全文获取类型
收费全文 | 100634篇 |
免费 | 6108篇 |
国内免费 | 437篇 |
专业分类
耳鼻咽喉 | 1113篇 |
儿科学 | 2516篇 |
妇产科学 | 1782篇 |
基础医学 | 12465篇 |
口腔科学 | 1753篇 |
临床医学 | 10652篇 |
内科学 | 20242篇 |
皮肤病学 | 1339篇 |
神经病学 | 10082篇 |
特种医学 | 3898篇 |
外国民族医学 | 3篇 |
外科学 | 16339篇 |
综合类 | 1083篇 |
一般理论 | 131篇 |
预防医学 | 8226篇 |
眼科学 | 2080篇 |
药学 | 6486篇 |
中国医学 | 105篇 |
肿瘤学 | 6884篇 |
出版年
2023年 | 563篇 |
2022年 | 935篇 |
2021年 | 2095篇 |
2020年 | 1325篇 |
2019年 | 2098篇 |
2018年 | 2549篇 |
2017年 | 1824篇 |
2016年 | 1986篇 |
2015年 | 2274篇 |
2014年 | 3443篇 |
2013年 | 4725篇 |
2012年 | 7562篇 |
2011年 | 7974篇 |
2010年 | 4583篇 |
2009年 | 4130篇 |
2008年 | 7125篇 |
2007年 | 7448篇 |
2006年 | 7176篇 |
2005年 | 6890篇 |
2004年 | 6716篇 |
2003年 | 6048篇 |
2002年 | 5705篇 |
2001年 | 837篇 |
2000年 | 556篇 |
1999年 | 889篇 |
1998年 | 1219篇 |
1997年 | 924篇 |
1996年 | 748篇 |
1995年 | 682篇 |
1994年 | 589篇 |
1993年 | 578篇 |
1992年 | 440篇 |
1991年 | 399篇 |
1990年 | 322篇 |
1989年 | 291篇 |
1988年 | 277篇 |
1987年 | 276篇 |
1986年 | 241篇 |
1985年 | 277篇 |
1984年 | 305篇 |
1983年 | 252篇 |
1982年 | 333篇 |
1981年 | 281篇 |
1980年 | 221篇 |
1979年 | 93篇 |
1978年 | 127篇 |
1977年 | 106篇 |
1976年 | 78篇 |
1975年 | 66篇 |
1973年 | 69篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
12.
Umar Nadia K. Badshah Maaz B. Sandrasegaran Kumar Ghabril Marwan Agarwal Saurabh Tann Mark Lacerda Marco Kwo Paul Y. 《Digestive diseases and sciences》2015,60(7):2196-2200
Digestive Diseases and Sciences - To determine whether the presence of portal vein thrombosis (PVT) where venous flow within the liver may be altered may delay the diagnosis of HCC and be... 相似文献
13.
14.
15.
16.
17.
In cystic fibrosis (CF), perturbations of total daily energy expenditure (TDEE) may be a major determinant of altered nutrition and growth. Measurement of TDEE is problematic, though the flex-heart rate method (FHRM) provides a close estimation of TDEE, as compared to the cost-prohibitive, gold standard, the double-labeled water method, and permits estimates of the energy cost of daily activities (ECA) above resting energy expenditure (REE). We hypothesize that alterations in ECA affects TDEE in CF. PURPOSE: To measure components of TDEE in adolescents with CF and normal lung function compared with controls, and to determine whether ECA can be improved by diet and exercise. METHODS: Clinically stable CF subjects (aged 9-13, n=12) and age- and gender-matched controls (n=13) had repeated measurements of TDEE by FHRM, REE, and maximal cardiopulmonary exercise testing (CPET) during a 6-week exercise and diet program. RESULTS: While the mean REE was similar in both groups, ECA was significantly lower in CF adolescents as compared to controls (p=0.02). During CPET, maximal exercise in CF was characterized by hyperventilation, which was unrelated to ventilation-perfusion mismatching. There were no changes in REE after dietary intervention. CONCLUSION: ECA in CF adolescents with normal lung function is lower when compared to healthy controls. These findings support the hypothesis that clinically stable patients with CF have inefficient energy metabolism or alternatively conserve energy during activities of daily living. 相似文献
18.
Mark W Woolrich Peter Chiarelli Daniel Gallichan Joanna Perthen Thomas T Liu 《Magnetic resonance in medicine》2006,56(4):891-906
The study of brain function using MRI relies on acquisition techniques that are sensitive to different aspects of the hemodynamic response contiguous to areas of neuronal activity. For this purpose different contrasts such as arterial spin labeling (ASL) and blood oxygenation level dependent (BOLD) functional MRI techniques have been developed to investigate cerebral blood flow (CBF) and blood oxygenation, respectively. Analysis of such data typically proceeds by separate, linear modeling of the appropriate CBF or BOLD time courses. In this work an approach is developed that provides simultaneous inference on hemodynamic changes via a nonlinear physiological model of ASL data acquired at multiple echo times. Importantly, this includes a significant contribution by changes in the static magnetization, M, to the ASL signal. Inference is carried out in a Bayesian framework. This is able to extract, from dual-echo ASL data, probabilistic estimates of percentage changes of CBF, R(2) (*), and the static magnetization, M. This approach provides increased sensitivity in inferring CBF changes and reduced contamination in inferring BOLD changes when compared with general linear model approaches on single-echo ASL data. We also consider how the static magnetization, M, might be related to changes in CBV by assuming the same mechanism for water exchange as in vascular space occupancy. 相似文献
19.
20.
Marlene L Hauck Susan M LaRue William P Petros Jean M Poulson Daohai Yu Ivan Spasojevic Amy F Pruitt Allison Klein Beth Case Donald E Thrall David Needham Mark W Dewhirst 《Clinical cancer research》2006,12(13):4004-4010
PURPOSE: To determine the maximum tolerated dose, dose-limiting toxicities, and pharmacokinetic characteristics of doxorubicin encapsulated in a low temperature sensitive liposome (LTSL) when given concurrently with local hyperthermia to canine solid tumors. EXPERIMENTAL DESIGN: Privately owned dogs with solid tumors (carcinomas or sarcomas) were treated. The tumors did not involve bone and were located at sites amenable to local hyperthermia. LTSL-doxorubicin was given (0.7-1.0 mg/kg i.v.) over 30 minutes during local tumor hyperthermia in a standard phase I dose escalation study. Three treatments, given 3 weeks apart, were scheduled. Toxicity was monitored for an additional month. Pharmacokinetics were evaluated during the first treatment cycle. RESULTS: Twenty-one patients were enrolled: 18 with sarcomas and 3 with carcinomas. Grade 4 neutropenia and acute death secondary to liver failure, possibly drug related, were the dose-limiting toxicities. The maximum tolerated dose was 0.93 mg/kg. Other toxicities, with the possible exception of renal damage, were consistent with those observed following free doxorubicin administration. Of the 20 dogs that received > or = 2 doses of LTSL-doxorubicin, 12 had stable disease, and 6 had a partial response to treatment. Pharmacokinetic variables were more similar to those of free doxorubicin than the marketed liposomal product. Tumor drug concentrations at a dose of 1.0 mg/kg averaged 9.12 +/- 6.17 ng/mg tissue. CONCLUSION: LTSL-doxorubicin offers a novel approach to improving drug delivery to solid tumors. It was well tolerated and resulted in favorable response profiles in these patients. Additional evaluation in human patients is warranted. 相似文献