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991.
使用草酸盐共沉淀法合成了LiNi0.5Mn0.5O2, 并研究了共沉淀时的pH条件对终产物的结构、形貌及电化学性能的影响. 采用X射线衍射(XRD)和扫描电镜(SEM)表征了在pH值为4.0、5.5、7.0和8.5时得到的共沉淀和终产物LiNi0.5Mn0.5O2的结构和形貌. 使用充放电实验研究了不同pH条件下得到的LiNi0.5Mn0.5O2的电化学性能. 结果表明, pH为7.0时, 合成的材料颗粒更小、分布最均匀, 材料具有良好的层状特征, 且材料中锂镍的混排程度最小. 电化学测试结果印证了pH为7.0时合成的材料具有更好的电化学性能, 在0.1C的倍率下, 材料的首次放电比容量达到了185 mAh·g-1, 在循环20周后, 放电比容量仍然保持在160 mAh·g-1. X射线光电子能谱(XPS)测试结果表明, pH为7.0时合成的LiNi0.5Mn0.5O2中Ni为+2价, Mn为+4价. 相似文献
992.
B. Simons 《Crystal Research and Technology》2010,45(2):124-132
Thermodynamic parameters of melts (ΔHS, A0, A1) in the system Anorthite‐Diopside and Bi2O3‐Bi4B2O9 have been calculated by a rigorous application of solution thermodynamics. The data are internally consistent and yield values of ΔHS for Anorthite = 133 kJ/mole, Diopside = 81 kJ/mole, Bi2O3 = 19 kJ/mole and Bi4B2O9 = 39 kJ/mole. The activity of Anorthite and Diopside in an anorhtitic melt deviates negative from ideality, whereas a diopsidic melt behaves almost ideal. In a “Bi2O3” melt the activity of the Bi2O3 component is strongly positive, that of Bi4B2O9 is strongly negative. The opposite is observed for the “Bi4B2O9” melt. All calculated liquidi except the Bi4B2O9 liquidus closely match the experimental ones. In contrast to the experimental liquidus the calculated Bi4B2O9 liquidus has an inflection point. The crest of the metastable spinode (solvus) for a “Bi2O3” melt is close to the liquidus indicating melt separation at undercooling. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
993.
采用傅里叶变换红外光谱仪记录了富含15N216O同位素的一氧化二氮样品在1650-3450 cm-1波段的高分辨振转光谱,得到了该同位素分子超过7300吸收谱线位置的实验值,经分析实验精确度好于5.0×10-4 cm-1. 基于有效哈密顿量模型预测和带带转动分析,确定了所有吸收线的归属;获得了29个新吸收带的振转光谱参数,并优化了其他44个吸收带的光谱参数值. 并且发现有效哈 相似文献
994.
995.
Robert A. Toth 《Journal of Molecular Spectroscopy》2011,265(2):59-68
The necessity to revisit water spectroscopy at 6 μm was prompted by recent work indicating that some prior measurements of H216O line strengths (ranging through seven orders of magnitude) had larger than expected systematic errors for the stronger transitions. To investigate this, linestrengths of stronger transitions were re-measured (with 14 new H2O spectra recorded with a Bruker 125 HR Fourier transform spectrometer at the Jet Propulsion Laboratory) and combined with re-analyzed prior results (obtained at higher optical densities from 32 spectra recorded with the FTS at Kitt Peak). Systematic differences for some of the older data sets were identified and corrected. In this paper, an internally-consistent sampling of 1243 selected line strengths are reported for (0 1 0)-(0 0 0) and (0 2 0)-(0 1 0) transitions between 783 and 2378 cm−1. To confirm experimental precisions, observed and calculated line strengths are compared. 相似文献
996.
The absorption spectrum of water vapor has been investigated by Intracavity Laser Absorption Spectroscopy (ICLAS) between 13 540 and 14 070 cm−1. This spectrum is dominated by relatively strong transitions of the 4δ polyad of vibrational states. The achieved sensitivity - on the order of αmin ∼ 10−9 cm−1 - has allowed one to newly measure 222 very weak transitions with intensities down to 5 × 10−28 cm/molecule at 296 K. Fifty new or corrected H216O energy levels belonging to a total of 13 vibrational states could be determined from the rovibrational analysis based on variational calculations by Schwenke and Partridge. The previous investigations in the region by Fourier Transform Spectroscopy were critically evaluated and used to construct the best to date set of energy levels accessed by transitions in the considered region. All the rovibrational transitions reaching these upper energy levels and having intensities larger than 4.0 × 10−28 cm/mol were calculated. In the resulting line list, the positions at the level of experimental accuracy were augmented with variational intensities leading to the most complete line list for water in normal isotopic abundance in the 13 500-14 100 cm−1 region. 相似文献
997.
A chirped pulse microwave spectrometer has been used to record microwave spectra of the 35Cl and 37Cl isotopologues of methyl chlorodifluoroacetate, CClF2C(O)OCH3, between 8 GHz and 16 GHz. The target compound was spectroscopically examined as it participated in a supersonic expansion of argon. Only one conformer was observed. The rotational spectra were recorded with sufficient resolution to observe (i) splittings due to the internal rotation of the methyl group, and (ii) splittings from the coupling of the chlorine quadrupolar nucleus. A total of 785 transitions have had quantum numbers assigned. Analysis of the spectra observed has produced an experimental barrier to the methyl group internal rotation, V3, of 370(2) cm−1. It is noted that this barrier is a little lower than that determined for methyl acetate [V3 = 425 cm−1, J. Sheridan, W. Bossert and A. Bauder, J. Mol. Spectrosc., 80 (1980) 1-11], and this is rationalized through a comparison of molecular structures. Lastly, all components of both the 35Cl and 37Cl chlorine nuclear electric quadrupolar coupling tensor have been determined. 相似文献
998.
Rui Zheng 《Journal of Molecular Spectroscopy》2011,265(2):102-105
The rovibrational spectrum of the N2-N2O van der Waals complex has been recorded in the N2O ν1 region (∼1285 cm−1) using a tunable diode laser spectrometer to probe a pulsed supersonic slit jet. The observed transitions together with the data observed previously in the N2O ν3 region are analyzed using a Watson S-reduced asymmetric rotor Hamiltonian. The rotational and centrifugal distortion constants for the ground and excited vibrational states are accurately determined. The band-origin of the spectrum is determined to be 1285.73964(14) cm−1. A restricted two-dimensional intermolecular potential energy surface for a planar structure of N2-N2O has been calculated at the CCSD(T) level of theory with the aug-cc-pVDZ basis sets and a set of mid-bond functions. With the intermolecular distance fixed at the ground state value R = 3.6926 Å, the potential has a global minimum with a well depth of 326.64 cm−1 at θN2 = 11.0° and θN2O = 84.3° and has a saddle point with a barrier height of 204.61 cm−1 at θN2 = 97.4° and θN2O = 92.2°, where θN2(θN2O) is the enclosed angle between the N-N axis (N-N-O axis) and the intermolecular axis. 相似文献
999.
采用高温固相法制备了荧光粉Y2-x(W,Mo)O6:Eu3+,xLi+,利用X射线衍射仪和电子扫描显微镜对样品的结构和形貌进行了表征,并利用荧光光谱法分析了样品的光谱特性.首先在Y2WO6中掺入少量的Mo6+离子,掺入Mo6+后增加了原Y2WO6:Eu3+的激发光谱在近紫外光区的吸收,扩展了激发光谱的谱宽,但却使Y2W... 相似文献
1000.