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21.
Thermo-sensitive poly(2-isopropyl-2-oxazoline)s (PiPrOx) were functionalized with end groups of different polarity by living cationic ring-opening polymerization using the initiator and/or termination method as well as sequential block copolymerization with 2-methyl-2-oxazoline. As end groups, methyl, n-nonyl, piperidine, piperazine as well as oligo(ethylenglygol) and oligo(2-methyl-2-oxazoline) were introduced quantitatively. The lower critical solution temperature (LCST) of the aqueous solutions was investigated. The introduction of hydrophobic end groups decreases the LCST, while hydrophilic polymer tails raise the cloud point. In comparison to poly(N-isopropyl acrylamide), the impact of the end group polarity upon the modulation of the LCST was found to be significantly stronger. Surprisingly, terminal oligoethylenegycol units also decrease the LCST of PiPrOx, thus acting as moieties of higher hydrophobicity as compared to the poly(2-oxazoline) main chain. Together with the possible variation of the side group polarity, this allows a broad modulation of the LCST of poly(2-oxazoline)s. 相似文献
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G. M. Fuchs T. Prohaska G. Friedbacher H. Hutter M. Grasserbauer 《Fresenius' Journal of Analytical Chemistry》1995,351(2-3):143-147
The Maximum Entropy Method (MEM) has been applied successfully to the deconvolution of images obtained by Atomic Force (AFM) and Scanning Tunneling Microscopy (STM) using a NanoScope III system. The images have been taken on graphite (STM) and NaCl (AFM) substrates. Image processing has been performed running the Cambridge MaxEnt Fortran 77 library MEMSYS-5 on an IBM RISC 6000/360. Among the possible hypotheses the optimal solution was selected using the standard entropy method. ICF and response function have been generated artificially to fit the correlation of physical structures for atomically resolved images. Comparison of MEM and FFT revealed, that the main advantage of MEM is its ability to reproduce atomic defects on regular structures, whereas FFT deconvolution tends to eliminate these perturbations. 相似文献
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M. Grasserbauer G. Friedbacher H. Hutter G. Stingeder 《Fresenius' Journal of Analytical Chemistry》1993,346(6-9):594-603
Summary The rapid progress in high technology constantly poses new challenges for Analytical Chemistry and prompts the development of new techniques and procedures. The influence is particularly strong in surface and interface analysis, which is developing at a rapid pace. This paper discusses some of the frontier areas like high-resolution depth-distribution analysis of trace elements, quantitative depth distribution analysis of ultra thin-layer systems, quantitative trace element analysis in monolayers, 3-dimensional stereometric analysis, molecular analysis, in-situ atomic resolution analysis of surfaces (chemical nanoscopy). Methodological approaches are discussed as well as results obtained mainly with solid state mass spectrometry and atomic force microscopy.Abbreviations and acronyms AES
Auger Electron Spectrometry
- AEM
Analytical Electron Microscopy
- AFM
Atomic Force Microscopy
- BSE
Back Scattered Electrons
- EPMA
Electron Probe Micro Analysis
- LRI-SNMS
Laser Resonance Ionization Sputtered Neutrals Mass Spectrometry
- SE
Secondary Electrons
- SEM
Scanning Electron Microscopy
- SIMS
Secondary Ion Mass Spectrometry
- STM
Scanning Tunneling Microscopy
- TEM
Transmission Electron Microscopy
- TOF-MS
Time-of-Flight Mass Spectrometer
- TXRF
Total Reflection X-Ray Spectrometry
- XPS
X-Ray Photoelectron Spectroscopy
Dedicated to Professor Dr. Wilhelm Fresenius on the occasion of his 80th birthday 相似文献
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Y. A. Berezin K. Hutter L. A. Spodareva 《Archive of Applied Mechanics (Ingenieur Archiv)》1998,68(3-4):169-178
Summary We study the stability of thin films of fluids subject to gravity along inclined planes, obeying a power-law constitutive
relation of the Ostwald-de Waele type. A first analysis, in which the inertia terms are ignored, shows such flow to be stable
against small, linear perturbations; a second analysis, in which the inertia terms are included, proves that there are stable
and unstable regimes that are separated by a critical Ostwald-de Waele number O. Numerical computations for selected values
of O demonstrate the decay and growth rate behavior of some finite amplitude disturbances.
Received 12 May 1997; accepted for publication 23 July 1997 相似文献
28.
The International Atomic Energy Agency's Mission to Kazakhstan studied the present environmental contamination and the exposure
risk from nuclear tests performed at the Semipalatinsk Test Site. On this mission, EML scientists collected in-situ gamma-ray
spectra, measured external gamma dose rates, and collected soil samples. With the exception of plowshare areas and near ground
zero, all the areas visited had external dose rates within typical environmental levels. Measurements within a 15 km radius
of ground zero showed elevated levels of137Cs,152Eu, and60Co. The dose rate within ≈1 km of ground zero ranged from 500 to 30000 nGy·h−1. 相似文献
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K. Hutter Rolf Jeltsch 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1992,43(6):1085-1086