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151.
针对大口径离轴凸非球面面形检测的困难,本文将光学系统波像差检验技术与子孔径拼接干涉技术相结合,提出了凸非球面系统拼接检测方法。对该方法的基本原理和具体实现过程进行了分析和研究,并建立了合理的子孔径拼接数学模型。当离轴三反光学系统的主镜和三镜加工完成以后,对整个系统进行装调和测试,并依次测定光学系统各视场的波像差分布,通过综合优化子孔径拼接算法和全口径面形数据插值可以求解得到大口径非球面全口径的面形信息,从而为非球面后续加工和系统的装调提供了依据和保障。结合工程实例,对一口径为287 mm×115 mm的离轴非球面次镜进行了系统拼接测试和加工,经过两个周期的加工和测试,其面形分布的RMS值接近1/30λ(λ=632.8 nm)。 相似文献
152.
Z. P. Niu Z. M. Zheng D. Y. Xing 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,60(3):281-287
Four-component Bogoliubov-de Gennes equations are applied to study
tunneling conductance spectra of ferromagnet/ferromagnet/d-wave
superconductor (F1/F2/d-wave S) tunnel junctions and to find
out signs of spin-triplet pairing correlations induced in the
proximity structure. The pairing correlations with equal spins
arises from the novel Andreev reflection (AR), which requires at
least three factors: the usual AR at the F2/S interface, spin
flip in the F2 layer, and superconducting coherence kept up in
the F2 layer. Effects of angle α between magnetizations of
the two F layers, polarizations of the F1 and F2 layers, the
thickness of the F2 layer, and the orientation of the d-wave S crystal on the tunneling conductance are investigated. A conversion
from a zero-bias conductance dip at α = 0 to a zero-bias
conductance peak at a certain value of α can be seen as a
sign of generated spin-triplet correlations. 相似文献
153.
Numerical analysis for the mixed Navier–Stokes and Darcy Problem with the Beavers–Joseph interface condition
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In this article, we consider the coupled Navier–Stokes and Darcy problem with the Beavers–Joseph interface condition. With suitable restrictions of physical parameters α and ν, we prove the existence and local uniqueness of a weak solution. Then we propose a coupled finite element scheme and a decoupled and linearized scheme based on two‐grid finite element. Under suitable further restrictions, their optimal error estimates are obtained. Finally numerical experiments indicate the validity of the theoretical results as well as the efficiency and effectiveness of the decoupled and linearized two‐grid algorithm. © 2014 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 31: 1009–1030, 2015 相似文献
154.
155.
《Journal of Saudi Chemical Society》2014,18(5):432-436
The compound 2-{5-[2-(2,6-dichlorophenylamino)benzyl]-4-p-tolyl-4H-1,2,4-triazol-3-ylthio}acetate has been prepared and characterized by IR, 1H NMR, 13C NMR and mass spectra. The crystal and molecular structure were further confirmed using single crystal X-ray diffraction. The crystal structure has been found to be stabilized by intermolecular C–H···O interaction generating bifurcated hydrogen bonds whereas the C–H···N interactions generate chain of molecules. The intramolecular N–H···N hydrogen bond forms a ring with S(7) graph-set motif. 相似文献
156.
Probing the CH⋅⋅⋅π Weak Hydrogen Bond in Anesthetic Binding: The Sevoflurane–Benzene Cluster
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Nathan A. Seifert Dr. Daniel P. Zaleski Dr. Cristóbal Pérez Dr. Justin L. Neill Prof. Brooks H. Pate Montserrat Vallejo‐López Prof. Alberto Lesarri Dr. Emilio J. Cocinero Prof. Fernando Castaño Prof. Isabelle Kleiner 《Angewandte Chemie (International ed. in English)》2014,53(12):3210-3213
Cooperativity between weak hydrogen bonds can be revealed in molecular clusters isolated in the gas phase. Here we examine the structure, internal dynamics, and origin of the weak intermolecular forces between sevoflurane and a benzene molecule, using multi‐isotopic broadband rotational spectra. This heterodimer is held together by a primary C? H???π hydrogen bond, assisted by multiple weak C? H???F interactions. The multiple nonbonding forces hinder the internal rotation of benzene around the isopropyl C? H bond in sevoflurane, producing detectable quantum tunneling effects in the rotational spectrum. 相似文献
157.
Juanxia Kang Yongcheng Wang Jingjing Wu Zhiming Zhu 《International journal of quantum chemistry》2020,120(5):e26109
In order to further explore the detailed reaction mechanism of carbon dioxide activated by [Re(CO)2]+ complex, CCSD(T) methods was performed to determine related potential energy surface (PES). Crossing point is determined by using a partially optimized method. The result shows that larger spin-orbital coupling (155.37 cm−1) and intersystem crossing probabilities in spin-forbidden region causes the electron to spin flip at the minimum energy crossing point and access to the lower singlet PES. Nonadiabatic rate constant k is estimated to be quite rapid, so transition state (1TS1) is rate-controlled steps. In addition, the electronic structure of oxygen-atom transfer process is further analyzed by localized molecular orbital and Mayer bond order. The analysis finds that the form of main bonding orbital is the electron contribution from the p(O) in CO2 to the empty d(Re) orbital. 相似文献
158.
Xuefang Liu Chen Yang Feifang Zhang Huiliang Geng Bingcheng Yang 《Journal of separation science》2020,43(8):1474-1478
A novel weak cation exchanger is described by encapsulating silica with a (or multiple) layer(s) of maleic anhydride–modified polyvinyl alcohol coating(s). The preparation method is facile and fast, which is simply performed by dipping silica particles into maleic anhydride–modified polyvinyl alcohol solution as‐synthesized, then filtering and curing thermally, and finally generating a thin coating onto silica particles. Multiple layers of maleic anhydride–modified polyvinyl alcohol coatings can be generated by repeating above steps, offering an easy way to manipulate the capacity. The obtained weak cation exchanger demonstrated high separation efficiency and good selectivity toward common inorganic cations, for example, high plate count of 81 000 per meter was obtained for NH4+. Simultaneous separation of alkali and alkaline earth metals could be achieved within 14 min under isocratic conditions. 相似文献
159.
吴惠仙 《高校应用数学学报(A辑)》2006,21(3):373-376
P.F.Sm ith曾提出一个公开问题:弱CS模的直和项是否为弱CS模?论文通过一个反例证明了弱CS模的直和项不一定是弱CS模.但满足条件C3的弱CS模对其直和项具有遗传性.最后讨论了弱CS模对一般子模的遗传性. 相似文献
160.