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951.
J. A. M. Janssen 《Journal of statistical physics》1989,57(1-2):171-185
The master equation for chemical reactions that proceed through a number of steps (complex reactions) is considered. Examples are studied in which the reaction constant of one of the steps is much larger than the others, and a reduced master equation is derived by means of a projection operator formalism. This reduction amounts to an elimination of intermediates. The consistency of the scheme is shown by means of the-expansion. 相似文献
952.
E. E. Korshin R. M. Eliseenkova T. A. Zyablikova L. G. Zakharova A. G. Akhmadullin V. D. Nusinovich Ya. A. Levin 《Russian Chemical Bulletin》1993,42(6):1071-1077
Reactions ofN-aryl- andN-methyl-amidines and -amides of -amino acids with RPCl2 afford 4-aryl(methyl)imino and 4-oxo-1,3,2-diazaphospholanes. 4-Phenylimino-1,3,2-diazaphosphorinane was obtained in a similar way by the interaction of N(1), N(2)-diphenyl--anilinoisobutyramidine with PhPCl2.For communication 5 see ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1116–1121, June, 1993. 相似文献
953.
M. Vorona G. Veinberg I. Shestakova I. Kanepe M. Petrova E. Liepinsh E. Lukevics 《Chemistry of Heterocyclic Compounds》2007,43(12):1567-1576
7α-Chloro-3-methyl-1,1-dioxoceph-3-ems with amide or keto group at position 4 have been synthesized by structural modification
of 7α-chloro-3-methyl-1,1-dioxoceph-3-em-4-carboxylic acid. Screening of these compounds for cytotoxic activity revealed compounds
with specific activity against cancer cells in vitro, capable of effective inhibition of the growth of sarcoma S-180 in vivo.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, 1849–1859, December 2007. 相似文献
954.
The Crystal Structure of KPdMIVF7 (MIV = Zr, Hf) Blue single crystals of KPdZrF7 are obtained by heating the binary fluorides in sealed Pt-tubes under dry argon (solid state reaction, T ≈? 720°C, t ≈? 14 d). The compound crystallizes orthorhombically in the space group Pnna-D (Nr. 52); lattice parameters are a = 1 132.3(5) pm, b = 797.5(2) pm, c = 639.8(1) pm; Z = 4 (Four cycle diffractometer data, AED2). According to [F4PdF2/1ZrF5] distortet [PdF6]-octaedra are connected with pentagonal-bipyramidal [ZrF7]-polyhedra via two bridging F?, resulting in [PdZrF11]-groups. These [PdZrF11]-groups built up a threedimensional-network with K+ in its spacings. KPdHfF7 crystallizes isotypically (a = 1 136.1(3) pm, b = 796.4(2) pm und c = 638.8(1) pm; four cycle diffractometer data, AED2). 相似文献
955.
芫花 (DaphnegenkwaSieb.etZucc.)属于瑞香科植物[1] ,芫花的浸取液对棉蛉虫、稻螟虫、菜青虫、班蝥等害虫具有较好的杀虫效果 ,且对人畜无害 ,是一种理想的无公害农药[2 ] 。为了提高药效 ,更好地开发这种无公害农药 ,本文对芫花中杀虫有效成分的提取工艺与杀虫效果进行了初步研究。1 实验部分1 1 试剂和仪器苯 ,氯仿和 95 %的乙醇均为分析纯 ;岛津UV -2 40型紫外可见分光光度仪 ;FT -80ANMR仪。1 2 实验方法芫花枝条干粉 1 5 0 0g,加水 1 0 .0 0L煮沸 1 2小时 ,煮沸过程中陆续补加少量水分。将煮沸… 相似文献
956.
Bis(benzoylpyridin-toluensulfonylhydrazido)nickel Ni(BPSH)2 · H2O — Relations between Structure, Redox, and Extraction Properties of Heterocyclic Sulfonamido Chelates The crystal structure of Ni(BPSH)2 · H2O was determined by x-ray diffraction: monoclinic, space group P21/c (Nr. 14); a = 15.077(4) Å, b = 14.901(3) Å, c = 16.335(3) Å, β = 95.74(1)°. R = 0.047 for a total of 5564 observed reflexions. Ni(BPSH)2 · H2O has a distorted tetrahedral structure with two six-membered chelate rings, one of them with a boat from. The electron system of the building blocks CNN? within the chelate rings approaches that of a diazallyl group. The result is a high electron density on the sp2-hybridized donor atom N? and, as a consequence, a short Ni? N?-distance (1.908 or 1.924 Å). The electronic properties of N? also explain the high NH-acidity of the acid H(BPSH) (pks = 9,51 in 75 per cent dioxane) and the ligand field strength of BPSH? which is low compared to that of other bidentate sulfonamido ligands and which is reflected in the paramagnetism of Ni(BPSH)2 · H2O. The redox behavior of metal chelates of the type, which is represented by Ni(BPSH)2 · H2O, is caused by a building block of the ligand which is also present in bipyridyl or in the 1,4-diaza-1,3-dienes. The central atoms M11 have only the function of interference factors. 相似文献
957.
The ion clusters H+X· (H2)n (X = N2, CO, O2 and H2 andn = 0, 1, 2) are investigated by means of SCF and CI computations in a double-zeta plus polarization gaussian basis It is found that hydrogen molecules attack the proton of H+X perpendicularly. The calculated stabilization energies are in agreement with experimental values of δH0. 相似文献
958.
N. Blidi Boukamel A. Krallafa D. Bormann L. Caron M. Canipelle S. Tilloy E. Monflier 《Journal of inclusion phenomena and macrocyclic chemistry》2002,42(3-4):269-274
Quantum mechanical calculations on the (4-tert-butylphenyl)(3-sulfonatophenyl) (phenyl) phosphine/-cyclodextrin inclusion complex werecarried out using semi-empirical calculations. Inclusion process pathways are describedand the most probable structures of the 1:1 complex are sought through a global potentialenergy scan. The calculations suggest that the most stable structure is obtained whenthe aromatic ring bearing the tert-butyl group is includedinto the hydrophobic cavity of the -cyclodextrin from theside of the primary hydroxyl groups. 相似文献
959.
M. SenŌ H. Noritomi Y. Kuroyanagi K. Iwamoto G. Ebert 《Colloid and polymer science》1984,262(11):896-901
The molecular conformations of poly(N5-dihydroxyethylaminopropyl-L-glutamine) and poly(N5-dihydroxyethyl-L-glutamine) were investigated in reversed micelles of AOT as well as in aqueous solutions. Both poly(-amino acid)s assume disordered structures in pure water. The conformation of poly(N5-dihydroxyethylaminopropyl-L-glutamine) transits into-helix in the reversed micelles as the molar ratio of water to AOT (w0=[H2O]/[AOT]) becomes smaller. A similar conformational transition was also observed in aqueous solutions when a certain amount of AOT was added. Under these conditions, however, poly(N5-dihydroxyethyl-L-glutamine) did not undergo a conformational transition into-helix. 相似文献
960.