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991.
Liying Liu Shengwei Yao Zengxin Wei 《Journal of Computational and Applied Mathematics》2008,220(1-2):422-438
In this paper, a new nonmonotone MBFGS algorithm for unconstrained optimization will be proposed. Under some suitable assumptions, the global and superlinear convergence of the new nonmonotone MBFGS algorithm on convex objective functions will be established. Some numerical experiments show that this new nonmonotone MBFGS algorithm is competitive to the MBFGS algorithm and the nonmonotone BFGS algorithm. 相似文献
992.
《Chemical physics letters》2006,417(1-3):48-52
Residual intermolecular dipolar interactions may result in undesired spectral features on highly concentrated samples in liquid NMR. Although homonuclear decoupling can be employed to suppress the interactions, it may cause a strong irradiation peak, which obscures the nearby peaks. In order to overcome this shortcoming, a modified CRAZED sequence with three radio-frequency pulses was proposed. The analytical expression derived from the dipolar field treatment was employed to select proper flip angles and phase cycling. Theoretical predictions, experimental observations, and computer simulations demonstrated that the new method effectively suppresses the undesired peaks due to residual dipolar effects. 相似文献
993.
Based on the charge conjugation invariance and the vacuum property of the Pomeron, we point out that the commonly used vector vertex of the Pomeron coupling to quark is incorrect since it contradicts with the Pomeron property. We also claim that the soft Pomeron could be a tensor glueball ξ(2230) with quantum numbers IG JPC = 0 2 and total decay width Γtot ≌ 100 MeV, which lies on the soft Pomeron trajectory αp = 1.08 0.20t. Therefore, the coupling vertex of the soft Pomeron to quark should be tensorial which is invariant under the charge conjugation and can explain why the inadequate vector coupling, γμ, of the soft Pomeron to quark is successful in dealing with Pomeron physics. 相似文献
994.
This article aims at studying two-direction refinable functions and two-direction wavelets in the setting ?s, s > 1. We give a sufficient condition for a two-direction refinable function belonging to L2(?s). Then, two theorems are given for constructing biorthogonal (orthogonal) two-direction refinable functions in L2(?s) and their biorthogonal (orthogonal) two-direction wavelets, respectively. From the constructed biorthogonal (orthogonal) two-direction wavelets, symmetric biorthogonal (orthogonal) multiwaveles in L2(?s can be obtained easily. Applying the projection method to biorthogonal (orthogonal) two-direction wavelets in L2(?s, we can get dual (tight) two-direction wavelet frames in L2(?m, where. m ≥ s From the projected dual (tight) two-direction wavelet frames in L2(?m, symmetric dual (tight) frames in L2(?m can be obtained easily. In the end, an example is given to illustrate theoretical results. 相似文献
995.
996.
研究了土壤提取液中游离氧化铁含量的FIA-ICP-AES测定法。考察了采术量以及提取剂(盐酸羟胺和草酯)的浓度对的影响。试验表明:如果选择50μL采样环进样,并将盐酸羟爱和草酸的浓度控制在10mg.mL^-1以下,则进样顺畅,不出现喷雾嘴堵塞的现象,分析线的背景干扰也得到有效抑制。此法的回收率为97.6%~100%,RSD≤3.5%。 相似文献
997.
998.
巯基类浮选药剂电子结构及其与金属离子作用的量子化学研究 总被引:1,自引:0,他引:1
用量子化学程序MOAN计算了巯基类浮选剂MBT,MBO和MBM的电子结构,讨论了其硫醇形式与硫酮形式的稳定性及与过渡金属离子Cu()的配位模式和配体的活性位置;研究了五元杂环中N,O,S是否参与配位和分子中苯环的作用及配位原子周围不同的化学环境对配位作用的影响,得到了螯合剂MAT,MBO和MAM与Pt,Pb,Fe,Zn,Cu金属离子作用的强弱顺序,解释了一些基本的实验事实. 相似文献
999.
《Electrochemistry communications》2001,3(10):549-552
The anodic oxidation of trifluoroborate-substituted thiophene 1 in CH3CN without added electrolyte yielded at ca. 1.0 V (vs. Ag+|Ag) a conjugated polymer film showing electroactivity both in water and organic media. The electrochemical and UV–visible spectroscopic responses of such a material were found to be dependent on the nature of cation. 相似文献
1000.
This paper discusses the global convergence of a class of nonmonotone conjugate gradient methods (NM methods) for nonconvex object functions. This class of methods includes the nonmonotone counterpart of modified Polak-Ribiere method and modified Hestenes-Stiefel method as special cases. 相似文献