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   29064篇
  免费   2290篇
  国内免费   86篇
耳鼻咽喉   386篇
儿科学   840篇
妇产科学   561篇
基础医学   3767篇
口腔科学   379篇
临床医学   2898篇
内科学   6340篇
皮肤病学   424篇
神经病学   2749篇
特种医学   1197篇
外科学   4980篇
综合类   306篇
现状与发展   1篇
一般理论   51篇
预防医学   2258篇
眼科学   433篇
药学   1477篇
中国医学   45篇
肿瘤学   2348篇
  2023年   289篇
  2022年   468篇
  2021年   1292篇
  2020年   707篇
  2019年   1020篇
  2018年   1231篇
  2017年   857篇
  2016年   831篇
  2015年   1005篇
  2014年   1361篇
  2013年   1654篇
  2012年   2425篇
  2011年   2381篇
  2010年   1291篇
  2009年   1024篇
  2008年   1579篇
  2007年   1654篇
  2006年   1464篇
  2005年   1331篇
  2004年   1147篇
  2003年   975篇
  2002年   835篇
  2001年   239篇
  2000年   228篇
  1999年   228篇
  1998年   171篇
  1997年   153篇
  1996年   157篇
  1995年   134篇
  1994年   119篇
  1993年   108篇
  1992年   157篇
  1991年   177篇
  1990年   155篇
  1989年   177篇
  1988年   142篇
  1987年   148篇
  1986年   127篇
  1985年   123篇
  1984年   133篇
  1983年   117篇
  1982年   105篇
  1981年   99篇
  1980年   77篇
  1979年   117篇
  1978年   119篇
  1977年   72篇
  1976年   67篇
  1973年   65篇
  1972年   58篇
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
121.
122.
Tissue microdissection is an important method for the study of disease states. However, it is difficult to perform high-throughput molecular analysis with current techniques. We describe here a prototype version of a novel technique (expression microdissection) that allows for the procurement of desired cells via molecular targeting. Expression microdissection (xMD) offers significant advantages over available methods, including an increase in dissection speed of several orders of magnitude. xMD may become a valuable tool for investigators studying cancer or other disease states in patient specimens and animal models.  相似文献   
123.
124.

Background  

International reports recommend the improvement in the amount and quality of training for mental health workers in low and middle income countries. The Scotland-Malawi Mental Health Education Project (SMMHEP) has been established to support the teaching of psychiatry to medical students in the University of Malawi. While anecdotally supportive medical educational initiatives appear of value, little quantitative evidence exists to demonstrate whether such initiatives can deliver comparable educational standards. This study aimed to assess the effectiveness of an undergraduate psychiatry course given by UK psychiatrists in Malawi by studying University of Malawi and Edinburgh University medical students' performance on an MCQ examination paper.  相似文献   
125.
126.
ABSTRACT

A study was conducted to evaluate mucoadhesive property and immunomodulatory effect of phytogenic gums from Boswellia frereana, Boswellia carteri andCommiphora myrrha on intranasal Peste des petits ruminants (PPR) vaccination in goats and sheep in an ex-vivo and in-vivo situations. Plant gums were purified, dried and compressed into 500gm tablets. Modified shear stress measurement technique was used on freshly excised trachea and intestine tissues of goat to measure peak adhesion time. Forty eight animals (24 goats and 24 sheep) were divided into eight groups (of 3 goats and 3 sheep) and immunized intranasally with gum-vaccine combinations in two ratios (1:1, 1:2). Antibody against PPR virus was measured on day 14, 28, 42 and 56 post vaccination using H-based PPR bELISA. The peak adhesion time of the different gums was transient. PPR virus antibodies were detected in all immunized goats and sheep but not in unvaccinated control. The best percentage inhibition was recorded for Boswellia carteri-vaccine combination group at a ratio of 1:1. Administration of Boswellia carteri-PPR vaccine combination through intranasal or subcutaneous route, elicited similar antibody titre, implying that the intranasal route may be used as a non-invasive alternative delivery in PPR vaccination of small ruminants.  相似文献   
127.
The Texas Department of Criminal Justice (TDCJ) houses many subjects with acquired immunodeficiency syndrome (AIDS) who receive medical care in a comprehensive AIDS treatment center. In this case-control autopsy survey, we compared pathological outcomes of TDCJ inmates treated at the center (n = 155) with nonincarcerated patients who died during the same period (n = 155). Using multiple regression analysis and a proportional hazards model, survival time in the prisoners was equivalent to that in the controls. With few exceptions, the prevalences of opportunistic viral, fungal, protozoal, and bacterial infections contributing to mortality were equivalent between groups. Mycobacterium tuberculosis was isolated more frequently in the inmates, and M avium intracellulare was isolated less frequently (P < .0001). The inmates had a higher prevalence of bacterial infection of the central nervous system (CNS) (9.1% v 1.4%; P < .006); half of all CNS bacterial infections were caused by M tuberculosis. Inmates had significantly lower prevalences of vacuolar myelopathy (P < .006) and severe wasting disease (P < .0009). We conclude that survival of prison inmates with AIDS treated in a comprehensive AIDS treatment center was equivalent to that of nonincarcerated subjects with AIDS. Prevalences of certain complications of AIDS differed in the inmates, showing that the prison environment influenced some of the underlying causes of AIDS morbidity and mortality.  相似文献   
128.
In light of evidence of linkage of obesity to chromosome 2q31-q37, we hypothesized that the calpain-10 gene 'high-risk' haplotype combination for non-insulin-dependent diabetes mellitus (NIDDM) is involved in early onset obesity. We screened the NIDDM 'high-risk'-haplotype combination formed by the alleles 112 and 121 of the polymorphisms UCSNP-43, -19, and -63 in 166 families consisting of an extremely obese child or adolescent (mean BMI percentile: 99.3+/-1.38), one or more obese sibs (mean BMI percentile: 97.42+/-2.88), and both of their parents. Genotyping for three calpain-10 gene polymorphisms was performed by polymerase chain reaction (PCR) with (a) length polymorphism detection (UCSNP-19) or (b) allele-specific PCR (UCSNP-43 and -63). To allow for correct haplotype assignment all individuals were additionally genotyped for two microsatellite markers (D2S125 and D2S2338). We followed a hierarchical test procedure. As the first step, model-free linkage analysis was performed using maximum likelihood binomial statistics. The second stage consisted of a one-sided asymptotic pedigree disequilibrium test for the UCSNP-43 and on an exploratory level for the other SNP-markers and all haplotypes formed by the three SNPs. The final stage investigated the reported haplotype combination. We failed to detect an initial linkage of obesity to this region (LOD score <0.4). All subsequent exploratory analyses were negative. Our analysis of the relationship between the NIDDM 'high-risk' haplotype combination and extreme early onset obesity revealed no evidence for linkage and association.  相似文献   
129.
African Americans appear less likely than caucasians to undergo surgery for gastroesophageal reflux disease (GERD). When they do, they appear to have higher conversion and complication rates. Nevertheless, satisfaction with surgery is similar to caucasians. BACKGROUND: There is little information comparing the prevalence and treatment of GERD in various ethnic populations. The purpose of this study was to examine the variations in outcomes between caucasians and African Americans undergoing antireflux surgery. METHODS: The records of all patients who underwent antireflux surgery for GERD or paraesophageal hernia by a single surgeon from January 1997 through December 2001 were reviewed for preoperative and postoperative symptoms, complications, and postoperative satisfaction with surgery. RESULTS: Of the 204 procedures performed, 198 patients were either African American (24) or caucasian (174). Of the 18 African Americans undergoing laparoscopic antireflux surgery (LARS), five were converted to open and four had grade-1 or -2 complications. Of the 160 caucasians undergoing LARS, 27 were converted, and 17 had grade-1, -2, or -3 complications. African-American females had a heavier weight (222 lbs. versus 175 lbs., p<0.05) and conversion rate (55% versus 18%, p<0.05), compared to caucasian females. Satisfaction rates for African Americans were 88%, compared to 82% for caucasians. CONCLUSION: This study demonstrated significant differences between conversion rates in African Americans and caucasians with respects to frequency of surgery for GERD and conversion rates for LARS. Nevertheless, African Americans appear more satisfied with their surgical outcome. Further research is needed to determine whether African Americans truly have a lower incidence of GERD or if bias exists in referral patterns or cultural attitudes.  相似文献   
130.
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