全文获取类型
收费全文 | 1257篇 |
免费 | 93篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 36篇 |
妇产科学 | 24篇 |
基础医学 | 164篇 |
口腔科学 | 11篇 |
临床医学 | 179篇 |
内科学 | 287篇 |
皮肤病学 | 20篇 |
神经病学 | 97篇 |
特种医学 | 18篇 |
外国民族医学 | 1篇 |
外科学 | 217篇 |
综合类 | 4篇 |
一般理论 | 1篇 |
预防医学 | 91篇 |
眼科学 | 27篇 |
药学 | 101篇 |
中国医学 | 1篇 |
肿瘤学 | 69篇 |
出版年
2023年 | 15篇 |
2022年 | 18篇 |
2021年 | 23篇 |
2020年 | 23篇 |
2019年 | 34篇 |
2018年 | 45篇 |
2017年 | 24篇 |
2016年 | 24篇 |
2015年 | 33篇 |
2014年 | 43篇 |
2013年 | 50篇 |
2012年 | 84篇 |
2011年 | 102篇 |
2010年 | 68篇 |
2009年 | 52篇 |
2008年 | 85篇 |
2007年 | 88篇 |
2006年 | 68篇 |
2005年 | 75篇 |
2004年 | 55篇 |
2003年 | 52篇 |
2002年 | 62篇 |
2001年 | 25篇 |
2000年 | 41篇 |
1999年 | 27篇 |
1998年 | 8篇 |
1997年 | 10篇 |
1996年 | 4篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 10篇 |
1991年 | 14篇 |
1990年 | 8篇 |
1989年 | 5篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1981年 | 3篇 |
1979年 | 9篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1975年 | 3篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1969年 | 2篇 |
1967年 | 2篇 |
1964年 | 2篇 |
1954年 | 2篇 |
排序方式: 共有1357条查询结果,搜索用时 31 毫秒
1.
2.
3.
Dysphoric Rumination Impairs Concentration on Academic Tasks 总被引:3,自引:0,他引:3
Three studies investigated the effects of dysphoric rumination on concentration during 3 academic tasks—reading a passage from the GRE (Study 1), watching a videotaped lecture (Study 2), and proofreading written text (Study 3). Before performing these tasks, dysphoric and nondysphoric students were induced either to ruminate about themselves or to distract themselves by focusing on neutral images (all three studies) or by planning an event (Study 1). The results supported our hypothesis that dysphoric rumination, relative to distraction, would impair students' concentration. In all 3 studies, dysphoric ruminators reported difficulty concentrating, as well as interfering thoughts, during the relevant academic tasks. Furthermore, dysphoric ruminators were slower than dysphoric distractors in completing the tasks—specifically, reading the GRE passage (Study 1) and answering lecture comprehension questions (Study 2). In addition, dysphoric participants who ruminated showed impaired reading strategies (Study 1), reduced comprehension of academic material (Study 2), and poor proofreading performance (Study 3). These findings suggest that, in addition to its documented adverse effects on mood, thinking, and problem-solving, self-focused rumination interferes with instrumental behavior. Implications for social relationships and job performance are discussed. 相似文献
4.
Deacon E. Harle Keri Davies Rakhee Shah Syma Hussain Susan Cowling Tejinder K. Panesar Jonathan Bourton Bruce J. W. Evans 《Ophthalmic & physiological optics》2007,27(1):100-105
Despite the current popularity of binocular indirect ophthalmoscopy, direct ophthalmoscopes are still commonly used by clinicians for fundus examination. They are considered to be expensive, however, and it has been suggested that this cost can prevent their use by healthcare professionals in developing countries. The Optyse Lens Free Ophthalmoscope is a novel direct ophthalmoscope, without a lens focus system, that allows for comparatively inexpensive manufacture and supply. We compared the clarity of view with the Optyse to that with standard direct ophthalmoscopes, over a sequential cohort of patients with a variety of refractive errors and ocular conditions. The grade of clarity of view with the Optyse Lens Free Ophthalmoscope was less than conventional ophthalmoscopes (Wilcoxon signed rank test, p < 0.0001). This grade of clarity of view was not associated with the ametropia of the ophthalmoscopic observation (Spearman r < or = 0.03, p > or = 0.28) but was with the presence of cataracts (chi2 test, p < 0.0001) with both the Optyse and the conventional ophthalmoscopes. Despite its limitations, the retinal view with Optyse was often within acceptable clinical limits suggesting that this relatively inexpensive ophthalmoscope may have a place when cost prohibits any other type of ophthalmoscope use. 相似文献
5.
Andreas V Alexopoulos Prakash Kotagal Tobias Loddenkemper Jeffrey Hammel William E Bingaman 《Seizure》2006,15(7):491-503
PURPOSE: To retrospectively review our experience with VNS in pediatric patients with pharmacoresistant epilepsy and examine the seizure-frequency outcome and rates of discontinuation in two age groups: adolescent and pre-adolescent children. RESULTS: Complete pre- and post-VNS data were available for 46/49 patients. Median age at implantation was 12.1 (range 2.3-17.9) and median duration of epilepsy 8.0 (1.9-16.9) years. Twenty-one patients (45.6%) were under 12 years at the time of surgery. Median follow-up was 2 years; follow-up exceeded 4 years in 9/46 patients. As compared to baseline, median seizure-frequency reduction in the setting of declining numbers was 56% at 3 months, 50% at 6, 63% at 12, 83% at 24 and 74% at 36 months. When a last observation carried forward analysis was employed median seizure-frequency reduction in the range of 60% was observed at 1, 2 and 3 years post-VNS. Twenty patients (43.5%) had >75% seizure-frequency reduction. No response (increase or <50% reduction) was observed in 19/46 (41.3%). Five patients (10.1%) were seizure-free for more than 6 months by their last follow-up. There was no difference in the number of AEDs used before and after VNS. The long-term discontinuation rate was 21.7% and reflected a lack of clinical response or infection. CONCLUSIONS: In this series VNS was well-tolerated and effective as add-on therapy for refractory seizures in children of all ages. Response was even more favorable in the younger group (<12 years at implantation). Infection and lack of efficacy were the most common reasons for discontinuation of long-term VNS therapy in this group. 相似文献
6.
7.
8.
9.
10.
Andrew Elagizi Carl J. Lavie Evan OKeefe Keri Marshall James H. OKeefe Richard V. Milani 《Nutrients》2021,13(1)
Interest in the potential cardiovascular (CV) benefits of omega-3 polyunsaturated fatty acids (Ω-3) began in the 1940s and was amplified by a subsequent landmark trial showing reduced CV disease (CVD) risk following acute myocardial infarction. Since that time, however, much controversy has circulated due to discordant results among several studies and even meta-analyses. Then, in 2018, three more large, randomized trials were released—these too with discordant findings regarding the overall benefits of Ω-3 therapy. Interestingly, the trial that used a higher dose (4 g/day highly purified eicosapentaenoic acid (EPA)) found a remarkable, statistically significant reduction in CVD events. It was proposed that insufficient Ω-3 dosing (<1 g/day EPA and docosahexaenoic acid (DHA)), as well as patients aggressively treated with multiple other effective medical therapies, may explain the conflicting results of Ω-3 therapy in controlled trials. We have thus reviewed the current evidence regarding Ω-3 and CV health, put forth potential reasoning for discrepant results in the literature, highlighted critical concepts such as measuring blood levels of Ω-3 with a dedicated Ω-3 index and addressed current recommendations as suggested by health care professional societies and recent significant scientific data. 相似文献