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41.
《Optimization》2012,61(5):785-796
In a network of processors, a distributed operating system must handle the management of shared resources. In this paper, it is shown how to solve this problem in using the model previously introduced in [1]. This model (interconnection of N Markov chains each representing locally a distributed process) allows us to prove the good functioning properties for some distributed problems such as the mutual exclusion problem and the deadlock problem, We also prove that fairness is a basic notion for setting the model’s parameters and obtain an optimal working of the network. 相似文献
42.
《Physics and Chemistry of Liquids》2012,50(4):411-420
Semi empirical equation developed by Yalkowsky and Valvani, and another equation extended by Jain and Yalkowsky were used to estimate the aqueous solubility S w , of some sulfonamides using experimental octanol-water partition coefficients P , entropies of fusion j S f , and melting points t m , determined by DSC measurements. The calculated solubilities were compared with those experimentally determined. When experimental j S f and t m were used, the S w calculated values were in good agreement in most cases. 相似文献
43.
《Journal of Coordination Chemistry》2012,65(1):17-32
Heterobi- and tri-nuclear complexes [LMM'Cl] and [(LM) 2 M'](M=Ni or Cu and M'=Mn, Fe or Co) have been synthesised. The heteronuclear complexes were prepared by stepwise reactions using two mononuclear Ni(II) and Cu(II) complexes of the general formula [HLM]·1/2H 2 O, as ligands towards the metal ions, Mn(II), Fe(III) and Co(II). The asymmetrical pentadentate (N 2 O 3 ) Schiff-base ligands used were prepared by condensing acetoacetylphenol and ethylenediamine, molar ratio 1 1, to yield a half-unit compound which was further condensed with either salicylaldehyde or naphthaldehyde to yield the ligands H 3 L 1 and H 3 L 2 which possess two dissimilar coordination sites, an inner four-coordinate N 2 O 2 donor set and an outer three-coordinated O 2 O set. 1 H NMR and IR spectra indicate that the Ni(II) and Cu(II) ions are bonded to the inner N 2 O 2 sites of the ligands leaving their outer O 2 O sites vacant for further coordination. Different types of products were obtained according to the type of metal ion. These products differ in stoichiometry according to the type of ligand in the parent compound. Electronic spectra and magnetic moments indicate that the structures of the parent Ni(II) and Cu(II) complexes are square-planar while the geometry around Fe(III), Mn(II) and Co(II) in their products are octahedral as elucidated from IR, UV-visible, ESR, 1 H NMR, mass spectrometry and magnetic moments. 相似文献
44.
45.
基于几何光学法(GO)、物理光学法(PO)、射线弹跳法(SBR)和等效电流法(MEC),提出了一种快速计算金属海面上电大尺寸目标电磁散射的解析算法。该算法考虑了阴影效应,运用GO/PO+SBR计算了目标与海面的镜面反射以及它们之间的多次相互作用,并运用MEC计算了目标的棱边绕射以改进计算结果。应用该算法计算了平板上方规则金属目标的双站雷达散射截面(RCS),并与传统矩量法(MoM)进行比较,验证了算法的有效性。最后,计算了PM(Pierson-Moskowitz)海浪谱的随机海洋粗糙面上舰船模型目标的散射特性,并对计算结果进行了分析,讨论了海洋面以及入射波参数对散射结果的影响。 相似文献
46.
Zheng-de Dai 《应用数学学报(英文版)》2008,(4)
By the variable transformation and generalized Hirota method,exact homoclinic and heteroclinic solutions for Davey-StewartsonⅡ(DSⅡ)equation are obtained.For perturbed DSⅡequation,the existence of a global attractor is proved.The persistence of homoclinic and heteroclinic flows is investigated,and the special homoclinic and heteroclinic structure in attractors is shown. 相似文献
47.
Manzetti S McCulloch DR Herington AC van der Spoel D 《Journal of computer-aided molecular design》2003,17(9):551-565
The matrix metalloproteases (MMPs) and the ADAMs (A Disintegrin And Metalloprotease domain) are proteolytic enzyme families containing a catalytic zinc ion, that are implicated in a variety of normal and pathological processes involving tissue remodeling and cancer. Synthetic MMP inhibitors have been designed for applications in pathological situations. However, a greater understanding of substrate binding and the catalytic mechanism is required so that more effective and selective inhibitors may be developed for both experimental and clinical purposes. By modeling a natural substrate spanning P4-P4' in complex with the catalytic domains, we aim to compare substrate-specificities between Stromelysin-1 (MMP-3), ADAM-9 and ADAM-10, with the aid of molecular dynamics simulations. Our results show that the substrate retains a favourable antiparallel beta-sheet conformation on the P-side in addition to the well-known orientation of the P'-region of the scissile bond, and that the primary substrate selectivity is dominated by the sidechains in the S1' pocket and the S2/S3 region. ADAM-9 has a hydrophobic residue as the central determinant in the S1' pocket, while ADAM-10 has an amphiphilic residue, which suggests a different primary specificity. The S2/S3 pocket is largely hydrophobic in all three enzymes. Inspired by our molecular dynamics calculations and supported by a large body of literature, we propose a novel, hypothetical, catalytic mechanism where the Zn-ion polarizes the oxygens from the catalytic glutamate to form a nucleophile, leading to a tetrahedral oxyanion anhydride transition state. 相似文献
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49.
Kanduluru Ananda Kumar Cirandur Suresh Reddy Chichili Devendranath Reddy 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6-7):1745-1748
6-Alkylcarbamato/alkylthiocarbamato-2,10-dichloro-12-trichloromethyl-12 H -dibenzo [d,g][1,3,2]-dioxaphosphocin 6-oxides have been synthesized by the condensation of 2,2-bis(2-hydroxy-5-chlorophenyl)-1,1,1-trichloroethane with dichlorophosphinyl carbamates of different alcohols/thiols in the presence of triethylamine in dry toluene and were characterized by different spectral studies. 相似文献
50.
Janina Baraniak Renata Kaczmarek Ewa Wasilewska Wojciech J. Stec 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6-7):1667-1670
Based upon 1,3,2-oxathiaphospholane chemistry, 5'-O-derivatization of nucleosides with the O-methyl esters of amino acids was performed and corresponding conjugates were obtained in satisfactory yield. 相似文献