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   1614668篇
  免费   123615篇
  国内免费   2550篇
耳鼻咽喉   21787篇
儿科学   53009篇
妇产科学   46297篇
基础医学   228497篇
口腔科学   47370篇
临床医学   141360篇
内科学   315701篇
皮肤病学   34202篇
神经病学   130738篇
特种医学   64860篇
外国民族医学   474篇
外科学   244385篇
综合类   39734篇
现状与发展   3篇
一般理论   545篇
预防医学   123074篇
眼科学   36592篇
药学   121520篇
  38篇
中国医学   2979篇
肿瘤学   87668篇
  2018年   14883篇
  2016年   12989篇
  2015年   15105篇
  2014年   20730篇
  2013年   31429篇
  2012年   42694篇
  2011年   44887篇
  2010年   26435篇
  2009年   25406篇
  2008年   43132篇
  2007年   45360篇
  2006年   46167篇
  2005年   44773篇
  2004年   44214篇
  2003年   42275篇
  2002年   41380篇
  2001年   75736篇
  2000年   78411篇
  1999年   66457篇
  1998年   17748篇
  1997年   16355篇
  1996年   16331篇
  1995年   16038篇
  1994年   15083篇
  1993年   14231篇
  1992年   55461篇
  1991年   53799篇
  1990年   52598篇
  1989年   50868篇
  1988年   47248篇
  1987年   46577篇
  1986年   44305篇
  1985年   42880篇
  1984年   32055篇
  1983年   27574篇
  1982年   16150篇
  1981年   14446篇
  1980年   13573篇
  1979年   30479篇
  1978年   21083篇
  1977年   17780篇
  1976年   16703篇
  1975年   17583篇
  1974年   21505篇
  1973年   20682篇
  1972年   18862篇
  1971年   17787篇
  1970年   16299篇
  1969年   15275篇
  1968年   13950篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.

Objectives

This study reported a hospital outbreak due to an extensively drug-resistant (XDR) OXA-72-producing strain of Acinetobacter baumannii (A. baumannii).

Methods and Results

The isolates were found to be genotypically indistinguishable by whole-genome multiple locus sequence typing, and to belong to the international clonal complex CC2. One of these isolates sequentially developed a high resistance to colistin and rifampicin under treatment, as a result of mutations in genes pmrB and rpoB, respectively. The blaOXA-72 gene was localised on a 10-kb transferable plasmid, named pAB-STR-1, whose sequence is nearly identical to that of another plasmid previously found in Lithuanian strains, pAB120.

Conclusion

This report highlighted the need to carefully monitor the emergence of colistin and rifampicin resistance in patients treated for infections with multidrug-resistant A. baumannii.  相似文献   
52.
Background and purpose — No difference in outcome has been demonstrated comparing cemented taper-slip and composite beam designs in short-term randomised trials; we assessed outcome differences using a registry analysis.

Patients and methods — All cemented stems with > 100 implantations were identified in the National Joint Registry of England and Wales from April 1, 2003 to September 31, 2013 and categorised as taper-slip or composite beam. Survival analyses using Kaplan–Meier and Cox regression were performed.

Results — We identified 292,987 cemented arthroplasties, of which 16% (47,586) were composite beam stems, with taper-slip stems making up the remainder (n = 245,401). There was a statistically significant increased chance of revision in the composite beam group compared with the taper-slip group (1.7% vs 1.3%, p < 0.001) but statistically no significant differences of survival estimates (p = 0.06). When the 2 groups were segregated to delineate the most implanted model in each category, the differences became more profound with the most implanted taper-slip stem (Exeter V40) showing statistically and clinically significant superior 8-year survival: 97.9% compared with 97.6% for all other taper-slip; 97.5% for the most implanted composite beam (Charnley cemented stem); and 97.7% for all other composite beam.

Interpretation — There was an increased incidence of revision for composite beam stems. The most implanted taper-slip stem demonstrated significant survival advantage vs. all other stems.  相似文献   

53.

Aims

To obtain an overview of the management and outcomes of children aged 18 years or younger diagnosed with differentiated thyroid carcinoma of follicular cell origin across the UK, by collecting and analysing data from the limited number of centres treating these patients. This multicentre data might provide a more realistic perspective than single-institution series.

Materials and methods

Six centres submitted data extracted from historical records on patients aged 18 years or younger, diagnosed between 1964 and 2017. The univariate and multivariable Cox proportional hazard model was used to identify potential predictors of progression-free survival, using national data as a control.

Results

Data on 166 patients were available for analysis. Females (74%) were predominant, and the age ranged from 3 to 19 years at diagnosis, mean 14.1 years. Nodal metastases were present in 51%; 12% had distant metastases. After surgery, 95% received radioactive iodine (39% on more than one occasion) and 4% received external beam radiotherapy. With a median follow-up duration of 5 years, 69% are alive with no evidence of disease; 20% are alive with a raised thyroglobulin level as the only evidence of residual disease; 6% have residual structural disease detectable on imaging; 2% have died, from cerebral metastases.

Conclusion

Despite most patients having advanced disease at presentation, outcomes are very good. A national prospective registry should allow systematic collection of good-quality data and may facilitate research to further improve outcomes.  相似文献   
54.
55.
56.
57.
58.
59.
60.
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