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   1357178篇
  免费   104074篇
  国内免费   4299篇
耳鼻咽喉   17043篇
儿科学   44470篇
妇产科学   36979篇
基础医学   201010篇
口腔科学   36200篇
临床医学   132567篇
内科学   262075篇
皮肤病学   26685篇
神经病学   114179篇
特种医学   48695篇
外国民族医学   366篇
外科学   186809篇
综合类   29363篇
现状与发展   1篇
一般理论   540篇
预防医学   117878篇
眼科学   29309篇
药学   100270篇
  6篇
中国医学   3186篇
肿瘤学   77920篇
  2021年   11681篇
  2019年   12454篇
  2018年   17165篇
  2017年   12895篇
  2016年   13897篇
  2015年   15856篇
  2014年   21693篇
  2013年   33290篇
  2012年   46134篇
  2011年   48745篇
  2010年   28060篇
  2009年   25717篇
  2008年   44116篇
  2007年   46380篇
  2006年   46503篇
  2005年   44858篇
  2004年   42651篇
  2003年   40436篇
  2002年   39162篇
  2001年   61111篇
  2000年   62781篇
  1999年   52543篇
  1998年   14799篇
  1997年   13430篇
  1996年   13250篇
  1995年   12596篇
  1994年   11721篇
  1993年   11014篇
  1992年   41751篇
  1991年   40916篇
  1990年   39629篇
  1989年   37504篇
  1988年   34726篇
  1987年   33838篇
  1986年   32277篇
  1985年   30786篇
  1984年   23137篇
  1983年   19689篇
  1982年   11833篇
  1979年   20914篇
  1978年   14890篇
  1977年   12134篇
  1976年   11930篇
  1975年   12176篇
  1974年   14876篇
  1973年   14565篇
  1972年   13428篇
  1971年   12487篇
  1970年   11540篇
  1969年   10461篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
91.
Bowel diseases of prematurity, including necrotizing enterocolitis, are dreaded ailments of neonates. Early diagnosis is difficult, with clinical and radiographic findings often inconclusive. We present a novel use of contrast-enhanced ultrasound in detection of pediatric bowel disease. Early identification of compromised blood flow or an at-risk bowel can be quantitatively detected and monitored. This ability has implications for guidance of emerging therapies, allowing targeting of inflammation. These findings represent an advancement in detection of bowel disease in neonates.  相似文献   
92.
A 17‐year‐old boy presented with recurring severe dermatitis of the face of 5‐months duration that resembled impetigo. He had been treated with several courses of antibiotics without improvement. Biopsy showed changes consistent with allergic contact dermatitis and patch testing later revealed sensitization to benzoyl peroxide, which the patient had been using for the treatment of acne vulgaris.  相似文献   
93.
94.
In 1963, Goffman argued that forming a group based on shared stigma may provide benefits. However, there is no empirical research on whether perception that a separate, unique, coherent group exists (i.e., group entitativity) influences coping, such as educating others or secrecy, for the stigmatized individual or his or her spouse. Further, little is known about how spouses influence each other in terms of promoting the education of others about a stigmatizing condition, especially when it comes to the role of believing that stigma-based groups, to which they may both belong, exist. This study provides a step toward bridging this gap in the research by applying the label management model in efforts to understand coping for couples in which one spouse is diagnosed with genetic mutations leading to alpha-1 antitrypsin deficiency (AATD). This study included 50 married couples in which one spouse is diagnosed with genetic mutations leading to alpha-1 antitrypsin deficiency (AATD). We found that group entitativity related to those with AATD counterbalanced the influence of genetic stigma on spouses’ intentions to keep the diagnosis secret or to educate others about it. Intrapersonal and interpersonal influences appeared among spouses. Attention is needed on the power of creating groups for stigmatized persons and their relatives. Indeed, people live within a dynamic world of group entities, and multiple social identities including spousal and familial. While attention has been paid to the diffusion of stigmas to loved ones, less has been paid to the uplift of group entities for them.  相似文献   
95.
96.
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   
97.
98.
99.
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