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   723篇
  免费   77篇
  2023年   5篇
  2022年   7篇
  2021年   7篇
  2020年   8篇
  2019年   9篇
  2018年   14篇
  2017年   8篇
  2016年   11篇
  2015年   22篇
  2014年   32篇
  2013年   42篇
  2012年   55篇
  2011年   57篇
  2010年   39篇
  2009年   27篇
  2008年   40篇
  2007年   43篇
  2006年   36篇
  2005年   46篇
  2004年   30篇
  2003年   26篇
  2002年   34篇
  2001年   10篇
  2000年   19篇
  1999年   16篇
  1998年   5篇
  1996年   12篇
  1995年   11篇
  1994年   3篇
  1993年   6篇
  1992年   7篇
  1991年   8篇
  1990年   9篇
  1989年   5篇
  1988年   5篇
  1985年   4篇
  1984年   3篇
  1983年   4篇
  1982年   3篇
  1981年   3篇
  1978年   4篇
  1977年   5篇
  1976年   6篇
  1975年   5篇
  1974年   4篇
  1973年   6篇
  1972年   4篇
  1970年   3篇
  1960年   3篇
  1925年   5篇
排序方式: 共有800条查询结果,搜索用时 15 毫秒
11.
A DNA fragment containing the genes for the eight ribosomal proteins HmaL3, HL6, HmaL23, HmaL2, HmaS19, HmaL22, HmaS3, and HmaL29 from Halobacterium marismortui has been cloned and sequenced. The organization of this gene cluster in general corresponds to the S10 operon of Escherichia coli although there exists some differences between them. The sequence analysis of the 5'- and 3'-region of the gene cluster revealed three open reading frames (orf1, orf2, and orf3) which do not code for any ribosomal protein whose structure is known. A putative promoter is located upstream of orf1. Out of the eight ribosomal proteins five have counterparts in eubacteria only, two in both eubacteria and eukaryotes, and one is exclusively related to an eukaryotic ribosomal protein.  相似文献   
12.
Postrhinoplasty "red nose": differential diagnosis and treatment by laser   总被引:1,自引:0,他引:1  
Prior to anticipated nasal surgery, the nasal and facial skin should be examined for any vascular lesions. The skin type should be ascertained. A history of any prior nasal surgery, particularly on the nasal dorsum, should be noted. If rosacea is a clinical possibility, a trial of 1.5 to 2.0 gm q.d. of tetracycline for 6 to 8 weeks is warranted. If, after rhinoplasty, a diffuse "redness" on the nasal dorsum results and one can exclude other diagnoses, then argon laser therapy should be considered. A 3-mm punch biopsy should be obtained to see whether superficial ectatic vessels are present, a finding that would be indicative of a good result from laser therapy.  相似文献   
13.
Synopsis The aim of this paper is the selective visualization of human blood basophils in autoradiographs. [3H]Thymidine-labelled basophils in buffy coat smears were fixed in methanol-formaldehyde followed by 5-aminoacridine hydrochloride and stained with basic Aldehyde Fuchsin prior to autoradiographic processing. The technique described represents a simple method for quantitative autoradiographic studies on basophil kinetics and the interaction of these cells with IgE-mediated atopias.  相似文献   
14.
15.
The effect of the thermal fluctuation on the orientation distribution pattern of globular protein molecules in a two-dimensional lattice was investigated by the method of computer simulation. A set of interaction parameters was assigned to interaction sites on each molecule and the interaction energy between two molecules was given by the product of the parameters of facing sites. Orientation fluctuation was assumed to take place with the probability proportional to the Boltzmann factor. Patterns having different degrees of order appeared with the change of temperature. The entropy and other thermodynamic quantities of these patterns were calculated, and gradual and transitional changes of the pattern were discussed in comparison with the case of simple atoms or molecules.  相似文献   
16.
17.
18.
Identification of single nucleotide polymorphisms (SNPs) is a key element in sequence-based genetic analysis. Next generation sequencing offers a cost-effective basis to generate the necessary, large sequence data sets, and bioinformatic methods are being developed to process sequencing machine readouts. We were interested in detection of SNPs in a 350 kb region of an EMS-mutagenized Arabidopsis chromosome 3. The region was selectively analyzed using PCR-generated, overlapping fragments for Solexa sequencing. The ensuing reads provided a high coverage and were processed bioinformatically. In order to assess the SNP candidates obtained with a frequently used alignment program and SNP caller, we developed an additional method that allows the identification of high confidence SNP loci. The method can easily be applied to complete genome sequence data of sufficient coverage.  相似文献   
19.
Members of the ADAM (a disintegrin and metalloprotease) family are type I transmembrane proteins involved in biological processes of proteolysis, cell adhesion, cell–matrix interaction, as well as in the intracellular signaling transduction. In the present study, expression patterns of seven members of the ADAM family were investigated at the early stages of the developing cochlea by in situ hybridization. The results show that each individual ADAM is expressed and regulated in the early developing cochlea. ADAM9, ADAM10, ADAM17, and ADAM23 are initially and widely expressed in the otic vesicle at embryonic day 2.5 (E2.5) and in the differential elements of the cochlear duct at E9, while ADAM12 is expressed in acoustic ganglion cells at E7. ADAM22 is detectable in cochlear ganglion cells as early as from E4 and in the basilar papilla from E7. Therefore, the present study extends our previous results and suggests that ADAMs also play a role in the early cochlear development.  相似文献   
20.
White matter lesions (WML) are clinically relevant since they are associated with strokes, cognitive decline, depression, or epilepsy, but the underlying etiology in young adults without classical risk factors still remains elusive. Our aim was to elucidate the possible clinical diagnosis and mechanisms leading to WML in patients carrying the D313Y mutation in the α-galactosidase A (GLA) gene, a mutation that was formerly described as nonpathogenic. Pathogenic GLA mutations cause Fabry disease, a vascular endothelial glycosphingolipid storage disease typically presenting with a symptom complex of renal, cardiac, and cerebrovascular manifestations. We performed in-depths clinical, biochemical and genetic examinations as well as advanced magnetic resonance imaging analyses in a pedigree with the genetically determined GLA mutation D313Y. We detected exclusive neurologic manifestations of the central nervous system of the “pseudo”-deficient D313Y mutation leading to manifest WML in 7 affected adult family members. Furthermore, two family members that do not carry the mutation showed no WML. The D313Y mutation resulted in a normal GLA enzyme activity in leukocytes and severely decreased activities in plasma. In conclusion, our results provide evidence that GLA D313Y is potentially involved in neural damage with significant WML, demonstrating the necessity of evaluating patients carrying D313Y more thoroughly. D313Y might broaden the spectrum of hereditary small artery diseases of the brain, which preferably occur in young adults without classical risk factors. In view of the existing causal therapy regime, D313Y should be more specifically taken into account in these patients.  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