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1.
2.
We give a coring version for the duality theorem for actions and coactions of a finitely generated projective Hopf algebra.
We also provide a coring analogue for a theorem of H.-J. Schneider, which generalizes and unifies the duality theorem for
finite Hopf algebras and its refinements.
This paper was written while the first author visited the Mathematics Departments of Syracuse University and California State
University Dominguez Hills. He would like to thank both departments for their hospitality. 相似文献
3.
B. Brocklehurst R.S. Dixon E.M. Gardy V.J. Lopata M.J. Quinn A. Singh F.P. Sargent 《Chemical physics letters》1974,28(3):361-363
Excited state formation by ion recombination in solutions of fluorene in squalene has been studied by pulse radiolysis at the center of a large electromagnet. The products of the slower part of the ion recombination are affected by an applied magnetic field. The fluorescence yield increases by a factor of about 1.5 whereas the triplet yield decreases. 相似文献
4.
Jesse L. Kuiper 《Journal of organometallic chemistry》2007,692(8):1653-1660
The reaction between the new hydroxy compound [PPh4][Ru(N)(OH)2Me2] and Pd(OSiMe3)2((−)-sparteine) produces (Me3Si)2O, H2O and a new heterobimetallic compound [PPh4][Ru(N)Me2(μ2-O)2Pd((−)-sparteine)] in good yield. The Ru/Pd bimetallic compound catalyzes the oxidation of aryl and allyl alcohols to the corresponding carbonyl compound in air and the rearrangement of allylic alcohols unsaturated aldehydes. It also oxidizes PPh3 to O-PPh3 under O2. 相似文献
5.
The ultrafast-folding 20-residue Trp-cage protein is quickly becoming a new benchmark for molecular dynamics studies. Already several all-atom simulations have probed its equilibrium and kinetic properties. In this work an all-atom Go model is used to accurately represent the side-chain packing and native atomic contacts of the Trp-cage. The model reproduces the hallmark thermodynamics cooperativity of small proteins. Folding simulations observe that in the fast-folding dominant pathway, partial alpha-helical structure forms before hydrophobic core collapse. In the slow-folding secondary pathway, partial core collapse occurs before helical structure. The slow-folding rate of the secondary pathway is attributed to the loss of side-chain rotational freedom, due to the early core collapse, which impedes the helix formation. A major finding is the observation of a low-temperature kinetic intermediate stabilized by a salt bridge between residues Asp-9 and Arg-16. Similar observations [R. Zhou, Proc. Natl. Acad. Sci. U.S.A. 100, 13280 (2003)] were reported in a recent study using an all-atom model of the Trp-cage in explicit water, in which the salt-bridge stabilized intermediate was hypothesized to be the origin of the ultrafast-folding mechanism. A theoretical mutation that eliminates the Asp-9-Arg-16 salt bridge, but leaves the residues intact, is performed. Folding simulations of the mutant Trp-cage observe a two-state free-energy landscape with no kinetic intermediate and a significant decrease in the folding rate, in support of the hypothesis. 相似文献
6.
[structure: see text] The first total synthesis of rollicosin, a member of a rare subgroup of Annonaceous acetogenins containing two terminal gamma-lactones, is reported. The approach features a highly regio- and stereoselective tandem ring-closing/cross-metathesis reaction for construction of the east-wing lactone and incorporation of the alkyl spacer. Establishment of the C4 stereocenter and addition of the west-wing lactone were achieved by Sharpless asymmetric dihydroxylation and enolate alkylation. 相似文献
7.
[reaction: see text] The influence of lithium ions on the conjugate addition of the monoorganocuprate reagent, Li[BuCuI], to a chiral crotonate has been investigated. The results show that iodotrimethylsilane (TMSI) is crucial for the asymmetric conjugate addition of the copper reagent, but only in THF or when 12-crown-4 is used. The reaction is thought not to involve any halosilane in any critical steps in the organocopper mechanisms conducted in Et(2)O. 相似文献
8.
Synthesis of some dibenzodiazepinone derivatives as potent and m2-selective antimuscarinic compounds
Victor I. Cohen Biyun Jin Miriam S. Gitler Rosanna A. La De Cruz Waclaw J. Rzeszotarski Barry R. Zeeberg Jesse Baumgold Richard C. Reba 《Journal of heterocyclic chemistry》1994,31(4):787-791
Two series of 5-[[4-[4-(dialkylamino)butyl]-l-cyclohexyl]acetyl], and 5-[(dialkylamino)acyl]-10,11-dihydro-5H- dibenzo[b,e][1,4]diazepin-11-ones were synthesized as potential m2-selective ligands 1,2. Their affinity and selectivity for the muscarinic cholinergic receptor m-AChR subtypes were determined. Replacing a nitrogen with CH in the piperidine ring of 5-[[4-[4-(dialkylamino)butyl]-l-piperidinyl]acetyl]-10,11-dihydro-5H-dibenzo-[b,e][1,4]diazepin-11-ones 3 significantly altered the affinity and selectivity to the muscarinic receptor subtypes. 相似文献
9.
Praic M. Keane Kyra O'Sullivan Fergus E. Poynton Bjrn C. Poulsen Igor V. Sazanovich Michael Towrie Christine J. Cardin Xue-Zhong Sun Michael W. George Thorfinnur Gunnlaugsson Susan J. Quinn John M. Kelly 《Chemical science》2020,11(32):8600
Ruthenium polypyridyl complexes which can sensitise the photo-oxidation of nucleic acids and other biological molecules show potential for photo-therapeutic applications. In this article a combination of transient visible absorption (TrA) and time-resolved infra-red (TRIR) spectroscopy are used to compare the photo-oxidation of guanine by the enantiomers of [Ru(TAP)2(dppz)]2+ in both polymeric {poly(dG-dC), poly(dA-dT) and natural DNA} and small mixed-sequence duplex-forming oligodeoxynucleotides. The products of electron transfer are readily monitored by the appearance of a characteristic TRIR band centred at ca. 1700 cm−1 for the guanine radical cation and a band centered at ca. 515 nm in the TrA for the reduced ruthenium complex. It is found that efficient electron transfer requires that the complex be intercalated at a G-C base-pair containing site. Significantly, changes in the nucleobase vibrations of the TRIR spectra induced by the bound excited state before electron transfer takes place are used to identify preferred intercalation sites in mixed-sequence oligodeoxynucleotides and natural DNA. Interestingly, with natural DNA, while it is found that quenching is inefficient in the picosecond range, a slower electron transfer process occurs, which is not found with the mixed-sequence duplex-forming oligodeoxynucleotides studied.Efficient electron transfer requires the complex to be intercalated at a G-C base-pair. Identification of preferred intercalation sites is achieved by TRIR monitoring of the nucleobase vibrations before electron transfer. 相似文献
10.
A solid-phase extraction method is described for the separation of alachlor, atrazine and metolachlor from groundwater using solid-phase disposable columns. The method is rapid, reproducible and uses considerably fewer reagents than classical liquid-liquid methods. The average recoveries were greater than 90% for all three compounds. 相似文献