全文获取类型
收费全文 | 777篇 |
免费 | 56篇 |
国内免费 | 15篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 40篇 |
妇产科学 | 11篇 |
基础医学 | 72篇 |
口腔科学 | 98篇 |
临床医学 | 76篇 |
内科学 | 153篇 |
皮肤病学 | 26篇 |
神经病学 | 22篇 |
特种医学 | 132篇 |
外科学 | 56篇 |
综合类 | 11篇 |
预防医学 | 33篇 |
眼科学 | 8篇 |
药学 | 34篇 |
肿瘤学 | 71篇 |
出版年
2022年 | 11篇 |
2021年 | 12篇 |
2020年 | 9篇 |
2019年 | 20篇 |
2018年 | 27篇 |
2017年 | 16篇 |
2016年 | 16篇 |
2015年 | 21篇 |
2014年 | 19篇 |
2013年 | 45篇 |
2012年 | 40篇 |
2011年 | 35篇 |
2010年 | 37篇 |
2009年 | 50篇 |
2008年 | 20篇 |
2007年 | 42篇 |
2006年 | 31篇 |
2005年 | 17篇 |
2004年 | 14篇 |
2003年 | 22篇 |
2002年 | 13篇 |
2001年 | 10篇 |
2000年 | 7篇 |
1999年 | 8篇 |
1998年 | 48篇 |
1997年 | 45篇 |
1996年 | 22篇 |
1995年 | 23篇 |
1994年 | 13篇 |
1993年 | 13篇 |
1992年 | 3篇 |
1991年 | 6篇 |
1990年 | 8篇 |
1989年 | 12篇 |
1988年 | 13篇 |
1987年 | 13篇 |
1986年 | 12篇 |
1985年 | 11篇 |
1984年 | 10篇 |
1983年 | 9篇 |
1982年 | 7篇 |
1981年 | 6篇 |
1980年 | 9篇 |
1979年 | 4篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 6篇 |
1971年 | 3篇 |
1967年 | 1篇 |
1966年 | 2篇 |
排序方式: 共有848条查询结果,搜索用时 15 毫秒
131.
Bernardes RJ Marchiori E Bernardes PM Monzo Gonzaga MB Simões LC 《Cardiology in the young》2006,16(3):281-288
AIMS: Our purpose was to assess the value of magnetic resonance angiography as a non-invasive alternative to catheterization in the evaluation of patients with tetralogy of Fallot, including those with pulmonary atresia. METHODS AND RESULTS: We evaluated prospectively, using magnetic resonance angiography, 30 patients, aged from 1 to 18 years, 15 with tetralogy of Fallot and pulmonary stenosis, and 15 with pulmonary atresia. The studies obtained using magnetic resonance provided adequate visualization of the aorta, and provided excellent imaging of the pulmonary trunk and its right and left branches. Compared with catheterization, magnetic resonance had 100 percent sensitivity, specificity and accuracy for defining the presence or absence of the pulmonary arteries. Magnetic resonance also had 93.9 percent sensitivity, 98.2 percent specificity, and 96.7 percent accuracy for detection of stenosis or hypoplasia of the pulmonary arteries. We detected 25 major aortopulmonary collateral arteries with magnetic resonance, but only 22 with conventional angiography. There was complete agreement between the two methods in detecting patency of the arterial duct in 6 patients, and of Blalock-Taussig shunts in 12 patients. CONCLUSION: Magnetic resonance angiography is a useful tool in the evaluation of patients with tetralogy of Fallot. It can be considered a non-invasive alternative to cardiac catheterization in the evaluation of the pulmonary vascular anatomy. 相似文献
132.
Cardoso-Júnior A Coelho LG Savassi-Rocha PR Vignolo MC Abrantes MM de Almeida AM Dias EE Vieira Júnior G de Castro MM Lemos YV 《Obesity surgery》2007,17(2):236-241
Background It has been suggested that obesity is associated with an altered rate of gastric emptying. The objective of the present study
was to determine whether the rates of solid and semi-solid gastric emptying differ between morbidly obese patients and lean
subjects.
Methods The Gastric-emptying time (GET) of solid and semi-solid meals were compared between lean healthy subjects and morbidly obese
patients enrolled in two previously published studies. GET of solid and semi-solid meals was measured using the 13C-octanoic acid breath test and 13C-acetic acid breath test, respectively, in 24 lean and 14 morbidly obese individuals of both sexes. Student t-test was used to compare the mean data between the lean and morbidly obese groups. The influence of sex, gender, BMI and
morbid obesity on the GET of solid meals was verified by linear regression analysis.
Results Mean t(1/2) values of solid GET (± standard deviation) were 203.6 ± 76.0 min and 143.5 ± 19.1 min for lean and obese subjects,
respectively (P = 0.0010). Mean t(lag) values of solid GET were 127.3 ± 42.7 min and 98.4 ± 13.0 min for lean and obese subjects, respectively
(P = 0.0044). No significant difference in semi-solid GET was observed between the lean and morbidly obese groups.
Conclusion The present study demonstrated a significantly enhanced gastric emptying of the solid meal test in morbidly obese patients
when compared to lean subjects. This finding is compatible with the hypothesis that rapid gastric emptying in morbidly obese
subjects increases caloric intake due to a more rapid loss of satiety. 相似文献
133.
MJ Hatfield L Tsurkan JL Hyatt X Yu CC Edwards LD Hicks RM Wadkins PM Potter 《British journal of pharmacology》2010,160(8):1916-1928
Background and purpose:
Carboxylesterases (CEs) metabolize a wide range of xenobiotic substrates including heroin, cocaine, meperidine and the anticancer agent CPT-11. In this study, we have purified to homogeneity human liver and intestinal CEs and compared their ability with hydrolyse heroin, cocaine and CPT-11.Experimental approach:
The hydrolysis of heroin and cocaine by recombinant human CEs was evaluated and the kinetic parameters determined. In addition, microsomal samples prepared from these tissues were subjected to chromatographic separation, and substrate hydrolysis and amounts of different CEs were determined.Key results:
In contrast to previous reports, cocaine was not hydrolysed by the human liver CE, hCE1 (CES1), either as highly active recombinant protein or as CEs isolated from human liver or intestinal extracts. These results correlated well with computer-assisted molecular modelling studies that suggested that hydrolysis of cocaine by hCE1 (CES1), would be unlikely to occur. However, cocaine, heroin and CPT-11 were all substrates for the intestinal CE, hiCE (CES2), as determined using both the recombinant protein and the tissue fractions. Again, these data were in agreement with the modelling results.Conclusions and implications:
These results indicate that the human liver CE is unlikely to play a role in the metabolism of cocaine and that hydrolysis of this substrate by this class of enzymes is via the human intestinal protein hiCE (CES2). In addition, because no enzyme inhibition is observed at high cocaine concentrations, potentially this route of hydrolysis is important in individuals who overdose on this agent. 相似文献134.
Ritter DE Gandini LG Pinto Ados S Ravelli DB Locks A 《World journal of orthodontics》2006,7(3):279-285
Optimal facial esthetics is one of the objectives in orthodontic treatment and an important issue in modern society. In this context, orthodontic treatment permits individuals with dental malpositions to achieve improved dentofacial esthetics. To reach this result, the orthodontist needs to recognize the characteristics considered normal and pleasant in dental arches and smiles. The objective of this article is to review and discuss criterion adopted by dental literature to technically analyze the smile, such as dental midline, smile line, dental exposure, negative space, dental proportion, and symmetry. This article proposes a way to visualize an ideal smile for each patient. 相似文献
135.
136.
137.
138.
139.
140.