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   58599篇
  免费   5086篇
  国内免费   1420篇
耳鼻咽喉   187篇
儿科学   809篇
妇产科学   478篇
基础医学   5800篇
口腔科学   572篇
临床医学   6246篇
内科学   5609篇
皮肤病学   650篇
神经病学   1143篇
特种医学   1049篇
外国民族医学   3篇
外科学   2991篇
综合类   13788篇
现状与发展   12篇
一般理论   38篇
预防医学   16488篇
眼科学   480篇
药学   3343篇
  301篇
中国医学   2998篇
肿瘤学   2120篇
  2024年   235篇
  2023年   1218篇
  2022年   2193篇
  2021年   2950篇
  2020年   2925篇
  2019年   2056篇
  2018年   1841篇
  2017年   1952篇
  2016年   1980篇
  2015年   1844篇
  2014年   3932篇
  2013年   4465篇
  2012年   3758篇
  2011年   4068篇
  2010年   3404篇
  2009年   2893篇
  2008年   3159篇
  2007年   2990篇
  2006年   2656篇
  2005年   2177篇
  2004年   1776篇
  2003年   1440篇
  2002年   1190篇
  2001年   1048篇
  2000年   853篇
  1999年   669篇
  1998年   601篇
  1997年   539篇
  1996年   475篇
  1995年   443篇
  1994年   351篇
  1993年   233篇
  1992年   224篇
  1991年   292篇
  1990年   219篇
  1989年   186篇
  1988年   198篇
  1987年   195篇
  1986年   195篇
  1985年   194篇
  1984年   200篇
  1983年   141篇
  1982年   177篇
  1981年   105篇
  1980年   103篇
  1979年   66篇
  1978年   70篇
  1977年   74篇
  1976年   73篇
  1975年   42篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
目的探讨三种不同方法治疗自身免疫型习惯性流产的临床效果。方法选取78例确诊为自身免疫异常引起的习惯性流产患者,分为4组,1为阿司匹林+泼尼松组(22例),2为阿司匹林+肝素组(18例),3为静丙组(20例),4为对照组(18例),不接受任何治疗,用卡方检验比较各组妊娠成功率。结果1、2、3组与对照组分别比较,差异均有统计学意义(P〈0.05),但3种治疗方法之间无显著差异(P〉0.05);1组出现了胎膜早破、妊娠期高血压疾病等妊娠合并症,2组出现了早产和消化道出血,但各组发生率无统计学差异(P〉0.05)。结论传统的激素、抗凝剂和被动免疫疗法均有一定疗效,但三者之间疗效无差异。  相似文献   
83.
Out-of-hours organisations are responsible for the care of patients 70% of the time, and their GPs act as gatekeepers to secondary care services. This observational study identifies the variations in GPs' out-of-hours referral rates to secondary care and factors that could explain these variations. One hundred and forty-nine GPs who worked in one UK general practice out-of-hours cooperative which served 19 practices with 167 000 registered patients. Data on patients who accessed the out-of-hours service over 3 years (2001-2004) were examined. Factors thought to be predictors of variation in referral rates were investigated using logistic regression analysis. There was a fivefold difference in referral rates between the lowest and highest referring quartiles of GPs (OR [odds ratio] = 4.56, CI [confidence interval] = 3.86 to 5.38). The sex (female) of the clinician, the time of the consultation (11 pm to 7 am), and the place of the consultation (home visit) accounted for some, but not all, of the increased referral rates. A doctor working out-of-hours disproportionately influences the fate of the patient, the number of hospital admissions, and extra costs to the health service. There is a need for follow-up studies to investigate the factors associated with referral behaviour, and how the variation relates to patient factors and the resources available. These findings could be used when planning the staffing of out-of-hours services to optimise appropriate care and minimise patients' exposure to unnecessary intrusive and expensive hospital care.  相似文献   
84.
Summary:  Cell–cell and cell–matrix interactions are of critical importance in immunobiology. Leukocytes make extensive use of a specialized repertoire of receptors to mediate such processes. Among these receptors, integrins are known to be of crucial importance. This review deals with the central role of integrins and their counterreceptors during the establishment of leukocyte–endothelium contacts, interstitial migration, and final encounter with antigen-presenting cells to develop an appropriate immune response. Particularly, we have addressed the molecular events occurring during these sequential processes, leading to the dynamic subcellular redistribution of adhesion receptors and the reorganization of the actin cytoskeleton, which is reflected in changes in cytoarchitecture, including leukocyte polarization, endothelial docking structure formation, or immune synapse organization. The roles of signaling and structural actin cytoskeleton-associated proteins and organized membrane microdomains in the regulation of receptor adhesiveness are also discussed.  相似文献   
85.
Varicella zoster virus (VZV) causes varicella (chickenpox) as the primary infection and zoster (shingles) on reactivation from latency, often many years later. One of the most common and most severe sequela of zoster is postherpetic neuralgia (PHN). Apart from age, factors which predispose towards PHN are unknown. In the present study, the concentration of a variety of Th1 and Th2 cytokines in the serum of 30 zoster patients at the time of the acute disease were correlated with the subsequent development of PHN in nine of these patients, but no association was found. In addition, although some cytokines such as IFN-gamma, IL-6 and IL-8 were slightly raised in the zoster group compared with a group of normal healthy subjects of a similar age distribution, these differences only verged on significance. Antibody titres to VZV were raised in the zoster group compared with the controls but these did not differ between the patients who developed PHN and those who did not. Biopsies of zoster lesions were collected from nine patients. There were significantly fewer infiltrating lymphocytes in the lesions of the three patients who subsequently developed PHN compared with the six who did not, although the expression of the neuropeptide, substance P, did not differ between the two groups. It is possible that the poor inflammatory response at the time of the acute zoster may result in less effective containment of the VZV and more damage in the dermatome, thus contributing to the persistence of the neuralgia.  相似文献   
86.
A rapid passive hemagglutination assay (Rubaquick) was developed that detects antibody to rubella virus in serum specimens. The test result is read visually after an incubation period of 15-30 minutes. When compared with a hemagglutination inhibition assay, the Rubaquick assay results obtained from 1,470 sera were greater than 99% specific, sensitive, and accurate. Studies of 179 paired serum specimens obtained before and 27 days after rubella vaccination showed that if antibody was detectable by the Rubaquick assay in the prevaccination specimens, the vaccine induced a secondary response consisting of increasing IgG antibody reactivity in the absence of a positive IgM response. In contrast to the positive prevaccination specimens, a negative prevaccination result was associated with IgM antibody in 98 of the 133 postvaccination specimens. Seroconversion was noted in all cases in which the prevaccination specimen was negative by the Rubaquick assay.  相似文献   
87.
An effective immune response to an antigen requires two sets of decisions: Decision 1, the sorting of the repertoire, and Decision 2, the regulation of effector class. The repertoire, because it is somatically generated, large, and random, must be sorted by a somatic mechanism that subtracts those specificities (anti-self) that, if expressed, would debilitate the host, leaving a residue (anti-nonself) that, if not expressed, would result in the death of the host by infection. The self-nonself discrimination is the metaphor used to describe Decision 1, the sorting of the repertoire. In order to be functional, the sorted repertoire must be coupled to a set of biodestructive and ridding effector functions, such that the response to each antigen is treated in a coherent and independent manner. Although a reasonably complete framework for Decision 1 exists, Decision 2 lacks conceptualization. The questions that must be considered to arrive at a proper framework are posed. It should be emphasized that manipulation at the level of Decision 2 is where clinical applications are likely to be found.  相似文献   
88.
National Taiwan University College of Medicine (NTUCM) introduced small groups of teaching and basic-clinical integrated courses for medical students in 1992. By using computer network and multimedia techniques, this study tried to overcome barriers to learning in small group teaching. The Department of Medical Informatics of NTUCM established campus networking and computer classrooms and provided Internet and intranet network services including mail, netnews, bulletin board systems (BBS), world wide web (WWW), gopher, ftp and local file servers. To implement an interactive learning environment, the authors first tried mail lists, newsgroups and BBS. Next an integrated learning system prototype on the WWW was developed to provide functions including online syllabus, discussion boards simulated to BBS, online talk, interactive case studies, virtual classroom with video on demand (VOD) and Internet medical resources. The results showed that after the medical students completed the required course of medical informatics and had good network access using a network to communicate with each other became a daily practice. In the future, the system will extend to the tutoring of clinical practice and continuing medical education. The authors expect a national medical education network and more international cooperation and exchange.  相似文献   
89.
In the event of smallpox bioterrorism, widespread vaccination may be required. Vaccinia immune globulin (VIG) has been used to treat complications from the smallpox vaccine. While the potency of VIG was defined by its ability to neutralize intracellular mature virus, a second form of vaccinia called the extracellular enveloped virus (EEV) is critical for virus spread in the host. The B5R-protein is one of many EEV-specific proteins. Immunoprecipitation and ELISA revealed that VIG recognizes the B5R-protein. An EEV plaque-reduction assay using a recombinant vaccinia that lacks the majority of the extracellular domain of B5R showed that the ability of VIG to neutralize EEV is principally directed at B5R. In addition, absorbing out the anti-B5R antibody present in VIG through the addition of recombinant B5R protein abrogated VIG's ability to significantly neutralize wild-type EEV. This work demonstrates the prominent role of B5R as a target of EEV-neutralizing activity of human antibodies.  相似文献   
90.
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