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   7068篇
  免费   402篇
  国内免费   12篇
耳鼻咽喉   88篇
儿科学   276篇
妇产科学   157篇
基础医学   895篇
口腔科学   61篇
临床医学   1226篇
内科学   1325篇
皮肤病学   70篇
神经病学   692篇
特种医学   92篇
外科学   575篇
综合类   88篇
一般理论   6篇
预防医学   916篇
眼科学   106篇
药学   380篇
中国医学   11篇
肿瘤学   518篇
  2023年   27篇
  2022年   46篇
  2021年   80篇
  2020年   77篇
  2019年   106篇
  2018年   126篇
  2017年   115篇
  2016年   107篇
  2015年   135篇
  2014年   199篇
  2013年   325篇
  2012年   456篇
  2011年   479篇
  2010年   293篇
  2009年   254篇
  2008年   467篇
  2007年   506篇
  2006年   517篇
  2005年   517篇
  2004年   464篇
  2003年   527篇
  2002年   496篇
  2001年   61篇
  2000年   63篇
  1999年   72篇
  1998年   104篇
  1997年   81篇
  1996年   70篇
  1995年   56篇
  1994年   55篇
  1993年   57篇
  1992年   34篇
  1991年   42篇
  1990年   29篇
  1989年   33篇
  1988年   35篇
  1987年   31篇
  1986年   20篇
  1985年   26篇
  1984年   33篇
  1983年   33篇
  1982年   26篇
  1981年   31篇
  1980年   26篇
  1979年   15篇
  1978年   18篇
  1977年   15篇
  1976年   21篇
  1974年   8篇
  1973年   12篇
排序方式: 共有7482条查询结果,搜索用时 15 毫秒
11.
The purpose of this study was to develop and evaluate a measure of perceived disruption during rebuilding following a disaster. Two eight-item scales, which measured intensity of disruption during the entire repair phase (Intensity-RP) and intensity of disruption during the past month (Intensity-PM) were developed and administered to 135 survivors of Hurricane Andrew. At 9 to 12 months postdisaster, Intensity-RP and Intensity-PM were both significantly associated with scores on the Global Severity Index of the SCL-90-R, and with scores on the Impact of Event-Intrusion Scale; Intensity-PM alone was significantly associated with PTSD scores. Regression analyses indicated that each scale contributed significant unique variance in predicting mental health symptoms, even after controlling for relevant demographic and initial disaster exposure variables.  相似文献   
12.
The purpose of this pilot study was to determine the effects of the addition of coping skills training for obese multiethnic parents whose overweight children were attending a weight management program. At 6 months, parents in the experimental group had significantly lower body mass index (BMI) and body fat percentage (BFP) and higher numbers of pedometer steps compared with those in the control group. Parents in the experimental group also demonstrated significant improvement in interpersonal relationships, behavior control, and stress management compared with those in the control group. Children in the experimental group demonstrated trends toward decreased BMI and BFP and increased pedometer steps.  相似文献   
13.
The aim of this study was to determine whether there are quantitative changes in the innervation of the anterior cruciate ligament in osteoarthritis. Eleven whole anterior cruciate ligaments were obtained at autopsy from cadavera of individuals with advanced osteoarthritis; five healthy ligaments were used as controls. The ligaments were transected and stained with hematoxylin and eosin, oil red O for fat, and a modification of Gairn's gold chloride method. The latter stain permits visualization of axons, mechanoreceptors, and free nerve endings that are not apparent on routine stains. The ratio of nerve tissue to periligamentous synovial tissue was determined histomorphometrically by the point-counting method. The nerve tissue was located almost exclusively in the periligamentous synovial tissue. There was a statistically significantly greater area of nerve tissue (as a percentage of the total area) around the anterior cruciate ligaments in the osteoarthritic group than around the ligaments in the control group (p < 0.02). The nerve tissue was distributed evenly throughout the periligamentous synovial tissue in the specimens in both groups. A neurological role has been proposed for the anterior cruciate ligament in osteoarthritis. This study provides morphological evidence for neural pathology of the anterior cruciate ligament in subjects with osteoarthritis.  相似文献   
14.
15.
This study examined comorbid psychiatric disorders in adolescents with bipolar disorder. Hospitalized bipolar adolescents (N=10) were compared to hospitalized adolescents with unipolar depression (N=33), and to adolescents with nonaffective psychiatric disorders (N=11). Results showed conduct disorder, attention-deficit hyperactivity disorder, psychosis, and having any DSM-III-R psychoactive substance use disorder were all significantly more common in the bipolar group than the unipolar depressed group. Comorbid anxiety disorder was present in 40–45% of the subjects in the unipolar and bipolar groups, but in none of the control group subjects. This study is supported in part by a grant to Dr. Borchardt from the University of Minnesota Graduate School.  相似文献   
16.
A genetically biotinylated single chain fragment variable antibody (scFv) against Venezuelan equine encephalitis virus (VEE) was applied in a system consisting of an immunofiltration enzyme assay (IFA) with a light addressable potentiometric sensor (LAPS) for the rapid identification of VEE. The IFA involved formation of an immunocomplex sandwich consisting of VEE, biotinylated antibody, fluoresceinated antibody and streptavidin, capture of the sandwich by filtration on biotinylated membrane, and labeling of the sandwich by anti-fluorescein urease conjugate. The concentration ratio of biotinylated to fluoresceinated antibodies was investigated and optimized. By the IFA/LAPS assay, the limit of detection (LOD) of VEE was approximately 30 ng/ml, similar to that achieved when chemically biotinylated monoclonal antibody (mAb) was applied. Total assay variance of the IFA/LAPS assay for both intra- and inter-assay precision was less than 20%. Assay accuracy was measured by comparing VEE concentrations estimated by IFA/LAPS standard curve to those obtained by conventional protein assay. VEE concentrations were found to differ by no more than 10%. The IFA/LAPS assay sensitivity was approximately equal to that of a conventional enzyme-linked immunosorbent assay (ELISA) utilizing polystyrene plates and a chromogenic substrate; however, less time and effort were required for performance of the IFA/LAPS assay. More importantly, use of genetically biotinylated scFv in the IFA/LAPS assay obviates the need for chemical biotinylation of antibody with resultant possible impairment of the antigen-binding site. Furthermore, the potential for batch-to-batch variability resulting from inequality in the number of biotin molecules labeled per antibody molecule is eliminated.  相似文献   
17.
18.
19.
In this study, we investigate the polymorphic microsatellite repeat (TCAT)n, in the insulin gene region that has been associated with susceptibility to type-1 diabetes in some Caucasian populations. The microsatellite repeat polymorphism begins at base pair 1,170 in intron 1 of the hTH gene, which is located on the short arm of chromosome 11. This study is the first to investigate the association of this microsatellite repeat polymorphism in African-American type-1 diabetes patients and controls. The predicted amplified sequence was 254 bp. We found five alleles among African Americans in the Washington, DC area. The alleles were labeled K5 (244 bp), K4 (248 bp), K3 (252 bp), K2 (256 bp), and K1 (260 bp), and heterozygosity was greater than 0.75. The most frequent allele of the hTH microsatellite repeats was K5 (248 bp) with a frequency 0.62 in controls and 0.66 in type-1 diabetes patients, which did not differ significantly. Although the largest allele was more frequent in controls, the difference was not statistically significant. The five alleles of the hTH microsatellite generated 15 different genotypes. The most frequent genotype in controls and patients was K5/K4, whose frequencies were 0.19 and 0.17, respectively. No significant differences in genotype frequencies were found between type-1 diabetes patients and controls. This data shifts the focus from hTH to the VNTR at the insulin gene for IDDM2, the second major candidate gene for type-1 diabetes.  相似文献   
20.
The oncogenic EBV protein LMP1 mimics a dysregulated CD40 receptor in vitro. To compare CD40 and LMP1-mediated events in vivo, transgenic mice were engineered to express mouse CD40 (mCD40tg) or a protein with extracellular mCD40 and cytoplasmic LMP1 (mCD40-LMP1tg). Transgenic and CD40(-/-) mice were bred so that only the transgenic CD40 molecule is expressed in B cells, macrophages, and dendritic cells. mCD40-LMP1tg mice had normal lymphocyte subsets, and immunization elicited an antibody response featuring normal isotype switching, affinity maturation, and germinal center (GC) formation. However, unimmunized mCD40-LMP1tg mice had expanded immature and germinal center B cells, produced autoantibodies, exhibited marked splenomegaly and lymphadenopathy, and elevated serum IL-6. Thus, signaling through the LMP1 cytoplasmic tail results in amplified and abnormal mimicry of CD40 functions in vivo, indicating possible ways in which LMP1 contributes to the pathogenesis of EBV-associated human disease.  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