全文获取类型
收费全文 | 30839篇 |
免费 | 2511篇 |
国内免费 | 47篇 |
专业分类
耳鼻咽喉 | 332篇 |
儿科学 | 988篇 |
妇产科学 | 719篇 |
基础医学 | 4176篇 |
口腔科学 | 567篇 |
临床医学 | 3650篇 |
内科学 | 5914篇 |
皮肤病学 | 535篇 |
神经病学 | 3068篇 |
特种医学 | 937篇 |
外国民族医学 | 2篇 |
外科学 | 4174篇 |
综合类 | 453篇 |
一般理论 | 29篇 |
预防医学 | 3107篇 |
眼科学 | 752篇 |
药学 | 2215篇 |
1篇 | |
中国医学 | 36篇 |
肿瘤学 | 1742篇 |
出版年
2022年 | 205篇 |
2021年 | 629篇 |
2020年 | 347篇 |
2019年 | 579篇 |
2018年 | 627篇 |
2017年 | 494篇 |
2016年 | 549篇 |
2015年 | 613篇 |
2014年 | 910篇 |
2013年 | 1253篇 |
2012年 | 1906篇 |
2011年 | 2020篇 |
2010年 | 1006篇 |
2009年 | 972篇 |
2008年 | 1653篇 |
2007年 | 1669篇 |
2006年 | 1666篇 |
2005年 | 1568篇 |
2004年 | 1556篇 |
2003年 | 1467篇 |
2002年 | 1279篇 |
2001年 | 610篇 |
2000年 | 620篇 |
1999年 | 579篇 |
1998年 | 356篇 |
1997年 | 252篇 |
1996年 | 282篇 |
1995年 | 255篇 |
1994年 | 207篇 |
1993年 | 222篇 |
1992年 | 477篇 |
1991年 | 451篇 |
1990年 | 445篇 |
1989年 | 410篇 |
1988年 | 410篇 |
1987年 | 397篇 |
1986年 | 384篇 |
1985年 | 403篇 |
1984年 | 322篇 |
1983年 | 259篇 |
1982年 | 189篇 |
1981年 | 172篇 |
1980年 | 168篇 |
1979年 | 275篇 |
1978年 | 201篇 |
1977年 | 154篇 |
1976年 | 149篇 |
1975年 | 149篇 |
1974年 | 149篇 |
1973年 | 151篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Meg Sears C Robin Walker Richard HC van der Jagt Paul Claman 《Paediatrics & child health》2006,11(4):229-234
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
32.
We would like to thank Professor Erdem Kasikcioglu for his interestin our article. In response to the initial question of why exhaustivephysical activity suppresses diastolic function, 相似文献
33.
Sanjay Sisodiya J Helen Cross Ingmar Blümcke David Chadwick John Craig Peter B Crino Paul Debenham Norman Delanty Frances Elmslie Mark Gardiner Jeffrey Golden David Goldstein David A Greenberg Renzo Guerrini Michael Hanna John Harris Paul Harrison Michael R Johnson George Kirov Dimitri M Kullman Andrew Makoff Carla Marini Rima Nabbout Lina Nashef Jeffrey L Noebels Ruth Ottman Munir Pirmohamed Asla Pitk?nen Ingrid Scheffer Simon Shorvon Graeme Sills Nicholas Wood Sameer Zuberi 《Epileptic Disord》2007,9(2):194-236
The Sixth Epilepsy Research Foundation workshop, held in Oxford in March 2006, brought together basic scientists, geneticists, epidemiologists, statisticians, pharmacologists and clinicians to consider progress, issues and strategies for harnessing genetics to improve the understanding and treatment of the epilepsies. General principles were considered, including the fundamental importance of clear study design, adequate patient numbers, defi ned phenotypes, robust statistical data handling, and follow-up of genetic discoveries. Topics where some progress had been made were considered including chromosomal abnormalities, neurodevelopment, hippocampal sclerosis, juvenile myoclonic epilepsy, focal cortical dysplasia and pharmacogenetics. The ethical aspects of epilepsy genetics were reviewed. Principles and limitations of collaboration were discussed. Presentations and their matched discussions are produced here. There was optimism that further genetic research in epilepsy was not only feasible, but might lead to improvements in the lives of people with epilepsy. 相似文献
34.
This column contains the presidential address presented during the Third Annual Meeting of the American Association of Heart Failure Nurses on June 28, 2007, in San Diego, California, titled "Building the Foundation of Excellence in Heart Failure Nursing." 相似文献
35.
36.
The danger management strategies of low‐income African American women who live in a public housing community characterized by chronic violence are examined. Based on qualitative interviews with 18 single mothers, we explored the violent community dangers with which women contend, the nature of this violence, the strategies used to deal with community violence, and their benefits and costs to family and community life. Findings show that multiple types of violence characterized life in the community and that this violence has specific physical locations, a particular set of actors, and a temporal rhythm. Women's responses to violence were nonconfrontational and family focused in nature. These efforts were effective in keeping women and their children safe, but did not reduce the prevalence of violence. 相似文献
37.
38.
Peter B. Richman MD Shari Dominguez MD David Kasper MD Frederick Chen MD Jeremy Friese MD Joseph Wood MD JD Joseph Collins MD Jeffrey A. Kline MD 《Academic emergency medicine》2006,13(3):295-301
Objectives: To determine interobserver agreement between radiologists for computed tomography (CT) angiography and venography. CT venography of the lower extremities combined with standard CT angiography of the chest may result in an increased overall diagnosis rate of venous thromboembolism (pulmonary embolism or deep venous thrombosis).
Methods: The study had a retrospective cohort design. The population consisted of emergency department patients who were evaluated for suspected pulmonary embolism. A random sample of 50 patients diagnosed and treated for venous thromboembolism and 50 age- and gender-matched patients whose CT angiograms and venograms were read as negative were enrolled. The original reading (R1) was compared with readings of two study radiologists: R2, a general radiologist, and R3, a radiologist with fellowship training in cross-sectional imaging. All readers were blinded to each other.
Results: Both R2 and R3 found both CT angiogram and venogram components technically adequate in 95% (95% CI = 89% to 98%) and 86% (95% CI = 78% to 92%) of studies, respectively. The agreement was very good for CT angiography (lowest agreement = 92%; lowest κ = 0.83) and was good for CT venography (85%, κ = 0.65). In nine cases, R1 read the CT angiogram as negative but the venogram as positive for DVT, whereas both R2 and R3 read both components as negative in four of these nine, suggesting a false-positive isolated DVT rate of 44% (95% CI = 19% to 73%). In no case did R1 read both scan components as negative when R2 and R3 agreed on presence of pulmonary embolism or DVT.
Conclusions: Diagnosis of pulmonary embolism on CT angiography is more reliable than diagnosis of isolated DVT on CT venography. 相似文献
Methods: The study had a retrospective cohort design. The population consisted of emergency department patients who were evaluated for suspected pulmonary embolism. A random sample of 50 patients diagnosed and treated for venous thromboembolism and 50 age- and gender-matched patients whose CT angiograms and venograms were read as negative were enrolled. The original reading (R1) was compared with readings of two study radiologists: R2, a general radiologist, and R3, a radiologist with fellowship training in cross-sectional imaging. All readers were blinded to each other.
Results: Both R2 and R3 found both CT angiogram and venogram components technically adequate in 95% (95% CI = 89% to 98%) and 86% (95% CI = 78% to 92%) of studies, respectively. The agreement was very good for CT angiography (lowest agreement = 92%; lowest κ = 0.83) and was good for CT venography (85%, κ = 0.65). In nine cases, R1 read the CT angiogram as negative but the venogram as positive for DVT, whereas both R2 and R3 read both components as negative in four of these nine, suggesting a false-positive isolated DVT rate of 44% (95% CI = 19% to 73%). In no case did R1 read both scan components as negative when R2 and R3 agreed on presence of pulmonary embolism or DVT.
Conclusions: Diagnosis of pulmonary embolism on CT angiography is more reliable than diagnosis of isolated DVT on CT venography. 相似文献
39.
D. Grant Richards Kevin G. Whithear Peter C. Scott Robin B. Gasser 《Acta parasitologica / Witold Stefański Institute of Parasitology, Warszawa, Poland》2006,51(2):156-159
Coccidiosis of chickens, caused by species of Eimeria (Protozoa, Apicomplexa), is an intestinal disease of major economic importance worldwide. In the present study, the reproductive
characteristics of a precocious line (designated E. tenella Rt3+15) from Australia were investigated in chicken embryos and the implications of the findings briefly discussed. 相似文献
40.
Nuray
. Kanbur Eudice Goldberg Leora Pinhas Robert M. Hamilton Robin Clegg Debra K. Katzman 《The International journal of eating disorders》2009,42(6):575-578
Anorexia nervosa (AN) can cause both functional and structural cardiac complications, including a variety of different conduction abnormalities. This is the first case report of symptomatic diurnal second‐degree atrioventricular (AV) block (Mobitz Type I) in an adolescent with AN. We present a 12‐year‐old girl with AN, restrictor sub‐type who reported cardiac symptoms during weight gain, at the time of the initial diagnosis of AV block. Second‐degree AV block (Mobitz Type I) is discussed as a possible complication of the AN, as well as being an intrinsic conduction system disease. © 2009 by Wiley Periodicals, Inc. Int J Eat Disord 2009 相似文献