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   86951篇
  免费   6359篇
  国内免费   204篇
耳鼻咽喉   1046篇
儿科学   2476篇
妇产科学   2127篇
基础医学   13828篇
口腔科学   2284篇
临床医学   8781篇
内科学   17681篇
皮肤病学   1217篇
神经病学   8186篇
特种医学   3665篇
外国民族医学   46篇
外科学   10904篇
综合类   796篇
一般理论   93篇
预防医学   7027篇
眼科学   1516篇
药学   6214篇
中国医学   212篇
肿瘤学   5415篇
  2022年   692篇
  2021年   1404篇
  2020年   946篇
  2019年   1384篇
  2018年   1650篇
  2017年   1202篇
  2016年   1398篇
  2015年   1599篇
  2014年   2031篇
  2013年   3384篇
  2012年   4541篇
  2011年   4737篇
  2010年   3103篇
  2009年   2675篇
  2008年   4111篇
  2007年   4293篇
  2006年   4186篇
  2005年   4070篇
  2004年   3975篇
  2003年   3585篇
  2002年   3628篇
  2001年   2666篇
  2000年   2705篇
  1999年   2463篇
  1998年   1171篇
  1997年   975篇
  1996年   866篇
  1995年   880篇
  1994年   766篇
  1993年   771篇
  1992年   1752篇
  1991年   1723篇
  1990年   1590篇
  1989年   1599篇
  1988年   1355篇
  1987年   1302篇
  1986年   1233篇
  1985年   1144篇
  1984年   864篇
  1983年   794篇
  1982年   557篇
  1981年   542篇
  1980年   453篇
  1979年   718篇
  1978年   461篇
  1977年   447篇
  1975年   467篇
  1974年   518篇
  1973年   417篇
  1972年   415篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
PurposeUnderstanding the value of genetic screening and testing for monogenic disorders requires high-quality, methodologically robust economic evaluations. This systematic review sought to assess the methodological quality among such studies and examined opportunities for improvement.MethodsWe searched PubMed, Cochrane, Embase, and Web of Science for economic evaluations of genetic screening/testing (2013-2019). Methodological rigor and adherence to best practices were systematically assessed using the British Medical Journal checklist.ResultsAcross the 47 identified studies, there were substantial variations in modeling approaches, reporting detail, and sophistication. Models ranged from simple decision trees to individual-level microsimulations that compared between 2 and >20 alternative interventions. Many studies failed to report sufficient detail to enable replication or did not justify modeling assumptions, especially for costing methods and utility values. Meta-analyses, systematic reviews, or calibration were rarely used to derive parameter estimates. Nearly all studies conducted some sensitivity analysis, and more sophisticated studies implemented probabilistic sensitivity/uncertainty analysis, threshold analysis, and value of information analysis.ConclusionWe describe a heterogeneous body of work and present recommendations and exemplar studies across the methodological domains of (1) perspective, scope, and parameter selection; (2) use of uncertainty/sensitivity analyses; and (3) reporting transparency for improvement in the economic evaluation of genetic screening/testing.  相似文献   
3.
4.
5.
6.
7.
Clinical Oral Investigations - The aim of this study was the analysis of WNT10A variants in seven families of probands with various forms of tooth agenesis and self-reported family history of...  相似文献   
8.
The aim of this study was to analyse the effect of body mass index (BMI), both low and high values, on the perioperative complication rate in patients with oral squamous cell carcinoma (OSCC). The medical records of 259 patients operated between 2014 and 2017 for OSCC were reviewed. Univariate and multivariate analyses were performed. Sixty of the 259 patients developed 87 complications. Low or high BMI was not associated with the perioperative complication rate. A longer operating time and increased blood loss were associated with a higher perioperative complication rate and higher Clavien–Dindo grade. Low BMI, American Society of Anesthesiologists score 2 and 3, a longer operating time, and increased blood loss were associated with a longer hospital stay. Low BMI was associated with a longer hospital stay. Neither low nor high BMI was associated with the perioperative complication rate. A longer operating time and increased blood loss were associated with a higher perioperative complication rate and higher Clavien–Dindo grade.  相似文献   
9.
Genetic and epigenetic alterations importantly contribute to the pathogenesis of lung cancer. In the study, we measured the frequency and distribution of molecular abnormalities of EGFR as well as the aberrant promoter methylations of BRCA1, MGMT, MLH1, and RASSF1A in Vietnamese lung adenocarcinomas. We investigated the association between genetic and epigenetic alteration, and between each abnormality with clinicopathologic parameters. Somatic EGFR mutation that was found in 49/139 (35.3%) lung adenocarcinomas showed a significant association with young age, female gender, and non-smokers. EGFR overexpression was identified in 82 tumors (59.0%) and statistical relationships with EGFR or BRCA1 methylation but not EGFR mutation. In addition, EGFR, BRCA1, MGMT, MLH1, and RASSF1A methylations were found in 33 (23.7%), 41 (29.5%), 46 (33.1%), 28 (20.1%), and 41 (29.5%) cases of a total of 139 lung adenocarcinomas, respectively. The RASSF1A methylation was found to be linked to the smoking habit. Methylations in MGMT and RASSF1A were also found to correlate with metastasis status. Furthermore, the distribution of EGFR mutation and that of BRCA1, MGMT or RASSF1A methylation were significantly exclusive in lung adenocarcinomas. The main finding of our study demonstrate that epigenetic abnormalities might play a critical role for the lung tumorigenesis in patients with smoking history and metastasis, and partly affect the predictive value of EGFR mutations through blocking expression due to promoter EGFR hypermethylation. Mutually exclusive distribution of genetic and epigenetic alterations reflects differently biological characteristics in the etiology of lung adenocarcinomas.  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