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931.
932.
Jacques Rault 《Macromolecular Symposia》1995,100(1):31-38
It is shown that by low frequency measurements in hydrophilic polymers only one state of water is observed. Water behave as a classical plasticizer and ice melting in polymer is similar to ice melting in binary simple mixture. The non crystallizable water in these systems is explained by the Tg regulation effect. In oriented swollen polymers, only one state of water is observed in the time scale ∼ 1/ωq = 10−5 s by deuterium NMR. This technique gives information on the mean orientation of D2O molecules in the oriented polymer and on the fraction of mobile water molecules. The concept of bound and unbound water is not relevant for explaining the DSC and D-NMR results. 相似文献
933.
Jean-Pascal Brison Loïc Glmot Hermann Suderow Andrew Huxley Shinsaku Kambe Jacques Flouquet 《Physica B: Condensed Matter》2000,280(1-4):165-171
The quest for a precise identification of the symmetry of the order parameter in heavy fermion systems has really started with the discovery of the complex superconducting phase diagram in UPt3. About 10 years latter, despite numerous experiments and theoretical efforts, this is still not achieved, and we will quickly review the present status of knowledge and the main open question. Actually, the more forsaken issue of the nature of the pairing mechanism has been recently tackled by different groups with macroscopic or microscopic measurement, and significant progress have been obtained. We will discuss the results emerging from these recent studies which all support non-phonon-mediated mechanisms. 相似文献
934.
Jacques Patarin 《Designs, Codes and Cryptography》2000,20(2):175-209
In 1 Matsumoto and Imai developed a new public key scheme, called C*, for enciphering or signing. (This scheme is completely different from and should not be mistaken with another scheme of Matsumoto and Imai developed in 1983 in 7 and broken in 1984 in 8). No attacks have been published as yet for this scheme. However, in this paper, we will see that—for almost all keys—almost every cleartext can be found from its ciphertext after only approximately m
2
n
4 log n computations, where m is the degree of the chosen field K and mn is the number of bits of text. Moreover, for absolutely all keys that give a practical size for the messages, it will be possible to find almost all cleartexts from the corresponding ciphertexts after a feasible computation. Thus the algorithm of 1 is insecure. 相似文献
935.
Alain Walcarius Jérôme Devoy Jacques Bessiere 《Journal of Solid State Electrochemistry》2000,4(6):330-336
Pure silica particles were dispersed within carbon paste and the resulting modified electrode was applied to the selective
voltammetric detection of mercury(II) species after their accumulation at open circuit. The remarkable selectivity observed
between pH 4 and 7 was attributed to the intrinsic adsorption mechanism which involves a condensation reaction between mercury(II)
hydroxide and hydroxyl groups on the silica surface, leading to the formation of an inner-sphere-type surface complex. After
optimization with respect to the electrode composition, the detection medium, and the voltammetric scan mode, a linear response
was obtained in the concentration range between 2 × 10−7 M to 1 × 10−5 M, by applying anodic stripping square wave voltammetry. Various silica samples were used and their sorption behavior was
discussed in relation to their specific surface area and porosity. The effect of chloride and pH on the accumulation of mercury(II)
on silica was also investigated.
Received: 4 September 1999 / Accepted: 5 January 2000 相似文献
936.
Buncha Pulpoka Jong Sueng Kim Seung Hwan Yang Jacques Vicens 《Journal of heterocyclic chemistry》2001,38(6):1383-1385
Two novel calix[4]cryptands were synthesized from 1,3‐alternate calix[4]bis‐azacrown. “Mappemonde II” consists of one 1,3‐calix[4]bis‐azacrown wrapped by a benzo‐crown ether loop. “Mill II” is composed of two 1,3‐calix[4]bis‐azacrowns linked by two benzo‐crown ether strands. 相似文献
937.
Etienne Gaudin Jean‐Pierre Chaminade Ahmed El Abed Jacques Darriet 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(9):1004-1005
The new oxychloride InTeO3Cl was synthesized from a mixture of In2O3, InCl3 and TeO2. Its structure has been determined from single‐crystal X‐ray diffraction data. The structure is composed of layers separated by a van der Waals gap. The layers consist of edge‐sharing chains of [InO4Cl2] octahedra linked through [TeO3] trigonal pyramids. No free Cl atoms are located between the layers. 相似文献
938.
Pierre Thury Martine Nierlich Jacques Vicens Bernardo Masci 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(7):833-834
The title compound, 7,13,21,27‐tetramethyl‐3,17‐dioxapentacyclo[23.3.1.15,9.111,15.19,23]ditriaconta‐1(29),5,7,9(30),11(31),‐12,14,19(32),20,22,25,27‐dodecaene‐29,30,31,32‐tetraol, C34H36O6, assumes in the solid state a very distorted cone‐like conformation stabilized by intramolecular simple and bifurcated hydrogen bonds involving both phenolic and ether O atoms. One part of the molecule, comprising an ether link, is included in the cavity of an adjacent calixarene related by a screw axis, giving rise to a one‐dimensional self‐inclusion polymer. 相似文献
939.
940.
V. Lemee D. Burget P. Jacques J. P. Fouassier 《Journal of polymer science. Part A, Polymer chemistry》2000,38(10):1785-1794
Rate constants of quenching of triplet excited ketones by several monomers were determined through time‐resolved laser spectroscopy or culled from the literature. The semi‐empirical calculation method PM3 allows the quenching mechanisms to be refined and can be used to predict the reactivity of aromatic ketones toward monomers. It is apparent from both experimental results and theoretical calculations that the rate constant (kq ) measured for the bimolecular quenching between the triplet state of a given aromatic ketone and both electron‐rich as well as electron‐poor monomers, depends linearly on the free enthalpy of formation of the regioselectively favored 1,4‐biradical, which is the primary reaction step of the ketone/monomer interaction. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1785–1794, 2000 相似文献