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   1284471篇
  免费   86818篇
  国内免费   1947篇
耳鼻咽喉   18257篇
儿科学   42268篇
妇产科学   37835篇
基础医学   187211篇
口腔科学   35421篇
临床医学   108309篇
内科学   251923篇
皮肤病学   26527篇
神经病学   99435篇
特种医学   50019篇
外国民族医学   366篇
外科学   197758篇
综合类   26520篇
现状与发展   1篇
一般理论   300篇
预防医学   92649篇
眼科学   29102篇
药学   97838篇
  18篇
中国医学   2497篇
肿瘤学   68982篇
  2018年   11851篇
  2015年   11634篇
  2014年   16015篇
  2013年   24361篇
  2012年   33564篇
  2011年   35954篇
  2010年   21213篇
  2009年   20022篇
  2008年   34990篇
  2007年   37953篇
  2006年   38505篇
  2005年   37798篇
  2004年   36397篇
  2003年   35376篇
  2002年   34923篇
  2001年   58096篇
  2000年   59587篇
  1999年   50695篇
  1998年   14234篇
  1997年   12810篇
  1996年   13073篇
  1995年   12347篇
  1994年   11758篇
  1993年   10861篇
  1992年   40987篇
  1991年   40363篇
  1990年   39887篇
  1989年   38708篇
  1988年   36108篇
  1987年   35349篇
  1986年   33724篇
  1985年   32135篇
  1984年   23923篇
  1983年   20818篇
  1982年   12377篇
  1981年   10927篇
  1980年   10204篇
  1979年   22636篇
  1978年   15879篇
  1977年   13729篇
  1976年   12970篇
  1975年   14201篇
  1974年   16683篇
  1973年   16077篇
  1972年   15318篇
  1971年   14230篇
  1970年   13215篇
  1969年   12731篇
  1968年   11978篇
  1967年   10478篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
Historically, no black fly (Diptera: Simuliidae) nuisance has been reported in the Murcia Region. Back in September 2016 the Ojós City Council has contacted the Regional Public Health General Directorate for help regarding a local insect nuisance, most probably based on mosquitoes. After sampling with a BG-sentinel 2 trap, collecting adult specimens with an entomological aspirator, and collect larvae and pupae on submerged giant cane stalks at the river, it turned out that Simulium sergenti was the insect species causing the nuisance. This species is not considered particularly anthropophilic; therefore, a low vector risk for human health was considered. However, the high fly density impaired the life quality of the people at the village. A management plan was recommended, treating the river with Bacillus thuringiensis var israelensis.  相似文献   
52.
53.
54.

Purpose

To conduct a systematic literature review of the reliability, construct validity, and responsiveness of the SF-36® Health Survey (SF-36) in patients with ulcerative colitis (UC).

Methods

We performed a systematic search of electronic medical databases to identify published peer-reviewed studies which reported scores from the eight scales and/or two summary measures of the SF-36 collected from adult patients with UC. Study findings relevant to reliability, construct validity, and responsiveness were reviewed.

Results

Data were extracted and summarized from 43 articles meeting inclusion criteria. Convergent validity was supported by findings that 83% (197/236) of correlations between SF-36 scales and measures of disease symptoms, disease activity, and functioning exceeded the prespecified threshold (r ≥ |0.40|). Known-groups validity was supported by findings of clinically meaningful differences in SF-36 scores between subgroups of patients when classified by disease activity (i.e., active versus inactive), symptom status, and comorbidity status. Responsiveness was supported by findings of clinically meaningful changes in SF-36 scores following treatment in non-comparative trials, and by meaningfully larger improvements in SF-36 scores in treatment arms relative to controls in randomized controlled trials. The sole study of SF-36 reliability found evidence supporting internal consistency (Cronbach’s α ≥ 0.70) for all SF-36 scales and test–retest reliability (intraclass correlation coefficient ≥0.70) for six of eight scales.

Conclusions

Evidence from this systematic literature review indicates that the SF-36 is reliable, valid, and responsive when used with UC patients, supporting the inclusion of the SF-36 as an endpoint in clinical trials for this patient population.
  相似文献   
55.
56.
57.
58.
59.
60.

Objective

To assess the incidence of pertussis (whooping cough) in subjects aged 50 years and older in France.

Methods

Participating family physicians (FPs) using the patient record management software AxiSanté® included patients aged 50 years and older, who had signed an informed consent form, presenting with persistent cough for 7 to 21 days. Bordetella genetic material was detected by polymerase chain reaction (PCR) on nasopharyngeal samples collected at the FP's discretion.

Results

A total of 42 FPs included 129 patients from June 2013 to August 2014 (large cities: 38; medium-sized cities: 57; rural areas: 34); 106 samples were analyzed. Overall, 30 pertussis cases were diagnosed: 10 cases confirmed by PCR, 18 purely clinical cases, and two direct epidemiological cases. The crude incidence rate per 100,000 patients aged  50 years was 103.6 (95% CI: 69.9–47.9): 77.1 in large cities, 103.1 in medium-sized cities, and 143.9 in rural areas. The extrapolated incidence rate per 100,000 persons aged  50 years was 187.1 (95% CI: 126.2–67.1): 131.1 in large cities, 256.1 in medium-sized cities, and 242.2 in rural areas.

Conclusion

The population aged 50 years and older can serve as a reservoir. Its role in Bordetella pertussis circulation should be taken into account for pertussis booster vaccination programs.  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