全文获取类型
收费全文 | 152篇 |
免费 | 1篇 |
国内免费 | 4篇 |
专业分类
系统科学 | 3篇 |
理论与方法论 | 5篇 |
现状及发展 | 25篇 |
研究方法 | 27篇 |
综合类 | 91篇 |
自然研究 | 6篇 |
出版年
2021年 | 1篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 2篇 |
2012年 | 13篇 |
2011年 | 19篇 |
2010年 | 6篇 |
2009年 | 3篇 |
2008年 | 10篇 |
2007年 | 9篇 |
2006年 | 14篇 |
2005年 | 11篇 |
2004年 | 16篇 |
2003年 | 5篇 |
2002年 | 15篇 |
2000年 | 4篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1980年 | 1篇 |
1974年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有157条查询结果,搜索用时 15 毫秒
121.
Patel H Cross H Proukakis C Hershberger R Bork P Ciccarelli FD Patton MA McKusick VA Crosby AH 《Nature genetics》2002,30(4):347-348
Troyer syndrome (TRS) is an autosomal recessive complicated hereditary spastic paraplegia (HSP) that occurs with high frequency in the Old Order Amish. We report mapping of the TRS locus to chromosome 13q12.3 and identify a frameshift mutation in SPG20, encoding spartin. Comparative sequence analysis indicates that spartin shares similarity with molecules involved in endosomal trafficking and with spastin, a molecule implicated in microtubule interaction that is commonly mutated in HSP. 相似文献
122.
Kanamaru S Leiman PG Kostyuchenko VA Chipman PR Mesyanzhinov VV Arisaka F Rossmann MG 《Nature》2002,415(6871):553-557
Bacteriophage T4 has a very efficient mechanism for infecting cells. The key component of this process is the baseplate, located at the end of the phage tail, which regulates the interaction of the tail fibres and the DNA ejection machine. A complex of gene product (gp) 5 (63K) and gp27 (44K), the central part of the baseplate, is required to penetrate the outer cell membrane of Escherichia coli and to disrupt the intermembrane peptidoglycan layer, promoting subsequent entry of phage DNA into the host. We present here a crystal structure of the (gp5-gp27)3 321K complex, determined to 2.9 A resolution and fitted into a cryo-electron microscopy map at 17 A resolution of the baseplate-tail tube assembly. The carboxy-terminal domain of gp5 is a triple-stranded beta-helix that forms an equilateral triangular prism, which acts as a membrane-puncturing needle. The middle lysozyme domain of gp5, situated on the periphery of the prism, serves to digest the peptidoglycan layer. The amino-terminal, antiparallel beta-barrel domain of gp5 is inserted into a cylinder formed by three gp27 monomers, which may serve as a channel for DNA ejection. 相似文献
123.
124.
Single-exciton optical gain in semiconductor nanocrystals 总被引:1,自引:0,他引:1
Klimov VI Ivanov SA Nanda J Achermann M Bezel I McGuire JA Piryatinski A 《Nature》2007,447(7143):441-446
Nanocrystal quantum dots have favourable light-emitting properties. They show photoluminescence with high quantum yields, and their emission colours depend on the nanocrystal size--owing to the quantum-confinement effect--and are therefore tunable. However, nanocrystals are difficult to use in optical amplification and lasing. Because of an almost exact balance between absorption and stimulated emission in nanoparticles excited with single electron-hole pairs (excitons), optical gain can only occur in nanocrystals that contain at least two excitons. A complication associated with this multiexcitonic nature of light amplification is fast optical-gain decay induced by non-radiative Auger recombination, a process in which one exciton recombines by transferring its energy to another. Here we demonstrate a practical approach for obtaining optical gain in the single-exciton regime that eliminates the problem of Auger decay. Specifically, we develop core/shell hetero-nanocrystals engineered in such a way as to spatially separate electrons and holes between the core and the shell (type-II heterostructures). The resulting imbalance between negative and positive charges produces a strong local electric field, which induces a giant ( approximately 100 meV or greater) transient Stark shift of the absorption spectrum with respect to the luminescence line of singly excited nanocrystals. This effect breaks the exact balance between absorption and stimulated emission, and allows us to demonstrate optical amplification due to single excitons. 相似文献
125.
126.
Yesica R. Nievas Veronica M. Coceres Victor Midlej Wanderley de Souza Marlene Benchimol Antonio Pereira-Neves Ajay A. Vashisht James A. Wohlschlegel Patricia J. Johnson Natalia de Miguel 《Cellular and molecular life sciences : CMLS》2018,75(12):2211-2226
Trichomonas vaginalis is a common sexually transmitted parasite that colonizes the human urogenital tract, where it remains extracellular and adheres to epithelial cells. Infections range from asymptomatic to highly inflammatory, depending on the host and the parasite strain. Despite the serious consequences associated with trichomoniasis disease, little is known about parasite or host factors involved in attachment of the parasite-to-host epithelial cells. Here, we report the identification of microvesicle-like structures (MVs) released by T. vaginalis. MVs are considered universal transport vehicles for intercellular communication as they can incorporate peptides, proteins, lipids, miRNA, and mRNA, all of which can be transferred to target cells through receptor–ligand interactions, fusion with the cell membrane, and delivery of a functional cargo to the cytoplasm of the target cell. In the present study, we demonstrated that T. vaginalis release MVs from the plasma and the flagellar membranes of the parasite. We performed proteomic profiling of these structures demonstrating that they possess physical characteristics similar to mammalian extracellular vesicles and might be selectively charged with specific protein content. In addition, we demonstrated that viable T. vaginalis parasites release large vesicles (LVs), membrane structures larger than 1 µm that are able to interact with other parasites and with the host cell. Finally, we show that both populations of vesicles present on the surface of T vaginalis are induced in the presence of host cells, consistent with a role in modulating cell interactions. 相似文献
127.
CL Cheung KS Lau AY Ho KK Lee SC Tiu EY Lau J Leung MW Tsang KW Chan CY Yeung YC Woo EY Cheung VH Hung HK Pang CS Hung PC Sham AW Kung 《Nature genetics》2012,44(9):1026-1029
Thyrotoxic periodic paralysis (TPP) is a potentially life-threatening complication of thyrotoxicosis. We conducted a genome-wide association study (GWAS) and a replication study with a total of 123 southern Chinese with TPP (cases) and 1,170 healthy controls and identified a susceptibility locus on chromosome 17q24.3 near KCNJ2 (rs312691: odds ratio (OR) = 3.3; P(meta-analysis) = 1.8 × 10(-14)). All subjects with TPP also had Graves' disease, and subsequent TPP versus Graves' disease comparison confirmed that the association at 17q24.3 was specific to TPP. The area under the curve (AUC) of rs312691 genotype for risk prediction of TPP in subjects with Graves' disease was 0.73. Expression quantitative trait locus (eQTL) analysis identified SNPs in the region flanking rs312691 (±10 kb) that could potentially affect KCNJ2 expression (P = 0.0001). Our study has identified a susceptibility locus associated with TPP and provides insight into the causes of TPP. 相似文献
128.
STAR Consortium Saar K Beck A Bihoreau MT Birney E Brocklebank D Chen Y Cuppen E Demonchy S Dopazo J Flicek P Foglio M Fujiyama A Gut IG Gauguier D Guigo R Guryev V Heinig M Hummel O Jahn N Klages S Kren V Kube M Kuhl H Kuramoto T Kuroki Y Lechner D Lee YA Lopez-Bigas N Lathrop GM Mashimo T Medina I Mott R Patone G Perrier-Cornet JA Platzer M Pravenec M Reinhardt R Sakaki Y Schilhabel M Schulz H Serikawa T Shikhagaie M Tatsumoto S Taudien S Toyoda A Voigt B Zelenika D Zimdahl H Hubner N 《Nature genetics》2008,40(5):560-566
The laboratory rat is one of the most extensively studied model organisms. Inbred laboratory rat strains originated from limited Rattus norvegicus founder populations, and the inherited genetic variation provides an excellent resource for the correlation of genotype to phenotype. Here, we report a survey of genetic variation based on almost 3 million newly identified SNPs. We obtained accurate and complete genotypes for a subset of 20,238 SNPs across 167 distinct inbred rat strains, two rat recombinant inbred panels and an F2 intercross. Using 81% of these SNPs, we constructed high-density genetic maps, creating a large dataset of fully characterized SNPs for disease gene mapping. Our data characterize the population structure and illustrate the degree of linkage disequilibrium. We provide a detailed SNP map and demonstrate its utility for mapping of quantitative trait loci. This community resource is openly available and augments the genetic tools for this workhorse of physiological studies. 相似文献
129.
130.
Vithana EN Morgan P Sundaresan P Ebenezer ND Tan DT Mohamed MD Anand S Khine KO Venkataraman D Yong VH Salto-Tellez M Venkatraman A Guo K Hemadevi B Srinivasan M Prajna V Khine M Casey JR Inglehearn CF Aung T 《Nature genetics》2006,38(7):755-757
Congenital hereditary endothelial dystrophy (CHED) is a heritable, bilateral corneal dystrophy characterized by corneal opacification and nystagmus. We describe seven different mutations in the SLC4A11 gene in ten families with autosomal recessive CHED. Mutations in SLC4A11, which encodes a membrane-bound sodium-borate cotransporter, cause loss of function of the protein either by blocking its membrane targeting or nonsense-mediated decay. 相似文献