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   1375223篇
  免费   106690篇
  国内免费   7378篇
耳鼻咽喉   17206篇
儿科学   44126篇
妇产科学   36774篇
基础医学   201831篇
口腔科学   36540篇
临床医学   134915篇
内科学   263611篇
皮肤病学   26698篇
神经病学   113690篇
特种医学   49608篇
外国民族医学   377篇
外科学   188125篇
综合类   38168篇
现状与发展   14篇
一般理论   464篇
预防医学   117790篇
眼科学   30045篇
药学   103392篇
  58篇
中国医学   6681篇
肿瘤学   79178篇
  2021年   13314篇
  2019年   13108篇
  2018年   17768篇
  2017年   13702篇
  2016年   14491篇
  2015年   17173篇
  2014年   23362篇
  2013年   34483篇
  2012年   47476篇
  2011年   50524篇
  2010年   29818篇
  2009年   27220篇
  2008年   45269篇
  2007年   47446篇
  2006年   47343篇
  2005年   45485篇
  2004年   43025篇
  2003年   40909篇
  2002年   39513篇
  2001年   61814篇
  2000年   63282篇
  1999年   52918篇
  1998年   14948篇
  1997年   13715篇
  1996年   13402篇
  1995年   12734篇
  1994年   11848篇
  1993年   11070篇
  1992年   41693篇
  1991年   40871篇
  1990年   39532篇
  1989年   37425篇
  1988年   34642篇
  1987年   33748篇
  1986年   32183篇
  1985年   30670篇
  1984年   23042篇
  1983年   19597篇
  1982年   11758篇
  1979年   20806篇
  1978年   14814篇
  1977年   12064篇
  1976年   11876篇
  1975年   12110篇
  1974年   14800篇
  1973年   14472篇
  1972年   13356篇
  1971年   12418篇
  1970年   11485篇
  1969年   10410篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
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   
102.
103.
104.
105.
106.
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   
107.
108.
109.

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   
110.
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