全文获取类型
收费全文 | 3057篇 |
免费 | 209篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 20篇 |
儿科学 | 86篇 |
妇产科学 | 18篇 |
基础医学 | 290篇 |
口腔科学 | 48篇 |
临床医学 | 357篇 |
内科学 | 584篇 |
皮肤病学 | 20篇 |
神经病学 | 236篇 |
特种医学 | 135篇 |
外国民族医学 | 1篇 |
外科学 | 571篇 |
综合类 | 41篇 |
一般理论 | 2篇 |
预防医学 | 406篇 |
眼科学 | 49篇 |
药学 | 240篇 |
肿瘤学 | 171篇 |
出版年
2023年 | 9篇 |
2022年 | 15篇 |
2021年 | 45篇 |
2020年 | 27篇 |
2019年 | 51篇 |
2018年 | 49篇 |
2017年 | 49篇 |
2016年 | 57篇 |
2015年 | 69篇 |
2014年 | 87篇 |
2013年 | 158篇 |
2012年 | 217篇 |
2011年 | 252篇 |
2010年 | 126篇 |
2009年 | 129篇 |
2008年 | 180篇 |
2007年 | 209篇 |
2006年 | 201篇 |
2005年 | 235篇 |
2004年 | 220篇 |
2003年 | 200篇 |
2002年 | 183篇 |
2001年 | 41篇 |
2000年 | 38篇 |
1999年 | 53篇 |
1998年 | 40篇 |
1997年 | 37篇 |
1996年 | 20篇 |
1995年 | 16篇 |
1994年 | 15篇 |
1993年 | 28篇 |
1992年 | 25篇 |
1991年 | 24篇 |
1990年 | 32篇 |
1989年 | 16篇 |
1988年 | 12篇 |
1987年 | 11篇 |
1986年 | 9篇 |
1985年 | 10篇 |
1984年 | 10篇 |
1983年 | 6篇 |
1982年 | 14篇 |
1981年 | 6篇 |
1980年 | 10篇 |
1979年 | 8篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1973年 | 3篇 |
1967年 | 3篇 |
1960年 | 2篇 |
排序方式: 共有3275条查询结果,搜索用时 15 毫秒
61.
62.
63.
Kraus CL Salazar NC Mitchell JR Florin WD Guenther B Brady D Swartzwelder SH White AM 《Alcoholism, clinical and experimental research》2005,29(9):1672-1676
BACKGROUND: Alcohol use by college students is commonly measured through the use of surveys. The validity of such data hinge on the assumption that students are aware of how much alcohol they actually consume. Recent studies call this assumption into question. Students tend to overestimate the appropriate sizes of standard drinks, suggesting that they might underestimate how much alcohol they consume. If this is true, then students' actual blood alcohol concentrations (BACs) should be higher than BACs estimated based on self-report data. The present study examined this issue METHODS: Breathalyzer readings and self-reported drinking data were collected from 152 college students during the fall of 2004. Estimated BACs were calculated by means of a standard formula, and the relation between actual and estimated BACs was examined. Factors contributing to discrepancies between the two values were identified RESULTS: Estimated BAC levels were significantly higher, not lower, than breath BAC measures. The accuracy of estimated BACs decreased as the number of drinks and amount of time spent drinking increased. Being male and drinking only beer predicted greater accuracy of estimated BACs CONCLUSIONS: Although laboratory data suggest that students underestimate how much they drink, the hypothesis was not supported by data collected in the field. It appears that students might actually overestimate rather than underestimate their levels of consumption when surveyed in the midst of a night of drinking. The findings corroborate observations made by other researchers and suggest that the findings of laboratory studies on college drinking do not necessarily extend to real-world settings. 相似文献
64.
65.
Noninvasive assessment of coronary vasodilation using magnetic resonance angiography 总被引:1,自引:0,他引:1
Terashima M Meyer CH Keeffe BG Putz EJ de la Pena-Almaguer E Yang PC Hu BS Nishimura DG McConnell MV 《Journal of the American College of Cardiology》2005,45(1):104-110
OBJECTIVES: The purpose of this study was to investigate the use of coronary magnetic resonance angiography (MRA) for assessing human epicardial coronary artery vasodilation. BACKGROUND: Coronary vasodilation plays a vital role in the human coronary circulation. Previous studies of epicardial coronary vasodilation have used invasive coronary angiography. Coronary MRA may provide an alternative noninvasive method to directly assess changes in coronary size. METHODS: Thirty-two subjects were studied: 12 patients (age 55 +/- 18 years) and 20 healthy subjects (age 34 +/- 4 years). High-resolution multi-slice spiral coronary MRA (in-plane resolution of 0.52 to 0.75 mm) was performed before and after sublingual nitroglycerin (NTG). Quantitative analysis of coronary vasodilation was performed on cross-sectional images of the right coronary artery (RCA). A time-course analysis of coronary vasodilation was performed in a subset of eight subjects for 30 min after NTG. Signal-to-noise ratio was also measured on the in-plane RCA images. RESULTS: Coronary MRA demonstrated a 23% increase in cross-sectional area after NTG (16.9 +/- 7.8 mm2 to 20.8 +/- 8.9 mm2, p <0.0001), with significant vasodilation between 3 and 15 min after NTG on time-course analysis. The MRA measurements had low interobserver variability (< or =5%) and good correlation with X-ray angiography (r=0.98). The magnitude of vasodilation correlated with baseline cross-sectional area (r=0.52, p=0.03) and age (r=0.40, p=0.019). Post-NTG images also demonstrated a 31% improvement in coronary signal-to-noise ratio (p = 0.002). CONCLUSIONS: Nitroglycerin-enhanced coronary MRA can noninvasively measure coronary artery vasodilation and is a promising noninvasive technique to study coronary vasomotor function. 相似文献
66.
Shanthi Ganesh Xue Shui Kevin P. Craig Jihye Park Weimin Wang Bob D. Brown Marc T. Abrams 《Molecular therapy》2018,26(11):2567-2579
67.
68.
McGarrigle CA Mercer CH Fenton KA Copas AJ Wellings K Erens B Johnson AM 《AIDS (London, England)》2005,19(1):77-84
OBJECTIVES: To estimate the prevalence of, and identify factors associated with, HIV testing in Britain. DESIGN: A large, stratified probability sample survey of sexual attitudes and lifestyles. METHODS: A total of 12,110 16-44 year olds completed a computer-assisted face-to-face interview and self-interview. Self-reports of HIV testing, i.e. the timing, reasons for and location of testing, were included. RESULTS: A total of 32.4% of men and 31.7% of women reported ever having had an HIV test, the majority of whom were tested through blood donation. When screening for blood donation and pregnancy were excluded, 9.0% of men and 4.6% of women had had a voluntary confidential HIV test (VCT) in the past 5 years. However, one third of injecting drug users and men who have sex with men had a VCT in the past 5 years. VCT in the past 5 years was significantly associated with age, residence, ethnicity, self-perceived HIV risk, reporting greater numbers of sexual partners, new sexual partners from abroad, previous sexually transmitted infection diagnosis, and injecting non-prescribed drugs for men and women, and same-sex partners (men only). Whereas sexually transmitted disease clinics were important sites for VCT, general practice accounted for almost a quarter of VCT. CONCLUSION: HIV testing is relatively common in Britain; however, it remains largely associated with population-based blood donation and antenatal screening programmes. In contrast, VCT remains highly associated with high-risk (sexual or drug-injecting) behaviours or population sub-groups at high risk. Strategies to reduce undiagnosed prevalent HIV infection will require further normalization and wider uptake of HIV testing. 相似文献
69.
Incidence and prognosis of c-KIT and FLT3 mutations in core binding factor (CBF) acute myeloid leukaemias 总被引:26,自引:0,他引:26
Care RS Valk PJ Goodeve AC Abu-Duhier FM Geertsma-Kleinekoort WM Wilson GA Gari MA Peake IR Löwenberg B Reilly JT 《British journal of haematology》2003,121(5):775-777
DNA from 110 adult de novo acute myeloid leukaemia (AML) patients exhibiting either inv(16) (n = 63) or t(8;21) (n = 47) was screened for mutations in the c-KIT (exon 8 and Asp816) and FLT3 (ITD and Asp835) genes. c-KIT exon 8 mutations were found in 15/63 (23.8%) inv(16) patients and 1/47 (2.1%) t(8;21) patients. c-KIT Asp816 mutations were present in 5/63 (7.9%) inv(16) AML and 5/47 (10.6%) t(8;21) AML. FLT3 mutations were identified in five patients (7.9%) with inv(16) and three patients (5.6%) with t(8;21) AML. All mutations were mutually exclusive; 40% of inv(16) AML patients possessed either a c-KIT or FLT3 mutation. c-KIT exon 8 mutations were shown to be a significant factor adversely affecting relapse rate. 相似文献
70.
Prof. Dr. T.F.E. Barth L. Floßbach H.-W. Bernd R. Bob M. Buck S.B. Cogliatti A.C. Feller M.L. Hansmann S. Hartmann H. Horn W. Klapper D. Kradolfer T. Mattfeldt P. Möller A. Rosenwald H. Stein C. Thorns G. Ott 《Der Pathologe》2013,34(4):329-334