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51.
Benjamin Byerly Kevin Kuhn Lisa Colletti Lynn Foster Russ Keller Elmer Lujan Alex Martinez Donivan Porterfield Dan Schwartz Khal Spencer Floyd Stanley Mariam Thomas Lisa Townsend Ning Xu Lav Tandon 《Journal of Radioanalytical and Nuclear Chemistry》2017,312(1):95-104
Thorough physical and chemical characterization of plutonium–beryllium (PuBe) neutron sources is an important capability with applications ranging from material accountancy to nuclear forensics. Characterization of PuBe sources is not trivial owing to range of existing source designs and the need for adequate infrastructure to deal with radiation and protect the analyst. This study demonstrates a method for characterization of three PuBe sources that includes physical inspection and imaging followed by controlled disassembly and destructive analysis. 相似文献
52.
In order to study the structural and dynamical aspects of the solubilization process of pentanol within a sodium octanoate micelle a molecular dynamics simulation is presented. In this initial study we discuss the results and detailed insights into the interactions between sodium octanoate, pentanol, and water. The total micellar radius and the hydrophobic core radius were determined. The calculated values are in fairly good agreement with experimental results. In contrast to pure sodium octanoate micelles the aggregate with dissolved pentanol attained a more spherical shape related to the time interval of the simulation. It is clear that the results of a molecular dynamics computer simulation are always limited by its total length and the total time used for data analysis. Nevertheless, from our simulation study it turned out that a part of the pentanol hydroxyl groups were located within the micellar core and some alcohol molecules were also observed at the surface region of the micelle. The corresponding partition coefficient was calculated and agreed well with the experiment. The evaluated radial distribution functions of the sodium ions, the octanoate oxygens, and the hydroxyl hydrogens reveal details of the interface region of the micelle and the bulk phase. Additionally, it was possible to calculate the trans-to-gauche ratios of the alkyl chains and to compare these results with the simulation of a pure octanoate micelle. 相似文献
53.
Gorzelle BM Hoffman AK Keyes MH Gray DN Ray DG Sanders CR 《Journal of the American Chemical Society》2002,124(39):11594-11595
Amphipathic polymers ("amphipols") were introduced several years ago (Tribet, C.; Audebert, R.; Popot, J.-L. Proc. Natl. Acad. Sci. U.S.A. 1996, 93, 15047-15050) as an alternative method for solubilizing integral membrane proteins in stable, nativelike conformations. However, direct maintenance of full membrane protein functionality in amphipol solutions has not previously been demonstrated in the absence of added lipid or detergent. In this contribution, the first zwitterionic amphipol "PMAL-B-100" is introduced. PMAL-B-100 not only maintains membrane protein structure and solubility, but also supports the full catalytic activity of an integral membrane enzyme, diacylglycerol kinase, in the complete absence of additional lipid or detergent. All of the roles which a lipid bilayer normally plays in maintaining diacylglycerol kinase's structure and in facilitating catalysis are satisfied by the environment and interactions supplied by PMAL-B-100. 相似文献
54.
A sequence of single photons is emitted on demand from a single three-level atom strongly coupled to a high-finesse optical cavity. The photons are generated by an adiabatically driven stimulated Raman transition between two atomic ground states, with the vacuum field of the cavity stimulating one branch of the transition, and laser pulses deterministically driving the other branch. This process is unitary and therefore intrinsically reversible, which is essential for quantum communication and networking, and the photons should be appropriate for all-optical quantum information processing. 相似文献
55.
Stable [C5H5Ni(NN)]BF4 complexes are formed by treatment of [C5H5Ni(SR2)2]BF4 (R = CH3) with some 1,2-diaminoalkylidenes NN; Chemical and spectroscopic properties are reported. 相似文献
56.
Dieter Klapstein Robert Kuhn John P. Maier Liubomir Misev Martin Ochsner 《Helvetica chimica acta》1984,67(5):1222-1232
Gas phase emission and laser excitation spectra of the Ã2E?X?2E (Σ = +½, ?½) transition of rotationally/vibrationally cooled 1-chloro- and 1-bromo-1,3-pentadiyne cations have been obtained. The emission was excited by electron impact on a seeded helium supersonic free jet and the fluorescence by laser excitation of cations produced by Penning ionization and collisional relaxation. From these two sets of data the origin bands of the spin-orbit systems are located and for the bromo species this leads to better values of the spin-orbit splitttings in the two electronic states and of the first adiabatic ionization energy. The vibrational frequencies of many of the fundamentals of these cations in the X?2E and Ã2E states have been obtained to within ±2 cm?1. 相似文献
57.
58.
R. Kuhn 《Colloid and polymer science》1978,256(3):300-301
Ohne Zusammenfassung 相似文献
59.
Peter Kuhn Ulrich Hauser Wolfgang Neuwirth 《Zeitschrift für Physik A Hadrons and Nuclei》1973,264(4):287-300
The Mössbauer spectra of Fe(CO)5 dissolved in 39 organic solvents were investigated. An influence on the quadrupole split was found only for those solvents containing carbonylic CO, but not for solvents containing another polar group. The change of the quadrupole split means always a reduction and is independent of temperature. The concentration dependence of the additional split indicates that it is caused only by nearest neighbours.—These results give a hint for a specific weak interaction between the carbonylic CO group of Fe(CO)5 and the solvents. This cannot be a general dipole-dipole interaction because of the missing influence of other polar solvents, so that a weak chemical bond is suggested. 相似文献
60.
Two experimental arrangements of an optical frequency up-converter using GaSe are described. Two wavelength regions have been covered by series of monochromatique rays (one ranging from 3.25 μ to 3.85 μ, the other one from 0.954 μ to 0.968 μ). 相似文献