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   1538篇
  免费   54篇
  国内免费   39篇
耳鼻咽喉   16篇
儿科学   58篇
妇产科学   38篇
基础医学   160篇
口腔科学   164篇
临床医学   115篇
内科学   280篇
皮肤病学   43篇
神经病学   142篇
特种医学   71篇
外科学   266篇
综合类   17篇
预防医学   79篇
眼科学   24篇
药学   99篇
中国医学   20篇
肿瘤学   39篇
  2023年   6篇
  2022年   24篇
  2021年   32篇
  2020年   27篇
  2019年   40篇
  2018年   36篇
  2017年   26篇
  2016年   32篇
  2015年   41篇
  2014年   50篇
  2013年   79篇
  2012年   127篇
  2011年   145篇
  2010年   91篇
  2009年   85篇
  2008年   101篇
  2007年   127篇
  2006年   100篇
  2005年   66篇
  2004年   60篇
  2003年   51篇
  2002年   48篇
  2001年   14篇
  2000年   7篇
  1999年   12篇
  1998年   22篇
  1997年   21篇
  1996年   25篇
  1995年   13篇
  1994年   25篇
  1993年   6篇
  1992年   2篇
  1991年   6篇
  1990年   7篇
  1989年   9篇
  1988年   7篇
  1987年   6篇
  1986年   8篇
  1985年   6篇
  1984年   6篇
  1982年   4篇
  1981年   2篇
  1980年   2篇
  1979年   2篇
  1978年   5篇
  1977年   12篇
  1976年   2篇
  1970年   1篇
  1965年   1篇
  1942年   1篇
排序方式: 共有1631条查询结果,搜索用时 15 毫秒
1.
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   
2.
Kim  SH; Chang  KH; Song  IC; Han  MH; Kim  HC; Kang  HS; Han  MC 《Radiology》1997,204(1):239
  相似文献   
3.
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   
4.
5.
6.
7.
8.
9.
Hyperparathyroidism contributes significantly to decreased bone mineral density (BMD) in end-stage renal disease patients, but this negative influence is not homogeneous throughout the skeleton. We studied the BMD by dual-energy X-ray absorptiometry on total body and on different regions of the skeleton in 42 patients with severe hyperparathyroidism on hemodialysis. We also evaluated the relationship between different risk factors and BMD found on the regions examined in these patients. The legs and other sites where cortical bone predominate were mostly affected, whereas trabecular bone was relatively preserved. This is probably the result of the different effects of hyperparathyroidism on cortical and trabecular bone, but we cannot rule out the interference of ectopic calcifications and sclerotic lesions of vertebral end-plates falsely increasing lumbar spine BMD. The main determinants of low total-body BMD were, in order of importance, immobility, high intact parathyroid hormone levels, low body mass index, and low albumin. Eleven patients presented with pathologic fractures, mainly in the legs, and BMD was lower in this group than in patients without fractures. In conclusion, our study makes clear that hyperparathyroidism is a great threat to bone density in hemodialysis patients, mainly in the legs, the site mostly affected by fragility fractures in our patients. Physicians must worry not only with high parathyroid hormone levels, but also with the nutritional state of these patients.  相似文献   
10.
The purpose of this study was to investigate the antiproliferative activity of 2,3,9-trimethoxypterocarpan, a known pterocarpan with cytotoxic activity against many tumor cell lines, in a panel of four leukemia cell lines (HL-60, Molt-4, Jurkat, and K562) and on human peripheral blood mononuclear cells (PBMC). The pterocarpan showed IC50 ranging from 0.1 to 0.5 μg/ml at leukemic cells after 72 h of incubation, with K562 being the most resistant cell line. This compound seemed to be selective to tumor cell lines, since at a concentration of 10 μg/ml after 72 h, it only reduced 19% of viable peripheral mononuclear cells.  相似文献   
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