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   1344808篇
  免费   102989篇
  国内免费   4295篇
耳鼻咽喉   16934篇
儿科学   44023篇
妇产科学   36629篇
基础医学   199203篇
口腔科学   36021篇
临床医学   131101篇
内科学   260121篇
皮肤病学   26594篇
神经病学   113019篇
特种医学   48446篇
外国民族医学   366篇
外科学   185478篇
综合类   28976篇
现状与发展   1篇
一般理论   466篇
预防医学   115920篇
眼科学   29192篇
药学   99535篇
  6篇
中国医学   3185篇
肿瘤学   76876篇
  2021年   11335篇
  2019年   11995篇
  2018年   16761篇
  2017年   12618篇
  2016年   13589篇
  2015年   15547篇
  2014年   21229篇
  2013年   32666篇
  2012年   45246篇
  2011年   47916篇
  2010年   27578篇
  2009年   25343篇
  2008年   43426篇
  2007年   45751篇
  2006年   45819篇
  2005年   44247篇
  2004年   42131篇
  2003年   39961篇
  2002年   38686篇
  2001年   60965篇
  2000年   62604篇
  1999年   52392篇
  1998年   14650篇
  1997年   13340篇
  1996年   13158篇
  1995年   12494篇
  1994年   11668篇
  1993年   10962篇
  1992年   41615篇
  1991年   40823篇
  1990年   39498篇
  1989年   37390篇
  1988年   34618篇
  1987年   33735篇
  1986年   32185篇
  1985年   30671篇
  1984年   23069篇
  1983年   19619篇
  1982年   11767篇
  1979年   20827篇
  1978年   14836篇
  1977年   12082篇
  1976年   11909篇
  1975年   12134篇
  1974年   14824篇
  1973年   14499篇
  1972年   13380篇
  1971年   12437篇
  1970年   11499篇
  1969年   10426篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
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   
92.
93.
94.
95.
96.
There is a large and growing population of long-term cancer survivors. Primary care physicians (PCPs) are playing an increasingly greater role in the care of these patients across the continuum of cancer survivorship. In this role, PCPs are faced with the responsibility of managing a range of medical and psychosocial late effects of cancer treatment. In particular, the sexual side effects of treatment which are common and have significant impact on quality of life for the cancer survivor, often go unaddressed. This is an area of clinical care and research that has received increasing attention, highlighted by the presentation of this special issue on Cancer and Sexual Health. The aims of this review are 3-fold. First, we seek to overview common presentations of sexual dysfunction related to major cancer diagnoses in order to give the PCP a sense of the medical issues that the survivor may present with. Barriers to communication about sexual health issues between patient/PCPs in order are also described in order to emphasize the importance of PCPs initiating this important conversation. Next, we provide strategies and resources to help guide the PCP in the management of sexual dysfunction in cancer survivors. Finally, we discuss case examples of survivorship sexual health issues and highlight the role that a PCP can play in each of these case examples.  相似文献   
97.
98.
99.

Background

Arterial vascular anomalies in patients undergoing kidney transplantation (KT) are correlated with a higher incidence of early surgical complications, potentially causing graft loss. Arterial reconstruction allows patients to overcome these surgical challenges, thus minimizing the risk of poor outcomes. The aim of the present study is to retrospectively investigate the safety and effectiveness of the multiple arterial reconstruction technique with a Teflon patch in case of an unavailable aortic patch: to do so, surgical complications, graft function, and patient survival were evaluated.

Methods

During the period January 2009 to August 2016, 202 adult deceased-donor KTs were performed at our center. Group A (n = 27; reconstruction of multiple arteries) and Group B (n = 175; control group) were compared.

Results

No differences were observed between the 2 groups in terms of early postoperative course, with no vascular complication observed in Group A. No vascular patch infections were reported, nor longer cold ischemia time rates. Similarly, long-term survival rates were similar between the 2 groups.

Conclusions

The Teflon-patch arterial reconstruction technique appears to be safe and effective, with an acceptable balance of benefits and potential risks of using a prosthetic material. Studies based on larger series are needed to further validate this approach.  相似文献   
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