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31.
With the solid phase reaction between pulsed-laser-deposited (PLD) ZnOfilm and α-Al2O3 substrate, ZnAl2O4/α-Al2O3 complex substrates were synthesized. X-ray diffraction (XRD) spectra show that as the reaction proceeds, ZnAl2O4 changes from the initial (111)-oriented single crystal to poly-crystal, and then to inadequate (111) orientation. Corresponding scanning electron microscope (SEM)images indicate that the surface morphology of ZnAl2O4 transforms from uniform islands to stick structures, and then to bulgy-line structures. In addition, XRDspectra present that ZnAl2O4 prepared at low temperature is unstable at the environment of higher temperature. On the as-obtained ZnAl2O4/α-Al2O3 substrates, GaN films were grown without any nitride buffer using light-radiation heating low-pressure MOCVD (LRH-LP-MOCVD). XRD spectra indicate that GaN film on this kind of complex substrate changes from c-axis single crystal to poly-crystal as ZnAl2O4 layer is thickened. For the single crystal GaN, its full width at half maximum (FWHM) of X-ray rocking curve is 0.4°. Results indicate that islands on thin ZnAl2O4 layer can promote nucleation at initial stage of GaN growth, which leadsto the (0001)-oriented GaN film. 相似文献
32.
本文通过模拟研究,讨论了最大似然方法和Bayes方法在分析结构方程模型中的相似点和不同之处。 相似文献
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Two externally biased electrodes were inserted into the plasma on the KT-5C tokamak to test the effects on modifying the radial electric field Er, other than single biasing. Using various combinations of biasing voltage,the influences of double biasing are compared with the single biasing. It turns out that the effect of dual-biasing is also effective as a single one, but the outer electrode seems to be shielded by the inner one and show less influence. The results clearly show that the radial electric field Er changed by external biasing is intrinsically an effect localized at the edge of the plasma, which is caused by the electrode induced radial current; and dualelectrode biasing using the method similar to the single biasing seems not to be able to increase more distinctly the peaking effect on Er than the single biasing. 相似文献
35.
Formation Mechanism and Orderly Structures of an Iron Film System Deposited on Silicone Oil Surfaces 总被引:4,自引:0,他引:4 下载免费PDF全文
A new iron film system,deposited on silicone oil surfaces by vapour phase deposition method,has been fabricated and its formation mechanism as well as orderly structures has been studied,It is found that the formation mechanism of the films obeys a two-stage growth model,which is similar to that to the other metallic films on liquid substrates,Large and orderly structures are observed in the continuous iron films.The experiments show that the orderly spatial structures result from the local material gathering in these nearly free sustained films. 相似文献
36.
本文给出了在劳动力供给带弹性条件下的So1ow增长模型,给出了经济增长的黄金律和均衡处资本稳定性的证明,并且与不带弹性的Solow模型作了比较. 相似文献
37.
Reduction of Dislocations in GaN Epilayer Grown on Si (111) Substrates using a GaN Intermedial Layer 下载免费PDF全文
GaN intermedial layers grown under different pressures are inserted between GaN epilayers and AIN/Si(111) substrates. In situ optical reflectivity measurements show that a transition from the three-dimensional (3D) mode to the 2I) one occurs during the GaN epilayer growth when a higher growth pressure is used during the preceding GaN intermedial layer growth, and an improvement of the crystalline quality of GaN epilayer will be made. Combining the in situ reflectivity and transmission electron microscopy (TEM) measurements, it is suggested that the lateral growth at the transition of growth mode is favourable for bending of dislocation lines, thus reducing the density of threading dislocations in the epilayer. 相似文献
38.
激光二极管泵浦的高重复频率Nd:YAG激光器 总被引:2,自引:1,他引:1
报道两个1.5W连续激光二极管端面泵浦的声光调QNd:YAG激光器,输出激光脉冲的最高重复频率为30kHz重复频率1kHz时,最窄脉宽为12ns,最高峰值功率为12.1kW。 相似文献
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40.
亚麻等麻类纤维与乙烯基类单体接枝共聚反应的研究进展 总被引:2,自引:1,他引:2
近年来,乙烯基类单体与亚麻、大麻、苧麻等麻类纤维的接枝共聚反应已得到关注。本文着重总结接枝的引发方法,包括:1.辐射引发接枝;2.光引发接枝;3.Ce(Ⅳ)离子引发接枝;4.锰盐引发接枝;5.V(Ⅴ)离子引发接枝;6.Fenton's 试剂(Fe~(2+)-H_2O_2)引发接枝;7.过硫酸盐氧化还原引发体系接枝。上述各类引发体系及接枝纤维的结构与性能表征均在本文中作了述评。 相似文献