全文获取类型
收费全文 | 199篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
化学 | 144篇 |
晶体学 | 3篇 |
力学 | 1篇 |
数学 | 24篇 |
物理学 | 28篇 |
出版年
2017年 | 1篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 20篇 |
2012年 | 6篇 |
2011年 | 1篇 |
2010年 | 3篇 |
2009年 | 2篇 |
2008年 | 6篇 |
2007年 | 20篇 |
2006年 | 14篇 |
2005年 | 20篇 |
2004年 | 19篇 |
2003年 | 15篇 |
2002年 | 11篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 2篇 |
排序方式: 共有200条查询结果,搜索用时 125 毫秒
41.
Numerous peptide aptamers that recognize inorganic materials have been isolated using in vitro peptide evolution systems. However, it remains unknown how peptides interact with inorganic materials or how specific those interactions are. We, therefore, assessed the target specificities of the peptide aptamer TBP-1 (RKLPDAPGMHTW) by monitoring its ability to bind 10 different metals. We found that phages displaying TBP-1 bound to Ti, Si, and Ag surfaces but not to Au, Cr, Pt, Sn, Zn, Cu, or Fe. As previously seen with Ti, binding to Si and Ag was diminished by R1A, P4A, or D5A mutation, suggesting that the same molecular mechanism underlies TBP-1 binding to all three materials. We also observed that a synthetic TBP-1 peptide mediated mineralization of both silica and Ag. It, thus, appears that although the overall chemical characteristics of Ti, Si, and Ag surfaces are dissimilar, they share a common subnanometric structure that is recognized by TBP-1. 相似文献
42.
Takahashi T Matsuoka K Takimiya K Otsubo T Aso Y 《Journal of the American Chemical Society》2005,127(25):8928-8929
A series of highly extensive quinoidal oligothiophenes carrying a dicyanomethylene group at both terminal positions is synthesized. As the quinoidal structures extend, they have highly amphoteric abilities and show strong electronic absorptions in the visible to near-infrared region. The higher homologues, quinquethiophene and sexithiophene, exist as equilibrium mixtures with the biradical species. 相似文献
43.
Onoda M Tokuyama H Uchiyama S Mawatari K Santa T Kaneko K Imai K Nakagomi K 《Chemical communications (Cambridge, England)》2005,(14):1848-1850
Strong fluorescence signals were observed after the reaction of novel reagents with hydroperoxides. 相似文献
44.
We study a curvature-dependent motion of plane curves in a two-dimensional infinite cylinder with spatially undulating boundary. The law of motion is given by V=κ+A, where V is the normal velocity of the curve, κ is the curvature, and A is a positive constant. The boundary undulation is assumed to be almost periodic, or, more generally, recurrent in a certain sense. We first introduce the definition of recurrent traveling waves and establish a necessary and sufficient condition for the existence of such traveling waves. We then show that the traveling wave is asymptotically stable if it exists. Next we show that a regular traveling wave has a well-defined average speed if the boundary shape is strictly ergodic. Finally we study what we call “virtual pinning”, which means that the traveling wave propagates over the entire cylinder with zero average speed. Such a peculiar situation can occur only in non-periodic environments and never occurs if the boundary undulation is periodic. 相似文献
45.
Shigeyoshi Fujiwara Ken-Ichi Imadome Masami Takei 《Experimental & molecular medicine》2015,47(1):e135
The development of highly immunodeficient mouse strains has allowed the reconstitution of functional human immune system components in mice. New-generation humanized mice generated in this manner have been extensively used for modeling viral infections that are exclusively human tropic. Epstein–Barr virus (EBV)-infected humanized mice reproduce cardinal features of EBV-associated B-cell lymphoproliferative disease and EBV-associated hemophagocytic lymphohistiocytosis (HLH). Erosive arthritis morphologically resembling rheumatoid arthritis (RA) has also been recapitulated in these mice. Low-dose EBV infection of humanized mice results in asymptomatic, persistent infection. Innate immune responses involving natural killer cells, EBV-specific adaptive T-cell responses restricted by human major histocompatibility and EBV-specific antibody responses are also elicited in humanized mice. EBV-associated T-/natural killer cell lymphoproliferative disease, by contrast, can be reproduced in a distinct mouse xenograft model. In this review, recent findings on the recapitulation of human EBV infection and pathogenesis in these mouse models, as well as their application to preclinical studies of experimental anti-EBV therapies, are described. 相似文献
46.
Upon guest recognition, a self-assembled hexa-ruthenium coordination cage shows a chromic shift resulting from the slight conformational change in the panel ligand. 相似文献
47.
Ito T Ali Z Furusawa M Iliya I Tanaka T Nakaya K Murata J Darnaedi D Iinuma M 《Chemical & pharmaceutical bulletin》2006,54(3):363-367
Three new resveratrol oligomers, cotylelophenol C (1) (resveratrol tetramer) and cotylelosides A (2) and B (3) (O-glucosides of resveratrol trimer), together with four known glucosides of resveratrol oligomers (vaticasides A, B, C, D) and piceid, were isolated from an acetone soluble part of stem of Cotylelobium lanceolatum (Dipterocarpaceae). The structures of new compounds were determined by spectral data analysis. The characteristic properties observed in the NMR spectra of 1 were also discussed. 相似文献
48.
Keiko Nakanishi Munehiro Katagi Kei Zaitsu Noriaki Shima Hiroe Kamata Akihiro Miki Hajime Kato Ken-Ichi Harada Hitoshi Tsuchihashi Koichi Suzuki 《Analytical and bioanalytical chemistry》2012,404(8):2427-2435
A liquid chromatography–electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) procedure was developed for the simultaneous determination of enantiomers of the prevalent designer drug 3,4-methylenedioxymethamphetamine (MDMA) and its phase I and phase II metabolites in urine with chiral derivatization. The analytes in urine were directly derivatized with chiral Marfey’s reagent, N α- (5-fluoro-2,4-dinitrophenyl)-d-leucinamide, without extraction. The diastereomers of the N α-(2,4-dinitrophenyl)-d-leucinamide derivatives generated were determined by LC-MS/MS. Satisfactory chromatographic separation was achieved for the enantiomers of MDMA and its metabolites 3,4-methylenedioxyamphetamine, 4-hydroxy-3-methoxymethamphetamine (HMMA), HMMA glucuronide, and HMMA sulfate on a semimicro octadecylsilane column using linear gradient elution. With use of multiple reaction monitoring mode, the limits of detection of these analytes ranged from 0.01 to 0.03?μg/mL. Linear calibration curves were obtained for all enantiomers from 0.1 to 20?μg/mL in urine. The method showed sufficient reproducibility and quantitative ability. This is the first report of a simple LC-MS/MS-based analytical procedure with direct chiral derivatization in aqueous media that allows simultaneous enantiomeric determination of drugs and their metabolites, including glucuronide and sulfate derivatives. 相似文献
49.
50.
Ken-Ichi Kawarabayashi 《Discrete Mathematics》2007,307(6):764-768
We prove that for any orientable surface S and any non-negative integer k, there exists an integer fS(k) such that every graph G embeddable in S has either k vertex-disjoint odd cycles or a vertex set A of cardinality at most fS(k) such that G-A is bipartite. Such a property is called the Erd?s-Pósa property for odd cycles. We also show its edge version. As Reed [Mangoes and blueberries, Combinatorica 19 (1999) 267-296] pointed out, the Erd?s-Pósa property for odd cycles do not hold for all non-orientable surfaces. 相似文献