全文获取类型
收费全文 | 5489篇 |
免费 | 299篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 108篇 |
儿科学 | 255篇 |
妇产科学 | 114篇 |
基础医学 | 506篇 |
口腔科学 | 254篇 |
临床医学 | 481篇 |
内科学 | 1101篇 |
皮肤病学 | 152篇 |
神经病学 | 461篇 |
特种医学 | 205篇 |
外科学 | 1059篇 |
综合类 | 22篇 |
预防医学 | 306篇 |
眼科学 | 174篇 |
药学 | 326篇 |
中国医学 | 23篇 |
肿瘤学 | 251篇 |
出版年
2023年 | 31篇 |
2022年 | 70篇 |
2021年 | 101篇 |
2020年 | 90篇 |
2019年 | 95篇 |
2018年 | 137篇 |
2017年 | 86篇 |
2016年 | 135篇 |
2015年 | 123篇 |
2014年 | 130篇 |
2013年 | 222篇 |
2012年 | 282篇 |
2011年 | 298篇 |
2010年 | 180篇 |
2009年 | 144篇 |
2008年 | 240篇 |
2007年 | 276篇 |
2006年 | 284篇 |
2005年 | 292篇 |
2004年 | 271篇 |
2003年 | 277篇 |
2002年 | 263篇 |
2001年 | 209篇 |
2000年 | 202篇 |
1999年 | 188篇 |
1998年 | 66篇 |
1997年 | 44篇 |
1996年 | 55篇 |
1995年 | 29篇 |
1994年 | 29篇 |
1993年 | 24篇 |
1992年 | 86篇 |
1991年 | 55篇 |
1990年 | 55篇 |
1989年 | 72篇 |
1988年 | 46篇 |
1987年 | 42篇 |
1986年 | 49篇 |
1985年 | 37篇 |
1984年 | 39篇 |
1983年 | 26篇 |
1981年 | 22篇 |
1979年 | 34篇 |
1977年 | 26篇 |
1975年 | 20篇 |
1974年 | 34篇 |
1973年 | 24篇 |
1970年 | 36篇 |
1967年 | 30篇 |
1966年 | 25篇 |
排序方式: 共有5798条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
AbstractThe leading cause of death of adolescents in developed countries is injury. Alcohol is a major contributor to adolescent injury. Most of the injury deaths in youth are caused by traffic crashes. Driving under the influence (DUI) and riding with a driver who is under the influence (RUI) of alcohol increase the risk of road crash. The focus of this study is how adolescents’ risk of DUI and RUI differ in relation to their experience of parental control and peer pressure to substance use, other risky behaviours and leisure time activities. The analyses are based on data from the European School Survey Project on Alcohol and Other Drugs collected from 15- to 16-year-old Finnish adolescents in 2015 (n?=?4049, response rate 88.7%). The study shows that problems tend to entangle in some adolescent groups in which DUI and RUI are also more common. Adolescents with higher probability of using various substances, of starting alcohol use at young age, of experiencing weak parental control, and high peer pressure are at higher risk of DUI and RUI. The results indicate that professionals and authorities handling underage DUI and RUI ought to consider adolescents’ situation as a whole. 相似文献
5.
6.
Gábor Márk Somfai Kata Miháltz Eszter Tulassay János Rigó 《Hypertension in pregnancy》2006,25(1):11-20
OBJECTIVE: Visual symptoms are common in patients with preeclampsia, and are caused by various underlying pathological changes in the retina. Blurred vision may be one of these symptoms. We describe three cases in which the underlying retinal pathology of blurred vision was clarified using optical coherence tomography (OCT), a novel, non-invasive ophthalmic imaging technique that provides micrometer-scale resolution images of the human retina. METHODS: Three patients with preeclampsia complained of blurred vision postpartum. In all cases, ophthalmoscopy was performed at the bedside, followed by the assessment of best corrected visual acuity, slit-lamp biomicroscopy, fluorescein angiography (FLA), and OCT. In all cases, the presence of central visual defects was examined by an Amsler-grid. RESULTS: In one case, the symptoms were bilateral. In all affected eyes, the patients complained of a relative central scotoma. Ophthalmoscopy showed edema in the affected maculae, while OCT examination clarified a serous neurosensory detachment of the macula. In one case, a neurosensory detachment was also detected in the papillomacular region of a fellow eye with no symptoms. In two cases, FLA was performed, but only in one case could we detect late leakage and subretinal exudates. The serous detachments observed showed total resolution in all cases within 5 to 10 weeks, with restoration of visual acuity. CONCLUSION: In patients with preeclampsia, OCT may provide a useful method for the precise assessment of retinal changes, distinguishing retinal edema from serous neurosensory detachments. This finding may help to clarify the pathophysiological circulatory changes seen in preeclampsia. 相似文献
7.
8.
Ethanol-induced inhibition of testosterone biosynthesis in rat Leydig cells: role of mitochondrial substrate shuttles and citrate 总被引:1,自引:1,他引:0
The mechanisms by which ethanol inhibits testicular testosterone synthesis in rats were studied in vitro using isolated rat Leydig cells. The ethanol-induced inhibition was reversed by 4-methylpyrazole, an alcohol dehydrogenase inhibitor, suggesting that ethanol metabolism was responsible for this inhibition. L-glutamate and pyruvate, when added to the Krebs-Ringer incubation medium, reversed the inhibition by ethanol. The membrane glutamate receptor agonists kainic acid and quisqualic acid had no effects, indicating metabolic mechanisms for the L-glutamate action. This was verified also by observations that the metabolic transaminase inhibitors aminooxyacetate and cycloserine inhibited testosterone synthesis. In the amino acid supplemented Krebs-Ringer, pyruvate could not fully prevent inhibition by ethanol alone, but addition of L-glutamate to this medium abolished ethanol-induced inhibition. Experiments performed using a new inhibitor of testosterone biosynthesis in intact Leydig cells, triethylcitrate, indicated that active citrate metabolism, and/or efflux from mitochondria, was essential for the steroidogenic pathway from pregnenolone to testosterone in the smooth endoplasmic reticulum. The early steps of hCG stimulation before pregnenolone formation were most sensitive to its effect. Our results indicate that the inhibition of steroidogenesis by ethanol results from decreased availability of the metabolites involved in the substrate shuttles maintaining the NAD(P)H redox states between the mitochondrial and the smooth endoplasmic reticulum compartments, and that the inhibition can be overcome by a proper selection of exogenous sources for these metabolites. 相似文献
9.
Formulation and in Vitro-in Vivo Evaluation of Sustained-Release Lithium Carbonate Tablets 总被引:1,自引:0,他引:1
Çiftçi Kadriye Çapan Yilmaz Öztürk Orhan Hincal A. Atilla 《Pharmaceutical research》1990,7(4):359-363
The release of lithium carbonate incorporated into polymethylmethacrylate, poly vinyl chloride, hy-drogenated vegetable oil, and carbomer matrix tablets was studied in vitro. The formulation containing 10% carbomer showed a sustained-release profile comparable to that of a standard, commercially available, sustained-release preparation containing 400 mg lithium carbonate embedded in a composite material. In vivo the newly formulated and standard sustained-release lithium carbonate tablets were compared to an oral solution and conventional lithium carbonate tablets in 12 healthy subjects. These crossover studies showed that the sustained-release tablets produced a flatter serum concentration curve than the oral solution and conventional tablet, without loss of total bioavailability. 相似文献
10.
Because of the lack of organs for heart transplantations, left ventricular assist devices (LVADs) have become more and more important during the last few years. They are used for both bridging the time until transplantation as well as destination therapy for patients who are not able or willing to undergo a heart transplantation. Forensic and clinical pathologists will increasingly be confronted with fatalities of patients with LVADs. Beside natural causes of death and typical unavoidable complications, technical problems and user errors must be resolved. Under certain circumstances a suicidal or homicidal manner of death by manipulation of the device also has to be considered. 相似文献