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   353篇
  免费   8篇
  国内免费   1篇
耳鼻咽喉   2篇
儿科学   8篇
妇产科学   4篇
基础医学   77篇
临床医学   29篇
内科学   89篇
皮肤病学   5篇
神经病学   30篇
特种医学   9篇
外科学   42篇
综合类   9篇
预防医学   24篇
眼科学   9篇
药学   6篇
肿瘤学   19篇
  2023年   2篇
  2022年   4篇
  2021年   11篇
  2020年   2篇
  2019年   8篇
  2018年   5篇
  2017年   3篇
  2016年   4篇
  2014年   5篇
  2013年   9篇
  2012年   15篇
  2011年   23篇
  2010年   9篇
  2009年   12篇
  2008年   16篇
  2007年   18篇
  2006年   27篇
  2005年   10篇
  2004年   14篇
  2003年   15篇
  2002年   14篇
  2001年   9篇
  2000年   11篇
  1999年   8篇
  1998年   7篇
  1997年   5篇
  1996年   5篇
  1995年   3篇
  1992年   2篇
  1991年   6篇
  1990年   8篇
  1989年   6篇
  1988年   5篇
  1987年   1篇
  1986年   1篇
  1985年   4篇
  1982年   2篇
  1981年   1篇
  1979年   4篇
  1977年   4篇
  1976年   3篇
  1974年   8篇
  1973年   6篇
  1972年   2篇
  1971年   7篇
  1970年   3篇
  1969年   6篇
  1968年   3篇
  1967年   1篇
  1966年   2篇
排序方式: 共有362条查询结果,搜索用时 10 毫秒
11.
We present here the characterization of the complete coding sequences, previously unavailable, of the human leukocyte antigen (HLA) alleles B*0707, B*1524, B*4405, B*4802, DRB1*0409, DRB1*0411, DRB1*1115, DRB1*1305, and that of a new allele, DRB1*0709. For the isolation of cDNA from the DRB1 gene, we designed a novel set of polymerase chain reaction (PCR) primers that makes it possible to amplify separately the groups of DRB1 alleles associated to each of the DRB3 and DRB4 loci. The primary structures, functional features, evolutionary relationships, haplotypic associations, and population distributions of each of the nine HLA-B and -DRB1 alleles reported here are reviewed.  相似文献   
12.
HLA-B44 is one of the most common HLA class I alleles in Caucasians. Exon 3 oligotyping and sequence analysis have define five B44 subtypes: B*4402, B*4403, B*4404, B*4405 and B*4406, with variations in exons 2 and 3. We have developed a conventional DNA typing system by using a single B12-group specific amplification including exon2-intron2-exon3 in combination with 6 oligoprobes to define all B44 subtypes. 140 HLA-B44 positive unrelated Spanish Caucasians were typed. Family studies established 30 B44-bearing haplotypes. The distribution of B44 subtypes in our population was: B*4402 32.5%, B*4403 66.5%, B*4404 0.5%, B*4405 0.5%, B*4406 not found. B*4402 and B*4403 represented the 99% of the B44 alleles, as described in Caucasians. However, these two major subtypes showed an inverted frequency when compared with other Caucasian populations, B*4403 twice as frequently as B*4402 in Spaniards. HLA-B44-associated chromosomes showed 20 different haplotypes (including HLA-A,-C,-DR,-DQ), although demonstrating clear separated haplotype composition between B*4402 and B*4403: B*4402 associated to class I alleles A2 ( ) and Cw5 ( ), and B*4403 associated to the class II allele DRB1*0701 ( ). These findings, in addition to the validation of a complete B44 oligotyping system, revealed further evidence of antigen frequency differences among populations of the same ethnic origin.  相似文献   
13.
Three new HLA class I alleles, HLA‐A*02:620, HLA‐B*27:150 and HLA‐B*07:05:01:02, were described in the Spanish Caucasoid population.  相似文献   
14.
Here we describe a new HLA class II null allele at the DRB5 gene. Serologic HLA typing of a Spanish gypsy family rendered the following paternal haplotype: A2-Cblk-B52-Bw4-DR15-DQ5. However, DNA typing demonstrated the presence of a DRB5 gene in the haplotype DRB1*1502-DRB5*0102-DQB1*05031. Complete DRB5 cDNA sequencing revealed a DRB5*0102 allele with a deletion of two nucleotides at exon 2 (239-240) in codon 80. This change generates a frame shift leading to a stop codon at position 86, and could explain the lack of DR51 protein at the cell surface. This is the second DRB5 null allele described together with DRB5*0108N, raising the number of HLA alleles with an expression disorder.  相似文献   
15.
Improving preventive care by prompting physicians   总被引:9,自引:0,他引:9  
OBJECTIVES: To assess the impact of prompting physicians on health maintenance, answer questions regarding the mode of delivery, and identify opportunities and limitations of this information intervention. METHODS: Systematic electronic and manual searches (January 1, 1966, to December 31, 1996) were conducted to identify clinical trial reports on prompting clinicians. Three eligibility criteria were applied: (1) randomized controlled clinical trial, (2) clinician prompt, alert, or reminder in the study group and no similar intervention in the control group, and (3) measurement of the intervention effect on the frequency of preventive care procedures. Data were abstracted by independent reviewers using a standardized abstraction form, and quality of methodology was scored. A series of meta-analyses on triggering clinical actions was performed using the random-effects method. The statistical analyses included 33 eligible studies, which involved 1547 clinicians and 54 693 patients. RESULTS: Overall, prompting can significantly increase preventive care performance by 13.1% (95% confidence interval [CI], 10.5%-15.6%). However, the effect ranges from 5.8% (95% CI, 1.5%-10.1%) for Papanicolaou smear to 18.3% (95% CI, 11.6%-25.1%) for influenza vaccination. The effect is not cumulative, and the length of intervention period did not show correlation with effect size (R = -0.015, P = .47). Academic affiliation, ratio of residents, and technique of delivery did not have a significant impact on the clinical effect of prompting. CONCLUSIONS: Dependable performance improvement in preventive care can be accomplished through prompting physicians. Vigorous application of this simple and effective information intervention could save thousands of lives annually. Health care organizations could effectively use prompts, alerts, or reminders to provide information to clinicians when patient care decisions are made.  相似文献   
16.
Traditional asthma education has been found to be time-consuming and limited in terms of availability. Our goal was to improve asthma care by meeting special needs of children with asthma and by building on their skills in using new technologies. Multimedia asthma education occurred through the viewing of short, animated vignettes on an exam room computer. Evaluation of 228 children showed significant improvement in days of asthma symptoms (p ??.01), in emergency room visits (p ??.05), in school days missed (p ??.05), and in days of activity limitation from baseline to the year-end follow-up (p ??.05). Effective multimedia education, if integrated into pediatric practice to supplement existing asthma care, can improve clinical outcomes.  相似文献   
17.
18.
Among the multifactorial causes of undernutrition in old age, gastrointestinal mucosa altered function and resulting specific malabsorption are the most relevant. Despite numerous studies that have dealt with the effects of aging on the digestive tract of mammals, results showed discrepancies in terms of proliferation and biochemical aging small intestine events. However, the slowing-down of the maturation process and the poor adaptation of metabolism and intestinal function are obvious and there is evidence that protective mechanisms are impaired with age and contribute to affecting the trophic activity and related systemic homeostasis. Good prospects to improve gastrointestinal function in the elderly are essential and research on nutritional intervention to limit and counteract age-related impairments must be extensive. Probiotics are good candidates and fermented milks might be of great interest. In the present study we first show the main structural and functional variations between 3- and 23-month-old rat small intestines. The trophic consequences of aging and nutritional adaptation under basal conditions are also analyzed and discussed after 20 days of a yogurt-supplemented specific diet in both young and aged rats. The main variations that occur with aging and yogurt diet are located in the proximal small intestine. The present findings indicate a slight improvement of morphological trophic parameters in both young and aged rats by yogurt, whereas enzymatic changes are more discrete. Despite the obvious age-related decrease in trophicity, we suggest that assessment of probiotic potentials on trophicity requires a more altered model than normal, healthy aging animals.  相似文献   
19.
Aspartate transcarbamylase initiates the de novo biosynthetic pathway for the production of the pyrimidine nucleotides, precursors of nucleic acids. This pathway is particularly active in rapidly growing cells and tissues. Thus, this enzyme has been tested as a potential target for antiproliferative drugs. In the present work, on the basis of its structural and mechanistic properties, a series of substrate analogues, including potential suicide-pseudosubstrates was synthesized and their putative inhibitory effects were tested using E. coli aspartate transcarbamylase as a model. Two of these compounds appear to be very efficient inhibitors of this enzyme.  相似文献   
20.
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