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   1278819篇
  免费   93038篇
  国内免费   1992篇
耳鼻咽喉   18221篇
儿科学   42330篇
妇产科学   37839篇
基础医学   187253篇
口腔科学   35441篇
临床医学   108361篇
内科学   251967篇
皮肤病学   26569篇
神经病学   99513篇
特种医学   50024篇
外国民族医学   366篇
外科学   197993篇
综合类   26537篇
现状与发展   1篇
一般理论   300篇
预防医学   92700篇
眼科学   29083篇
药学   97882篇
  1篇
中国医学   2498篇
肿瘤学   68970篇
  2018年   11843篇
  2015年   11644篇
  2014年   16044篇
  2013年   24430篇
  2012年   33610篇
  2011年   36017篇
  2010年   21258篇
  2009年   20072篇
  2008年   35054篇
  2007年   38033篇
  2006年   38575篇
  2005年   37871篇
  2004年   36454篇
  2003年   35447篇
  2002年   34990篇
  2001年   58154篇
  2000年   59657篇
  1999年   50765篇
  1998年   14271篇
  1997年   12832篇
  1996年   13095篇
  1995年   12364篇
  1994年   11786篇
  1993年   10879篇
  1992年   41033篇
  1991年   40414篇
  1990年   39932篇
  1989年   38761篇
  1988年   36154篇
  1987年   35395篇
  1986年   33765篇
  1985年   32177篇
  1984年   23963篇
  1983年   20861篇
  1982年   12403篇
  1981年   10953篇
  1980年   10222篇
  1979年   22666篇
  1978年   15900篇
  1977年   13752篇
  1976年   12985篇
  1975年   14222篇
  1974年   16694篇
  1973年   16095篇
  1972年   15333篇
  1971年   14248篇
  1970年   13228篇
  1969年   12736篇
  1968年   11982篇
  1967年   10486篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
91.

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   
92.
93.
94.
95.
96.
97.
98.

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   
99.
100.
Iron-oxide nanoparticles (NPs) generated by environmental events are likely to represent health problems. α-Fe2O3 NPs were synthesized, characterized and tested in a model for toxicity utilizing human whole blood without added anticoagulant. MALDI-TOF of the corona was performed and activation markers for plasma cascade systems (complement, contact and coagulation systems), platelet consumption and release of growth factors, MPO, and chemokine/cytokines from blood cells were analyzed. The coronas formed on the pristine α-Fe2O3 NPs contained contact system proteins and they induced massive activation of the contact (kinin/kallikrein) system, as well as thrombin generation, platelet activation, and release of two pro-angiogeneic growth factors: platelet-derived growth factor and vascular endothelial growth factor, whereas complement activation was unaffected. The α-Fe2O3 NPs exhibited a noticeable toxicity, with kinin/kallikrein activation, which may be associated with hypotension and long-term angiogenesis in vivo, with implications for cancer, arteriosclerosis and pulmonary disease.  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