全文获取类型
收费全文 | 169篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
丛书文集 | 1篇 |
理论与方法论 | 5篇 |
现状及发展 | 47篇 |
研究方法 | 28篇 |
综合类 | 89篇 |
自然研究 | 3篇 |
出版年
2023年 | 1篇 |
2020年 | 1篇 |
2018年 | 3篇 |
2017年 | 1篇 |
2014年 | 5篇 |
2013年 | 7篇 |
2012年 | 9篇 |
2011年 | 16篇 |
2010年 | 4篇 |
2009年 | 4篇 |
2008年 | 16篇 |
2007年 | 16篇 |
2006年 | 21篇 |
2005年 | 15篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 11篇 |
2001年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1992年 | 3篇 |
1986年 | 1篇 |
1982年 | 1篇 |
1979年 | 3篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1972年 | 1篇 |
1970年 | 2篇 |
1968年 | 2篇 |
1965年 | 1篇 |
1961年 | 1篇 |
1946年 | 5篇 |
1945年 | 1篇 |
排序方式: 共有173条查询结果,搜索用时 974 毫秒
151.
Glucagon-like peptide-1(1-37) inhibits chemokine-induced migration of human CD4-positive lymphocytes
Nikolaus Marx Mathias Burgmaier Philipp Heinz Mirjam Ostertag Angelina Hausauer Helga Bach Renate Durst Vinzenz Hombach Daniel Walcher 《Cellular and molecular life sciences : CMLS》2010,67(20):3549-3555
The present study examined the effect of GLP-1(1-37) on chemokine-induced CD4-positive lymphocyte migration as an early and
critical step in atherogenesis. Pretreatment with GLP-1(1-37) reduced the SDF-induced migration of isolated human CD4-positive
lymphocytes in a concentration-dependent manner. Similar effects were seen when RANTES was used as a chemokine. GLP-1(1-37)’s
effect on CD4-positive lymphocyte migration was mediated through an early inhibition of chemokine-induced PI-3 kinase activity.
Downstream, GLP-1(1-37) inhibited SDF-induced phosphorylation of MLC and cofilin and limited f-actin formation as well as
ICAM3 translocation. Furthermore, exendin-4 inhibited SDF-induced migration of CD4-positive lymphocytes similarly to GLP-1(1-37),
and transfection of these cells with GLP-1 receptor siRNA abolished GLP-1(1-37)’s action on chemokine-induced ICAM3 translocation,
suggesting an effect mediated via the GLP-1 receptor. Thus, GLP-1(1-37) inhibits chemokine-induced CD4-positive lymphocyte
migration by inhibition of the PI3-kinase pathway and via the GLP-1 receptor. This effect provides a potential novel mechanism
for how GLP-1(1-37) may modulate vascular disease. 相似文献
152.
153.
154.
FACL4, encoding fatty acid-CoA ligase 4, is mutated in nonspecific X-linked mental retardation 总被引:1,自引:0,他引:1
Meloni I Muscettola M Raynaud M Longo I Bruttini M Moizard MP Gomot M Chelly J des Portes V Fryns JP Ropers HH Magi B Bellan C Volpi N Yntema HG Lewis SE Schaffer JE Renieri A 《Nature genetics》2002,30(4):436-440
X-linked mental retardation (XLMR) is an inherited condition that causes failure to develop cognitive abilities, owing to mutations in a gene on the X chromosome. The latest XLMR update lists up to 136 conditions leading to 'syndromic', or 'specific', mental retardation (MRXS) and 66 entries leading to 'nonspecific' mental retardation (MRX). For 9 of the 66 MRX entries, the causative gene has been identified. Our recent discovery of the contiguous gene deletion syndrome ATS-MR (previously known as Alport syndrome, mental retardation, midface hypoplasia, elliptocytosis, OMIM #300194), characterized by Alport syndrome (ATS) and mental retardation (MR), indicated Xq22.3 as a region containing one mental retardation gene. Comparing the extent of deletion between individuals with ATS-MR and individuals with ATS alone allowed us to define a critical region for mental retardation of approximately 380 kb, containing four genes. Here we report the identification of two point mutations, one missense and one splice-site change, in the gene FACL4 in two families with nonspecific mental retardation. Analysis of enzymatic activity in lymphoblastoid cell lines from affected individuals of both families revealed low levels compared with normal cells, indicating that both mutations are null mutations. All carrier females with either point mutations or genomic deletions in FACL4 showed a completely skewed X-inactivation, suggesting that the gene influences survival advantage. FACL4 is the first gene shown to be involved in nonspecific mental retardation and fatty-acid metabolism. 相似文献
155.
156.
本书介绍了贯穿整个模块系统设计方法论的系统性质形式证法。该方法沦将子系统的共同验证与虚拟系统部件的系统精化和复用性相结合,通过规约的形式与非形式方法相结合,由UML和B语言来完成。这样就允许通过经证明的子系统的合成来验证系统规约(对于接口则给予某些特别的注意,符合VSIA/SLIF方法)。将B语言与C、VHDL和SystemC语言相连。将通过构造校正设计的过程扩展到较低的单片系统开发阶段。因此证明嵌入式软件产品是与证明硬件产品相配套的。书中开发了用于从UML和B语言产生代码的原型工具,现有的B语言验证工具被拓展成支持IP的再使用,这部是根据VSIA的推荐。书中所涉及的方法论及工具是通过开发三个工业应用来验证的,即无线移动终端、建立在HIPERLAN/2协议基础上的电信单片系统、以及汽车的防碰撞组件。 相似文献
157.
Conformational change and protein-protein interactions of the fusion protein of Semliki Forest virus 总被引:1,自引:0,他引:1
Gibbons DL Vaney MC Roussel A Vigouroux A Reilly B Lepault J Kielian M Rey FA 《Nature》2004,427(6972):320-325
Fusion of biological membranes is mediated by specific lipid-interacting proteins that induce the formation and expansion of an initial fusion pore. Here we report the crystal structure of the ectodomain of the Semliki Forest virus fusion glycoprotein E1 in its low-pH-induced trimeric form. E1 adopts a folded-back conformation that, in the final post-fusion form of the full-length protein, would bring the fusion peptide loop and the transmembrane anchor to the same end of a stable protein rod. The observed conformation of the fusion peptide loop is compatible with interactions only with the outer leaflet of the lipid bilayer. Crystal contacts between fusion peptide loops of adjacent E1 trimers, together with electron microscopy observations, suggest that in an early step of membrane fusion, an intermediate assembly of five trimers creates two opposing nipple-like deformations in the viral and target membranes, leading to formation of the fusion pore. 相似文献
158.
Martin J Han C Gordon LA Terry A Prabhakar S She X Xie G Hellsten U Chan YM Altherr M Couronne O Aerts A Bajorek E Black S Blumer H Branscomb E Brown NC Bruno WJ Buckingham JM Callen DF Campbell CS Campbell ML Campbell EW Caoile C Challacombe JF Chasteen LA Chertkov O Chi HC Christensen M Clark LM Cohn JD Denys M Detter JC Dickson M Dimitrijevic-Bussod M Escobar J Fawcett JJ Flowers D Fotopulos D Glavina T Gomez M Gonzales E Goodstein D Goodwin LA Grady DL Grigoriev I Groza M Hammon N Hawkins T 《Nature》2004,432(7020):988-994
159.
Microscopic artificial swimmers 总被引:2,自引:0,他引:2
Microorganisms such as bacteria and many eukaryotic cells propel themselves with hair-like structures known as flagella, which can exhibit a variety of structures and movement patterns. For example, bacterial flagella are helically shaped and driven at their bases by a reversible rotary engine, which rotates the attached flagellum to give a motion similar to that of a corkscrew. In contrast, eukaryotic cells use flagella that resemble elastic rods and exhibit a beating motion: internally generated stresses give rise to a series of bends that propagate towards the tip. In contrast to this variety of swimming strategies encountered in nature, a controlled swimming motion of artificial micrometre-sized structures has not yet been realized. Here we show that a linear chain of colloidal magnetic particles linked by DNA and attached to a red blood cell can act as a flexible artificial flagellum. The filament aligns with an external uniform magnetic field and is readily actuated by oscillating a transverse field. We find that the actuation induces a beating pattern that propels the structure, and that the external fields can be adjusted to control the velocity and the direction of motion. 相似文献
160.
To meet their need for nitrogen in the restricted foraging environment provided by their host plants, some arboreal ants deploy group ambush tactics in order to capture flying and jumping prey that might otherwise escape. Here we show that the ant Allomerus decemarticulatus uses hair from the host plant's stem, which it cuts and binds together with a purpose-grown fungal mycelium, to build a spongy 'galleried' platform for trapping much larger insects. Ants beneath the platform reach through the holes and immobilize the prey, which is then stretched, transported and carved up by a swarm of nestmates. To our knowledge, the collective creation of a trap as a predatory strategy has not been described before in ants. 相似文献