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131.
M. Carmen Barral Santiago Herrero Reyes Jiménez-Aparicio M. Rosario Torres Francisco A. Urbanos 《Journal of organometallic chemistry》2008,693(8-9):1597-1604
The reaction of [Ru2(O2CMe)(DPhF)3(H2O)]BF4 (DPhF = N,N′-diphenylformamidinate) with CO gas leads to [Ru2(O2CMe)(DPhF)3(CO)]BF4 (1), that is the first isolated carbonyl complex containing the Ru25+ unit. The nitrosyl analogue [Ru2(O2CMe)(DPhF)3(NO)]BF4 (2) is prepared by reaction of Ru2Cl(O2CMe)(DPhF)3 with NOBF4. However, the attempts to obtain the cyanide derivative by reaction of Ru2Cl(O2CMe)(DPhF)3 or [Ru2(O2CMe)(DPhF)3(H2O)]BF4 with NaCN were unsuccessful. The structure of compounds 1 · CH2Cl2 and 2 · CH2Cl2 are described. Both compounds are isomorphous. The magnetic measurements at variable temperature demonstrate that 1 is paramagnetic with one unpaired electron in all range of temperature, in contrast to the three unpaired electrons usually present in Ru25+ complexes. The analogous nitrosyl compound 2 is diamagnetic. 相似文献
132.
Concellón JM Rodríguez-Solla H Méjica C Blanco EG García-Granda S Rosario Díaz M 《The Journal of organic chemistry》2008,73(10):3828-3836
An efficient chromium-promoted alkyl- or silylcyclopropanation of alpha,beta-unsaturated amides is described. These reactions can be carried out on (E)- or (Z)-alpha,beta-enamides in which the C-C double bond is di-, or trisubstituted. This process takes place with total stereospecificity and the new stereogenic center is generated with high or total stereoselectivity. Some synthetic applications of the obtained silylcyclopropyl amides are also reported. Two mechanisms based on the generation of carbenoid or carbene complexes have been proposed to explain this cyclopropanation reaction. 相似文献
133.
Dr. José A. Carmona Dr. Patricia Rodríguez-Salamanca Prof. Rosario Fernández Prof. José M. Lassaletta Dr. Valentín Hornillos 《Angewandte Chemie (International ed. in English)》2023,62(35):e202306981
An atroposelective Ir-catalyzed dynamic kinetic resolution (DKR) of 2-(quinolin-8-yl)benzaldehydes/1-naphthaldehydes by transfer hydrogenative coupling of allyl acetate is disclosed. The allylation reaction takes place with simultaneous installation of central and axial chirality, reaching high diastereoselectivities and excellent enantiomeric excesses when ortho-cyclometalated iridium-DM-BINAP is used as the catalyst. The racemization of the substrates occurs through a designed transient Lewis acid-base interaction between the quinoline nitrogen atom and the aldehyde carbonyl group. 相似文献
134.
Bastiaan Kooij Paul Varava Farzaneh Fadaei-Tirani Rosario Scopelliti Dimitrios A. Pantazis Gerard P. Van Trieste III David C. Powers Kay Severin 《Angewandte Chemie (International ed. in English)》2023,62(4):e202214899
Homometallic copper complexes with alkenylidene ligands are discussed as intermediates in catalysis but the isolation of such complexes has remained elusive. Herein, we report the structural characterization of copper complexes with bridging and terminal alkenylidene ligands. The compounds were obtained by irradiation of CuI complexes with N-heterocyclic diazoolefin ligands. The complex with a terminal alkenylidene ligand required isolation in a crystalline matrix, and its structural characterization was enabled by in crystallo photolysis at low temperature. 相似文献
135.
136.
A new class of benzimidazole-substituted 8-hydroxyquinoline ligands has been prepared that contain a monoanionic tridentate N,N,O-coordinating unit. These ligands form charge-neutral lanthanide complexes of the type [Ln(L-R) 3]. nH 2O or [Ln 2(L2) 3]. nH 2O ( n = 1-3) with early lanthanides from La (III) to Gd (III) inclusive. Crystallographic characterization was carried out for 11 complexes with 6 different ligands. In all of these structures, the lanthanide ion was found to be nine-coordinated by three ligands arranged in an "up-up-down" fashion around the metal center. The coordination environment can be described as a tricapped trigonal prism, with N atoms of quinoline rings occupying capping positions. Upon deprotonation of the ligand and complex formation, a new absorption band appears in the visible range of the spectrum with a maximum in the range of 466-483 nm and molar absorption coefficient of (7.2 - 18) x 10 (3) M (-1) cm (-1). Its origin is likely to be an intraligand phenolate-to-pyridyl charge transfer transition centered on the 8-hydroxyquinolate chromophore. Upon excitation in ligand absorption bands, new Nd (III) complexes display characteristic metal-centered luminescence in the near-infrared region from 850 to 1450 nm with quantum yields and lifetimes in solid state at room temperature as high as 0.34% and 1.2 mus, respectively. 相似文献
137.
Marta Falcone Dr. Christos E. Kefalidis Rosario Scopelliti Prof. Laurent Maron Prof. Marinella Mazzanti 《Angewandte Chemie (International ed. in English)》2016,55(40):12290-12294
Uranium nitrides are important materials with potential for application as fuels for nuclear power generation, and as highly active catalysts. Molecular nitride compounds could provide important insight into the nature of the uranium–nitride bond, but currently little is known about their reactivity. In this study, we found that a complex containing a nitride bridging two uranium centers and a cesium cation readily cleaved the C≡O bond (one of the strongest bonds in nature) under ambient conditions. The product formed has a [CsU2(μ‐CN)(μ‐O)] core, thus indicating that the three cations cooperate to cleave CO. Moreover, the addition of MeOTf to the nitride complex led to an exceptional valence disproportionation of the CsUIV–N–UIV core to yield CsUIII(OTf) and [MeN=UV] fragments. The important role of multimetallic cooperativity in both reactions is illustrated by the computed reaction mechanisms. 相似文献
138.
(1S,2R)-1-Aminoindan-2-ol-derived thioureas behave as efficient H-bonding organocatalysts for the nucleophilic conjugate addition of formaldehyde hydrazones to beta,gamma-unsaturated alpha-keto esters as enoate surrogates, affording the corresponding adducts in good yields and enantioselectivities. 相似文献
139.
López-Alberca MP Mancheño MJ Fernandez I Gómez-Gallego M Sierra MA Torres R 《Organic letters》2007,9(9):1757-1759
[reaction: see text] The Pd-catalyzed reaction of beta-arylaminochromium(0) carbene complexes produces by transmetalation the first isolated and X-ray structurally characterized bis-Pd(II) carbene complex, as well as other alternative reaction pathways, such as the oxidative addition-transmetalation sequence, not seen before in this chemistry. 相似文献
140.
This study examines the application of coupled-column LC-photochemically induced fluorimetry-fluorescence detection (LC-LC-PIF-FD), demonstrating its potential for the quantitative and selective detection of six herbicides, including propanil and the phenylureas monuron, monolinuron, chlorotoluron, diuron and neburon in groundwater samples. An AQUASIL C18 50 x 4.6 mm(2) id column coupled to an AQUASIL C18 150 x 4.6 mm(2) id column for analyte clean-up and determination were used, respectively. A simple SPE with Cl8 cartridges was carried out, yielding average recoveries between 80 and 112% (n = 6) with RSDs between 0.5 and 9%. The LODs ranged from 0.0083 to 0.0833 microg/L in the groundwater samples. 相似文献