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   2539528篇
  免费   169558篇
  国内免费   6905篇
耳鼻咽喉   35124篇
儿科学   81421篇
妇产科学   70571篇
基础医学   356060篇
口腔科学   70720篇
临床医学   228427篇
内科学   493897篇
皮肤病学   58891篇
神经病学   207051篇
特种医学   97638篇
外国民族医学   730篇
外科学   380506篇
综合类   55171篇
现状与发展   7篇
一般理论   929篇
预防医学   194596篇
眼科学   57363篇
药学   185108篇
  63篇
中国医学   5172篇
肿瘤学   136546篇
  2018年   27075篇
  2017年   20757篇
  2016年   24059篇
  2015年   27139篇
  2014年   37673篇
  2013年   56834篇
  2012年   75362篇
  2011年   79370篇
  2010年   47867篇
  2009年   45655篇
  2008年   74440篇
  2007年   79464篇
  2006年   80426篇
  2005年   77458篇
  2004年   75072篇
  2003年   72301篇
  2002年   69862篇
  2001年   117993篇
  2000年   120512篇
  1999年   102109篇
  1998年   29654篇
  1997年   26493篇
  1996年   26670篇
  1995年   25662篇
  1994年   23611篇
  1993年   22198篇
  1992年   80516篇
  1991年   77756篇
  1990年   75302篇
  1989年   72987篇
  1988年   66932篇
  1987年   65768篇
  1986年   61903篇
  1985年   59115篇
  1984年   44400篇
  1983年   37811篇
  1982年   22969篇
  1981年   20482篇
  1979年   40652篇
  1978年   28833篇
  1977年   24514篇
  1976年   22660篇
  1975年   24230篇
  1974年   29066篇
  1973年   27773篇
  1972年   26157篇
  1971年   24266篇
  1970年   22589篇
  1969年   21730篇
  1968年   19987篇
排序方式: 共有10000条查询结果,搜索用时 859 毫秒
91.

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   
92.
In a prospective study, we sought to determine acceptability of linkage of administrative and clinical trial data among Canadian patients and Research Ethics Boards (REBs). The goal is to develop a more harmonized approach to data, with potential to improve clinical trial conduct through enhanced data quality collected at reduced cost and inconvenience for patients. On completion of the original LY.12 randomized clinical trial in lymphoma (NCT00078949), participants were invited to enrol in the Long-term Innovative Follow-up Extension (LIFE) component. Those consenting to do so provided comprehensive identifying information to facilitate linkage with their administrative data. We prospectively designed a global assessment of this innovative approach to clinical trial follow-up including rates of REB approval and patient consent. The pre-specified benchmark for patient acceptability was 80%. Of 16 REBs who reviewed the research protocol, 14 (89%) provided approval; two in Quebec declined due to small patient numbers. Of 140 patients invited to participate, 115 (82%, 95% CI 76 to 88%) from across 9 Canadian provinces provided consent and their full name, date of birth, health insurance number and postal code to facilitate linkage with their administrative data for long-term follow-up. Linkage of clinical trial and administrative data is feasible and acceptable. Further collaborative work including many stakeholders is required to develop an optimized secure approach to research. A more coordinated national approach to health data could facilitate more rapid testing and identification of new effective treatments across multiple jurisdictions and diseases from diabetes to COVID-19.  相似文献   
93.
locStra is an ‐package for the analysis of regional and global population stratification in whole‐genome sequencing (WGS) studies, where regional stratification refers to the substructure defined by the loci in a particular region on the genome. Population substructure can be assessed based on the genetic covariance matrix, the genomic relationship matrix, and the unweighted/weighted genetic Jaccard similarity matrix. Using a sliding window approach, the regional similarity matrices are compared with the global ones, based on user‐defined window sizes and metrics, for example, the correlation between regional and global eigenvectors. An algorithm for the specification of the window size is provided. As the implementation fully exploits sparse matrix algebra and is written in C++, the analysis is highly efficient. Even on single cores, for realistic study sizes (several thousand subjects, several million rare variants per subject), the runtime for the genome‐wide computation of all regional similarity matrices does typically not exceed one hour, enabling an unprecedented investigation of regional stratification across the entire genome. The package is applied to three WGS studies, illustrating the varying patterns of regional substructure across the genome and its beneficial effects on association testing.  相似文献   
94.
95.
96.
97.
98.
99.
100.
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