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   81693篇
  免费   6115篇
  国内免费   181篇
耳鼻咽喉   1053篇
儿科学   2316篇
妇产科学   1964篇
基础医学   13664篇
口腔科学   1951篇
临床医学   7497篇
内科学   16281篇
皮肤病学   1247篇
神经病学   7678篇
特种医学   3362篇
外国民族医学   46篇
外科学   10275篇
综合类   599篇
一般理论   89篇
预防医学   6986篇
眼科学   1502篇
药学   5817篇
中国医学   171篇
肿瘤学   5491篇
  2022年   615篇
  2021年   1346篇
  2020年   887篇
  2019年   1216篇
  2018年   1524篇
  2017年   1118篇
  2016年   1273篇
  2015年   1529篇
  2014年   1925篇
  2013年   3063篇
  2012年   4114篇
  2011年   4225篇
  2010年   2753篇
  2009年   2452篇
  2008年   3750篇
  2007年   3971篇
  2006年   3895篇
  2005年   3722篇
  2004年   3608篇
  2003年   3373篇
  2002年   3302篇
  2001年   2783篇
  2000年   2834篇
  1999年   2546篇
  1998年   1116篇
  1997年   939篇
  1996年   849篇
  1995年   849篇
  1994年   720篇
  1993年   758篇
  1992年   1792篇
  1991年   1700篇
  1990年   1644篇
  1989年   1626篇
  1988年   1357篇
  1987年   1322篇
  1986年   1235篇
  1985年   1158篇
  1984年   830篇
  1983年   756篇
  1982年   521篇
  1981年   509篇
  1980年   424篇
  1979年   701篇
  1978年   428篇
  1977年   401篇
  1975年   418篇
  1974年   470篇
  1973年   383篇
  1972年   379篇
排序方式: 共有10000条查询结果,搜索用时 21 毫秒
1.
2.
3.
4.
5.
6.
7.

Background

Early dumping is a poorly defined and incompletely understood complication after Roux-en-Y gastric (RYGB).

Objective

We performed a mixed-meal tolerance test in patients after RYGB to address the prevalence of early dumping and to gain further insight into its pathophysiology.

Setting

The study was conducted in a regional hospital in the northern part of the Netherlands.

Methods

From a random sample of patients who underwent primary RYGB between 2008 and 2011, 46 patients completed the mixed-meal tolerance test. The dumping severity score for early dumping was assessed every 30 minutes. A sum score at 30 or 60 minutes of ≥5 and an incremental score of ≥3 points were defined as indicating a high suspicion of early dumping. Blood samples were collected at baseline, every 10 minutes during the first half hour, and at 60 minutes after the start.

Results

The prevalence of a high suspicion of early dumping was 26%. No differences were seen for absolute hematocrit value, inactive glucagon-like peptide-1, and vasoactive intestinal peptide between patients with or without early dumping. Patients at high suspicion of early dumping had higher levels of active glucagon-like peptide-1 and peptide YY.

Conclusion

The prevalence of complaints at high suspicion of early dumping in a random population of patients after RYGB is 26% in response to a mixed-meal tolerance test. Postprandial increases in both glucagon-like peptide-1 and peptide YY are associated with symptoms of early dumping, suggesting gut L-cell overactivity in this syndrome.  相似文献   
8.
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   
9.
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   
10.
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   
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