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141.
The computer operation is used to find all the possible layer sequences of poly-types. Identical arrangements are separated using the corresponding values of calculated structure factor. 相似文献
142.
An efficient and reliable synthesis of new thiazole-(amino)methylphosphonic, phosphinic acids, and phosphine oxides is reported. The synthetic protocol is based on nucleophilic addition of phosphorous species to thiazole derived imines. Unexpectedly, it was discovered that heating of thiazole-2-yl-(amino)methylphosphonates and phosphinates with aqueous HCl leads to their decomposition resulting in a rupture of the C-P bond, rejecting of the phosphorus containing fragment and formation of the corresponding secondary N-(thiazole-2-yl-methyl)-alkylamines. Two alternative mechanisms for this cleavage are postulated. 相似文献
143.
144.
We prove various generalizations of classical Sard's theorem to mappings f:M m →N n between manifolds in Hölder and Sobolev classes. It turns out that if f ∈ C k,λ (M m ,N n ), then—for arbitrary k and λ—one can obtain estimates of the Hausdorff measure of the set of critical points in a typical level set f ?1(y). The classical theorem of Sard holds true for f ∈ C k with sufficiently large k, i.e., k>max(m?n,0); our estimates contain Sard's theorem (and improvements due to Dubovitskii and Bates) as special cases. For Sobolev mappings between manifolds, we describe the structure of f ?1(y). 相似文献
145.
146.
Wilkinson's complex [RhCl(PPh3)3], anchored to phosphino-organosiloxane macromolecules grafted onto chrysotile asbestos, appeared to be an unusually effective and selective catalyst for the synthesis of vinylsilanes via gas-phase hydrosilylation of acetylene, particularly by methyldichlorosilane in a continuous-flow microreactor as well as in a laboratory reactor. Catalytic and kinetic parameters show an advantage for the catalyst based on the chrysotile-polyorganosiloxane support (catalyst CHR–Rh) over the phosphinated silica (catalyst A). 相似文献
147.
Hai Yu Eric M. Kennedy Md. Azhar Uddin Simon P. Sullivan Bogdan Z. Dlugogorski 《国际化学动力学杂志》2005,37(3):134-146
Thermal pyrolysis of halon 1211 (CBrClF2), diluted in nitrogen, in a tubular alumina reactor, has been studied over the temperature range of 773–1073 K at residence times from 0.3 to 2 s. At temperatures below 973 K, the major products were CCl2F2, CBr2F2, C2Cl2F4, C2BrClF4, C2F4, and C2Br2F4. Further increasing temperature resulted in the formation of CBrF3, CClF3, and many other species whose formation necessitated the rupture of C? F bonds. Coke formation was also observed on the surface of the reactor at high temperatures. A kinetic reaction scheme involving 16 species and 25 reaction steps was developed and applied to model the thermal pyrolysis of halon 1211 over the temperature range of 773–973 K. Sensitivity analysis suggests that the reaction CBrClF2 + CClF2→CCl2F2 + CBrF2 constitutes the major pathway for the decomposition of halon 1211 under the conditions investigated. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 134–146, 2005 相似文献
148.
149.
A. N. Kalenchuk A. E. Koklin V. I. Bogdan L. M. Kustov 《Russian Chemical Bulletin》2017,66(7):1208-1212
Catalytic hydrogenation of benzene, biphenyl, and ortho-, metha-, and para-isomers of terphenyl over a 3 wt.% Pt/C at 180 °C and 70 atm was studied. The directions of hydrogenation of each substrate were revealed. Relationships between structures of the substrate and hydrogen consumption rates were found. It was shown that hydrogenation rate decreases on going from benzene to terphenyl and with increasing degree of the substrate hydrogenation. Hydrogenation rate of terphenyl isomers decreases in the following order: p-terphenyl > > m-terphenyl > o-terphenyl. 相似文献
150.
D. Versaci R. Nasi U. Zubair J. Amici M. Sgroi M. A. Dumitrescu C. Francia S. Bodoardo N. Penazzi 《Journal of Solid State Electrochemistry》2017,21(12):3429-3435
In the production of commercial Li-ion batteries, the active materials slurries are generally prepared using polyvinylidene fluoride (PVdF) as binder because of its good adhesion properties and electrochemical stability. Unfortunately, there are some disadvantages related to the use of PVdF: the most important is the use of toxic and environmentally unfriendly solvents, such as N-methyl-pyrrolidone (NMP), and the second is the high costs. In the light of these considerations, it seemed straightforward to investigate the suitability of some water-soluble, inexpensive, and eco-friendly materials to test as alternative binders (sodium alginate, chitosan tragacanth gum, gelatin). The rheological properties of these materials have been investigated in addition to the electrochemical characterization. Furthermore, graphite electrodes with PVdF, carboxymethyl cellulose (CMC), and styrene-butadiene rubber (SBR) binders have been considered for sake of comparison. We found that some of these water-soluble binders, besides good electrochemical performances, showed a high adhesion to the current collector and a good electrochemical stability under the experimental conditions employed, which makes them interesting for the next generation of Li-ion batteries. 相似文献