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141.
142.
The potential energy curves of the 69 Ω states generated from the 24 Λ-S states of sulfur monoxide are calculated for the first time using the internally contracted multireference configuration interaction method with the Davidson correction and the entirely uncontracted aug-cc-pV5Z basis set. Spin-orbit coupling is taken into account by the state interaction approach with the full Breit-Pauli Hamiltonian. Very good agreement is achieved between our computed spectroscopic properties and the available experimental data. The transition properties of the B(3)Σ(-) -X(3)Σ(-) and (4)1-X0(+) transitions are predicted, and our computed Franck-Condon factors and radiative lifetimes match the experimental results very well. The predissociation mechanisms are investigated, and various new predissociation channels are located. We present a new interpretation on the breaking-off of the rotational levels of the B(3)Σ(-) lower vibrational states observed in experiment, and propose that the predissociation is induced by the Coriolis coupling between the B(3)Σ(-) rovibrational levels and the A(3)Π state. Our calculations indicate that, at ν' = 9, the B(3)Σ(-) state predissociates via the C(3)Π state; around ν' = 14, three spin-orbit-induced predissociation pathways via (1)(5)Σ(+) , (2)(5)Π, and e(1)Π would be open; around ν' = 17, the pathways via (2)(1)Σ(+) , (2)(3)Σ(+) and (2)(5)Σ(+) would contribute. These satisfactorily explain the experimental results about the diffuseness of the B(3)Σ(-) bands. Furthermore, various predissociation pathways of the C'(3)Π state are predicted, through which the C'(3)Π state could predissociate rapidly. 相似文献
143.
Shuai DongDongdong Qi Yi ZhangJianzhuang Jiang Yongzhong Bian 《Vibrational Spectroscopy》2011,56(2):245-249
The infrared spectroscopic data for a series of three 2,3,9,10,16,17,23,24-octakis(hexylsulfonyl)phthalocyanine compounds with eight strong electron-withdrawing hexylsulfonyl groups at the peripheral positions M[Pc(SO2C6H13)8] [M = 2H (1), Cu (2), Zn (3)] have been collected with resolution of 2 cm−1. The infrared spectra of compounds 1 and 3 have also been calculated at the density functional B3LYP level. Detailed assignments of the vibrational bands in the IR spectra have been achieved through comparison of the experimental and calculated results. The influence of the metalation and the substitution of eight strong electron-withdrawing alkylsulfonyl groups on the IR characteristics of the phthalocyanines has been discussed based on the comparison between corresponding data. 相似文献
144.
Shuang Li Di Yao Hedong Bian Zhenfeng Chen Jing Yu Qing Yu Hong Liang 《Journal of solution chemistry》2011,40(4):709-718
The interaction of plumbagin (PLU) with human serum albumin (HSA) in physiological buffer (pH=7.4) was studied by fluorescence spectroscopy. Results obtained from analysis of the fluorescence spectra indicated that PLU has a strong ability to quench the intrinsic fluorescence of HSA through a static quenching procedure. Fluorescence quenching data revealed that the quenching constants (K) are 4.43×104, 3.26×104 and 1.69×104 L?mol?1 at 293, 303 and 313 K, respectively. The thermodynamic parameters ΔH° and ΔS° were calculated to be ?36.63 kJ?mol?1, and ?35.702 J?mol?1?K?1 respectively, which suggested that van der Waals interactions and hydrogen bonds play a major role in the interaction of PLU with HSA. The distance between donor (HSA) and acceptor (PLU) was calculated to be 3.76 nm based on Förster’s non-radiative energy transfer theory. The results of synchronous fluorescence spectra showed that binding of PLU to HSA can induce conformational changes in HSA. 相似文献
145.
J. Bian X.W. WeiH.L. Lin S.J. GongH. Zhang Z.P. Guan 《Polymer Degradation and Stability》2011,96(10):1833-1840
Modified graphite oxide (MGO)/Poly (propylene carbonate) (PPC) composites with excellent thermal and mechanical properties have been prepared via a facile solution intercalation method. An intercalated structure of MGO/PPC composites was confirmed by X-ray diffraction and scanning electron microscope. The thermal and mechanical properties of MGO/PPC composites were investigated by thermal gravimetric analysis, differential scanning calorimetric, dynamic mechanical analysis, and electronic tensile tester. Due to the nanometer-sized dispersion of layered graphite in PPC matrix and the strong interfacial interaction between MGO and PPC, the prepared MGO/PPC composites exhibit improved thermal and mechanical properties in comparison with pure PPC. Compared with pure PPC, the MGO/PPC composites show the highest thermal stability and the Tg is 13.8 °C higher than that of pure PPC, while the tensile strength (29.51 MPa) shows about 2 times higher than that of pure PPC when only 3.0 wt.% MGO is incorporated. These results indicate that this approach is an efficient method to improve the properties of PPC. 相似文献
146.
147.
The kibdelones are aromatic polyketide natural products featuring isoquinolinone and tetrahydroxanthone ring systems. They display potent cytotoxicity toward a range of human cancer cell lines. Here, we present an enantioselective total synthesis of kibdelone C that utilizes a Shi epoxidation to establish the absolute and relative stereochemistry, an acid-catalyzed cyclization to form the tetrahydroxanthone, and a C-H arylation to complete the hexacyclic skeleton. 相似文献
148.
A new pyridoxal‐5‐phosphate (PLP) derivative FHMDP was developed for the transamination of different peptides with three most hindered amino acid residues (Leu, Ile, Val) as their N‐terminus. Compared to the previously reported reactions of PLP derivatives, the N‐terminus transamination could be accomplished efficiently with the new compound. 相似文献
149.
150.
Zhu QY Wang JP Qin YR Shi Z Han QH Bian GQ Dai J 《Dalton transactions (Cambridge, England : 2003)》2011,40(9):1977-1983
Though numerous metal-organic frameworks or polymers have been reported, the organic building blocks are usually not redox-active. On the other hand, some mono-, di- or tri-nuclear compounds with tetrathiafulvalene (TTF) have been prepared, although little is known about the coordination polymers combined with paramagnetic metals and organic TTF ligands. We report herein a series of coordination polymers of copper(II) and manganese(II) with TTF dicarboxylate ligand (L). Compound 1, [CuL(2,2-bpy)](n), is a one-dimensional (1-D) coordination polymer with five-coordinated square-pyramidal Cu(II) centers. Mn(II) complex 2, [MnL(2,2-bpy)](n), also takes a 1-D structure, showing a double-bridged mode by carboxylate groups. The 4,4-bipyridine compound 3, [MnL(4,4-bpy)(H(2)O)](n)·CH(3)CN, takes a 2-D grid network. A zinc(II) compound 4, [ZnL(4,4-bpy)(H(2)O)](n)·CH(3)CN, isomorphous structure with 3, is also presented. The electrochemical properties of the solid-state compounds were investigated by cyclic voltammetry using surface-modified electrodes. As usually observed in TTF derivatives, two sets of redox-waves were observed. The values of E(1/2)(1) of compounds 1-4 are in the order of 2(Mn) ≈ 3(Mn) < 1(Cu) < 4(Zn), indicating that the metal coordination can affect the potential shift of the TTF ligand. Weak antiferromagnetic exchanges are observed for compounds 1, 2, and 3. 相似文献