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   398篇
  免费   36篇
耳鼻咽喉   1篇
儿科学   47篇
妇产科学   4篇
基础医学   58篇
口腔科学   4篇
临床医学   27篇
内科学   91篇
皮肤病学   8篇
神经病学   8篇
特种医学   22篇
外科学   60篇
综合类   7篇
预防医学   29篇
眼科学   12篇
药学   33篇
中国医学   3篇
肿瘤学   20篇
  2022年   2篇
  2021年   8篇
  2017年   6篇
  2016年   6篇
  2015年   4篇
  2014年   11篇
  2013年   12篇
  2012年   19篇
  2011年   16篇
  2010年   13篇
  2009年   19篇
  2008年   14篇
  2007年   15篇
  2006年   9篇
  2005年   10篇
  2004年   18篇
  2003年   11篇
  2002年   11篇
  2001年   13篇
  2000年   9篇
  1999年   15篇
  1998年   12篇
  1997年   12篇
  1996年   15篇
  1995年   8篇
  1994年   13篇
  1993年   13篇
  1992年   5篇
  1991年   2篇
  1990年   10篇
  1989年   10篇
  1988年   11篇
  1987年   5篇
  1986年   8篇
  1985年   6篇
  1984年   5篇
  1983年   8篇
  1982年   3篇
  1981年   5篇
  1980年   3篇
  1979年   3篇
  1978年   3篇
  1977年   2篇
  1976年   5篇
  1975年   4篇
  1974年   4篇
  1955年   2篇
  1954年   1篇
  1949年   1篇
  1939年   2篇
排序方式: 共有434条查询结果,搜索用时 15 毫秒
81.
The BRCA1 and BRCA2 genes are involved in breast and ovarian cancer susceptibility. About 2 to 4% of breast cancer patients with positive family history, negative for point mutations, can be expected to carry large rearrangements in one of these two genes. We developed a novel diagnostic genetic test for the physical mapping of large rearrangements, based on molecular combing (MC), a FISH-based technique for direct visualization of single DNA molecules at high resolution. We designed specific Genomic Morse Codes (GMCs), covering the exons, the noncoding regions, and large genomic portions flanking both genes. We validated our approach by testing 10 index cases with positive family history of breast cancer and 50 negative controls. Large rearrangements, corresponding to deletions and duplications with sizes ranging from 3 to 40 kb, were detected and characterized on both genes, including four novel mutations. The nature of all the identified mutations was confirmed by high-resolution array comparative genomic hybridization (aCGH) and breakpoints characterized by sequencing. The developed GMCs allowed to localize several tandem repeat duplications on both genes. We propose the developed genetic test as a valuable tool to screen large rearrangements in BRCA1 and BRCA2 to be combined in clinical settings with an assay capable of detecting small mutations.  相似文献   
82.
Objectives To determine the feasibility of medical students being involved in sex education in secondary schools, as lesson leaders in peer group discussions.
Design 1. Questionnaires and interviews to determine pupil and professional opinions about the present sex education provision and the possible involvement of medical students. 2. A pilot scheme in one school involving medical students as peer educators.
Setting Six central Edinburgh secondary schools; local sex education services; Edinburgh University.
Sample 1. Thirty schoolteachers and 205 pupils returned questionnaires. From this, 18 teachers and 12 pupil groups (six to eight pupils each) were interviewed. 2. Pilot scheme involved three sessions with three groups of six to eight pupils per session. Twenty-nine returns for the evaluative (pupil) questionnaire were received.
Main outcome measures Questionnaire analysis; anecdotal evidence from interviews; evaluative questionnaire given to pupils participating in pilot study.
Results Ninety-four percent of teachers and 93% of pupils were in favour of medical student involvement in schools. Teachers identified large class size and lack of resources for small group work as factors limiting the effectiveness of present sex education. Pupils identified teacher embarrassment in certain issues as a barrier to communication, and 89% found communication to be easier with medical students.
Conclusions Response to the idea of medical student involvement was very favourable from all parties involved, and a continuation of the study has been integrated as an options course into the Edinburgh University undergraduate medical curriculum.  相似文献   
83.
Cancer incidence rates and patterns are reported for a rural population, living in the Eastern Cape Province of South Africa for the period 1998–2002. The population‐based cancer registry has operated for 20 years, using both active and passive methods for case finding, through collaborations with 19 health facilities: 11 district hospitals, 7 referral hospitals and 1 regional laboratory. The age standardized incidence rates for all cancers were 73.1 per 100,000 in males and 64.1 per 100,000 in females. The leading top 5 cancers for males were oesophagus (32.7 per 100,000), lung (5.8 per 100,000), prostate (4.4 per 100,000), liver (4.4 per 100,000) and larynx (2.5 per 100,000) whereas for females they were cervix (21.7 per 100,000), oesophagus (20.2 per 100,000), breast (7.5 per 100,000), ovary (0.9 per 100,000) and liver (0.9 per 100,000). The incidence of Kaposi sarcoma was low, and higher for males (1.6 per 100,000) than females (0.3 per 100,000). Lung cancer in both males and females was relatively low compared to the high incidence of oesophagus cancer.  相似文献   
84.
Ariel is a mouse mutant that suffers from skeletal muscle myofibrillar degeneration due to the rapid accumulation of large intracellular protein aggregates. This fulminant disease is caused by an ENU-induced recessive mutation resulting in an L342Q change within the motor domain of the skeletal muscle myosin protein MYH4 (MyHC IIb). Although normal at birth, homozygous mice develop hindlimb paralysis from Day 13, consistent with the timing of the switch from developmental to adult myosin isoforms in mice. The mutated myosin (MYH4(L342Q)) is an aggregate-prone protein. Notwithstanding the speed of the process, biochemical analysis of purified aggregates showed the presence of proteins typically found in human myofibrillar myopathies, suggesting that the genesis of ariel aggregates follows a pathogenic pathway shared with other conformational protein diseases of skeletal muscle. In contrast, heterozygous mice are overtly and histologically indistinguishable from control mice. MYH4(L342Q) is present in muscles from heterozygous mice at only 7% of the levels of the wild-type protein, resulting in a small but significant increase in force production in isolated single fibres and indicating that elimination of the mutant protein in heterozygotes prevents the pathological changes observed in homozygotes. Recapitulation of the L342Q change in the functional equivalent of mouse MYH4 in human muscles, MYH1, results in a more aggregate-prone protein.  相似文献   
85.
86.
ObjectiveTo present results of virological study of wild birds inhabiting Western Mongolia.MethodsOver a period of 2003–2008, we isolated 13 influenza A viruses: H1N1, H3N6, H13N8 and H4N6 subtypes. We did not isolate any H5N1 subtype, that still cause epizooty in wild birds and poultry.ResultsWe revealed taxonomic and ecological heterogeneity of the birds involved in maintenance of circulation of influenza viruses in the given territory. Influenza viruses were isolated from birds of 6 orders; among them there are species preferring water and semi-aquatic biotopes, one species preferring dry plain region, and also one species which can inhabit both dry and water biotopes.ConclusionsRepresentatives of all main orders of Western Mongolia avifauna are involved in support of influenza A virus circulation, highly pathogenic H5N1 influenza viruses were registered in Mongolia thus it's necessary to continue permanent influenza virus surveillance in wild birds' populations.  相似文献   
87.
ObjectiveTo explore the prevalence, pathogenicity, and antibiotic susceptibility patterns of urinary tract infections at the University of Port Harcourt Teaching Hospital.MethodsSamples from 400 patients with a presumptive diagnosis of urinary tract infection including 250 non pregnant females and 150 males were used for this study. They were distributed into two groups: children aged 2 to 17 (Group A) and adults aged 18 to 75 (Group B). The standard wire loop and agar diffusion technique were employed for culture and susceptibility testing, respectively. Data obtained were analysed using SPSS, version 14.Results30.0% of Group A and 41.0% of Group B had significant bacteriuria with 66.7% and 79.3% as females, respectively. The commonest isolates cultured were Escherichia coli (32.8%), Staphylococcus aureus (17.2%), and Klebsiella spp. (16.4%). About 76.6% of isolates were sensitive to the fluorinated quinolones, 31.2% to the aminoglycosides, and 22.7% to the urinary antiseptic, nitrofurantoin. The isolates were non-sensitive to tetracycline (93.8%), cotrimoxazole (92.2%), and nalidixic acid (86.7%). Most isolates showed non-uniform sensitivity patterns to the cephaloporins (cefuroxime and ceftazidime). Pseudomonas spp. isolates were generally resistant to the fluorinated quinolones.ConclusionThough the fluorinated quinolones are still largely effective for empirical therapy in urinary tract infections, the importance of prior sensitivity testing in checking the emergence of bacterial antibiotic resistance can not be overemphasized.  相似文献   
88.
89.
90.
林晓映  沈燕  王舒 《辽宁中医杂志》2013,(11):2231-2233
女性进入围绝经期后,随着雌激素分泌水平的下降,高血压病的患病率逐年升高。鉴于其不可治愈性,对"高血压前期"给予早期有效的干预,控制高血压病的发生发展,是当前预防围绝经期女性高血压病的有效措施。然而指南指出激素替代疗法和雌激素受体调节剂均不应用于围绝经期女性心血管疾病的预防,针灸作为一种既能同时调节血压和雌激素,又没有明显副作用的治疗方式,给围绝经期女性高血压病的预防带来了新的希望。文章通过探讨针灸、雌激素和高血压病三者的关系,阐释逆针灸预防围绝经期女性高血压病的可行性,为临床诊治提供参考。  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