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91.
Pradeep Mathur Radhe Shyam Ji Amrendra K. Singh 《Journal of organometallic chemistry》2010,695(17):1986-141
Photolysis of a hexane solution containing ironpentacarbonyl, 1-ferrocenyl-4-phenyl-1,3-butadiyne at low temperature yields six new products: [Fe(CO)2{η2:η2-PhCCCC(Fc)C(CCPh)C(Fc)Fe(CO)3}-μ-CO] (1), [Fe2(CO)6{μ-η1:η1:η2:η2-PhCCCC(Fc)-C(O)-C(Fc)CCCPh}] (2), [Fe2(CO)6{μ-η1:η1:η2:η2-FcCC(CC Ph)-C(O)-C(Fc)CCCPh}] (3), [Fe2(CO)6{μ-η1:η1:η2:η2-FcCCCC(Fc)-C(O)-C(Fc)CCCPh}] (4), [Fe(CO)3{μ-η2: η2-[FcCC(CCPh)C(CCPh)C(Fc)}CO] (5) and [Fe(CO)3{μ-η2: η2-[FcCC(CCPh)C(CCPh)C(Fc)}CO] (6) formed by coupling of acetylenic moieties with CO insertion on metal carbonyl support. In presence of CO, formation of another new product 2,5-bis(ferrocenyl)-3,6-bis(tetracarbonylphenylmaleoyliron)quinone (7) was observed which on further reaction with ferrocenylacetyene gave the quinone, 2,5-bis(ferrocenyl)-3,6-bis(ethynylphenyl)quinone (8). Structures of 1-5 and 8 were established crystallographically. 相似文献
92.
Sardar PS Maity SS Ghosh S Chatterjee J Maiti TK Dasgupta S 《The journal of physical chemistry. B》2006,110(42):21349-21356
Human placental ribonuclease inhibitor (hRI) containing six tryptophan (Trp) residues located at positions 19, 261, 263, 318, 375, and 438 and its complex with RNase A have been studied using steady-state and time-resolved fluorescence (298 K) as well as low-temperature phosphorescence (77 K). Two Trp residues in wild-type hRI and also in the protein-protein complex with RNase A are resolved optically. The accessible surface area values of Trp residues in the wild-type hRI and its complex and consideration of inter-Trp energy transfer in the wild-type hRI reveal that one of the Trp residues is Trp19, which is located in a hydrophobic buried region. The other Trp residue is tentatively assigned as Trp375 based on experimental results on wild-type hRI and its complex. This residue in the wild-type hRI is more or less solvent exposed. Both the Trp residues are perturbed slightly on complex formation. Trp19 moves slightly toward a more hydrophobic region, and the environment of Trp375 becomes less solvent exposed. The complex formation also results in a more heterogeneous environment for both the optically resolved Trp residues. 相似文献
93.
H. C. Verma S. Misra M. Shyam Prasad N. Bijlani A. Tripathi Horton Newsom 《Hyperfine Interactions》2008,182(1-3):15-22
The partly filled skutterudites A x Fe4Sb12 (A = La, Pr, Nd, Eu, Yb, and the monovalent homologue Tl) were investigated at 4.2 K by 57Fe Mössbauer spectroscopy in external fields up to 13.5 T. Two Fe sites were identified. The observed relative spectral areas are not for all compounds in agreement with filling factors for the A-atoms determined from X-ray experiments. The change in sign and the small value of the induced hyperfine fields for magnetically ordered compounds are strong hints for itinerant ferromagnetism with small ordered moments. 相似文献
94.
S. Sundhar Ram A. Nedić V. V. Veeravalli 《Journal of Optimization Theory and Applications》2010,147(3):516-545
We consider a distributed multi-agent network system where the goal is to minimize a sum of convex objective functions of
the agents subject to a common convex constraint set. Each agent maintains an iterate sequence and communicates the iterates
to its neighbors. Then, each agent combines weighted averages of the received iterates with its own iterate, and adjusts the
iterate by using subgradient information (known with stochastic errors) of its own function and by projecting onto the constraint
set. 相似文献
95.
Norton P. Peet Shyam Sunder Robert J. Barbuch Anna P. Vinogradoff 《Journal of heterocyclic chemistry》1986,23(1):129-134
The Gewald syntheses were employed to prepare a series of 2-amino-3-carboethoxythiophenes, and the syntheses of two of these, namely, the 3,4-trimethylene ( 1f ) and 3,4-tetramethylene ( 1g ) derivatives, were examined in detail. In two preparations of 1f , octahydro-6a-(4-morpholinyl)-2-thioxocyclopenta[b]pyrrole-3-carboxylic acid ( 7 ) was a co-product. The structure of 7 was ascertained from its 300 MHz 1H nmr and 13C nmr spectra, and by its conversion to 1,4,5,6-tetrahydro-2-mercaptocyclopenta[b]pyrrole-3-carboxylic acid ethyl ester ( 8 ). Isolation of 7 and other observations led to postulated mechanisms for three of the Gewald thiophene syntheses. 相似文献
96.
The synthesis of a novel rotenone-like molecule, 9-methoxy-8-methyl-6,6a,12,12a-tetrahydro[1]benzopyrano-[3,4-b][1]benzopyran-12-one ( 2 ) is described. Efficient syntheses of 3,4-dihydro-2H-[1]benzopyran-3-one ( 9 ) from ethyl 3-hydroxy-2H-[1]benzopyran-4-carboxylate ( 6 ), an intermediate in the synthesis of 2 , were developed. Thermolysis of 6 and 9 in decalin yielded 6,8-dihydro-14H-bis[1]benzopyrano[3,4-b:4′,3′-e]pyran-14-one ( 8 ), which has previously been described. Also produced in the thermolysis was the isomeric 1H-bis[1]-benzopyrano[3,4-b:3′,4′-á]pyran-7-(9H)one ( 10 ), the first member of a novel, pentacyclic ring system. 相似文献
97.
Neil G. Keats Shyam K. Singh Lindsay A. Summers 《Journal of heterocyclic chemistry》1987,24(4):1029-1035
4-Carboxy-5-methyl-2-aryl-2H-1,2,3-triazoles undergo considerable fragmentation on electron impact including loss of OH and H2O from the molecular ions and rupture of the triazole ring. 4-Carboxy-5-phenyl-2-aryl-2H-1,2,3-triazoles, on the other hand, show no loss of H2O from the molecular ions. 相似文献
98.
Several methods were explored for preparing certain 4,5-disubstituted-1,2,3-thiadiazoles. The reaction of phenoxyacetyl chlorides with diazoacetylamides yielded α-diazo-β-ketoacetamides which were cyclized, with hydrogen sulfide and ammonium hydroxide, to 4-carboxamido-5-phenoxymethyl-1,2,3-thiadiazoles. However, treatment of α-diazo-α-benzoylacetamides with hydrogen sulfide and ammonium hydroxide yielded hydrazones rather than thiadiazoles. The reaction of α-[(ethoxycarbonyl)hydrazono]benzenepropanoic acid ( 25 ) with thionyl chloride yielded 5-phenyl-1,2,3-thiadiazole-4-carbocylic acid (26a) , the corresponding acid chloride 26b , and 5-(phenylmethyl)-2H-1,3,4-oxadiazine-2,6(3H)dione ( 27 ). The yields of 26a, 26b , and 27 were dependent on the reaction conditions employed. Oxadiazine 27 could also be converted to acid chloride 26b with thionyl chloride. Reduction of 1-([5-(4-chlorophenoxy)methyl-1,2,3-thiadiazol-4-yl]-carbonyl)piperidine ( 10b ) with diborane yielded a boron complex which produced 1-([5-((4-chlorophenoxy)methyl)-1,2,3-thiadiazol-4-yl]methyl)piperidine ( 31 ) upon recrystallization from ethanol. 相似文献
99.
Mannan Zubaer Ibna Adhikari Shyam Prasad Kim Hyongsuk Chua Leon 《Nonlinear dynamics》2020,99(4):3169-3196
Nonlinear Dynamics - This paper presents an in-depth and rigorous mathematical analysis of a family of nonlinear dynamical circuits whose only nonlinear component is a Chua Corsage Memristor (CCM)... 相似文献
100.
Benjoe Rey B. Visayas Shyam K. Pahari Tugba Ceren Gokoglan James A. Golen Ertan Agar Patrick J. Cappillino Maricris L. Mayes 《Chemical science》2021,12(48):15892
Recent advances in clean, sustainable energy sources such as wind and solar have enabled significant cost improvements, yet their inherent intermittency remains a considerable challenge for year-round reliability demanding the need for grid-scale energy storage. Nonaqueous redox flow batteries (NRFBs) have the potential to address this need, with attractive attributes such as flexibility to accommodate long- and short-duration storage, separately scalable energy and power ratings, and improved safety profile over integrated systems such as lithium-ion batteries. Currently, the low-solubility of NRFB electrolytes fundamentally limits their energy density. However, synthetically exploring the large chemical and parameter space of NRFB active materials is not only costly but also intractable. Here, we report a computational framework, coupled with experimental validation, designed to predict the solubility trends of electrolytes, incorporating both the lattice and solvation free energies. We reveal that lattice free energy, which has previously been neglected, has a significant role in tuning electrolyte solubility, and that solvation free energies alone is insufficient. The desymmetrization of the alkylammonium cation leading to short-chain, asymmetric cations demonstrated a modest increase in solubility, which can be further explored for NRFB electrolyte development and optimization. The resulting synergistic computational–experimental approach provides a cost-effective strategy in the development of high-solubility active materials for high energy density NRFB systems.Active-material solubility is critical in determining NRFB energy density, yet a predictive model accounting for solid-state cohesion energy has remained elusive. Herein we present such, based on an empirically calibrated computational framework. 相似文献