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91.
本文应用取代基效应(SCS)方法研究了乙烯-乙烯醇(EVA)共聚物,得到了羟基(-OH)在两种不同溶剂中的SCS参数:在苯酚+重水(80/20W/W)中参数为S_1=42.77±0.08ppm,S_2=7.155±0.06ppm,S_3(s)=-4.08±0.02ppm,S_3(t)=-3.09±0.02ppm,S_4=0.48±0.03ppm,S_5=0.26±0.05ppm,在以邻二氯苯为溶剂时参数为S_1=44.97±0.61ppm,S_2=7.40±0.00ppm,S_3(s)=-4.51±0.17ppm,S_3(t)=-3.13±0.00ppm,S_4=0.63±0.04ppm,S_5=0.36±0.00ppm,同时利用所得到的SCS参数对该共聚物的~(13)C NMR谱进行了归属。 相似文献
92.
We have upgraded a Self-consistent-field – Hartree–Fock routine to include a finite nuclear mass correction for molecules developed in our laboratory. The new routine can handle isotopomers without calculating any nuclear kinetic energy matrix element. Tests on H2, LiH, HF, F2, and H2O isotopomers indicate the equivalence of our correction to the standard diagonal adiabatic correction. A further original application to C2H6 illustrates the usefulness of the method for polyatomic molecules. The resulting molecular orbitals carry the nuclear mass signature, exemplified with Koopmans ionization potentials.From the Proceedings of the 28th Congreso de Químicos Teóricos de Expresión Latina (QUITEL 2002) 相似文献
93.
Masaaki?HanedaEmail author Isao?Nakamura Tadahiro?Fujitani Hideaki?Hamada 《Catalysis Surveys from Asia》2005,9(4):207-215
Comprehensive studies combining surface science and real catalyst were performed to get further insight into catalytic active
site and reaction mechanism for NO decomposition over supported palladium and cobalt oxide-based catalysts. On palladium single-crystal
model catalysts, adsorption, dissociation and desorption behavior of NO was found to be closely related to the surface structures,
the stepped surface palladium being active for dissociation of NO. In accordance with this result, the activity of powder
Pd/Al2O3 catalysts for NO decomposition was directly related to the number of step sites exposed on the surface, suggesting that the
step sites act as the catalytic active site for NO decomposition on Pd/Al2O3. NO decomposition over cobalt oxide was found to be significantly promoted by addition of alkali metals. Surface science
study and catalyst characterization led to the same conclusion that the interface between the alkali metal and Co3O4 serves as the catalytic active site. From the results of in situ Fourier transform infrared (FT-IR) spectroscopy and isotopic transient kinetic analysis, a reaction mechanism was proposed
in which the reaction is initiated by NO adsorption onto alkali metals to form NO2− species and then NO2− species react with the adsorbed NO species to form N2 over the interface between the alkali metal and Co3O4. 相似文献
94.
A class of extended 2,5‐disubstituted‐1,3,4‐oxadiazoles R1‐C6H4‐{OC2N2}‐C6H4‐R2 (R1=R2=C10H21O 1 a , p‐C10H21O‐C6H4‐C?C 3 a , p‐CH3O‐C6H4‐C?C 3 b ; R1=C10H21O, R2=CH3O 1 b , (CH3)2N 1 c ; F 1 d ; R1=C10H21O‐C6H4‐C?C, R2=C10H21O 2 a , CH3O 2 b , (CH3)2N 2 c , F 2 d ) were prepared, and their liquid‐crystalline properties were examined. In CH2Cl2 solution, these compounds displayed a room‐temperature emission with λmax at 340–471 nm and quantum yields of 0.73–0.97. Compounds 1 d , 2 a – 2 d , and 3 a exhibited various thermotropic mesophases (monotropic, enantiotropic nematic/smectic), which were examined by polarized‐light optical microscopy and differential scanning calorimetry. Structure determination by a direct‐space approach using simulated annealing or parallel tempering of the powder X‐ray diffraction data revealed distinctive crystal‐packing arrangements for mesogenic molecules 2 b and 3 a , leading to different nematic mesophase behavior, with 2 b being monotropic and 3 a enantiotropic in the narrow temperature range of 200–210 °C. The structural transitions associated with these crystalline solids and their mesophases were studied by variable‐temperature X‐ray diffractometry. Nondestructive phase transitions (crystal‐to‐crystal, crystal‐to‐mesophase, mesophase‐to‐liquid) were observed in the diffractograms of 1 b, 1 d , 2 b, 2 d , and 3 a measured at 25–200 °C. Powder X‐ray diffraction and small‐angle X‐ray scattering data revealed that the structure of the annealed solid residue 2 b reverted to its original crystal/molecular packing when the isotropic liquid was cooled to room temperature. Structure–property relationships within these mesomorphic solids are discussed in the context of their molecular structures and intermolecular interactions. 相似文献
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97.
Toshio Nishi Hideyuki Nukaga So Fujinami Ken Nakajima 《高分子科学》2007,(1):35-41
Atomic force microscopy (AFM) has the advantage of obtaining mechanical properties as well as topographic information at the same time. By analyzing force-distance curves measured over two-dimensional area using Hertzian contact mechanics, Young's modulus mapping was obtained with nanometer-scale resolution. Furthermore, the sample deformation by the force exerted was also estimated from the force-distance curve analyses. We could thus reconstruct a real topographic image by incorporating apparent topographic image with deformation image. We applied this method to carbon black reinforced natural rubber to obtain Young's modulus distribution image together with reconstructed real topographic image. Then we were able to recognize three regions; rubber matrix, carbon black (or bound rubber) and intermediate regions. Though the existence of these regions had been investigated by pulsed nuclear magnetic resonance, this paper would be the first to report on the quantitative evaluation of the interfacial region in real space. 相似文献
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On Chalcogenolates. 206. N-Thioacetyl Dithiocarbamates and Esters of N-Thioacetyl Dithiocarbamic Acid Thioacetamide reacts with carbon disulfide in the presence of KH to form via the tetrabutyl ammonium salt dark yellow N-thioacetyl dithiocarbamates M[S2C? NH? CS? CH3], where M = K, Rb, Cs. The salts as well as the methyl and ethyl ester have been characterized by means of electron absorption, infrared, nuclear magnetic resonance (1H and 13C), and mass spectra. Attempts to synthesize N-thioacetyl dithiocarbamic acid were not successful. 相似文献