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961.
为了满足测量的高分辨率和灵敏度,基于光栅为关键元件的光学测量方法要求光栅有很高的频率。在已有的高折射率介质制栅方法的基础上提出了一种新的制作超高频全息光栅的方法,该方法制栅准确、简单、方便,其特点是所制光栅的频率与激光波长及介质的折射率无直接关系,而是等于制栅光路所得频率与两倍母栅频率之和。实验表明,利用该方法制得10000线/mm的光栅是完全可能的 相似文献
962.
J. Tomkinson 《Pramana》2008,71(4):745-754
The role that model compounds can play in understanding the vibrational eigenvectors of molecules is discussed. Assigning
the spectra of model compounds is of particular importance and the individual-scaling approach, that has been used with isolated
molecule ab-initio calculations, is outlined. Special emphasis is given to recent work on assigning the spectra of three 5–6 heterobicyclic
systems; indole, benzimidazole and isatin.
相似文献
963.
Martin Hanke Nuutti Hyvönen Manfred Lehn Stefanie Reusswig 《BIT Numerical Mathematics》2008,48(2):245-264
We investigate the inverse source problem of electrostatics in a bounded and convex domain with compactly supported source.
We try to extract all information about the unknown source support from the given Cauchy data of the associated potential,
adopting by this previous work of Kusiak and Sylvester to the case of electrostatics. We introduce, and for the unit disk
we also compute numerically, what we call the discoidal source support, i.e., the smallest set made up by the intersection of disks within the domain, which carries a source compatible with the
given data.
AMS subject classification (2000) 35R30, 65N21 相似文献
964.
Hydrophobins are small fungal proteins, which have remarkable surface-chemical properties. They self-assemble at hydrophobic/hydrophilic interfaces and work as adhesive agents and coatings. Sixteen layer Langmuir-Blodgett films of hydrophobins HFBI and HFBII from the fungus Trichoderma reesei were prepared and studied using grazing-incidence X-ray diffraction and reflectivity techniques. Both kind of films contain hexagonally ordered crystallites on the substrate with unit cell parameters of a = b = 54 Å (HFBI) and a = b = 55 Å (HFBII). The structure is similar to the structure of monolayer Langmuir-Blodgett films. 相似文献
965.
The claim of Mohapatra and Maharana thattb(s) is a better scaling variable thant(lns)2 is put to test in the case of Λ-p scattering, after parametrizingb(s) asC
1 +C
2(lns)α. It was observed that in this case the data also prefer anα value which is close to those obtained by Mohapatra and Maharana for other scattering processes. 相似文献
966.
M. A. Abdel-Raouf 《Il Nuovo Cimento D》1989,11(3):433-453
Summary The inelastic scattering of positrons by 11 lithium-isoelectronic ions, (with nuclear chargesZ=4,5,… 14) is investigated for the first time within the framework of the coupled-static and frozen-core approximations. It
is assumed that the elastic and positronium channels, in each process, are open and all excitation channels of the target
are closed. The calculations of the total cross-sections are carried out by employing eight partial waves, (corresponding
to 0≤l≤7, wherel is the total angular momentum of the scattering problem considered). Also, the effect of switching on the polarization potentials
of the positroniums on the rearrangement cross-sections is investigated in details. Particular attention is devoted to the
relation between the positronium formation cross-sections and the increase in the nuclear charge of the targets.
To speed up publication, the author of this paper has agreed to not receive the proofs for correction. 相似文献
967.
非水体系中哌啶在银电极表面的表面增强喇曼散射 总被引:1,自引:0,他引:1
本文测定了哌啶在甲醇溶液中吸附在银电极表面的表面增强喇曼散射(SERS)光谱,及其随电位的变化,同时还测定了电极经不同氧化-还原循环(ORC)预处理时的SERS谱,对所得结果进行了分析比较,并进一步研究了非水体系和水体系SERS谱之间的关系.实验结果表明:哌啶在甲醇体系中比在水体系中SERS谱的增强因子要小,并且它们的SERS谱线随电位的变化也有一定的差别. 相似文献
968.
There have been a few recent numerical implementations of the stress‐jump condition at the interface of conjugate flows, which couple the governing equations for flows in the porous and homogenous fluid domains. These previous demonstration cases were for two‐dimensional, planar flows with simple geometries, for example, flow over a porous layer or flow through a porous plug. The present study implements the interfacial stress‐jump condition for a non‐planar flow with three velocity components, which is more realistic in terms of practical flow applications. The steady, laminar, Newtonian flow in a stirred micro‐bioreactor with a porous scaffold inside was investigated. It is shown how to implement the interfacial jump condition on the radial, axial, and swirling velocity components. To avoid a full three‐dimensional simulation, the flow is assumed to be independent of the azimuthal direction, which makes it an axisymmetric flow with a swirling velocity. The present interface treatment is suitable for non‐flat surfaces, which is achieved by applying the finite volume method based on body‐fitted and multi‐block grids. The numerical simulations show that a vortex breakdown bubble, attached to the free surface, occurs above a certain Reynolds number. The presence of the porous scaffold delays the onset of vortex breakdown and confines it to a region above the scaffold. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
969.
G K Raju K Venkataramaniah M S Prasad K Narasimhamurty V A Narasimhamurty 《Pramana》1986,26(4):327-335
Differential incoherent scattering cross-section ratios of 279.2 keV photons by zirconium, tin, tantalum, lead and uranium
elements are experimentally determined by comparing the peak areas under the degraded photon energy with that of an equivalent
aluminium foil employing a high resolution 35 c.c. coaxial Ge(Li) detector. Studies have been made in single configuration
in an angular range of 20° to 115°. The results are compared with theoretical values obtained from the non-relativistichfs model of Hubbell and co-workers. The cross-section ratios decrease as the atomic number increases for a given scattering
angle. 相似文献
970.
N. Herrmann Y. Hemar P. Lemaréchal D.J. McClements 《The European physical journal. E, Soft matter》2001,5(2):183-188
The flocculation of silicone oil-in-water emulsions ( φ = 0.1) containing quasi-monodisperse droplets was studied by ultrasound.
The ultrasonic attenuation spectra of emulsions with different particle sizes (200-1600 nm) were measured between 0.5 and
10 MHz using an interferometer. Flocculation was induced by adding excess sodium dodecyl sulphate micelles to the emulsions
to increase the attractive forces between the droplets. Droplet flocculation decreased the ultrasonic attenuation at low frequencies
because of overlap of the thermal waves caused by the close proximity of the droplets within the flocs. A mean-field model
which takes into account this effect was used to determine the droplet volume fraction within the flocs and thus to estimate
the distance between the droplets.
Received 17 July 2000 相似文献