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   1338013篇
  免费   102301篇
  国内免费   4269篇
耳鼻咽喉   16850篇
儿科学   43726篇
妇产科学   36438篇
基础医学   198451篇
口腔科学   35966篇
临床医学   130166篇
内科学   258981篇
皮肤病学   26403篇
神经病学   112250篇
特种医学   48284篇
外国民族医学   366篇
外科学   184467篇
综合类   28825篇
现状与发展   1篇
一般理论   463篇
预防医学   114908篇
眼科学   29188篇
药学   99142篇
  6篇
中国医学   3167篇
肿瘤学   76535篇
  2021年   10953篇
  2019年   11694篇
  2018年   16397篇
  2017年   12336篇
  2016年   13315篇
  2015年   15279篇
  2014年   20914篇
  2013年   32205篇
  2012年   44425篇
  2011年   47111篇
  2010年   27202篇
  2009年   25030篇
  2008年   42905篇
  2007年   45268篇
  2006年   45378篇
  2005年   43795篇
  2004年   41740篇
  2003年   39653篇
  2002年   38490篇
  2001年   60967篇
  2000年   62655篇
  1999年   52387篇
  1998年   14630篇
  1997年   13321篇
  1996年   13154篇
  1995年   12495篇
  1994年   11666篇
  1993年   10963篇
  1992年   41667篇
  1991年   40869篇
  1990年   39546篇
  1989年   37448篇
  1988年   34667篇
  1987年   33798篇
  1986年   32258篇
  1985年   30714篇
  1984年   23102篇
  1983年   19644篇
  1982年   11790篇
  1979年   20871篇
  1978年   14855篇
  1977年   12097篇
  1976年   11907篇
  1975年   12144篇
  1974年   14839篇
  1973年   14504篇
  1972年   13386篇
  1971年   12457篇
  1970年   11501篇
  1969年   10438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