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151.
152.
A Facile Diversity‐Oriented Multicomponent One‐Pot Synthesis of 3‐Amino‐6,7‐dihydrobenzo[c]thiophen‐4(5H)‐one Derivatives from α‐Oxo‐N,S‐ketene Acetal
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Swapnil G. Yerande Sunil D. More Mayur Bhandari Kiran M. Newase Kareem Khoury Kan Wang Alexander Dömling 《Journal of heterocyclic chemistry》2014,51(Z1):E358-E363
A convenient one‐pot multicomponent method for the preparation of 3‐amino‐6,7‐dihydrobenzo[c]thiophen‐4(5H)‐one derivative has been developed. Reaction of 1,3‐cyclohexanedione and phenyl isothiocynate gave α‐oxo‐N,S‐ketene acetal that were reacted in situ with 2‐chloromethylquniazoline‐4‐one derivatives, in the presence of sodium hydride to afford the target compound in reasonable overall yields. 相似文献
153.
Chang GF Wang CH Lu HC Kan LS Chao I Chen WH Kumar A Lo L dela Rosa MA Hung CH 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(40):11332-11343
Group 12 and silver(I) tetramethyl‐m‐benziporphodimethene (TMBPDM) complexes with phenyl, methylbenzoate, or nitrophenyl groups as meso substituents were synthesized and fully characterized. The dimeric silver(I) complex displays an unusual η2,π coordination from the β‐pyrrolic C?C bond to the silver ion. All of the complexes displayed a close contact between the metal ion and the inner C(22)? H(22) on the m‐phenylene ring. The downfield chemical shifts of H(22) and large coupling constants between CdII and H(22) strongly support the presence of an agostic interaction between the metal ion and inner C(22)–H(22). Crystal structures revealed that the syn form is the predominant conformation for TMBPDM complexes. This is distinctively different from the exclusive anti conformation observed in m‐benziporphyrin and tetraphenyl‐m‐benziporphodimethene (TPBPDM) complexes. Evidently, intramolecular hydrogen‐bonding interactions between axial chloride and methyl groups stabilize syn conformations. Unlike the merely syn conformation observed in the solid‐state structures of TMBPDM complexes that contain an axial chloride, in solution these complexes display highly solvent‐ and temperature‐dependent syn/anti ratio changes. The observation of dynamic 1H NMR spectroscopic scrambling between syn and anti conformations from the titration of chloride ion into the solution of the TMBPDM complex suggests that axial ligand exchange is a likely pathway for the conversion between syn and anti forms. Theoretical calculations revealed that intermolecular hydrogen‐bonding interactions between the axial chloride and CHCl3 stabilizes the anti conformation, which explains the increased ratio for the anti form when dichloromethane or chloroform was used as the solvent. 相似文献
154.
Koichi Kan Jinfeng Yang Kimihiro Norizawa Takafumi Kondoh Yoichi Yoshida Atsushi Ogata 《Radiation Physics and Chemistry》2011,80(12):1323-1326
A novel method to generate high-power THz radiation is proposed. If a beam with a bunch length on the order of 100 fs is injected into an electron–hole plasma of a semiconductor with a plasma frequency on the order of THz, THz wake fields are coherently generated. If the beam moves on the axis of a hollow tube covered by a metal, the frequency spectrum of the radiation is composed of discrete components. Monochromatic radiation is obtained by making only the lowest frequency component coherent. 相似文献
155.
Atmospheric pressure plasma (APP) treatment was applied as a pretreatment process to enhance the deposition of printing paste
in order to improve the final colour properties of digital ink-jet printed cotton fabrics. Three printing pastes containing
natural polymers, i.e. (1) sodium alginate, (2) chitosan and (3) sodium alginate-chitosan mixture, were prepared separately.
After APP treatment, cotton fabric was padded with different printing pastes prior to digital ink-jet printing. Experimental
results showed that APP pretreatment could increase the colour yield of the digital ink-jet printed cotton fabric significantly
even after washing. In addition, other properties such as colour fastness to crocking, colour fastness to laundering, outline
sharpness and anti-bacterial properties were also improved when compared with those of the control cotton fabric printed without
APP pretreatment. However, the influence of printing paste on the colour properties of the digital ink-jet printed cotton
fabrics depended very much on the composition of the printing paste. The scanning electron microscope images evidenced that
the APP treatment could enhance the deposition of printing paste on the cotton fabric surface as proved qualitatively by both
the contact angle and wetting time measurement as well as quantitatively by both the X-ray photoelectron spectroscopy and
carboxyl group/nitrogen content analysis. 相似文献
156.
In this study, CO2 laser was used for treating cotton fabric to create surface effects which were found to vary with laser process parameters,
i.e. resolution and pixel time. The resolutions used were 40, 50 and 60 dpi while the pixel time used were 100, 110 and 120 μs.
Both physical and chemical properties at the surface of fabrics treated with different combinations of resolution and pixel
time were analysed by the Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy with Attenuated Total
Reflection mode (FTIR-ATR), and X-ray Photoelectron Spectroscopy (XPS). SEM investigation revealed the appearance of various
numbers of pores, cracks and fragments present on the fibre surface after laser treatment. FTIR-ATR spectra showed that the
laser-treated cotton fabric suffered changes in chemical structure with the hydroxyl (–OH) stretching group being oxidised
to carbonyl/carboxyl groups. The XPS analysis revealed a change in surface elemental composition after laser treatment. Furthermore,
the wicking property of the laser-treated cotton fabrics was evaluated. 相似文献
157.
We use UV resonance Raman spectroscopy to probe the lowest energy allowed electronic transitions of aqueous solutions containing Cl(-) salts. We show that the waters hydrating the Cl(-) are involved in charge transfer transitions that transfer electron density from Cl(-) to the water molecules. These charge transfer transitions cause significant change in the H-O-H bond angle in the excited state, which results in a strong enhancement of the preresonance Raman intensity of the water bending modes. Our work gives the first insight into the lowest allowed electronic transition of hydrated Cl(-). 相似文献
158.
Highly diastereoselective and enantioselective catalytic capture of chiral zinc enolates using nitroolefins as electrophiles is described. The tandem products γ-nitro ketones were obtained in good yields with high diastereoselectivities and enantioselectivities. The γ-nitro ketones were readily hydrogenated to the optically enriched and diastereomerically pure chiral pyrrolidines with four contiguous stereocentres under mild conditions. 相似文献
159.
Ruthenium complexes of 1,4,7-trimethyl-1,4,7-triazacyclononane for atom and group transfer reactions
Sharon Lai-Fung Chan Yu-He Kan Ka-Lai Yip Jie-Sheng Huang Chi-Ming Che 《Coordination chemistry reviews》2011,255(7-8):899-919
With support by macrocyclic tertiary amine ligand 1,4,7-trimethyl-1,4,7-triazacyclononane (Me3tacn), a number of mononuclear metal–ligand multiple bonded complexes have been isolated. Starting with a brief summary of these complexes, the present review focuses on ruthenium-oxo and -imido complexes of Me3tacn. A family of monooxoruthenium(IV) complexes [RuIV(Me3tacn)O(N–N)]2+ (N–N = 2,2′-bipyridines) and a cis-dioxoruthenium(VI) complex cis-[RuVI(Me3tacn)O2(CF3CO2)]+ have been isolated, and the structures of [RuIV(Me3tacn)O(bpy)](ClO4)2 (bpy = 2,2′-bipyridine) and cis-[RuVI(Me3tacn)O2(CF3CO2)]ClO4 have been determined by X-ray crystallography. Oxidation of [RuIII(Me3tacn)(NHTs)2(OH)] (Ts = p-toluenesulfonyl) with Ag+ and electrochemical oxidation of [RuIII(Me3tacn)(H2L)](ClO4)2 (H3L = α-(1-amino-1-methylethyl)-2-pyridinemethanol) are likely to generate ruthenium-imido complexes supported by Me3tacn. DFT calculations on cis-[RuVI(Me3tacn)O2(CF3CO2)]+ and proposed ruthenium-imido complexes have been performed. Complexes [RuIV(Me3tacn)O(N–N)]2+ are reactive toward alkene epoxidation, and cis-[RuVI(Me3tacn)O2(CF3CO2)]+ efficiently oxidizes various organic substrates including concerted [3+2] cycloaddition reactions with alkynes and alkenes to selectively afford α,β-diketones, cis-diols, or CC bond cleavage products. Related oxidation reactions catalyzed by ruthenium Me3tacn complexes include epoxidation of alkenes, cis-dihydroxylation of alkenes, oxidation of alkanes, alcohols, aldehydes, and arenes, and oxidative cleavage of CC, CC, and C–C bonds, all of which exhibit high selectivity. Ruthenium Me3tacn complexes are also active catalysts for amination of saturated C–H bonds. 相似文献
160.
Xue Y Liu JQ Zheng KW Kan ZY Hao YH Tan Z 《Angewandte Chemie (International ed. in English)》2011,50(35):8046-8050
A matter of speed: When allowed to fold in a K(+) /poly(ethylene glycol) solution, the guanine?(G)-rich strand of vertebrate telomere DNA forms a parallel/antiparallel G-quadruplex, which is a (3+1) hybrid, within microseconds before slowly transforming into the parallel one within hours. Thus, the conformation that a G-quadruplex initially adopts under physiological conditions may not be the one it adopts at the equilibrium state. 相似文献