法为指标测定生、制僵蚕以及制僵蚕的不同部位的抗凝血活性大小以及总氮、铵态氮、蛋白质和草酸铵的含量。结果制僵蚕的抗凝活性、蛋白质和草酸铵含量均大于生僵蚕。制僵蚕不同部位凝血酶时间和蛋白质含量比较 ,其顺序是 :透明胶状物 >全药 >僵蚕皮 >绿褐色物。结论生、制僵蚕以及僵蚕不同部位抗凝活性和蛋白质等成分含量不一致 ,建议根据用药目的选择生、制僵蚕 ,作为抗凝药物应用时 ,可选择制僵蚕或其某一个或几个部位  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