首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2282篇
  免费   129篇
  国内免费   15篇
耳鼻咽喉   19篇
儿科学   94篇
妇产科学   33篇
基础医学   449篇
口腔科学   19篇
临床医学   296篇
内科学   457篇
皮肤病学   45篇
神经病学   219篇
特种医学   48篇
外科学   176篇
综合类   12篇
预防医学   210篇
眼科学   30篇
药学   190篇
中国医学   3篇
肿瘤学   126篇
  2023年   17篇
  2022年   19篇
  2021年   45篇
  2020年   31篇
  2019年   45篇
  2018年   64篇
  2017年   45篇
  2016年   54篇
  2015年   57篇
  2014年   87篇
  2013年   118篇
  2012年   181篇
  2011年   200篇
  2010年   104篇
  2009年   94篇
  2008年   161篇
  2007年   157篇
  2006年   145篇
  2005年   130篇
  2004年   107篇
  2003年   116篇
  2002年   92篇
  2001年   21篇
  2000年   16篇
  1999年   27篇
  1998年   25篇
  1997年   16篇
  1996年   17篇
  1995年   13篇
  1994年   13篇
  1993年   9篇
  1992年   9篇
  1991年   6篇
  1990年   12篇
  1989年   16篇
  1988年   15篇
  1987年   9篇
  1986年   12篇
  1985年   12篇
  1984年   7篇
  1980年   7篇
  1979年   8篇
  1977年   7篇
  1976年   6篇
  1974年   7篇
  1973年   5篇
  1971年   5篇
  1970年   6篇
  1967年   5篇
  1966年   5篇
排序方式: 共有2426条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
Background: Scleromyxoedema is a rare disease of unknown aetiology that is characterized by deposition of mucin and sclerotic induration of the skin; it is associated with paraproteinaemia. Patients suffer from progressive disability due to immobilization and cosmetic disfigurement. Treatment of scleromyxoedema is a therapeutic challenge. The antimalarial hydroxychloroquine has a rapid and reliable effect in reticular erythematous mucinosis. Patients and methods: Four consecutive patients (two women, two men; median age: 50 years) with scleromyxoedema, three of them with IgG λ paraprotein, were treated with hydroxychloroquine. Treatment was initiated with 600 mg p. o. for 10 days, followed by 400 mg for at least 4 weeks, and 200 mg thereafter. Results: Complete remission of skin manifestations was achieved in one patient, whereas three patients achieved a partial remission of 61+, 5 and 25 months' duration. Notably, three patients felt increased mobility and reduced firmness of skin during the first week of treatment, which was reflected in a rapid reduction in dermal thickness. In one patient, dysphagia was reverted as evidenced by normalization of oesophageal clearance. Paraproteinaemia was not influenced at all. Side effects included one case of electroretinogram abnormalities after 19 months of therapy and one case of leucopenia after 3 months. Conclusion: Hydroxychloroquine is an effective form of therapy for scleromyxoedema, leading to rapid and prolonged alleviation of symptoms.  相似文献   
7.
Prosopagnosia is currently viewed within the constraints of two competing theories of face recognition, one highlighting the analysis of features, the other focusing on configural processing of the whole face. This study investigated the role of feature analysis versus whole face configural processing in the recognition of facial expression. A prosopagnosic patient, SC made expression decisions from whole and incomplete (eyes-only and mouth-only) faces where features had been obscured. SC was impaired at recognizing some (e.g., anger, sadness, and fear), but not all (e.g., happiness) emotional expressions from the whole face. Analyses of his performance on incomplete faces indicated that his recognition of some expressions actually improved relative to his performance on the whole face condition. We argue that in SC interference from damaged configural processes seem to override an intact ability to utilize part-based or local feature cues.  相似文献   
8.
9.
This study aimed to identify interferon-gamma (IFN-gamma) gene variants in cattle for diagnostic purposes. Therefore, the entire bovine IFN-gamma gene (BoIFNG) and 2605 bp of its promoter DNA were sequenced. The BoIFNG DNA sequence conforms to the published part of Bo-IFN-gamma cDNA. Primer extension experiments show the presence of a 5' extension of exon 1 by 42 nucleotides (nt). One SINE element (Bov-A2) is located in the 5'-region, and two SINE elements (Bov-tA, Bov-B) are contained in the 3'-region of BoIFNG. The variants were detected by comparative sequence analysis of PCR amplicons from different bovine species. Four polymorphic mononucleotide repeats are situated in the promoter and in intron 1. Four distinct series of single nucleotide polymorphisms (SNP) were found in functionally important regions of BoIFNG. The region between the two intron 1 microsatellites contains the highest density of SNPs in Bos taurus breeds. One G-T transversion in the coding region of exon 1 causes a Gly(14) to Val(14) exchange in the BoIFNG signal peptide of different bovine species. A G-A transition in exon 2 encodes a Ser(19) to Asn(19) change in the mature protein of the Tibetan yak. Genotyping of randomly sampled Holstein Friesian cows at selected SNPs and of both intron 1 microsatellites revealed two dominant BoIFNG microhaplotypes. The detected SNPs improve the recently reported genotyping system of cattle.  相似文献   
10.
The rat pulmonary microvasculature was studied using scanning and transmission electron microscopy of vascular corrosion casts and tissue sections. Special emphasis was placed on small pulmonary venous vessels. The shape of vascular casts was analyzed and interpreted concerning the wall composition of corresponding vessels studied in tissue sections. On the casts of pulmonary venules and small pulmonary veins, narrow or wider annular constrictions were regularly observed. Within these constrictions, marks of circularly running grooves were seen as an additional structural detail, which obviously mimic impressions of single or grouped smooth muscle cells. The depth of the constrictions varies; it may be more or less pronounced, occasionally narrowing down the luminal diameter to approximately 50%. These constrictions are caused by muscular sphincters. In tissue sections of small pulmonary veins, sphincter regions were identified as abruptly appearing single or grouped true smooth muscle cells. Smooth muscle cells may be arranged side by side in a group or bundle or even staked in two or three layers. Between the sphincter regions, the venous wall consists merely of endothelium and an accompanying connective tissue layer. The smooth muscle cells of a sphincter are regularly positioned between endothelial layer and elastic lamina. The smooth muscle cells next to the endothelium form myoendothelial junctions. Autonomic nerves near the sphincters were never seen. The venous sphincters described are suggested to be effective devices involved in blood flow regulation. Blood-borne substances or local tissue hormones might govern sphincter function. © 1992 Wiley-Liss, Inc.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号