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891.
The objective of this study was to use synchrotron light sourced FTIR microspectroscopy as a novel approach to characterize protein molecular structure of plant tissue: compared yellow and brown Brassica canola seed within cellular dimensions. Differences in the molecular chemistry and the structural-chemical characteristics were identified between two type of plant tissues. The yellow canola seeds contained a relatively lower (P < 0.05) percentage of model-fitted -helices (33 vs. 37), a higher (P < 0.05) relative percentage of model-fitted β-sheets (27 vs. 21) and a lower (P < 0.05) ratio of -helices to β-sheets (1.3 vs. 1.9) than the brown seeds. These results may indicate that the protein value of the yellow canola seeds as food or feed was different from that of the brown canola seeds. The cluster analysis and principal component analysis did not show clear differences between the yellow and brown canola seed tissues in terms of protein amide I structures, indicating they are related to each other. Both yellow and brown canola seeds contain the same proteins but in different ratios. 相似文献
892.
Martin Krger 《Physics Reports》2004,390(6):2311-551
893.
Anton M. Krivtsov 《Meccanica》2003,38(1):61-70
Technique for creation of polycrystalline computer materials is presented. The method considered allows for the obtaining of not only polycrystalline particle packings with various grains sizes but also the creating of materials with the preset value of porosity. Plate impact experiments were performed to compare strength properties of mono- and polycrystalline computer materials and also to investigate influence of the material porosity on the shock wave penetration and spallation processes. The experiments show significant differences in the impact fracture processes between mono- and polycrystalline materials. Smearing the shock waves due to heterogeneity of the granular structure of the polycrystals decreases localization effects, and the fracture occupies larger areas but with the smaller level of injury. Porosity adds significant resistance due to the strong plastic deformation during the pore collapsing. This effect can strongly decrease the penetration distance of the shock wave and even prevent the spallation. 相似文献
894.
Ferrocene-terminated trans-Ru(dppm)2 (dppm=Ph2PCH2pph2)-containing molecular wires with alligator clips were prepared.They are suitable for self-assembly on gold electrode to investigate the influence of metal incorporation on the electron transportation property of the molecular wires. 相似文献
895.
The structure of ultrathin Mo films on SrTiO3(1 0 0) was studied by in situ reflection high-energy electron diffraction (RHEED). A different structure was observed for films less than 20 Å thick than for thicker films. These films were epitaxial and had a metastable structure. Thicker films had the dimensions of equilibrium bcc Mo(1 1 0). Relaxation processes transformed the metastable Mo into bcc Mo, resulting in the following orientation relationships between Mo and SrTiO3: (1 1 0)[0 0 1]bcc Mo ∥ (1 0 0)[0 0 1]SrTiO3 and (1 1 0)[1 1 1]bcc Mo ∥ (1 0 0)[0 1 1]SrTiO3. The formation of such specific orientations is related to transformations via the Bain and Needle Path, respectively. 相似文献
896.
Makoto Kudo Tomoyoshi Mishima Satoshi Iwamoto Toshihiro Nakaoka Yasuhiko Arakawa 《Physica E: Low-dimensional Systems and Nanostructures》2004,21(2-4):275
Self-assembled GaSb quantum dots (QDs) with a photoluminescence wavelength longer than 1.3 μm were successfully grown by suppressing the replacement of As and Sb on the surface of the GaSb QDs. This result means that GaSb can thus join InAs or GaInAs as a suitable material for QD lasers for optical communications. 相似文献
897.
The rotational spectrum of methyl phosphonic difluoride has been reinvestigated using a pulsed-molecular-beam Fabry-Perot cavity microwave spectrometer. The enhanced resolution of the Fourier transform microwave (FTMW) spectrometer (compared to the original work done in a conventional Stark spectrometer) has allowed the measurement of small A-E splittings of many of the rotational transitions caused by the internal rotation of the methyl top. The barrier to internal rotation, V3 = 676 (25) cm−1, has been determined experimentally from the A-E splittings of the rotational transitions in the ground vibrational state. This barrier height is substantially lower than the previously determined value for the barrier, which was 1252 (14) cm−1. High-level ab initio calculations at the MP2/aug-cc-pVTZ level predict a barrier to internal rotation of 638 cm−1, in agreement with the experimentally determined value found here. The high sensitivity of the FTMW spectrometer has also permitted the measurement of the 13C and 18O isotopomers in natural abundance. The addition of these two isotopomers has allowed an improved structural determination. 相似文献
898.
对50 000个金属Al原子从液态急冷形成非晶态结构的过程进行了分子动力学模拟研究.采用原子键型和原子团簇类型指数法,发现在其微观结构的转变过程中,与不断增加的1551键型密切相关的二十面体及其缺陷结构的形成起了非常突出的作用.通过各种键型原子团簇的计算,获得团簇多面体结构的分布数据.在可视化的显示下,得到一幅十分清晰的关于团簇多面体结构的特征及其演变的图景.建立了一种简单而有效的团簇多面体结构研究方法.同时也对模拟计算结果的微观机理给出了相应的讨论,这对于深入理解非晶态结构的形成机制及其微观过程,将有重 相似文献
899.
900.
The calculation of the molecular electrostatic potential from simplified models of the electron density is considered. Results are shown for water, hydrogen fluoride and ammonia. Little loss of accuracy is evident when the density is represented by a linear sum of well-chosen Gaussians. When these are further simplified into sets of point charges the inner parts of the molecule are poorly represented. More elaborate point moments make the representation worse. On the other hand a mixed representation with point charges and one diffuse Gaussian gives all the essential features of the potential of these molecules. 相似文献