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   652篇
  免费   42篇
  国内免费   2篇
耳鼻咽喉   1篇
儿科学   15篇
妇产科学   10篇
基础医学   76篇
口腔科学   84篇
临床医学   50篇
内科学   165篇
皮肤病学   5篇
神经病学   25篇
特种医学   2篇
外科学   59篇
综合类   2篇
预防医学   98篇
眼科学   3篇
药学   36篇
肿瘤学   65篇
  2023年   1篇
  2022年   3篇
  2021年   14篇
  2020年   8篇
  2019年   8篇
  2018年   13篇
  2017年   11篇
  2016年   10篇
  2015年   9篇
  2014年   17篇
  2013年   13篇
  2012年   34篇
  2011年   41篇
  2010年   23篇
  2009年   25篇
  2008年   42篇
  2007年   29篇
  2006年   38篇
  2005年   31篇
  2004年   33篇
  2003年   28篇
  2002年   32篇
  2001年   26篇
  2000年   28篇
  1999年   19篇
  1998年   11篇
  1997年   6篇
  1996年   5篇
  1995年   4篇
  1994年   6篇
  1993年   4篇
  1992年   14篇
  1991年   6篇
  1990年   13篇
  1989年   12篇
  1988年   13篇
  1987年   13篇
  1986年   9篇
  1985年   11篇
  1984年   5篇
  1983年   8篇
  1982年   4篇
  1981年   3篇
  1980年   1篇
  1979年   4篇
  1977年   3篇
  1976年   2篇
  1974年   1篇
  1966年   1篇
  1871年   1篇
排序方式: 共有696条查询结果,搜索用时 343 毫秒
1.
2.
OBJECTIVE: To investigate the association between the use of fluoroquinolone agents and the risk of tendinitis in a large population-based case-control study. METHODS: The study was performed by linking automated health databases from the Region of Lombardia, Italy. Cases were patients aged > or =18 years who had a hospital discharge diagnosis of non-traumatic tendinitis in 2002-3. For each case, up to five controls were randomly selected among those eligible for inclusion in the study. A conditional logistic regression model was used to estimate the odds ratio of tendinitis associated with the current, recent and past use of fluoroquinolones. Odds ratios were adjusted for exposure to other antibacterials and other drugs. RESULTS: 22,194 cases and 104,906 controls met the inclusion criteria. Current use of fluoroquinolones significantly increased the risk of tendon disorders as a whole (odds ratio [OR] = 1.7; 95% CI 1.4, 2.0), tendon rupture (OR = 1.3; 95% CI 1.0, 1.8) and rupture of the Achilles' tendon (OR = 4.1; 95% CI 1.8, 9.6). Concomitant use of corticosteroids and fluoroquinolones increased the risk of both tendon rupture (OR = 3.1; 95% CI 1.5, 6.3) and rupture of the Achilles' tendon (OR = 43.2; 95% CI 5.5, 341.1). DISCUSSION: Evidence that exposure to fluoroquinolones is associated with the sudden occurrence of tendinitis is supported by this large population-based study. We can estimate that a single case of rupture of the Achilles' tendon would occur for every 5958 persons treated with fluoroquinolones (95% CI 2148, 23,085). The corresponding number needed to harm is 979 (95% CI 122, 9172) for patients who concomitantly use corticosteroids and 1638 (95% CI 351, 8843) for those aged >60 years. CONCLUSION: Clinicians should be aware of this adverse effect, and the increased risk for fluoroquinolone-associated tendinitis in elderly patients with corticosteroid use must be considered when these agents are prescribed.  相似文献   
3.
The influence of several clinical and microbiological variables on the site-specific risk of attachment loss was studied in Navajo Indian adolescents aged 14-19. Diagnoses were made at mesio-buccal sites of the four first permanent molars. Case-control analytical methods were used, with A. actinomycetemcomitans, B. gingivalis, and B. intermedius considered the "risk" variables, and with calculus, gingival bleeding, age, and gender treated as possible confounders. The presence of B. intermedius significantly increased the likelihood that attachment loss would be diagnosed at a site (odds ratio = 2.86). However, this association was confounded by calculus and gingival bleeding; when either or both were present, the effect of B. intermedius was markedly weaker. Step-wise multiple logistic regression analyses showed that, of the variables considered, the combination of calculus, gingival bleeding, and B. intermedius gave the most parsimonious explanation of the presence of attachment loss. The chance that attachment loss would be diagnosed was increased five times when calculus was present, 16.5 times in the presence of both calculus and gingival bleeding, and 37 times when these variables plus B. intermedius were observed at a particular site.  相似文献   
4.
The serotype c antigen from Actinobacillus actinomycetemcomitans was purified with fractional ethanol precipitation of cell-free culture supernatant, sequential ion-exchange chromatography, and gel filtration chromatography. The preparation obtained demonstrated a single precipitin line in immunodiffusion, immunoelectrophoresis, and crossed immunoelectrophoresis when rabbit antisera to serotype c whole bacterial cells were used. No immunological reaction was detected with antisera to serotype c lipopolysaccharide, indicating that lipopolysaccharide was not present in the preparation. The serotype c antigen was composed of 95% carbohydrate, 2% protein, and 3.1% phosphate. Gas chromatographic analysis of the antigen obtained from growth in either complex or chemically defined media revealed that the carbohydrate constituent was composed of 84 to 90.1% mannose, 4.8 to 16% glucose, 1.9% N-acetylglucosamine, 1.4% fucose, and 0.2% galactose. The present data suggest that A. actinomycetemcomitans serotype c antigen is predominantly a mannose-containing carbohydrate suggestive of a mannan.  相似文献   
5.
To confirm an infection with the new coronavirus (SARS-CoV) causing the severe acute respiratory syndrome (SARS) diagnostic assays for detection of SARS-CoV specific antibody are necessary. To evaluate the diagnostic performance of laboratories an external quality assurance (EQA) study was performed in 2004. Participating laboratories (9/20) correctly detected anti-SARS antibodies in serum samples without false positive results in an immunofluorescence assay. In contrast, only 4/13 laboratories detected most of the anti-SARS antibody positive samples without false positive results using enzyme immunoassays (EIA) and/or immunoblot. The overall results clearly demonstrate that serological diagnosis of SARS-CoV remains at an early stage of development, with further technical improvements required, particularly with respect to the use of SARS specific EIAs.  相似文献   
6.
A recombinant vaccinia virus encoding rotavirus protein NSP3 driven by an internal ribosome entry site (IRES) from the encephalomyocarditis (EMC) virus was able to abate protein synthesis in BSC1 cells by 25-fold, with as much as 30% of the remaining protein synthesis being NSP3. Hence NSP3 shuts off host cell protein synthesis down to the level seen during rotavirus infection but is unable to prevent translation from EMC IRES-driven genes. This effect was abolished by deletions in the eIF4G-binding (aa 274-313) and the dimerization (aa 150-206) but not the viral mRNA-binding (aa 83-149) domains, supporting that NSP3 functions in vivo as a dimer. Binding of eIF4G by NSP3 has been implicated in interfering with mRNA 5'-3' circularization, hence such circularization is essential for translation in mammalian cells.  相似文献   
7.
Anastomotic strictures and urinary incontinence are severe complications after a radical prostatectomy. We report on two patients suffering from both complications. We treated the anastomotic stricture with a Urolume Wallstent and inserted an AMS 800 artificial sphincter prosthesis 4 to 6 months later for treating urinary incontinence. Finally, the patients were fully continent with no evidence of recurrent strictures.  相似文献   
8.
BACKGROUND: Tobacco smoking is one of the main risk factors for oral, pharyngeal and oesophageal cancers in developed countries. Information on the role of the tar yield of cigarettes in upper digestive tract carcinogenesis is sparse and needs to be updated because the tar yield of cigarettes has steadily decreased over the last few decades. PATIENTS AND METHODS: We analysed two case-control studies, from Italy and Switzerland, conducted between 1992 and 1999, involving 749 cases of oral and pharyngeal cancer and 1770 controls, and 395 cases of squamous-cell oesophageal carcinoma and 1066 matched controls. Odds ratios (ORs) were estimated by unconditional multiple logistic regression models, including terms for age, sex, study centre, education and alcohol consumption. RESULTS: Based on the brand of cigarettes smoked for the longest time, the multivariate ORs for current smokers compared with never smokers were 6.1 for <20 mg and 9.8 for >or=20 mg tar for oral and pharyngeal neoplasms, and 4.8 and 5.4 for oesophageal cancer, respectively. For the cigarette brand smoked in the previous six months, the ORs for >or=10 mg compared with <10 mg were 1.9 for cancer of the oral cavity and pharynx and 1.8 for oesophageal cancer, after allowance for number of cigarettes and duration of smoking. CONCLUSIONS: The present study confirms the direct relationship between the tar yield of cigarettes and upper digestive tract neoplasms, and provides innovative information on lower tar cigarettes, which imply reduced risks compared with higher tar ones. However, significant excess risks were observed even in the lower tar category, thus giving unequivocal indications for stopping smoking as a priority for prevention of upper digestive tract neoplasms.  相似文献   
9.
OBJECTIVE: To assess the antibody response to influenza vaccine of children vertically infected with HIV. DESIGN: Prospective study in HIV infected children vaccinated during the winter of 1994-5. SETTING: Family HIV clinic at St Mary's Hospital, Paddington. SUBJECTS: 25 children, aged 1-11 years, vertically infected with HIV. MAIN OUTCOME MEASURES: Responses to influenza antigens (H1N1-A/Taiwan/1/86, H3N2-A/Shandong/9/93, B/Panama/45/ 90) were tested by haemagglutination inhibition. Antibody responses were assessed according to clinical symptoms and immune function, stratified according to the 1994 revised classification for HIV infection in children. RESULTS: 23 children (92%) had either very low or no detectable antibody before vaccination. New protective antibody responses were made by 10 children (40%): in seven to a single antigen, in two to two antigens, and in one to all three antigens. For each antigen there was an overall small increase in the mean geometric titre of antibody produced, but this only reached a protective level for antigen H1N1 and for children with minimal symptoms. Less symptomatic children were significantly more likely to produce a protective antibody response to influenza vaccination. No association was found between immune function, as measured by CD4 count, and vaccine response. CONCLUSIONS: Only vaccination of the least symptomatic HIV infected children against influenza is likely to be effective. This will not only protect them against influenza, but will also protect other more immunosuppressed and vulnerable members of their families.  相似文献   
10.
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