全文获取类型
收费全文 | 946817篇 |
免费 | 76967篇 |
国内免费 | 2543篇 |
专业分类
耳鼻咽喉 | 13783篇 |
儿科学 | 27294篇 |
妇产科学 | 27219篇 |
基础医学 | 135647篇 |
口腔科学 | 27502篇 |
临床医学 | 82277篇 |
内科学 | 183229篇 |
皮肤病学 | 18830篇 |
神经病学 | 77950篇 |
特种医学 | 38564篇 |
外国民族医学 | 194篇 |
外科学 | 148301篇 |
综合类 | 26181篇 |
现状与发展 | 2篇 |
一般理论 | 303篇 |
预防医学 | 71843篇 |
眼科学 | 21844篇 |
药学 | 71699篇 |
3篇 | |
中国医学 | 2087篇 |
肿瘤学 | 51575篇 |
出版年
2018年 | 9177篇 |
2016年 | 8013篇 |
2015年 | 9443篇 |
2014年 | 13358篇 |
2013年 | 20080篇 |
2012年 | 27130篇 |
2011年 | 28389篇 |
2010年 | 16817篇 |
2009年 | 15659篇 |
2008年 | 26622篇 |
2007年 | 28831篇 |
2006年 | 28530篇 |
2005年 | 27968篇 |
2004年 | 27828篇 |
2003年 | 26847篇 |
2002年 | 26001篇 |
2001年 | 39174篇 |
2000年 | 39768篇 |
1999年 | 33548篇 |
1998年 | 10255篇 |
1997年 | 9339篇 |
1996年 | 9200篇 |
1995年 | 8704篇 |
1994年 | 8351篇 |
1992年 | 28241篇 |
1991年 | 27669篇 |
1990年 | 26924篇 |
1989年 | 25967篇 |
1988年 | 24388篇 |
1987年 | 23948篇 |
1986年 | 22763篇 |
1985年 | 22001篇 |
1984年 | 17067篇 |
1983年 | 14614篇 |
1982年 | 9229篇 |
1981年 | 8546篇 |
1980年 | 7986篇 |
1979年 | 17225篇 |
1978年 | 12475篇 |
1977年 | 10510篇 |
1976年 | 9623篇 |
1975年 | 10533篇 |
1974年 | 13064篇 |
1973年 | 12542篇 |
1972年 | 11910篇 |
1971年 | 11031篇 |
1970年 | 10534篇 |
1969年 | 10226篇 |
1968年 | 9202篇 |
1967年 | 8508篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Thomas W. McDade Alexander V. Georgiev Christopher W. Kuzawa 《Evolution, Medicine, and Public Health》2016,2016(1):1-16
Immune defenses provide resistance against infectious disease that is critical to survival. But immune defenses are costly, and limited resources allocated to immunity are not available for other physiological or developmental processes. We propose a framework for explaining variation in patterns of investment in two important subsystems of anti-pathogen defense: innate (non-specific) and acquired (specific) immunity. The developmental costs of acquired immunity are high, but the costs of maintenance and activation are relatively low. Innate immunity imposes lower upfront developmental costs, but higher operating costs. Innate defenses are mobilized quickly and are effective against novel pathogens. Acquired responses are less effective against novel exposures, but more effective against secondary exposures due to immunological memory. Based on their distinct profiles of costs and effectiveness, we propose that the balance of investment in innate versus acquired immunity is variable, and that this balance is optimized in response to local ecological conditions early in development. Nutritional abundance, high pathogen exposure and low signals of extrinsic mortality risk during sensitive periods of immune development should all favor relatively higher levels of investment in acquired immunity. Undernutrition, low pathogen exposure, and high mortality risk should favor innate immune defenses. The hypothesis provides a framework for organizing prior empirical research on the impact of developmental environments on innate and acquired immunity, and suggests promising directions for future research in human ecological immunology. 相似文献
92.
More than just crushing: a prospective pre‐post intervention study to reduce drug preparation errors in patients with feeding tubes 下载免费PDF全文
93.
94.
95.
96.
97.
98.
L. Misery E. Weisshaar E. Brenaut A.W.M. Evers F. Huet S. Ständer A. Reich E. Berardesca E. Serra-Baldrich J. Wallengren D. Linder J.W. Fluhr J.C. Szepietowski H. Maibach for the Special Interest Group on sensitive skin of the International Forum for the Study of Itch 《Journal of the European Academy of Dermatology and Venereology》2020,34(2):222-229
The special interest group on sensitive skin of the International Forum for the Study of Itch previously defined sensitive skin as a syndrome defined by the occurrence of unpleasant sensations (stinging, burning, pain, pruritus and tingling sensations) in response to stimuli that normally should not provoke such sensations. This additional paper focuses on the pathophysiology and the management of sensitive skin. Sensitive skin is not an immunological disorder but is related to alterations of the skin nervous system. Skin barrier abnormalities are frequently associated, but there is no cause and direct relationship. Further studies are needed to better understand the pathophysiology of sensitive skin – as well as the inducing factors. Avoidance of possible triggering factors and the use of well-tolerated cosmetics, especially those containing inhibitors of unpleasant sensations, might be suggested for patients with sensitive skin. The role of psychosocial factors, such as stress or negative expectations, might be relevant for subgroups of patients. To date, there is no clinical trial supporting the use of topical or systemic drugs in sensitive skin. The published data are not sufficient to reach a consensus on sensitive skin management. In general, patients with sensitive skin require a personalized approach, taking into account various biomedical, neural and psychosocial factors affecting sensitive skin. 相似文献
99.
100.
Although hepatitis E virus (HEV) is the primary cause of enterically transmitted acute hepatitis and jaundice in developing countries, locally acquired HEV infections are increasing in nonendemic countries. As such, HEV is emerging as an underdiagnosed cause of infection. This report describes three clinically variable cases of HEV infection with unusual clinical presentations. These cases highlight the fact that HEV should be considered in the differential diagnosis of patients with unexplained hepatitis (acute or chronic) with or without extrahepatic manifestations. HEV should also be considered in patients with persistently elevated liver enzymes who have not travelled to known HEV-endemic regions. Lack of knowledge among physicians and an absence of standardized diagnostic tests may result in increased morbidity and mortality from HEV infection. 相似文献