全文获取类型
收费全文 | 1539篇 |
免费 | 89篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 13篇 |
儿科学 | 201篇 |
妇产科学 | 16篇 |
基础医学 | 227篇 |
口腔科学 | 28篇 |
临床医学 | 161篇 |
内科学 | 297篇 |
皮肤病学 | 22篇 |
神经病学 | 118篇 |
特种医学 | 138篇 |
外科学 | 148篇 |
综合类 | 17篇 |
预防医学 | 100篇 |
眼科学 | 7篇 |
药学 | 98篇 |
中国医学 | 1篇 |
肿瘤学 | 37篇 |
出版年
2022年 | 6篇 |
2021年 | 14篇 |
2020年 | 9篇 |
2019年 | 14篇 |
2018年 | 17篇 |
2017年 | 15篇 |
2016年 | 25篇 |
2015年 | 26篇 |
2014年 | 25篇 |
2013年 | 50篇 |
2012年 | 66篇 |
2011年 | 61篇 |
2010年 | 59篇 |
2009年 | 48篇 |
2008年 | 56篇 |
2007年 | 74篇 |
2006年 | 60篇 |
2005年 | 71篇 |
2004年 | 55篇 |
2003年 | 52篇 |
2002年 | 58篇 |
2001年 | 56篇 |
2000年 | 51篇 |
1999年 | 31篇 |
1998年 | 35篇 |
1997年 | 43篇 |
1996年 | 32篇 |
1995年 | 35篇 |
1994年 | 31篇 |
1993年 | 42篇 |
1992年 | 30篇 |
1991年 | 21篇 |
1990年 | 38篇 |
1989年 | 27篇 |
1988年 | 34篇 |
1987年 | 22篇 |
1986年 | 30篇 |
1985年 | 28篇 |
1984年 | 12篇 |
1983年 | 13篇 |
1982年 | 19篇 |
1981年 | 23篇 |
1980年 | 7篇 |
1979年 | 7篇 |
1978年 | 13篇 |
1977年 | 15篇 |
1976年 | 17篇 |
1975年 | 9篇 |
1974年 | 5篇 |
1972年 | 6篇 |
排序方式: 共有1629条查询结果,搜索用时 15 毫秒
91.
Radiographs, computed tomograms, and radionuclide bone scans were obtained preoperatively in three children with fibromatosis involving the bones and soft tissues of the extremities. Two of the children had identical scar-like bone lesions of the proximal tibia, which, to the authors' knowledge, have not been reported before in this disease. The lesions recurred in two children. 相似文献
92.
93.
94.
95.
Georg Reiser Rolf Heumann Wayne Kemper Edith Lautenschlager Bernd Hamprecht 《Brain research》1977,130(3):495-504
Electrical excitability is one of the various neuronal properties of neuroblastoma × glioma hybrid cells. At a Ca2+ concentration of 1.8mM the action potential is inhibited by tetrodotoxin, suggesting that the inward current is carried by Na+ ions. In contrast, at a Ca2+ concentration of 20–36mM and even in the absence of Na+, spikes (sometimes repetitive) with strong hyperpolarizing afterpotential occur, which are no longer affected by tetrodotoxin. They are, however, blocked by antagonists of Ca2+ like La3+, Co2+, Mn2+, and the synthetic compounds D-600 and BAY a-1040. This seems to indicate that at high concentrations of Ca2+, the inward current of the action potential is essentially carried by Ca2+. Sr2+, but not Mg2+ can effectively substitute for Ca2+. It shows down the time course of the action potential. Ba2+ depolarizes the membrane gradually. If Ca2+ is also present, Ba2+ causes a reduced depolarization and spontaneous action potentials with no hyperpolarizing after-potential are observed. 相似文献
96.
Koppes LL Twisk JW Van Mechelen W Snel J Kemper HC 《Journal of studies on alcohol》2005,66(6):713-721
OBJECTIVE: Serum lipids, blood pressure and body mass may mediate the U-shaped relationship of alcohol consumption with type 2 diabetes mellitus and coronary heart disease. This study examines the cross-sectional and long-term longitudinal relationships of (changes in) alcohol consumption with (changes in) serum lipids, blood pressure and body mass indices. METHOD: In this prospective, observational cohort study, two measurements of alcohol consumption, serum total and high-density lipoprotein cholesterol, triglycerides, blood pressure, body weight, the thickness of four skinfolds and waist circumference were performed 4 years apart in healthy volunteers (143 men and 174 women, 32 years old at the first measurement). Alcohol consumption from beer, wine and distilled spirits was assessed using an extensive dietary history interview. Linear regression analyses were performed to study the cross-sectional relationships between the amount of alcohol consumed at the age of 32 years and the levels of the lipids, blood pressure and body weight indices, and to study the longitudinal relationships between the changes in the amount of alcohol consumed over the 4 years of follow-up and the concurrent changes in the lipids, blood pressure and body weight indices. Nonlinearity was investigated for the cross-sectional relationships. RESULTS: A 10-g/day difference in alcohol consumption was positively related with a 0.05 mmol/L (1.9 mg/dl) difference in high-density lipoprotein cholesterol in both cross-sectional (p = .004), and longitudinal (p < .0001) analyses. This relationship did not differ for men and women or for the consumption of beer, wine or distilled spirits. Relationships with changes in total cholesterol, triglycerides, systolic, diastolic, and pulse pressure, body weight and the sum of four skinfolds were not significant. A borderline significant inverse longitudinal relationship was found with waist circumference. The other lifestyle behaviors (tobacco smoking, physical activity and dietary habits) were major confounders of most cross-sectional relationships between alcohol and serum lipids, blood pressure and body mass indices. The longitudinal relationships, however, were not confounded by changes in the other lifestyle behaviors. A significant nonlinear relationship was found for systolic blood pressure, in which drinkers of about 30 g/day had the lowest values. CONCLUSIONS: Moderate alcohol consumption and moderate long-term changes in alcohol consumption are positively related with the levels and changes in high-density lipoprotein cholesterol in healthy adult men and women. A moderate inverse association between alcohol and waist circumference may be expected. No relationships were found with triglycerides, blood pressure, body weight and the sum of the thickness of four skinfolds. Other lifestyle behaviors confound the cross-sectional, but not the longitudinal, relationships between alcohol consumption and serum lipids, blood pressure and body mass indices. Gender and type of beverage do not modify the relationships between alcohol consumption and these indices. 相似文献
97.
Kremers SP Visscher TL Brug J Chin A Paw MJ Schouten EG Schuit AJ Seidell JC Van Baak MA Van Mechelen W Kemper HC Kok FJ Saris WH Kromhout D 《European journal of clinical nutrition》2005,59(4):498-507
OBJECTIVE: To outline the rationale, objectives and strategies used in a systematically designed research programmme to study specific weight gain-inducing behaviours, their social-psychological as well as environmental determinants, and the effects of interventions aimed at the prevention of weight gain. DESIGN: The evidence for potential behavioural determinants and strategies to prevent weight gain was reviewed, and the methods applied within the Netherlands Research programme weight gain prevention (NHF-NRG) project were described. The project is designed according to the Intervention Mapping protocol. SETTING: The Netherlands. SUBJECTS: The main target groups are (a) adolescents (12-16 y) in secondary school, (b) young adults (20-40 y) at the workplace and (c) recently retired people (55-65 y) at home. INTERVENTIONS: Each intervention includes an individual component, in which computer-tailored information is provided. Additionally, interventions are aimed at changing environmental components. RESULTS: The short-term results of this project can be expected by the beginning of 2005. Guidelines for nationwide weight gain prevention, based on this research programme, will become available in 2007. CONCLUSIONS: Based on the few interventions that were evaluated to date, no robust conclusions can be drawn regarding the effectiveness of obesity prevention. The systematic and multidisciplinary design of the NHF-NRG programme enables the identification of potentially effective methods and strategies for the prevention of weight gain. 相似文献
98.
In the past 20 years, our understanding of the workings of complement regulatory protein, CD46 (membrane cofactor protein),
has grown as has the impressive list of pathogens interacting with this membrane-bound complement inhibitor. Referred to as
a “pathogen magnet,” CD46 serves as a receptor for seven human pathogens. Initially discovered as a widely expressed C3b-
and C4b-binding protein, it was subsequently shown to be a cofactor for the serine protease factor I to inactivate by limited
proteolysis these two opsonins and components of the convertases. The involvement of CD46 in reproductive processes continues
to be an emerging story. It is a protector of placental tissue, but it may also play a more direct role in reproduction through
its expression on the inner acrosomal membrane of spermatozoa. Cross-linking CD46 with antibodies or natural or pathogenic
ligands induces rapid turnover and signaling events. In this regard, much attention is currently focused on generating human
T lymphocyte regulatory cells by cross-linking CD46. Finally, highlighting its importance in protecting cells against excessive
complement activation is the discovery that even a heterozygous deficiency of CD46 predisposes to hemolytic uremic syndrome. 相似文献
99.
100.
Computed tomography of abdominal fatty masses 总被引:2,自引:0,他引:2