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1.
Host–Guest Chemistry of a Bis‐Calix[4]pyrrole Derivative Containing a trans/cis‐Switchable Azobenzene Unit with Several Aliphatic Bis‐Carboxylates 下载免费PDF全文
Grazia Cafeo Franz H. Kohnke Giovanni Mezzatesta Aldo Profumo Camillo Rosano Antonino Villari Andrew J. P. White 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(14):5323-5327
The azobenzene unit used as a photochemically and thermally switchable linker in the assembly of a bis‐calix[4]pyrrole receptor provides a means to modulate the binding of bis‐carboxylates of significant biological importance in cancer research. Conversely, the complexation of different bis‐anionic guests has significant kinetic effects on both the photochemical and thermal trans/cis isomerization of the azobenzene unit. 相似文献
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ABSTRACTThe compound Ca3Co2O6 undergoes a transition into a spin-density wave (SDW) state near 24?K. Below ~10?K, this unstable SDW state coexists with a nearly- degenerate commensurate antiferromagnetic state as well as short-range magnetic order. Clear signatures of this strong magnetic disorder have been observed in the response of entropy to changing magnetic field and temperature. We performed a calorimetry study of Ca3Co2O6 and Ca3Co1.9Zn0.1O6 in order to compare their entropic responses at low temperature. Our results for Ca3Co2O6 reveal that ΔS(T, H)?≡?S(T, H)?S(T, H?=?0) increases as either temperature or magnetic field increase. In contrast, ΔS data for Ca3Co1.9Zn0.1O6 were relatively unresponsive to changes in temperature or field, suggesting that Zn substitution may reduce the low-temperature magnetic disorder observed in Ca3Co2O6. These results are discussed within the context of two cases (Ca3Co2O6 under applied pressure and Ca2.75R0.25Co2O6 (R?=?Dy, Lu)) in which a single magnetic ground state is stabilised. 相似文献
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We report the addition of M–H bonds (M = Al, Zn, Mg) to a Rh(iii) intermediate generated from the reductive elimination of triethylsilane from [Cp*Rh(H)2(SiEt3)2]. A series of new heterobimetallic complexes possessing Rh–M bonds have been isolated and characterised by a number of spectroscopic (1H, 29Si, 13C, 103Rh NMR, infrared, and X-ray diffraction) and computational techniques (NBO and QTAIM analysis). Experimental and computational data are consistent with cleavage of the M–H bond upon addition to rhodium with formation of new Rh–M and Rh–H bonds. Upon photolysis the Al analogue of this series undergoes a further elimination reaction producing triethylsilane and a highly unusual Rh2Al2H4 containing cluster proposed to contain an Al(i) bridging ligand. 相似文献
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Chengzhi Chen Tingting Yuan Prof. Ping Lan Prof. Lorenzo V. White Prof. Jing Chen Prof. Dr. Martin G. Banwell 《European journal of organic chemistry》2023,26(16):e202300003
Total syntheses of the title marine natural products have been achieved and so confirming the structures originally assigned to them. Upon subjecting agesasine A and its corresponding ethyl ester to Mitsunobu conditions, a 1,5-cyclodehydration reaction takes place to give 2-oxazolines. In contrast, on subjecting agesasine B to the same Mitsunobu conditions, a simple dehydration reaction occurs to give the corresponding acrylate. A total synthesis of longamide E was achieved by engaging a 1,2-disubstituted pyrrole in a lactam-forming reaction and this was followed by a two-fold and fully regio-controlled bromination reaction. A distinctly different and possibly biomimetic route was used to synthesize, via the open-chain natural product nakamurine B, longamide B and its methyl ester. Preliminary biological evaluations of the title alkaloids and various analogues against a small human cancer cell line panel reveals cytotoxic properties that vary significantly with structure. 相似文献
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Synthesis,Characterisation and Reactivity of Copper(I) Amide Complexes and Studies on Their Role in the Modified Ullmann Amination Reaction 下载免费PDF全文
Simon Sung Dr. D. Christopher Braddock Prof. Alan Armstrong Dr. Colin Brennan Dr. David Sale Dr. Andrew J. P. White Dr. Robert P. Davies 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(19):7179-7192
A series of copper(I) alkylamide complexes have been synthesised; copper(I) dicyclohexylamide ( 1 ), copper(I) 2,2,6,6‐tetramethylpiperidide ( 2 ), copper(I) pyrrolidide ( 3 ), copper(I) piperidide ( 4 ), and copper(I) benzylamide ( 5 ). Their solid‐state structures and structures in [D6]benzene solution are characterised, with the aggregation state in solution determined by a combination of DOSY NMR spectroscopy and DFT calculations. Complexes 1 , 2 and 4 are shown to exist as tetramers in the solid state by X‐ray crystallography. In [D6]benzene solution, complexes 1 , 2 and 5 were found by using 1H DOSY NMR to exist in rapid equilibrium between aggregates with average aggregation numbers of 2.5, 2.4 and 3.3, respectively, at 0.05 M concentration. Conversely, distinct trimeric, tetrameric and pentameric forms of 3 and 4 were distinguishable by one‐dimensional 1H and 1H DOSY NMR spectroscopy. Complexes 3 – 5 are found to react stoichiometrically with iodobenzene, in the presence or absence of 1,10‐phenanthroline as an ancillary ligand, to give arylamine products indicative of their role as potential intermediates in the modified Ullmann reaction. The role of phenanthroline has also been explored both in the stoichiometric reaction and in the catalytic Ullmann protocol. 相似文献