全文获取类型
收费全文 | 4921篇 |
免费 | 336篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 32篇 |
儿科学 | 125篇 |
妇产科学 | 267篇 |
基础医学 | 583篇 |
口腔科学 | 102篇 |
临床医学 | 503篇 |
内科学 | 931篇 |
皮肤病学 | 32篇 |
神经病学 | 925篇 |
特种医学 | 163篇 |
外科学 | 542篇 |
综合类 | 62篇 |
预防医学 | 383篇 |
眼科学 | 48篇 |
药学 | 358篇 |
肿瘤学 | 205篇 |
出版年
2021年 | 62篇 |
2019年 | 44篇 |
2018年 | 66篇 |
2017年 | 41篇 |
2016年 | 37篇 |
2015年 | 60篇 |
2014年 | 96篇 |
2013年 | 134篇 |
2012年 | 192篇 |
2011年 | 224篇 |
2010年 | 135篇 |
2009年 | 122篇 |
2008年 | 201篇 |
2007年 | 177篇 |
2006年 | 194篇 |
2005年 | 189篇 |
2004年 | 167篇 |
2003年 | 160篇 |
2002年 | 155篇 |
2001年 | 148篇 |
2000年 | 162篇 |
1999年 | 127篇 |
1998年 | 53篇 |
1997年 | 46篇 |
1996年 | 36篇 |
1995年 | 48篇 |
1994年 | 71篇 |
1993年 | 30篇 |
1992年 | 152篇 |
1991年 | 135篇 |
1990年 | 133篇 |
1989年 | 146篇 |
1988年 | 132篇 |
1987年 | 151篇 |
1986年 | 131篇 |
1985年 | 115篇 |
1984年 | 98篇 |
1983年 | 71篇 |
1982年 | 56篇 |
1981年 | 47篇 |
1980年 | 43篇 |
1979年 | 85篇 |
1978年 | 62篇 |
1977年 | 41篇 |
1976年 | 50篇 |
1975年 | 45篇 |
1974年 | 37篇 |
1973年 | 40篇 |
1972年 | 53篇 |
1970年 | 36篇 |
排序方式: 共有5261条查询结果,搜索用时 15 毫秒
61.
J P Weiner 《The Milbank quarterly》1987,65(3):426-461
Primary care--often considered the weak link in the United States health care delivery system--is the focal point of several European systems. Thoughtful analysis of structural and service differences and similarities among these approaches--whether "corporatized" or "socialized"--reveals areas for helpful innovation in the United States. Matters of access to and continuity of services, preventive care for children, long-term care, and accountability are especially relevant for primary care in an American context. 相似文献
62.
Conflicting results continue to be reported for studies contrasting the therapeutic efficacy of bilateral and unilateral nondominant electroconvulsive therapy (ECT). At least in part, the therapeutic advantage for bilateral ECT observed by some investigators may be related to the use of nonoptimum unilateral ECT technique. Consideration of technique-related factors, such as stimulus electrode location, contact at the electrode-scalp interface, stimulus dosing, and seizure monitoring, will allow unilateral ECT to be carried out with maximal therapeutic potency. 相似文献
63.
64.
The effects of amphetamine on the partial punishment effect (PPE) at one trial per day, were examined. Two groups of animals were trained to run in a straight alley. The continuously reinforced (CRF) group received food reward on every trial. The partially punished (PP) group received food reward on every trial but in addition, received footshocks of a gradually increasing intensity in the goal box on a random 50% of the trials. In the test stage, all animals received both food and footshock on each trial. dl-Amphetamine 1.5 mg/kg was administered in a 2 × 2 design, i.e. drug-no drug in training and drug-no drug in test. The partially punished animals exhibited increased persitence in running to the goal box during test, and this partial punishment effect was unaffected by amphetamine. 相似文献
65.
Yei-Mei Peng Ph.D. David S. Alberts Vivian Graham Earl A. Surwit Sheldon Weiner Frank L. Meyskens Jr. 《Investigational new drugs》1986,4(3):245-249
The present study was undertaken to evaluate the systemic absorption and cervical tissue uptake of all-transretinoic acid (TRA), delivered via a collagen spongecervical cap delivery device in patients with intraepithelial cervical dysplasia. Ten patients with histologically proven mild or moderate cervical dysplasia were included in this pharmacologic study. The two TRA concentrations (0.05% and 0.372%) selected for study represent the starting and maximally tolerated doses used in phase I clinical trial. All-trans-retinoic-11-3H acid (3H-TRA, 500 Ci) was used to facilitate cervical tissue uptake studies. Cervical biopsies and post-treatment blood samples were obtained from each patient after TRA exposure. The uptake of TRA into cervical tissues four hours after drug administration was significantly increased at the maximally tolerated TRA dose. There was a rapid decrease in cervical tissue concentration of TRA at the 0.372% dose between 4 and 24 h after drug exposure, suggesting a relatively short elimination half-life of TRA in cervical tissues. HPLC analysis of post-treatment blood samples indicate that there was no systemic absorption of TRA after local cervical administration. 相似文献
66.
67.
Improvement in quality of life following coronary artery bypass surgery is a function of a number of complex variables. This outcome, based on objective medical and subjective social criteria, must be assessed to determine the success of this financially expensive surgical intervention for management of patients with coronary artery disease. The majority of patients undergoing coronary artery bypass surgery demonstrate, at least early on, an improved quality of life. Subsets of patients have also been shown to have improved survival. With new surgical techniques aimed at improvement in flow to the areas of ischemic myocardium, even better results can be expected. Future studies will determine the extent of this improvement in quality of life over time and will serve to predict for which patients early surgical intervention will be most beneficial. 相似文献
68.
69.
A case of a melanotic schwannoma presenting as a soft tissue mass of the abductors of the hip is reported. The radiographic findings suggested myositis ossificans, but several subtle findings raised the concern for something else. A bilobed appearance, lack of classic zoning pattern of the ossification, and atypical pain pattern should alert the physician. Biopsy should be considered if the radiographic and clinical presentations are not classic for myositis ossificans. 相似文献
70.
Quantitative follow-up of patients with multiple sclerosis using MRI: technical aspects 总被引:1,自引:0,他引:1
Kikinis R Guttmann CR Metcalf D Wells WM Ettinger GJ Weiner HL Jolesz FA 《Journal of magnetic resonance imaging : JMRI》1999,9(4):519-530
A highly reproducible automated procedure for quantitative analysis of serial brain magnetic resonance (MR) images was developed for use in patients with multiple sclerosis (MS). The intracranial cavity (ICC) was identified on standard dual-echo spin-echo brain MR images using a supervised automated procedure. MR images obtained from one MS patient at 24 time points in the course of a 1-year follow-up were aligned with the images of one of the time points. Next, the contents of the ICC in each MR exam were segmented into four tissues, using a self-adaptive statistical algorithm. Misclassifications due to partial voluming were corrected using a combination of morphologic operators and connectivity criteria. Finally, a connectivity detection algorithm was used to separate the tissue classified as lesions into individual entities. Registration, classification of the contents of the ICC, and identification of individual lesions are fully automatic. Only identification of the ICC requires operator interaction. In each MR exam, the program estimated volumes for the ICC, gray matter (GM), white matter (WM), white matter lesions (WML), and cerebrospinal fluid (CSF). The reproducibility of the system was superior to that of supervised segmentation, as evidenced by the coefficient of variation: CSF supervised 45.9% vs. automated 7.7%, GM 16.0% vs. 1.4%, WM 15.7% vs. 1.3%, and WML 39.5% vs 52.0%. Our results demonstrate that this computerized procedure allows routine reproducible quantitative analysis of large serial MRI data sets. 相似文献