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51.
A. L. Chistyakov I. V. Stankevich N. P. Gambaryan I. A. Tikhonova V. B. Shur 《Russian Chemical Bulletin》1995,44(6):997-1004
Geometries and electronic structures of the complexes of halide anions with cyclic trimerico-phenylenemercury, (o-C6H4Hg)3, perfluoro-o-phenylenemercury, (o-C6F4Hg)3, vinylenemercury, (C2H2Hg)3, and perfluorovinylenemercury, (C2F2Hg)3, were modelled by the MNDO method. Calculations were performed for [L-X]– semisandwich complexes, [X-L-X]2– bipyramidal complexes, and [L-X-L]– sandwich complexes (where X=Hal,L is a mercury-containing macrocycle). Based on the results of calculations, we concluded that it was advantageous to describe the chemical bonding between halide anions and mercury-containing macrocycles in terms of generalized chemical bonds, which were successfully used for -complexes of transition metals. In the [L-X]– semisandwich complexes, the halide anion and the metallacycle are involved in the formation of three generalized chemical bonds: one headlight-shaped -bond and two two-lobe -bonds. In the [X-L-X]2– bipyramidal complexes, each halide anion forms three generalized chemical bonds with the macrocycle. It is possible because the macrocycleL has unoccupied molecular orbitals suitable for the formation of such bonds; these MOs consist mainly of the orbitals of mercury atoms directed toward both the upper and lower halogen atoms. In the [L-X-L]– sandwich complexes, the halide anion cannot be bonded to each ringvia three bonds, and, hence, an unsymmetrical structure is formed, in which the rings are located at different distances from the central atom: the [L-X]– semisandwich complex solvated by macrocycleL.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1035–1042, June, 1995.The authors are grateful to V. I. Faustov for valuable remarks.This work was supported by the Russian Foundation for Basic Research (Project No. 93-03-18342). 相似文献
52.
Yoshiyuki Tanaka Makoto Arakawa Yohei Yamaguchi Chieko Hori Masahiro Ueno Takeyuki Tanaka Tatsushi Imahori Yoshinori Kondo 《化学:亚洲杂志》2006,1(4):581-585
A metal‐free acetylide was observed by using NMR spectroscopy. Metal‐free acetylides are closely related to reactive intermediates (carbanions) in solution; therefore, they have been regarded as unobservable species. However, we generated this highly reactive and unstable species through the deprotonation of phenylacetylene by using the strong nonmetallic phosphazene base tBu‐P4. In the presence of tBu‐P4, the J coupling between the ethynyl carbon and hydrogen nuclei (1JC,H) of phenylacetylene disappeared; this indicates the deprotonation of the alkyne terminal. Furthermore, a large low‐field shift (approximately 90 ppm) of the alkyne carbon resonance was observed. We concluded that we have observed a metal‐free carbanion with a formal charge on an sp‐hybridized carbon atom for the first time. 相似文献
53.
掺杂阴离子对电化学合成的聚邻甲苯胺性质的影响 总被引:3,自引:0,他引:3
邻甲苯胺在酸性介质中的聚合速率与酸的种类有关,聚合速率影响了各种掺杂阴离子聚合物膜的形态,聚合物的电导率、循环伏安曲线形状受掺杂阴离子的影响,其电容量与掺杂阴离子的种类及形态有关,阴离子的种类对电极电位和紫外-可见光谱无影响。 相似文献
54.
Spectroscopic constants and molecular properties of selected diatomic anions namely CN?, SiH?, PO?, SO?, SF?, and SiS? in their ground states have been studied in detail using the hybrid HF/DF B3LYP method. The consistency of the calculated values has been verified with four different basis sets, with improved quality. The spectroscopic constants and molecular properties calculated with the aug‐cc‐pVTZ basis set agree very well with the experimental and theoretical values wherever available. Most of the spectroscopic constants and molecular properties of the selected diatomic anions, particularly the spectroscopic constants and molecular properties of SO? and SiS? are reported for the first time. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004 相似文献
55.
Tikhonova I. A. Shubina E. S. Dolgushin F. M. Tugashov K. I. Teplitskaya L. N. Filin A. M. Sivaev I. B. Petrovskii P. V. Furin G. G. Bregadze V. I. Epstein L. M. Shur V. B. 《Russian Chemical Bulletin》2003,52(3):594-600
The reaction of cyclic trimeric perfluoro-o-phenylenemercury (o-C6F4Hg)3 (1) with the polyhedral [B12H11SCN]2– anion in THF at 20 °C affords the {[(o-C6F4Hg)3](B12H11SCN)}2– (4) and {[(o-C6F4Hg)3]2(B12H11SCN)}2– (5) complexes. Complex 5 was isolated as the tetrabutylammonium salt. X-ray diffraction analysis showed that this complex has a bent-sandwich structure in which the [B12H11SCN]2– anion is located between the planes of two molecules 1 and is coordinated to both these molecules through B—H—Hg bridges and S—Hg bonds. The stability constants of complexes 4 and 5 in THF (20 °C), which were determined from the IR spectroscopic data, are 16 L mol–1 and 992 L2 mol–2, respectively. 相似文献
56.
Pentafluorophenyliodine(III) Compounds. 2. Fluorine-Aryl Substitution Reactions on Iodinetrifluoride: Synthesis of Pentafluorophenyliodinedifluoride C6F5IF2 and Bis(pentafluorophenyl)iodonium Pentafluorophenylfluoroborates[(C6F5)2I]+[(C6F5)nBF4?n]? Mono- and disubstitution can be achieved in the fluorine-aryl substitution reaction on the low-temperature phase IF3 in CH2Cl2 at ?78°C depending on the aryl transfer reagent. With B(C6F5)3 [(C6F5)2I]+ [(C6F5)nBF4?n]? (68% yield) and with Cd(C6F5)2 C6F5IF2 (97% yield) is obtained whereas with C6F5SiMe3 no fluorine-aryl substitution takes place on IF3 even under basic conditions (EtCN or F? addition). At ?78°C in EtCN solution IF3 does not disproportionate but attacks the solvent under formation of HF. 相似文献
57.
R. M. Lazorenko-Manevich A. N. Podobaev L. A. Sokolova 《Russian Journal of Electrochemistry》2007,43(1):42-50
Based on the model of spatial separation of the dissolution and passivation of hydrophilic metals, the effect of strong specific adsorption of anions on the shape of curves for the relaxation of anodic current of metals in acid solutions after switching an anodic activation pulse off is considered by using iron as an example. 相似文献
58.
Structural tuning of coordination polymers by 4-connecting metal node and secondary building process
Due to variation in ligand's conformation, metal node's connecting geometry, and secondary building process by anions, bat-like, dumbell-like, diamondoid, or pillar-layer topologies are achieved. 相似文献
59.
Hiroki FurutaToyohisa Takase Hisafumi HayashiRyoji Noyori Yuji Mori 《Tetrahedron》2003,59(49):9767-9777
An efficient method has been developed for the synthesis of trans-fused tetrahydropyrans with angular methyl groups adjacent to the ring oxygen. The procedure involves the coupling reaction of a sulfonyl-stabilized oxiranyl anion with an appropriate triflate followed by 6-endo cyclization, and is effective for the construction of 6/6- and 6/7/6-cyclic ether ring systems with sterically congested 1,3-diaxial methyl groups. 相似文献
60.
A flow injection–capillary electrophoresis system with contactless conductivity detection and hydrostatic-pressure-generated flow was used for the fast and sensitive speciation of Se(IV) and Se(VI). The sample throughput was 25 samples per hour using a background electrolyte solution containing 8.75 mM l-histidine (His) adjusted to pH 4.00 with acetic acid. The repeatability of peak areas (n=8) was better than 1.41% and the limits of detection were 190 g L–1 and 7.5 g L–1 for Se(IV) and Se(VI), respectively. The interference from carbonate, typically present in water samples, was eliminated by using a low-pH electrolyte in which carbonate is uncharged and migrates at the EOF front. The method was applied to the analysis of Se(IV) and Se(VI) in soil samples that were spiked with both selenium species and the results for recovery of both selenium species were in good agreement with their introduced concentrations. 相似文献