全文获取类型
收费全文 | 102篇 |
免费 | 1篇 |
专业分类
化学 | 73篇 |
力学 | 3篇 |
数学 | 8篇 |
物理学 | 19篇 |
出版年
2020年 | 1篇 |
2018年 | 2篇 |
2015年 | 1篇 |
2014年 | 3篇 |
2013年 | 2篇 |
2011年 | 3篇 |
2009年 | 4篇 |
2008年 | 2篇 |
2007年 | 7篇 |
2006年 | 5篇 |
2005年 | 4篇 |
2004年 | 7篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 4篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1996年 | 6篇 |
1994年 | 2篇 |
1993年 | 7篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 5篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1937年 | 2篇 |
排序方式: 共有103条查询结果,搜索用时 15 毫秒
1.
Patrick Mather Nino Grizzuti Glenn Heffner Mathias Ricker Willie E. Rochefort Markus Seitz Hans-Werner Schmidt Dale S. Pearson 《Liquid crystals》1994,17(6):811-826
In this paper, we report on the synthesis and detailed characterization of a new semiflexible nematic liquid crystalline polyester which could serve as a 'model' polyester for a variety of physical and physico-chemical investigations. The polymer is a nematic liquid over a wide temperature range-from the glass transition temperature at ∼95°C to the isotropic transition at ∼240°C. We expect this polyester to be particularly useful for studying the effect of flow on the orientation of liquid crystalline polymers, as well as the production and removal of disclinations. 相似文献
2.
M. Okumura K. Fukushi S. N. Willie R. E. Sturgeon 《Fresenius' Journal of Analytical Chemistry》1993,345(8-9):570-574
Summary Atomic fluorescence (AFS), absorption (AAS) and emission (AES) systems were evaluated for the determination of inorganic mercury. Identical vapour generation and amalgamation procedures were used to permit direct comparison of the performance of a commercial long-path AAS instrument to laboratory constructed non-dispersive AFS as well as He-MIP based AES instruments. Instrumental noise-limited detection limits (LOD) were 0.94, 2.4, 2.8 pg for AAS, AES and AFS techniques, respectively. Methodological LOD's were found to be blank controlled and similar for all three instruments, viz. 9, 25 and 16 pg for AAS, AFS and AES, respectively. All three systems produced accurate results at the low ng/l concentration, as verified by the analysis of a certified river water reference material (NRCC ORMS-1). 相似文献
3.
4.
A detection system for hydrogen peroxide, i.e., luminol chemiluminescence (CL) in a hexadecyltrimethylammonium bromide (CTAB) reversed micellar system, was coupled to enzyme reactions. The use of CTAB reversed micellar medium allows one to conduct both the oxidase enzymatic and CL detection reactions simultaneously at mild pH (l-amino acid system, pH 8.7; glucose system, pH 8.5) in the absence of any co-oxidant or catalyst. Based on this result, simple and unique determinations of l-amino acids and glucose as substrates were developed. The calibration graph for a representative amino acid, l-phenylalanine, was linear in the concentration range 4.0×10?6?200×10?6M with a relative standard deviation of 5.78% (five determinations). The method established for l-phenylalanine was also applicable for the assay of fourteen other l-amino acids. The calibration graph for glucose was linear in the concentration range 5.4×10??540×10?6M with a relative standard deviation of 4.27% (eight determinations). This method was compared with a standard spectrophotometric method (hexokinase) and successfully applied to the determination of glucose in human serum. 相似文献
5.
Hsiu-Rong Chang Willie Lau Hsing-Yeh Parker David G. Westmoreland 《Macromolecular Symposia》1996,111(1):253-263
Electron spin resonance (ESR) techniques have been applied to a detailed study of batch and semicontinuous emulsion polymerization of methyl methacrylate; butyl acrylate and styrene have been briefly studied. Quenching of samples from the polymerization reactor followed by ESR analysis are useful, but we have developed continuous flow techniques which are preferable in many cases. ESR techniques can provide valuable information relating to the nature of free radical reactions, the concentration of propagating free radicals, and the kinetic processes in these reactions. Direct ESR analysis is most valuable but is not applicable to all systems. Spin trapping techniques can be useful for systems not accessible by direct analysis. 相似文献
6.
Jeffery S. Edmiston Jason W. Flora Mariano J. Scian Guoya Li Gaurav S. J. B. Rana Timothy B. Langston Tapas K. Sengupta Willie J. McKinney 《Analytical and bioanalytical chemistry》2009,394(6):1609-1620
Phosphorylation is the most widely studied posttranslational modification (PTM) and is an important regulatory mechanism used
during cellular responses to external stimuli. The kinases and phosphatases that regulate protein phosphorylation are known
to be affected in many human diseases. Cigarette smoking causes cardiovascular disease (CVD). Endothelial cells play a pivotal
role in CVD initiation and development; however, there have been limited investigations of the specific signaling cascades
and protein phosphorylations activated by cigarette smoke in endothelial cells. The purpose of this research was to better
understand the differential protein phosphorylation in endothelial cells stimulated with extracts of cigarette smoke total
particulate matter (CS-TPM) in vitro. Human microvascular endothelial cells were exposed in vitro to CS-TPM at concentrations
that were shown to cause endothelial cell dysfunction. The phosphorylated proteins were isolated using phosphoprotein-specific
chromatography, followed by enzymatic digestion and nano-flow capillary liquid chromatography (ncap-LC) coupled to high resolution
mass spectrometry. This study putatively identified 94 proteins in human microvascular endothelial cells that were differentially
bound to a phosphoprotein-specific chromatography column following exposure to CS-TPM suggesting differential phosphorylation.
Pathway analysis has also been conducted and confirmations of several observations have been made using immunoaffinity-based
techniques (e.g., Western blotting).
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
7.
TRANSMISSION OF HUMAN EPIDERMIS AND STRATUM CORNEUM AS A FUNCTION OF THICKNESS IN THE ULTRAVIOLET AND VISIBLE WAVELENGTHS 总被引:8,自引:1,他引:8
Wiel A. G. Bruls H. Slaper Jan C. van der Leun L. Berrens 《Photochemistry and photobiology》1984,40(4):485-494
Abstract The dependence of radiation transmission on sample thickness was studied in isolated samples of human stratum corneum and full-thickness epidermis. The investigation also included samples of skin repeatedly exposed to UV-B. Transmission was measured in the ultraviolet and in the visible from 248–546 nm. Two methods, one microscopic and the other mechanical, were used to measure thickness. There was a good correlation between the results.
The dependence of transmission on thickness in these samples could be described satisfactorily by an exponential function, implying that the Lambert-Beer law is approximately valid. Thus, a single parameter, such as the half-value layer ( d½ ), is sufficient to characterize absorption in the skin samples.
Water content of the isolated stratum corneum was influenced by maintenance conditions: samples floating on water containing a small amount of NaCl were more hydrated than samples floating on a more concentrated salt solution, or stored in air. Changes in water content of the samples resulted in changes of thickness and, to a lesser extent, of transmission. Approximate in vivo values of d½ were computed after estimating the in vivo water content of stratum corneum.
Differences found in the shape of the transmission spectra of stratum corneum and full-thickness epidermis may reflect differences in chemical composition. The influence of wetting of the skin on its sensitivity to sunlight is explained in a new way. 相似文献
The dependence of transmission on thickness in these samples could be described satisfactorily by an exponential function, implying that the Lambert-Beer law is approximately valid. Thus, a single parameter, such as the half-value layer ( d
Water content of the isolated stratum corneum was influenced by maintenance conditions: samples floating on water containing a small amount of NaCl were more hydrated than samples floating on a more concentrated salt solution, or stored in air. Changes in water content of the samples resulted in changes of thickness and, to a lesser extent, of transmission. Approximate in vivo values of d
Differences found in the shape of the transmission spectra of stratum corneum and full-thickness epidermis may reflect differences in chemical composition. The influence of wetting of the skin on its sensitivity to sunlight is explained in a new way. 相似文献
8.
D. Finsterbusch H. Willig B. Wolf G. Bruls B. Lüthi M. Waffenschmidt O. Stockert A. Schrder H. V. Lhneysen 《Annalen der Physik》1996,508(2):184-196
We report on a detailed comparison of the thermodynamic properties of the heavy-fermion system CeCu6 which can be described as a Fermi liquid at low temperatures T < 0.1 K, and CeCu5.9Au0.1 where strong deviations from the Fermi-liquid behaviour were found previously in the T dependence of the specific heat C, magnetization M and electrical resistivity p. The specific heat, magnetization and elastic constants are investigated in a large range of magnetic fields, corroborating the idea that the non-Fermi-liquid behaviour arises from low-lying spin excitations. For the elastic constants, a striking linear T dependence is found for CeCu5.9Au0.1 in contrast to the T2 Fermi-liquid behaviour of CeCu6. 相似文献
9.
William H. Bearden Valorie M. Cargin Willie R. Roberson 《Magnetic resonance in chemistry : MRC》1981,15(2):131-132
While there is a useable paramagnetic relaxation reagent (PARR) for use in nonpolar or low polarity solvents, there has not been a practical PARR for use in highly polar solvents. A reagent, Gd(NO3)3-inositol, is described which appears to satisfy this need. The performance of the reagent is given in terms of its effect on the T1, NOE and line width values of N,N-dimethylformamide. In addition, the application of this reagent to adenosine is also reported. 相似文献
10.
Helmut Willie 《Queueing Systems》1990,6(1):109-112
Explicit formulas for the individual call loss probabilities are derived which arise when a finite collection of independent
general stationary traffic streams with exponentially distributed service times are offered simultaneously to a single server.
The formulas show a modified insensitivity property of the given model. 相似文献