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   85631篇
  免费   6310篇
  国内免费   206篇
耳鼻咽喉   1152篇
儿科学   2469篇
妇产科学   2138篇
基础医学   13644篇
口腔科学   2016篇
临床医学   8071篇
内科学   16863篇
皮肤病学   1263篇
神经病学   8332篇
特种医学   3476篇
外国民族医学   45篇
外科学   11273篇
综合类   1146篇
现状与发展   1篇
一般理论   110篇
预防医学   6711篇
眼科学   1858篇
药学   6110篇
中国医学   202篇
肿瘤学   5267篇
  2022年   605篇
  2021年   1447篇
  2020年   922篇
  2019年   1322篇
  2018年   1617篇
  2017年   1112篇
  2016年   1340篇
  2015年   1551篇
  2014年   1929篇
  2013年   3275篇
  2012年   4361篇
  2011年   4413篇
  2010年   3025篇
  2009年   2611篇
  2008年   4048篇
  2007年   4239篇
  2006年   4093篇
  2005年   4058篇
  2004年   4052篇
  2003年   3711篇
  2002年   3697篇
  2001年   2509篇
  2000年   2580篇
  1999年   2336篇
  1998年   1119篇
  1997年   929篇
  1996年   859篇
  1995年   877篇
  1994年   707篇
  1993年   786篇
  1992年   1697篇
  1991年   1622篇
  1990年   1573篇
  1989年   1561篇
  1988年   1321篇
  1987年   1304篇
  1986年   1249篇
  1985年   1191篇
  1984年   876篇
  1983年   796篇
  1982年   620篇
  1981年   598篇
  1980年   514篇
  1979年   741篇
  1978年   467篇
  1977年   456篇
  1975年   478篇
  1974年   545篇
  1973年   445篇
  1972年   424篇
排序方式: 共有10000条查询结果,搜索用时 406 毫秒
1.
2.
3.
4.
5.
ABSTRACT

Domestic chickens (Gallus gallus domesticus) were exposed to imidacloprid by gavage once daily for 7 consecutive days at 0, 0.03, 0.34, 3.42, 10.25, and 15.5 mg/kg/day (n = 20 per group; 5 6-week-old males, 5 6-week-old females, 5 9-week-old males, and 5 9-week-old females). The severity and duration of neurobehavioral abnormalities were recorded. Components of the innate and adaptive immune system were assessed with 7 standard functional assays. Temporary neurobehavioral abnormalities were observed in a dose-dependent manner, including muscle tremors, ataxia, and depressed mentation. Based upon mean clinical severity scores, the no observed adverse effect level (NOAEL) was 3.42 mg/kg/day, and the lowest observed adverse effect level (LOAEL) was 10.25 mg/kg/day. The effective dose value for the presence of any neurobehavioral abnormalities in 50% of the test group (ED50) was 4.62 ± 0.98 mg/kg/day. The ED50 for an adjusted score that included both severity and duration of neurobehavioral abnormalities was 11.24 ± 9.33 mg/kg/day. These ED50 values are equivalent to a 1 kg bird ingesting 29 or 70 imidacloprid treated soybean seeds respectively. Immunotoxicity was not documented, possible causes include the assays were insensitive, relevant immune functions were not examined, or imidacloprid is not immunotoxic at this dosing schedule in this species. Neurobehavioral abnormalities were a more sensitive indicator of the sublethal effects of imidacloprid than immunotoxicity.  相似文献   
6.
7.
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.
10.
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   
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