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   67636篇
  免费   4900篇
  国内免费   165篇
耳鼻咽喉   837篇
儿科学   1840篇
妇产科学   1644篇
基础医学   10985篇
口腔科学   1805篇
临床医学   6372篇
内科学   13650篇
皮肤病学   992篇
神经病学   6366篇
特种医学   2849篇
外国民族医学   45篇
外科学   8683篇
综合类   536篇
一般理论   89篇
预防医学   5387篇
眼科学   1215篇
药学   5036篇
中国医学   167篇
肿瘤学   4203篇
  2022年   398篇
  2021年   1081篇
  2020年   693篇
  2019年   990篇
  2018年   1196篇
  2017年   853篇
  2016年   997篇
  2015年   1179篇
  2014年   1488篇
  2013年   2526篇
  2012年   3324篇
  2011年   3457篇
  2010年   2423篇
  2009年   2046篇
  2008年   3100篇
  2007年   3306篇
  2006年   3231篇
  2005年   3094篇
  2004年   3102篇
  2003年   2839篇
  2002年   2866篇
  2001年   2206篇
  2000年   2233篇
  1999年   2023篇
  1998年   937篇
  1997年   778篇
  1996年   685篇
  1995年   699篇
  1994年   586篇
  1993年   633篇
  1992年   1460篇
  1991年   1408篇
  1990年   1355篇
  1989年   1329篇
  1988年   1108篇
  1987年   1109篇
  1986年   1053篇
  1985年   962篇
  1984年   702篇
  1983年   654篇
  1982年   465篇
  1981年   446篇
  1980年   382篇
  1979年   625篇
  1978年   375篇
  1977年   357篇
  1975年   374篇
  1974年   415篇
  1973年   347篇
  1972年   340篇
排序方式: 共有10000条查询结果,搜索用时 375 毫秒
1.
2.
3.
4.
There is increasing public interest in natural or herbal-based healthcare products. This trend is not only visible in supermarkets and dental practices, but also in the scientific world. An improving number of clinical trials are being conducted to validate the claims made about these products in regards to periodontal health. Among single component preparations, Aloe vera and green tea are the most studied natural ingredients. Concerning polyherbal mixtures, triphala has garnered great interest. The effects of these natural products on periodontal health is encouraging, with almost all studies showing an inhibitory effect on plaque accumulation and an improvement in gingival health. However, more studies are needed to be able to design clinical guidelines to guide the use of these natural products in periodontal practice. For most of these products, few studies are available and, moreover, the available studies are limited in duration, the number of participants, and the specific composition of the natural product is often not described in detail.  相似文献   
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