全文获取类型
收费全文 | 3290篇 |
免费 | 177篇 |
国内免费 | 15篇 |
专业分类
耳鼻咽喉 | 24篇 |
儿科学 | 56篇 |
妇产科学 | 53篇 |
基础医学 | 508篇 |
口腔科学 | 69篇 |
临床医学 | 286篇 |
内科学 | 672篇 |
皮肤病学 | 102篇 |
神经病学 | 375篇 |
特种医学 | 205篇 |
外科学 | 473篇 |
综合类 | 18篇 |
一般理论 | 2篇 |
预防医学 | 133篇 |
眼科学 | 43篇 |
药学 | 240篇 |
中国医学 | 18篇 |
肿瘤学 | 205篇 |
出版年
2023年 | 27篇 |
2022年 | 35篇 |
2021年 | 68篇 |
2020年 | 50篇 |
2019年 | 59篇 |
2018年 | 73篇 |
2017年 | 57篇 |
2016年 | 60篇 |
2015年 | 86篇 |
2014年 | 130篇 |
2013年 | 152篇 |
2012年 | 236篇 |
2011年 | 273篇 |
2010年 | 163篇 |
2009年 | 162篇 |
2008年 | 246篇 |
2007年 | 212篇 |
2006年 | 200篇 |
2005年 | 199篇 |
2004年 | 165篇 |
2003年 | 186篇 |
2002年 | 161篇 |
2001年 | 46篇 |
2000年 | 36篇 |
1999年 | 37篇 |
1998年 | 32篇 |
1997年 | 29篇 |
1996年 | 22篇 |
1995年 | 20篇 |
1994年 | 21篇 |
1993年 | 16篇 |
1992年 | 17篇 |
1991年 | 21篇 |
1990年 | 18篇 |
1989年 | 13篇 |
1988年 | 16篇 |
1987年 | 16篇 |
1986年 | 12篇 |
1985年 | 9篇 |
1984年 | 7篇 |
1983年 | 19篇 |
1982年 | 5篇 |
1981年 | 8篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1973年 | 4篇 |
1971年 | 5篇 |
1969年 | 3篇 |
1964年 | 5篇 |
排序方式: 共有3482条查询结果,搜索用时 687 毫秒
11.
Manic episode with psychotic symptoms induced by subthalamic nucleus stimulation in a patient with Parkinson's disease. 总被引:5,自引:0,他引:5
Jan Herzog Julia Reiff Paul Krack Karsten Witt Bettina Schrader Dieter Müller Günther Deuschl 《Movement disorders》2003,18(11):1382-1384
Deep brain stimulation of the subthalamic nucleus (STN-DBS) is an established therapy for Parkinson's disease (PD). A manic episode with psychotic symptoms induced by STN-DBS occurred in a previously psychiatrically healthy patient, focusing on the role of STN-DBS in influencing not only motor but also emotional behaviour. 相似文献
12.
European Society of Neuroradiology (ESNR) 相似文献
13.
14.
Richard Werner Karsten Alfke Tobias Schaeffter Arya Nabavi H Maximilian Mehdorn Olav Jansen 《Magnetic resonance in medicine》2004,52(6):1443-1447
A new method for the selective spin labeling of left- or right-sided supplying arteries of the brain without the need for additional RF coils is demonstrated. A clinical 1.5 T scanner was used. The spatial selectivity of the labeling process is based on the limited coverage of the excitation field of a standard send/receive head coil together with an oblique positioning of the labeling plane. A computer simulation was used to optimize key labeling parameters under the condition of laminar flow. The validity of the computer model results was confirmed by MRI measurements with a flow model. For human studies, a double-inversion continuous arterial spin labeling (CASL) sequence was modified to allow for arbitrary positioning of the labeling plane. The obtained perfusion-weighted images showed a clear delineation of the perfusion territories of the selected arteries in the anterior circulation of the brain and good gray/white matter contrast. 相似文献
15.
Patrick Fransen MD Jacques Favre MD Philippe Maeder MD Heinz Fankhauser MD 《Journal of clinical neuroscience》1994,1(4):274-276
Lhermitte-Duclos disease (dysplastic gangliocytoma of the cerebellum) is a rare pseudo-neoplastic disorder of the cerebellum with typical MRI findings. A 25-year-old man presenting with progressive neck pain, dizziness, and impaired vision is reported. CT and MRI revealed a left cerebellar haemispheric mass and obstructive hydrocephalus. Lhermitte-Duclos disease was histologically confirmed after surgical removal of the lesion. The typical MRI appearance of a nonenhancing haemispheric cerebellar mass with preservation and exaggeration of the normal gyral pattern allows pre-operative diagnosis of this condition. The literature is reviewed and clinical presentation, radiology and histopathology are discussed. 相似文献
16.
Thomas Ngele Uwe Klose Wolfgang Grodd Karsten Voigt Fridtjof Nüsslin 《Journal of magnetic resonance imaging : JMRI》1995,5(4):416-420
An RF excitation pulse for three-dimensional (3D) time-of-flight (TOP) MR angiography (MRA) with a nonlinear excitation profile was numerically calculated under the condition of uniform vessel signal across the excitation volume (slab), and the superiority of the optform pulse as compared with conventional RF pulses and TONE pulses was demonstrated. For this purpose we acquired MRA of the lower leg and of the carotid and vertebral arteries in a 30-year-old healthy volunteer. Although the flow velocity ranges in these two anatomic locations are different by about a factor of 10, in both cases the corresponding optform pulse provided the best signal homogeneity at the highest level. 相似文献
17.
Karsten Schrör Christoph Thiemermann Peter Ney 《Naunyn-Schmiedeberg's archives of pharmacology》1988,338(3):268-274
Summary This study investigates the action of intravenous PGE1 on myocardial reperfusion injury and the possible involvement of antineutrophil activities. Cats were subjected to 3 h of temporary ligation of the left anterior descending coronary artery, followed by 2 h of reperfusion. Animals were treated with PGE1 (5 g/kg x min) or vehicle (saline solution), starting 0.5 h after coronary artery occlusion. Vehicle-treated cats exhibited a significant loss of cardiac creatine phosphokinase specific activity at 5 h, accompanied by a significant ischemia-induced rise in the ST segment of the ECG and development of a Q wave after starting reperfusion. All of these alterations were largely prevented by PGE1 treatment. PGE1 exerted some blood-pressurelowering activity at 5 h (P > 0.05) but did not reduce myocardial contractile force and oxygen consumption. PGE1 modestly antagonized ischemia-induced formation of platelet aggregates. However, PGE1 prevented the rise in peripheral white blood cell count during ischemia and reperfusion and inhibited the generation of reactive oxygen species (myeloperoxidase assay) from zymosan-stimulated whole blood ex vivo. The ratio of generation of reactive oxygen species/white blood count remained unchanged. It is concluded that PGE1 protects the ischemic myocardium from acute reperfusion injury and that this effect involves an action of the compound on neutrophils, probably by improved myocardial tissue preservation, resulting in reduced formation of chemotactic products and, consequently, less local neutrophil accumulation and release of noxious metabolites.Parts of these results have been presented to the 29th Spring meeting of the Deutsche Gesellschaft für Pharmakologie und Toxikologie, Mainz, 1988
Send offprint requests to K. Schrör at the above address 相似文献
18.
A method is described based on crossed immunoelectrophoresis of a complex antigen mixture in agarose gel followed by incubation of the gel with the monoclonal antibody. The bound monoclonal antibody is detected by the use of a secondary enzyme-labelled antibody.Using this technique we have been able to identify the precipitate arc in crossed immunoelectrophoresis of major histocompatibility complex (MHC) class I molecules in a mixture of all detergent solubilized cell membrane molecules by means of a monoclonal antibody, the specificity of which was known independently to be against MHC class I molecules. In other experiments using the same technique we demonstrated the reaction of a monoclonal antibody specific for chicken Ig light chains. 相似文献
19.
20.
A recent polyploidy superimposed on older large-scale duplications in the Arabidopsis genome 总被引:16,自引:0,他引:16
下载免费PDF全文
![点击此处可从《Genome research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The Arabidopsis genome contains numerous large duplicated chromosomal segments, but the different approaches used in previous analyses led to different interpretations regarding the number and timing of ancestral large-scale duplication events. Here, using more appropriate methodology and a more recent version of the genome sequence annotation, we investigate the scale and timing of segmental duplications in Arabidopsis. We used protein sequence similarity searches to detect duplicated blocks in the genome, used the level of synonymous substitution between duplicated genes to estimate the relative ages of the blocks containing them, and analyzed the degree of overlap between adjacent duplicated blocks. We conclude that the Arabidopsis lineage underwent at least two distinct episodes of duplication. One was a polyploidy that occurred much more recently than estimated previously, before the Arabidopsis/Brassica rapa split and probably during the early emergence of the crucifer family (24-40 Mya). An older set of duplicated blocks was formed after the monocot/dicot divergence, and the relatively low level of overlap among these blocks indicates that at least some of them are remnants of a larger duplication such as a polyploidy or aneuploidy. 相似文献