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61.
Jim J. Lin Steve Harich Dennis W. Hwang Malcom S. Wu Yuan T. Lee Xueming Yang 《中国化学会会志》1999,46(3):435-444
Elimination of atomic hydrogen (H) and molecular hydrogen (H2) are important elementary chemical processes in photochemistry and combustion chemistry. Recently, unique and sensitive detection techniques for atomic and molecular hydrogen detection were developed in our laboratory. Using the advanced molecular beam methods, we have studied the photodissociation of a few typical hydrocarbons at 157 nm excitation, especially their atomic and molecular hydrogen elimination processes. In this report, we will briefly describe the results from photodissociation of propane, ethylene, propyne and methanol at 157 nm excitation. These molecules represent different classes of hydrocarbons such as alkane, alkene, alkyne and alcohol. Through careful studies on differently deuterated compounds, clear pictures of selective atomic and molecular hydrogen elimination processes can be constructed for all of the above compounds. These results will help us to understand the dissociation dynamics of the small hydrocarbon molecules. 相似文献
62.
Phuong Y. Ghi David J. T. Hill Andrew K. Whittaker 《Journal of polymer science. Part A, Polymer chemistry》1999,37(19):3730-3737
The free radical copolymerizations of hydroxyethyl methacrylate and tetrahydrofurfuryl methacrylate have been investigated at 50°C. The compositions of polymers prepared at low conversions have been determined using 13C-NMR, and the glass transition temperatures determined by DSC. The copolymerizations were found to be best described by a terminal model with reactivity ratios of rH = 1.79 and rT = 0.76. The triad fraction sequence distributions have been calculated based on the terminal model and the calculated reactivity ratios. The glass transitions have been fitted to the Gordon–Taylor equation. The best value of the Gordon–Taylor constant was found to be kH = 1.42 ± 0.2, indicating nonideal mixing of the two monomer components in the copolymers. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3730–3737, 1999 相似文献
63.
Emel Önal Cheng Zhang Derya Davarcı Ümit İşci Guillaume Pilet Andrew K. Whittaker Fabienne Dumoulin 《Tetrahedron letters》2018,59(6):521-523
A cyclotriphosphazene substituted with six 3,5-bis(trifluoromethyl) benzyloxy units was designed as a novel 19F MRI contrast agent. The resulting molecule has 36 magnetically equivalent fluorine atoms and exhibited suitable MRI properties with high imaging sensitivity, confirming the proof-of-concept as a convenient scaffold for the production of new 19F MRI contrasts agents. 相似文献
64.
Nathan?BrownloweEmail author David?Pask Jacqui?Ramagge David?Robertson Michael?F.?Whittaker 《Semigroup Forum》2017,94(3):500-519
We study the external and internal Zappa–Szép product of topological groupoids. We show that under natural continuity assumptions the Zappa–Szép product groupoid is étale if and only if the individual groupoids are étale. In our main result we show that the \(C^*\)-algebra of a locally compact Hausdorff étale Zappa–Szép product groupoid is a \(C^*\)-blend, in the sense of Exel, of the individual groupoid \(C^*\)-algebras. We finish with some examples, including groupoids built from \(*\)-commuting endomorphisms, and skew product groupoids. 相似文献
65.
66.
Lower and upper bounds are given for the the number of permutations of length n generated by two stacks in series, two stacks in parallel, and a general deque. 相似文献
67.
Steve Butler Ron Graham Gerhard Guettler Colin Mallows 《Discrete and Computational Geometry》2010,44(3):487-507
An Apollonian configuration of circles is a collection of circles in the plane with disjoint interiors such that the complement
of the interiors of the circles consists of curvilinear triangles. One well-studied method of forming an Apollonian configuration
is to start with three mutually tangent circles and fill a curvilinear triangle with a new circle, then repeat with each newly
created curvilinear triangle. More generally, we can start with three mutually tangent circles and a rule (or rules) for how
to fill a curvilinear triangle with circles. 相似文献
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70.
Wayne Barrett Steve Butler H. Tracy Hall John Sinkovic Wasin So Colin Starr Amy Yielding 《Linear algebra and its applications》2012,436(12):4489-4502
We consider the problem of computing inertia sets for graphs. By using tools for combining the inertia sets of smaller graphs we can reduce this problem to understanding the inertia sets for three-connected graphs that are not joins. We term such graphs atoms and give the inertia sets for all atoms on at most seven vertices. This can be used to compute the inertia sets for all graphs on at most seven vertices. 相似文献