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991.
992.
对高聚物以流体配位模型状态方程进行了简化,忽略了其中的Q项,以简化的状态方程对42个纯高聚物(聚丙烯、聚苯乙烯、聚异丁烯和聚丁烯-1),2种纯溶剂(苯,环己烷)和2个高聚物/溶剂混合系(聚异丁烯/苯和聚异丁烯/环己烷)进行关联,结果表明,简化的状态方程与原方程同样具有很好的关联精度和温度适用性。 相似文献
993.
E. V. Voronina E. P. Yelsukov A. V. Korolyov A. E. Yelsukova 《Hyperfine Interactions》2006,168(1-3):1079-1083
The experimental data from Mössbauer spectroscopy and magnetic measurements are presented as functions of the temperature and external magnetic field for a B2-type ordered Fe 66 Al 34 alloy. 相似文献
994.
《Journal of Coordination Chemistry》2012,65(12):1025-1032
Two novel coordination polymers, [Cu(II)(NO3)2(bbmb)] n (1) and [Mn(II)(Cl2)(BBMB)2] (2) [bbmb = 1,4-bis(1-benzimidazolylmethyl)benzene], were synthesized and characterized by IR and thermal analyses. Single-crystal X-ray diffraction analysis shows that Polymer 1 exhibits a distorted metal tetrahedron in its structure, involving two nitrogen atoms from bbmb ligands and two oxygen atoms from NO3 groups. Each Cu(II)(NO3)2 unit is bridged by bbmb to form a zigzag chain structure. Polymer 2 possesses a two-dimensional network. The coordination environment around Mn(II) is a distorted octahedron and its solid-state structure exhibits a layered packing mode. In the polymers the two coordinating nitrogen atoms on bridging bbmb ligands are trans to the central benzene plane. 相似文献
995.
C. Etz D. Stoeffler 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,54(4):429-434
We investigate the electronic structure of bulk
Sr2CoMoO6-δ double perovskites using the
ab initio Full Potential Linearized Augmented Plane Wave
method in order to study their magnetic properties
within the GGA and GGA+U methods. We discuss the relative stability of ferromagnetic (FM) and antiferromagnetic (AFM) orders
(i) without and with
taking into account the observed tilting of the oxygen octahedra
and (ii) by introducing oxygen vacancies. We show that a very good agreement with experimental results — AFM order for δ=
0 and FM order for δ= 1/2 — is obtained only when the tilting of the oxygen tetrahedra
is taking into account and when the GGA+U method is used. 相似文献
996.
G. Campi E. Cappelluti Th. Proffen X. Qiu E. S. Bozin S. J.L. Billinge S. Agrestini N. L. Saini A. Bianconi 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,52(1):15-21
We have studied temperature evolution of the local as well as the
average crystal structure of MgB2 using real-space atomic pair
distribution function (PDF) measured by high resolution neutron powder
diffraction in a wide temperature range of T=10–600 K. We find small
positive correlation factors for the B–B and B–Mg pairs, determined by
mean-square displacements (MSD) and the mean-square relative
displacements (MSRD). We analyze the PDF using both Einstein and
force constant models finding a good agreement between the
experimental data and the two models. This indicates that B and Mg
atomic correlations are not sensitive to the details of phonon
dispersion. 相似文献
997.
M. Salazar Ligia E. Zamora G. A. Prez Alcazar J. A. Plascak W. R. Aguirre 《Physica B: Condensed Matter》2002,320(1-4):236-238
In this work we present a theoretical study of the magnetic behavior of disordered Fe–Al alloys on the basis of a simple-diluted quantum Heisenberg spin model with the assumption that the exchange interaction J depends on the Al concentration q. We calculated the critical temperature and exponents through the mean field renormalization group method. An acceptable fit to the experimental phase diagram for Al concentration in the range 0.30q0.45 is obtained. 相似文献
998.
We report the results of the Monte Carlo simulation of the phase diagram of fcc binary alloys using a 3-D Ising model with
nearest and next-nearest neighbour repulsive interactions. Calculations are carried out for a ratio of second- to first-neighbour
interaction energies of 0.4. The resulting phase diagram contains three superstructures A2B2, A2B and A5B, each separated by a disordered fcc phase. There was no evidence for the formation of an A3B phase. These results are in qualitative agreement with CVM results. 相似文献
999.
Summary We have investigated the Aharonov-Bohm (AB) effects of electronic thermal capacityC
v
in a one-dimensional normal ring using the free-electron model. The results show that the thermal capacity is an oscillation
function of external magnetic flux with periods ϕ0=hc/e, ϕ0/2, ϕ0/3,... The amplitude of the capacity fluctuation decreases when temperature increases forT>3T
* (T
*=ħ V
F/(K
BπL)). We suggest an appropriate temperatureT∼3T
* to observe in experiment the capacity-flux characteristic for metallic rings.
The authors of this paper have agreed to not receive the proofs for correction. 相似文献
1000.
Summary The polymer beds described are synthesized in aqueous solution directly in the column or batchwise in the form of large clusters of small particles. The conventional, expensive step involving prepreparation of beads in an organic solvent is thus omitted. Beds were synthesized from piperazine diacrylamide, methacrylamide and allyl glycidyl ether. The epoxy-activated beds thus obtained were used for covalent attachment of either nonpolar ligands (e.g. octadecanol) or polar OH-rich substances (e.g. dextran). The non-polar beds were used for reversed-phase chromatography, as were polar ones following coupling with 1,2-epoxyoctadecane. Coating with OH-rich substances serves two purposes: (I) the matrix becomes hydrophilic, decreasing nonspecific interactions (modifiers can be excluded) and hence increases resolution and (II) many—OH groups are available (e.g. for coupling to epoxides), a prerequisite for high ligand density. Resolution of proteins was high even at high flow rates. Depending on the method used for the synthesis of the bed, resolution of proteins either increased with an increase in flow rate or decreased slinghtly. Choice of the correct temperature was very important for high resolution of CNRr-digested peptides. 相似文献