全文获取类型
收费全文 | 530篇 |
免费 | 13篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 2篇 |
妇产科学 | 7篇 |
基础医学 | 71篇 |
口腔科学 | 11篇 |
临床医学 | 78篇 |
内科学 | 173篇 |
皮肤病学 | 1篇 |
神经病学 | 17篇 |
特种医学 | 18篇 |
外科学 | 54篇 |
一般理论 | 1篇 |
预防医学 | 52篇 |
眼科学 | 3篇 |
药学 | 13篇 |
中国医学 | 1篇 |
肿瘤学 | 32篇 |
出版年
2021年 | 5篇 |
2020年 | 5篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2017年 | 6篇 |
2016年 | 7篇 |
2015年 | 8篇 |
2014年 | 12篇 |
2013年 | 18篇 |
2012年 | 25篇 |
2011年 | 13篇 |
2010年 | 9篇 |
2009年 | 13篇 |
2008年 | 16篇 |
2007年 | 24篇 |
2006年 | 18篇 |
2005年 | 22篇 |
2004年 | 31篇 |
2003年 | 19篇 |
2002年 | 18篇 |
2001年 | 14篇 |
2000年 | 11篇 |
1999年 | 13篇 |
1998年 | 5篇 |
1997年 | 10篇 |
1996年 | 6篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 10篇 |
1992年 | 10篇 |
1991年 | 19篇 |
1990年 | 13篇 |
1989年 | 8篇 |
1988年 | 9篇 |
1987年 | 15篇 |
1986年 | 12篇 |
1985年 | 16篇 |
1984年 | 7篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1979年 | 13篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1975年 | 6篇 |
1974年 | 5篇 |
1972年 | 6篇 |
1966年 | 4篇 |
1963年 | 2篇 |
排序方式: 共有543条查询结果,搜索用时 0 毫秒
31.
Tapani Luukkainen Niels-Christian Nielsen Karl-Gösta Nygren Tapani Pyörälä Ahti Kosonen 《Contraception》1979,19(1):1-9
A randomized study was conducted simultaneously in three countries to compare the clinical performance of two new IUDs, the Nova-T and Copper-T-200. Forty-four persons, midwives, general practitioners, residents and specialists in obstetrics and gynecology inserted 907 Nova-Ts and 936 Copper-Ts. The pregnancy rate of Nova-T (0.7 at one year) was significantly lower than that of Copper-T (2.2 at one year). No significant differences were observed in other termination rates. The continuation rates were 72.6 for Nova-T and 71.3 for Copper-T-200. The total experience was based on 18,035 woman months of use, with a lost to follow-up of less than 7 per cent for both IUDs. 相似文献
32.
33.
Liposomes, which are biodegradable and essentially non-toxic vehicles, can encapsulate both hydrophilic and hydrophobic materials, and are utilized as drug carriers in drug delivery systems. In addition, liposomes can be used to carry radioactive compounds as radiotracers can be linked to multiple locations in liposomes. One option is the hydrated compartment inside the liposome, another the lipid core into which especially hydrophobic conjugates can be attached, and the third option is the outer lipid leaflet where molecules can be bound by covalent linkage. Delivery of agents to the reticuloendothelial system (RES) is easily achieved, since most conventional liposomes are trapped by the RES. For the purpose of delivery of agents to target organs other than RES, long-circulating liposomes have been developed by modifying the liposomal surface. Understanding of the in vivo dynamics of liposome-carried agents is required for the evaluation of the bioavailability of drugs encapsulated in liposomes. In this review, we focus on the in vivo trafficking of liposomes visualized by positron emission tomography (PET) and discuss the characteristics of liposomes that affect the targeting of drugs in vivo. 相似文献
34.
With the help of radiolabeled compounds, drug development can be made faster; especially with microdosing and radiopharmacokinetics, some elements of phase I and II trials necessary for conventional cancer drug development can be avoided. Imaging may proof the principle of actual targeting. However, radiopharmacokinetics is dependent on the radionuclide, the radionuclide linker with the drug and the size of the drug molecule. Optimally, some of the drug molecule atoms may be replaced with a radionuclide that can be visualized. In this article drug development utilizing radionuclides both in PET and SPET has been reviewed. 相似文献
35.
Girman CJ Rhodes T Mercuri M Pyörälä K Kjekshus J Pedersen TR Beere PA Gotto AM Clearfield M;S Group the AFCAPS/TexCAPS Research Group 《The American journal of cardiology》2004,93(2):136-141
The metabolic syndrome, which is a set of lipid and nonlipid risk factors of metabolic origin linked with insulin resistance, is believed to be associated with an elevated risk for cardiovascular disease, but few have studied this association in prospective long-term cardiovascular outcomes trials. Placebo data from the Scandinavian Simvastatin Survival Study (4S) and the Air Force/Texas Coronary Atherosclerosis Prevention Study (AFCAPS/TexCAPS) were used post hoc to estimate the long-term relative risk of major coronary events (MCEs) associated with the metabolic syndrome, after excluding diabetes mellitus. In 4S and AFCAPS/TexCAPS, respectively, placebo-treated patients with the metabolic syndrome were 1.5 (95% confidence interval 1.2 to 1.8) and 1.4 (95% confidence interval 1.04 to 1.9) times more likely to have MCEs than those without it. Of the components of the metabolic syndrome, low high-density lipoprotein levels were associated with elevated risk of MCEs in both studies, whereas high triglycerides in 4S and elevated blood pressure and obesity in AFCAPS/TexCAPS were associated with significantly increased relative risk. Patients with the metabolic syndrome showed increased risk of MCEs irrespective of their Framingham-calculated 10-year risk score category (>20% vs =20%). These data demonstrate that the metabolic syndrome is associated with increased risk of MCEs in both hypercholesterolemic patients with coronary heart disease in 4S and in those with low high-density lipoprotein cholesterol but without coronary heart disease in AFCAPS/TexCAPS. It appears that the metabolic syndrome is associated with risk that is not entirely accounted for by traditional risk scoring paradigms. 相似文献
36.
de Backer G Ambrosioni E Borch-Johnsen K Brotons C Cifkova R Dallongeville J Ebrahim S Faergemane O Graham I Mancia G Manger Cats V Orth-Gomér K Perk J Pyörälä K Rodicio J Sans S Sansoy V Sechtem U Silber S Thomsen T Wood D;Tercer Grupo de Trabajo de las Sociedades Europeas y otras Sociedades Sobre la Prevención Cardiovascular en la Práctica Clínica 《Atencion primaria / Sociedad Espa?ola de Medicina de Familia y Comunitaria》2004,34(9):484-492
37.
The effects of transdermal estrogen therapy on bone mass and turnover in early postmenopausal smokers: a prospective, controlled study 总被引:2,自引:0,他引:2
Välimäki MJ Laitinen KA Tähtelä RK Hirvonen EJ Risteli JP 《American journal of obstetrics and gynecology》2003,189(5):1213-1220
OBJECTIVE: The purpose of this study was to investigate whether smoking reduces the effects of transdermal estrogen replacement therapy on bone. STUDY DESIGN: One hundred forty-eight women (0.5-5 years after menopause, aged 46-58 years) completed the study. Smokers were assigned randomly to receive either 1.0 mg (n=32 women) or 1.5 mg (n=31 women) of transdermal estradiol in gel daily, and nonsmokers (n=46 women) were assigned to receive 1.0 mg of transdermal estradiol for 2 years. The control group consisted of 17 smokers and 22 nonsmokers. Bone mineral density was measured by dual-energy x-ray absorptiometry. Bone turnover was assessed by measurements of urinary aminoterminal telopeptide of type I collagen and serum aminoterminal propeptide of type I procollagen. RESULTS: Lumbar spine bone mineral density increased similarly in smoking (+3.6%) and nonsmoking (+2.6%) estrogen users (P<.0001 to a decrease of 2.5% in the control group). Femoral neck bone mineral density increased 2.2% to 2.4% in smoking and nonsmoking estrogen users but decreased 0.2% in control subjects (P<.05). Urinary aminoterminal telopeptide of type I collagen decreased similarly in all estrogen-using groups (P<.05 to control group), but serum aminoterminal propeptide of type I procollagen decreased more in smoking than in nonsmoking estrogen users (P=.006). Serum 25-hydroxyvitamin D was 20% lower (P=.004) in smokers than in nonsmokers. CONCLUSION: Transdermal estrogen treatment protects smoking women as effectively as nonsmokers from osteoporosis. Smoking worsens the vitamin D state of postmenopausal women. 相似文献
38.
The concept of maximal lactate steady state: a bridge between biochemistry,physiology and sport science 总被引:8,自引:0,他引:8
Billat VL Sirvent P Py G Koralsztein JP Mercier J 《Sports medicine (Auckland, N.Z.)》2003,33(6):407-426
The maximal lactate steady state (MLSS) is defined as the highest blood lactate concentration (MLSSc) and work load (MLSSw) that can be maintained over time without a continual blood lactate accumulation. A close relationship between endurance sport performance and MLSSw has been reported and the average velocity over a marathon is just below MLSSw. This work rate delineates the low- to high-intensity exercises at which carbohydrates contribute more than 50% of the total energy need and at which the fuel mix switches (crosses over) from predominantly fat to predominantly carbohydrate. The rate of metabolic adenosine triphosphate (ATP) turnover increases as a direct function of metabolic power output and the blood lactate at MLSS represents the highest point in the equilibrium between lactate appearance and disappearance both being equal to the lactate turnover. However, MLSSc has been reported to demonstrate a great variability between individuals (from 2-8 mmol/L) in capillary blood and not to be related to MLSSw. The fate of enhanced lactate clearance in trained individuals has been attributed primarily to oxidation in active muscle and gluconeogenesis in liver. The transport of lactate into and out of the cells is facilitated by monocarboxylate transporters (MCTs) which are transmembrane proteins and which are significantly improved by training. Endurance training increases the expression of MCT1 with intervariable effects on MCT4. The relationship between the concentration of the two MCTs and the performance parameters (i.e. the maximal distance run in 20 minutes) in elite athletes has not yet been reported. However, lactate exchange and removal indirectly estimated with velocity constants of the individual blood lactate recovery has been reported to be related to time to exhaustion at maximal oxygen uptake. 相似文献
39.
40.
n-3 Fatty acids and 5-y risks of death and cardiovascular disease events in patients with coronary artery disease 总被引:4,自引:0,他引:4
Erkkilä AT Lehto S Pyörälä K Uusitupa MI 《The American journal of clinical nutrition》2003,78(1):65-71
BACKGROUND: Data on the association of n-3 fatty acid content in serum lipids with mortality in patients with coronary artery disease (CAD) are limited. OBJECTIVE: We hypothesized that a high proportion of n-3 fatty acids in serum lipids would be associated with reduced risks of death and coronary events in patients with established CAD. DESIGN: We measured dietary intakes via food records and the fatty acid composition of serum cholesteryl esters (CEs) in 285 men and 130 women with CAD (x age: 61 y; range: 33-74 y). The patients participating in the EUROASPIRE (European Action on Secondary Prevention through Intervention to Reduce Events) study were followed up for 5 y. RESULTS: During the follow-up, 36 patients died, 21 had myocardial infarctions, and 12 had strokes. The relative risks (RRs) of death adjusted for cardiovascular disease risk factors for subjects in the highest tertile of fatty acids in CEs compared with those in the lowest tertile were 0.33 (95% CI: 0.11, 0.96) for alpha-linolenic acid, 0.33 (0.12, 0.93) for eicosapentaenoic acid, and 0.31 (0.11, 0.87) for docosahexaenoic acid (P for trend = 0.063, 0.056, and 0.026, respectively). A high proportion of eicosapentaenoic acid in CEs was associated with a low risk of CAD death. Compared with no consumption, consumption of fish tended to be associated with a lower risk of death [1-57 g/d, RR = 0.50 (0.20, 1.28); > 57 g/d, RR = 0.37 (0.14, 1.00); P for trend = 0.059]. CONCLUSION: High proportions of n-3 fatty acids in serum lipids are associated with a substantially reduced risk of death. 相似文献