全文获取类型
收费全文 | 100篇 |
免费 | 0篇 |
国内免费 | 2篇 |
专业分类
系统科学 | 2篇 |
丛书文集 | 2篇 |
教育与普及 | 2篇 |
理论与方法论 | 14篇 |
现状及发展 | 20篇 |
研究方法 | 10篇 |
综合类 | 51篇 |
自然研究 | 1篇 |
出版年
2020年 | 1篇 |
2018年 | 4篇 |
2017年 | 6篇 |
2016年 | 3篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 3篇 |
2012年 | 8篇 |
2011年 | 14篇 |
2010年 | 1篇 |
2009年 | 1篇 |
2008年 | 11篇 |
2007年 | 4篇 |
2006年 | 8篇 |
2005年 | 7篇 |
2004年 | 4篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1995年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有102条查询结果,搜索用时 0 毫秒
91.
Often the data units are described with discrete distributions (work described with citation distribution over time, population pyramid described as age-sex distribution etc.).When the set of such units is very large, appropriate clustering methods can reveal the typical patterns hidden in the data. 相似文献
92.
Irina I. Zaitseva Monica Hultcrantz Vladimir Sharoyko Malin Flodström-Tullberg Sergei V. Zaitsev Per-Olof Berggren 《Cellular and molecular life sciences : CMLS》2009,66(23):3787-3795
Pancreatic beta cell damage caused by pro-inflammatory cytokines interleukin-1β (IL-1β), interferon-γ (IFNγ) and tumor necrosis factor-α (TNFα) is a key event in the pathogenesis of type 1 diabetes. The suppressor of cytokine signaling-1 (SOCS-1) blocks IFNγ-induced signaling and prevents diabetes in the non-obese diabetic mouse. Here, we investigated if SOCS-1 overexpression in primary beta cells provides protection from cytokine-induced islet cell dysfunction and death. We demonstrate that SOCS-1 does not prevent increase in NO production and decrease in glucose-stimulated insulin secretion in the presence of IL-1β, IFNγ, TNFα. However, it decreases the activation of caspase-3, -8 and -9, and thereby, promotes a robust protection from cytokine-induced beta cell death. Our data suggest that SOCS-1 overexpression may not be sufficient in preventing all the biological activities of IFNγ in beta cells. In summary, we show that interference with IFNγ signal transduction pathways by SOCS-1 inhibits cytokine-stimulated pancreatic beta cell death. 相似文献
93.
Yoshiura K Kinoshita A Ishida T Ninokata A Ishikawa T Kaname T Bannai M Tokunaga K Sonoda S Komaki R Ihara M Saenko VA Alipov GK Sekine I Komatsu K Takahashi H Nakashima M Sosonkina N Mapendano CK Ghadami M Nomura M Liang DS Miwa N Kim DK Garidkhuu A Natsume N Ohta T Tomita H Kaneko A Kikuchi M Russomando G Hirayama K Ishibashi M Takahashi A Saitou N Murray JC Saito S Nakamura Y Niikawa N 《Nature genetics》2006,38(3):324-330
Human earwax consists of wet and dry types. Dry earwax is frequent in East Asians, whereas wet earwax is common in other populations. Here we show that a SNP, 538G --> A (rs17822931), in the ABCC11 gene is responsible for determination of earwax type. The AA genotype corresponds to dry earwax, and GA and GG to wet type. A 27-bp deletion in ABCC11 exon 29 was also found in a few individuals of Asian ancestry. A functional assay demonstrated that cells with allele A show a lower excretory activity for cGMP than those with allele G. The allele A frequency shows a north-south and east-west downward geographical gradient; worldwide, it is highest in Chinese and Koreans, and a common dry-type haplotype is retained among various ethnic populations. These suggest that the allele A arose in northeast Asia and thereafter spread through the world. The 538G --> A SNP is the first example of DNA polymorphism determining a visible genetic trait. 相似文献
94.
Sally A. Nicholas Vladimir V. Bubnov Inna M. Yasinska Vadim V. Sumbayev 《Cellular and molecular life sciences : CMLS》2011,68(1):151-158
Inflammatory reactions to ssRNA viruses are induced by the endosomal Toll-like receptors (TLRs) 7 and 8. TLR7/8-mediated inflammatory
reaction results in activation of the Nalp3 inflammasome via an unknown mechanism. Here we report for the first time that
TLR7/8 mediate activation of xanthine oxidase (XOD) in an HIF-1α-dependent manner. XOD produces uric acid and reactive oxygen
species, which could activate Nalp3 and therefore induce activation of caspase 1, known to convert inactive pro-IL-1β into
active IL-1β. Specific inhibition of the XOD activity attenuates TLR7/8-mediated activation of caspase 1 and IL-1β release.
These results were obtained using human THP-1 myeloid macrophages. The findings were verified by conducting in vivo experiments
on mice. 相似文献
95.
McKay JD Hung RJ Gaborieau V Boffetta P Chabrier A Byrnes G Zaridze D Mukeria A Szeszenia-Dabrowska N Lissowska J Rudnai P Fabianova E Mates D Bencko V Foretova L Janout V McLaughlin J Shepherd F Montpetit A Narod S Krokan HE Skorpen F Elvestad MB Vatten L Njølstad I Axelsson T Chen C Goodman G Barnett M Loomis MM Lubiñski J Matyjasik J Lener M Oszutowska D Field J Liloglou T Xinarianos G Cassidy A;EPIC Study Vineis P Clavel-Chapelon F Palli D Tumino R Krogh V Panico S González CA 《Nature genetics》2008,40(12):1404-1406
We carried out a genome-wide association study of lung cancer (3,259 cases and 4,159 controls), followed by replication in 2,899 cases and 5,573 controls. Two uncorrelated disease markers at 5p15.33, rs402710 and rs2736100 were detected by the genome-wide data (P = 2 x 10(-7) and P = 4 x 10(-6)) and replicated by the independent study series (P = 7 x 10(-5) and P = 0.016). The susceptibility region contains two genes, TERT and CLPTM1L, suggesting that one or both may have a role in lung cancer etiology. 相似文献
96.
Comparing resemblance measures 总被引:4,自引:0,他引:4
In the paper some types of equivalences over resemblance measures and some basic results about them are given. Based on induced partial orderings on the set of unordered pairs of units a dissimilarity between two resemblance measures over finite sets of units can be defined. As an example, using this dissimilarity standard association coefficients between binary vectors are compared both theoretically and computationally.Extended version of the paper presented at DISTANCIA'92, June 22–26, 1992, Rennes, France. This work was supported in part by the Ministry for Science and Technology of Slovenia, J2-6191-101-94. We would like to thank the editor and two anonymous referees for numerous remarks and suggestions that significantly improved the presentation of the material. 相似文献
97.
CRD-BP mediates stabilization of betaTrCP1 and c-myc mRNA in response to beta-catenin signalling 总被引:1,自引:0,他引:1
Noubissi FK Elcheva I Bhatia N Shakoori A Ougolkov A Liu J Minamoto T Ross J Fuchs SY Spiegelman VS 《Nature》2006,441(7095):898-901
98.
Societal needs for greater security require dramatic improvements in the sensitivity of chemical and biological sensors. To meet this challenge, increasing emphasis in analytical science has been directed towards materials and devices having highly nonlinear characteristics; semiconducting organic polymers (SOPs), with their facile excited state (exciton) transport, are prime examples of amplifying materials. SOPs have also been recognized as promising lasing materials, although the susceptibility of these materials to optical damage has thus far limited applications. Here we report that attenuated lasing in optically pumped SOP thin films displays a sensitivity to vapours of explosives more than 30 times higher than is observed from spontaneous emission. Critical to this achievement was the development of a transducing polymer with high thin-film quantum yield, a high optical damage threshold in ambient atmosphere and a record low lasing threshold. Trace vapours of the explosives 2,4,6-trinitrotoluene (TNT) and 2,4-dinitrotoluene (DNT) introduce non-radiative deactivation pathways that compete with stimulated emission. We demonstrate that the induced cessation of the lasing action, and associated sensitivity enhancement, is most pronounced when films are pumped at intensities near their lasing threshold. The combined gains from amplifying materials and lasing promise to deliver sensors that can detect explosives with unparalleled sensitivity. 相似文献
99.
Vladimir V. Frolkis 《Cellular and molecular life sciences : CMLS》1981,37(10):1043-1046
100.
The ion selectivity of pumps and channels is central to their ability to perform a multitude of functions. Here we investigate the mechanism of the extraordinary selectivity of the human voltage-gated proton channel, H(V)1 (also known as HVCN1). This selectivity is essential to its ability to regulate reactive oxygen species production by leukocytes, histamine secretion by basophils, sperm capacitation, and airway pH. The most selective ion channel known, H(V)1 shows no detectable permeability to other ions. Opposing classes of selectivity mechanisms postulate that (1) a titratable amino acid residue in the permeation pathway imparts proton selectivity, or (2) water molecules 'frozen' in a narrow pore conduct protons while excluding other ions. Here we identify aspartate 112 as a crucial component of the selectivity filter of H(V)1. When a neutral amino acid replaced Asp?112, the mutant channel lost proton specificity and became anion-selective or did not conduct. Only the glutamate mutant remained proton-specific. Mutation of the nearby Asp?185 did not impair proton selectivity, indicating that Asp?112 has a unique role. Although histidine shuttles protons in other proteins, when histidine or lysine replaced Asp?112, the mutant channel was still anion-permeable. Evidently, the proton specificity of H(V)1 requires an acidic group at the selectivity filter. 相似文献