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921.
A new, convenient, ecofriendly synthesis of 3,5-diarylisoxazoles is reported from α,β-unsaturated ketoximes. Similarly, a novel synthesis of isoxazole carboxylic acids is also reported. Both the methods use efficient, environmentally friendly, and nontoxic iodoxybenzoic acid (IBX) as an oxidative cyclizing reagent. Easy procedure, environmentally benign reaction conditions, and nontoxicity are advantages to the methodology. 相似文献
922.
Mehmet Y?lmaz 《Tetrahedron》2011,67(43):8255-8263
Manganese(III) acetate based radical cyclization of various fluorinated 1,3-dicarbonyl compounds with 2-thienyl and 2-furyl substituted alkenes produced 3-trifluoroacetyl and 2-trifluoromethyl-dihydrofurans in good yields. The radical cyclizations of 2-methyl-5-[(E)-2-phenylvinyl]furan 2b and 2-[(E)-2-phenylvinyl]thiophene 2c led to the formations of 5-(5-methyl-2-furyl)-4,5-dihydrofuran and 5-(2-thienyl)-4,5-dihydrofuran, respectively. In the reactions of 1,3-dicarbonyls with alkenes, 2-thienyl substituted alkenes formed 4,5-dihydrofurans in higher yields than 2-furyl substituted alkenes. 相似文献
923.
Shuya. Wei Xiaoyang. Fang Xuejun. Cao Manfred Schreiner 《Journal of Analytical and Applied Pyrolysis》2011,91(1):147-153
Chinese ink stick has a long history and a special importance in Chinese culture. Its main components are soot (normally pine wood soot and lamp soot) and animal glue; however, additives were added from time to time for different purposes. In order to see whether the two types of soot can be differentiated and the other constituents in Chinese ink sticks can be identified or not by Pyrolysis-Gas Chromatography-Mass Spectrometry (Py-GC-MS) and GC-MS techniques, an initial study has been carried out. The main polycyclic aromatic hydrocarbons (PAHs) in soot could be identified, which are anthracene, fluoranthene, triphenylene and benz[e]acephenanthrylene. The main difference between those two types of soot is that the detectable amount of PAHs in lamp soot is much lower than in pine wood soot. In addition to this, the relative concentration of the main polycyclic aromatic hydrocarbons including anthracene, fluoranthene, pyrene, triphenylene and its isomer, benzo[k]fluoranthene and its isomers are different in the two types of soot. The relative content of benzo[k]fluoranthene is higher in pine soot than in lamp soot, which could be used to as a criterion to differentiate the two types of soot. Py-GC-MS technique is a very effective method to identify the main components of Chinese ink sticks, including the PAHs of soot, binding media and the additives of camphor and borneol in one analysis. 相似文献
924.
I. I. Guseinov 《Journal of mathematical chemistry》2011,49(1):290-295
Using symmetrical one-range addition theorems the series expansion formulae in terms of multicenter charge density expansion
coefficients for noninteger n Slater type orbitals (STO), parameters of Coulomb-Yukawa like correlated interaction potentials (CIP) of noninteger indices
and linear combination coefficients of molecular orbitals are established for the potential of electrostatic field produced
by the charges of molecule. The final results are useful for the study of interaction between atomic-molecular systems containing
any number of closed and open shells when the Hartree–Fock–Roothaan (HFR) approximation and the explicitly correlated methods
based upon the use of STO as basis functions and Coulomb–Yukawa like CIP are employed. As an example of application, the calculations
have been performed for the Coulomb interaction potential produced by the ground state of CH
2 molecule (1a12 2a12 1b12 3a11 1b11,3B1 ){(1a_1^2 2a_1^2 1b_1^2 3a_1^1 1b_1^1,^3B_1 )}. 相似文献
925.
Metallosurfactant complexes of the type trans- [Co(DH)2(HA)X], where DH = Dimethyl glyoxime, HA = Hexadecyl amine and X = Cl−, Br−, I−, N3
−, NO2
− or SCN−, were synthesized and characterized by physico-chemical and spectroscopic methods. In addition, the single crystal X-ray
structure of the ionic complex trans-[Co(DH)2(HA)2][Co(DH)2(I)2)] is presented. The critical micelle concentration values of the complexes in ethanol were obtained by measuring the absorption
at 290 nm. Specific conductivity data (at 303–313 K) served for the evaluation of the thermodynamics of micellization
) \left( {\Updelta G^{0}_{{{\text{m}}}}, \Updelta H^{0}_{{{\text{m}}}}, \Updelta S^{0}_{\text{m}} } \right) . Steady-state photolysis, cyclic voltammetry and biological activities of the complexes were studied. The compounds were
tested for antimicrobial activity. 相似文献
926.
Tutorial review: to achieve molecule-based spintronic devices, an organic conducting magnet that exhibits both conductivity and magnetism in a cooperative manner must be constructed. As a building block for such new materials, a spin-polarized donor radical, which serves as a molecular "spin-filter" in its singly oxidized state, was designed and synthesized. The resistivity of ion radical salts of selenium-substituted, tetrathiafulvalene-based spin-polarized donor radicals decreased substantially in the presence of a magnetic field, thus indicating cooperative conductivity and magnetism. 相似文献
927.
E. F. Keskenler S. Doğan B. Diyarbakır S. Duman B. Gürbulak 《Journal of Sol-Gel Science and Technology》2011,60(1):66-70
ZnO thin films were deposited onto glass subsrates by a Sol-gel spin coating method. The structural and optical properties
of ZnO thin films were investigated. The molar ratios of the zinc acetate dihydrate to Monoethanolamine were maintained 1:1.
The as-grown film was sintered 250 °C for 10 min, then annealed in air at 500 °C for 30 min. The XRD results indicate that
ZnO films were strongly oriented to the c-axis of the hexagonal nature. Absorption measurements were carried out as a function
of temperature with 10 K steps in the range 10–320 K. The band gap energy was measured 3.275 and 3.267 eV for 0.5 and 1.0
molarity (M) ZnO thin films at 300 K. The steepness parameters were observed between 10 and 320 K and their extrapolations
converged at (E0, α0) = 3.65 eV, 172,819 cm−1 and 3.70 eV, 653,436 cm−1 for 0.5 and 1.0 M ZnO thin films, respectively. 相似文献
928.
Yasemin Oztekin Zafer Yazicigil Ali Osman Solak Zafer Ustundag Zeynel Kilic Selen Bilge 《Surface and interface analysis : SIA》2011,43(5):923-930
Modification of glassy carbon (GC) surfaces with phenanthroline derivatives (PDs) such as 5‐amino‐1,10‐phenanthroline (5AP) and 5,6‐diamino‐1,10‐phenanthroline (56DAP) is described in this study. Surface modification experiments were performed by cyclic voltammetry (CV) scanning from + 1.2 to + 2.7 V at scan rate of 100 mV/s applying 30 potential scans in acetonitrile (CH3CN) containing 1 mM PDs and 100 mM tetrabutylammoniumtetrafluoroborate (TBATFB). The presence of PDs on GC electrode was confirmed using CV, electrochemical impedance spectroscopy (EIS), contact angle measurements and ellipsometry and comparing with the results of bare GC electrode. A mechanism was proposed for the electrochemical modification of the GC electrode surface with PDs. The structure of the 5AP and 56DAP films was also discussed in the light of electrochemical and spectroscopic data. The complex‐forming ability of the modified surfaces against metal cations was investigated by square‐wave voltammetry (SWV). It was shown that surfaces having 1,10‐phenanthroline ligands with different functional groups were quite useful for the determination of transition metal ions. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
929.
First principles calculations are performed to investigate the structural, mechanical, and electronic properties of C2N2(NH). Our calculated lattice parameters are in good agreement with the experimental data and previous theoretical values. Orthorhombic C2N2(NH) phase is found to be mechanically stable at an ambient pressure. Based on the calculated bulk modulus and shear modulus of polycrystalline aggregate, C2N2(NH) can be regarded as a potential candidate of ultra-incompressible and hard material. Furthermore, the elastic anisotropy and Debye temperatures are also discussed by investigating the elastic constants and moduli. Density of states and electronic localization function analysis show that the strong C-N covalent bond in CN4 tetrahedron is the main driving force for the high bulk and shear moduli as well as small Poisson's ratio of C2N2(NH). 相似文献
930.
O. B. Kazakova é. F. Khusnutdiniva K. Yu. Suponitskii 《Journal of Structural Chemistry》2011,52(5):1030-1032
The molecular and crystal structure of methyl 1-isopropenyl-5a,5b,8,8,14a-pentamethyl-1,2,3,3a,4,5,5a,5b, 6,7,7a,8,9,14,14a,14b,15,16,16a,16b-icosahydrocyclopenta[7,8]phenenthro[2,1-b]carbazole-3a-carboxylate is determined. Compound C37H51NO2
II crystallizes in the C2 chiral space group: a = 27.0380(5) ?, b = 7.9817(15) ?, c = 18.1980(3) ?, β = 123.580(3)°. 相似文献