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91.
Ba8Cu16P30 – a New Ternary Variant of the Clathrate I Type Structure Ba8Cu16P30 (a = 14.117(1) Å, b = 10.093(1) Å, c = 28.022(2) Å) was prepared by heating a mixture of the elements (800°C; excess of Ba and P; removal of the by-products by acetic acid/H2O2). The compound crystallizes orthorhombically (Pbcn; Z = 4) in a new superstructure of the cubic clathrate I type structure with an ordered distribution of the atoms. The structure is characterized by a three-dimensional framework of CuP4 tetrahedra with cavities in the form of pentagonal dodecahedra and tetrakaidecahedra, which are occupied by the Ba atoms. The compound shows semiconduction, therefore the composition should be Ba8Cu15.5P30.5. 相似文献
92.
93.
Synthesis and Crystal Structure of the Copper Complex of 7,16-Bis(2-hyd roxy-5-met hylbenzyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane 总被引:1,自引:0,他引:1
A lariat crown ether ligand 7,16-bis (2-hydroxy-5-methylbenzyl)- 1,4,10,13-tetraoxa-7,16-diazacyclooctadeeane (L1) has been prepared via one-pot Mannich reaction. Its copper(Ⅱ) complex Cu-L1 was synthesized and characterized by elemental analysis, IR and UV-visible spectroscopy. The crystal structure of the complex has been determined by X-ray diffraction analysis. The result shows that the copper(Ⅱ) ion is six-coordinated by two nitrogen and four oxygen atoms, two from the crown ether and the other two from the deprotonated phenolate anions, forming an elongated octahedral complex. Electrochemical study indicates that the complex undergoes reversible reduction in DMF solution. 相似文献
94.
Shaobin Miao Zhan Yu Qian-Feng Zhang Yinglin Song Alexander Rothenberger Wa-Hung Leung 《Journal of Cluster Science》2006,17(3):495-507
Two isostructural crown-like heteroselenometallic cluster compounds, [Et4N]4[(μ5-WSe4)(CuX)5(μ-X)2] (X = Cl 1, Br 2), were prepared from the reactions of [Et4N]2[WSe4] with CuX and [Et4N]X· xH2O in the presence of 2-picoline and characterized by single-crystal diffraction analysis. The [(μ5-WSe4)(Cu-X)5(μ-X)2]4− anions in the cluster compounds consists of five CuX fragments coordinated to the five edges of the tetrahedral [WSe4]2− moiety along with two bridging halides connected to each of the two pairs of the symmetric copper atoms, exhibiting a novel
crown-like core structure. The nonlinear optical absorption and refraction of cluster compound 2 were determined to be α2 = 6.15 × 10−10 m/W and n
2 = 4.18 × 10−11 esu, respectively. 相似文献
95.
Nenaidenko V. G. Korotchenko V. N. Shast A. V. Tyur D. A. Balenkova E. S. 《Russian Chemical Bulletin》2003,52(8):1835-1840
The mechanism of formation of alkene stereoisomers in the catalytic olefination reaction of carbonyl compounds was studied. 4-Chlorobenzaldehyde hydrazone 1 stereoselectively reacts with a number of F-, Cl-, Br-, and I-containing polyhaloalkanes in the presence of catalytic amounts of CuCl to give -substituted styrenes 2 with the more thermodynamically stable alkene isomer being the major product. A model for the formation of the stereoisomers of alkenes 2 in the olefination reaction is proposed. Stereoselectivity of the reaction is determined by elimination of copper(ii) halides from the lowest-lying conformers of organocopper intermediates II. According to quantum-chemical calculations, the elimination should involve the staggered conformations with antiperiplanar arrangement of C—Hal and C—Cu bonds and proceed by the E2 anti-elimination mechanism. The results of quantum-chemical calculations are in good agreement with the experimental E/Z alkene isomer ratios. 相似文献
96.
Trapping Copper Phthalocyanine in a Silica Sono-Xerogel 总被引:1,自引:0,他引:1
R. Litrán E. Blanco M. Ramírez-del-solar L. Esquivias 《Journal of Sol-Gel Science and Technology》1997,8(1-3):985-990
A copper phthalocyanine (CuPc) has been encapsulated in silica. The trapping effects were studied comparing the UV-Vis absorption
spectra of some CuPc solutions and composites prepared under different conditions. The trapped organic molecules’ stability
was monitored during the gelation and drying processes. Leachability test have been carried out with the aim of checking the
trapping efficiency. Hydrolysis water of pH=2 and a molar ratioR
w
=6 mol acid H2O/mol TMOS leads to a higher CuPc stacking angle homogeneity. The increase of Pc induces a narrower mesopore distribution
and helps the stabilization of the composite. 相似文献
97.
Copper is a bioessential element in biology with truly unique chemical characteristics in its two relevant oxidation states +I and +II. Significant progress has been made in recent years in the elucidation of the frequently surprising biochemistry of this trace element. Those advances were especially furthered through mutual stimulation involving results from biochemistry, molecular biology, and medicine on one hand and the synthesis as well as the structural and spectroscopic characterization of low molecular weight model complexes on the other. The most notable features of protein-bound active copper are its almost exclusive function in the metabolism of O2 or N/O compounds (NO, N2O) and its frequent association with oxidizing organic and inorganic radicals such as tyrosyl, semiquinones, superoxide, or nitrosyl. This unique biological role of copper can be rationalized given its chemical and assumed evolutionary background. 相似文献
98.
The apparent molar heat capacities of dilute aqueous solutions of acetic, propanoic and succinic acid and sodium salts of the two monofunctional acids were measured at 300 Kp,2
o
. After subtracting the heat capacity of a point mass, the remaining heat capacity was successfully decomposed into functional group contributions at all temperatures. Together with the results of our previous paper on alcohols and diols the heat capacity contributions of the CH2, CH3, OH, COOH, (COOH)2, and COONa groups are now available and these allow reasonably accurate predictions of the heat capacities of all compounds composed of these groups in this temperature range. 相似文献
99.
100.
Katalin Selmeczi Marius Réglier Gábor Speier Gábor Peintler 《Reaction Kinetics and Catalysis Letters》2004,81(1):143-151
The oxidation of 3,5-di-tert-butylcatechol to 3,5-di-tert-butyl-o-benzoquinone catalyzed by dinuclear copper(II) complexes {[Cu2(L1)(CF3SO3)2(H2O)4]-(CF3SO3)2 (1) and [Cu2(L2O)](CF3SO3)2 (2)| has been investigated in methanol saturated with O2 at ambient temperature. Detailed kinetic studies were carried out and for the treatment the fitting software ZiTa was applied. On the basis of the results in the kinetic studies a possible mechanism of the catalytic reaction is proposed.This revised version was published online in December 2005 with corrections to the Cover Date. 相似文献