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   1391篇
  免费   79篇
  国内免费   33篇
耳鼻咽喉   46篇
儿科学   100篇
妇产科学   9篇
基础医学   113篇
口腔科学   40篇
临床医学   146篇
内科学   387篇
皮肤病学   92篇
神经病学   69篇
特种医学   82篇
外科学   101篇
综合类   39篇
一般理论   1篇
预防医学   25篇
眼科学   93篇
药学   102篇
中国医学   5篇
肿瘤学   53篇
  2023年   9篇
  2022年   26篇
  2021年   36篇
  2020年   16篇
  2019年   33篇
  2018年   61篇
  2017年   26篇
  2016年   34篇
  2015年   24篇
  2014年   36篇
  2013年   67篇
  2012年   96篇
  2011年   60篇
  2010年   47篇
  2009年   59篇
  2008年   46篇
  2007年   90篇
  2006年   43篇
  2005年   44篇
  2004年   53篇
  2003年   49篇
  2002年   51篇
  2001年   35篇
  2000年   33篇
  1999年   36篇
  1998年   28篇
  1997年   24篇
  1996年   31篇
  1995年   16篇
  1994年   25篇
  1993年   10篇
  1992年   20篇
  1991年   19篇
  1990年   25篇
  1989年   20篇
  1988年   19篇
  1987年   17篇
  1986年   15篇
  1985年   12篇
  1984年   12篇
  1981年   6篇
  1980年   5篇
  1979年   9篇
  1978年   6篇
  1977年   13篇
  1976年   7篇
  1975年   7篇
  1974年   10篇
  1973年   5篇
  1971年   9篇
排序方式: 共有1503条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
BACKGROUND: On December 26, 2004, the biggest earthquake for 40 years, measuring 9.0 on the Richter scale, triggered a tsunami that pounded the coastal areas of South Asia and East Africa. The effects of the tsunami on skin conditions have not been evaluated. OBJECTIVE: To determine the influence of the tsunami on skin conditions by evaluating the skin problems of patients presenting at hospitals after the tsunami. METHODS: Between 5 and 25 January 2005, two dermatologists evaluated patients who complained of skin problems at an outpatient clinic and emergency room of a general hospital in Banda Aceh, Aceh Province, Indonesia. RESULTS: The total number of patients that presented during the study period was 235 (131 males and 104 females), and they had a total of 265 skin problems. In terms of age distribution, most subjects were in their fourth decade (23.0%), followed by the third (22.6%) and fifth decade (16.6%). The most prevalent skin problems were infections-infestations (32.5%), followed by eczemas (29.8%) and traumatic skin disorders (29.4%). In males, traumatic skin disorders were most common. The great majority of infection-infestation cases involved superficial fungal infections. Contact dermatitis accounted for three-quarters of eczema cases, and mainly involved the arms (40.0%) and legs (27.1%). The majority of traumatic skin disorders were lacerations, punctures and penetrations, and the feet (44.7%) and hands (18.8%) were most frequently affected. CONCLUSIONS: Unhygienic conditions, exposure to a hazardous environment and contact with various objects during and after the tsunami probably increased the prevalence of infections-infestations, traumatic skin disorders and contact dermatitis. To prevent these problems and associated secondary bacterial infections, health-related education and early medical management are required.  相似文献   
5.
Kim  SH; Chang  KH; Song  IC; Han  MH; Kim  HC; Kang  HS; Han  MC 《Radiology》1997,204(1):239
  相似文献   
6.
Pesticide regulation is examined in the context of Health Canada’s Pest Management Regulatory Agency’s assessment of the chlorophenoxy herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) for turf. 2,4-D is the most common herbicide used to kill weeds in grass.The medical literature does not uniformly indicate harms from herbicides. However, the balance of epidemiological research suggests that 2,4-D can be persuasively linked to cancers, neurological impairment and reproductive problems. These may arise from 2,4-D itself, from breakdown products or dioxin contamination, or from a combination of chemicals.Regulators rely largely on toxicology, but experiments may not replicate exposures from 2,4-D application to lawns because environmental breakdown products (eg, 2,4-dichlorophenol) may not accumulate and selected herbicides are possibly less contaminated. Dioxins are bioaccumulative chemicals that may cause cancer, harm neurological development, impair reproduction, disrupt the endocrine system and alter immune function. No dioxin analyses were submitted to the Pest Management Regulatory Agency, and the principal contaminants of 2,4-D are not among the 17 congeners covered in pesticide regulation. Independent assessment of all dioxins is needed, in tissues and in the environment.The 2,4-D assessment does not approach standards for ethics, rigour or transparency in medical research. Canada needs a stronger regulator for pesticides. Potentially toxic chemicals should not be registered when more benign solutions exist, risks are not clearly quantifiable or potential risks outweigh benefits. Until landscaping pesticides are curtailed nationally, local bylaws and Quebec’s Pesticide Code are prudent measures to protect public health. Physicians have a role in public education regarding pesticides.  相似文献   
7.
8.
9.
Piceatannol (3,4,3',5'-tetrahydroxy-trans-stilbene) (NSC 365798) has recently been isolated and was subsequently synthesized for NCI tumor panel testing as a new antileukemic natural product from the seeds of Euphorbia lagascae. During the synthesis, a bioactive reaction mixture of several partially O-methylated piceatannol analogues was obtained. This mixture has now been maximized and subjected to bioactivity-directed fractionation, using brine shrimp lethality, to yield 3,3',5'-tri-O-methylpiceatannol (NSC 381281); this new compound has improved stability and better bioactivity in several systems than piceatannol itself. To confirm the structure, 5 was synthesized from vanillin. In addition, the isovanillin analogue, 4,3',5'-tri-O-methylpiceatannol (NSC 381864), another new compound, was synthesized and found to be bioactive.  相似文献   
10.
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