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181.
Photon-stimulated ion desorption from deuterated formic acid chemisorbed on Si(100) has been studied using pulsed synchrotron radiation in the energy region of the oxygen 1s electron excitation. The O 1s electrons of hydroxyl oxygen and carbonyl oxygen could be selectively excited in the O K-edge region because the chemical environments are different. It is found that the CDO+ yield is enhanced at the O 1s(C---O)→σ*(C---O) resonance and the CD+ yield at the O 1s(C=O)→σ*(C---O) resonance. The results indicate that ion desorption is related both to the antibonding character of excited molecular orbitals and the local character of core hole orbitals. 相似文献
182.
183.
Katagiri S Watanabe Y Yaoita Y Kikuchi M Machida K 《Natural product communications》2011,6(12):1901-1904
Two new glycosides, named dideoxyplicatumoside A (1) and erythro-syringylglycerol-beta-O-4'-(+)-isoeucommin A 4'-O-beta-D-glucopyranoside (2), together with seven known compounds, were isolated from the leaves of Viburnum plicatum Thunb. ex Murray var. plicatum f. plicatum. Their structures were established on the basis of NMR, MS and chemical data. 相似文献
184.
Shunsuke Katagiri Dr. Ryota Sakamoto Hiroaki Maeda Dr. Yoshihiko Nishimori Tomochika Kurita Prof. Dr. Hiroshi Nishihara 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(16):5088-5096
This article completes our comprehensive understanding of the electron transport properties of our original π‐conjugated redox‐active molecular wires comprising Fe bridged by p‐phenylene linkers (tpy=2,2′:6′,2′′‐terpyridine). The Fe(tpy)2 oligomer wires comprise three types of tpy ligands: the anchor tpy ligand ( A series) makes a junction between the wire and electrode, the bridging bis‐tpy ligand ( L series) connects the Fe(tpy)2 units, and the terminal tpy ligand ( T series) possesses a redox site as a probe for the long‐range electron transport ability. Taking advantage of the precise tunability of the composition of the Fe(tpy)2 oligomer wires, thus far we investigated how A and L impacted on the electron‐transport ability. The excellent long‐range electron transport ability with ultrasmall attenuation constants (βd, 0.002 Å?1 as the minimum) depends on L significantly [Chem. Asian J. 2009 , 4, 1361], whereas A is unrelated to the βd value, but influences the zero‐distance electron‐transfer rate constant, ket0 [J. Am. Chem. Soc. 2010 , 132, 4524]. Herein we study the influence of terminal ligand T x (x=1–3). βd is independent of T , however, T3 , with a cyclometallated Ru complex as the redox site, gives rise to a ket0 value greater than T1 and T2 with ferrocene. This series of simple but definitive conclusions indicates that we have reached the stage of being able to precisely design molecular wires to attain desirable single‐molecule electron conduction. 相似文献
185.
(pi-Allyl)palladium triflate bearing a 1,2-bis(4-methoxyphenyl)-3,4-bis(2,4,6-tri-tert-butylphenylphosphinidene)cyclobutene ligand (DPCB-OMe), [Pd(eta(3)-C(3)H(5))(DPCB-OMe)]OTf, efficiently catalyzes deallylation of a variety of allyl ethers in aniline to give corresponding alcohols in high yields under mild conditions. The reactions can be performed in air without loss of a variety of functionalities including vinyl, alkynyl, hydroxy, acetoxy, silyloxy, and acetal groups. Allyl 2-allyloxybenzoate selectively undergoes deallylation of the allyloxy group to give allyl salicylate in quantitative yield. 相似文献
186.
Kazuyoshi Tanaka Hiromi Kobayashi Mayumi Okada Masahiro Kobashi Tokio Yamabe 《International journal of quantum chemistry》1992,42(1):45-54
Electronic-phase transition associated with the singlet instability problem of the Hartree-Fock solution of the extended system is studied employing the metallic trans-polyacetylene. Concerning the eigenstates of the stability matrix set up for the crystal orbitals at the Fermi level, classification of the electronic phases is attempted and the origin of their emergence in relation to the interelectronic interaction is discussed. 相似文献
187.
Kataoka-Hamai C Inoue H Miyahara Y 《Langmuir : the ACS journal of surfaces and colloids》2008,24(17):9916-9920
We describe an electronic detection method for charged lipid bilayers supported on a Si 3N 4/SiO 2/Si substrate. The flat-band voltage was used to monitor the charge of the bilayers. We show that the flat-band voltage varies with lipid adsorption depending on the polarity and mole ratio of the charged lipids, the salt concentration, and the surface coverage. Cationic and anionic bilayers produced a decrease and an increase in the flat-band voltage, respectively. The voltage change increased as the percentage of charged lipid components was elevated in the planar bilayers with full surface coverage. In addition, the voltage variation increased when the salt concentration was decreased or when the surface coverage of planar bilayer patches was increased. These results demonstrate that charged bilayers can be detected from the field effect that they exert on a solid support. 相似文献
188.
A two‐level hierarchical parallelization scheme including the second‐order Møller–Plesset perturbation (MP2) theory in the divide‐and‐conquer method is presented. The scheme is a combination of coarse‐grain parallelization assigning each subsystem to a group of processors, with fine‐grain parallelization, where the computational tasks for evaluating MP2 correlation energy of the assigned subsystem are distributed among processors in the group. Test calculations demonstrate that the present scheme shows high parallel efficiency and makes MP2 calculations practical for very large molecules. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011 相似文献
189.
190.
Hiroshi Katagiri Masao Morimoto Kenichi Sakai 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(7):o357-o360
The structures of diastereomeric pairs consisting of (S)‐ and (R)‐2‐methylpiperazine with (2S,3S)‐tartaric acid are both 1:1 salts, namely (S)‐2‐methylpiperazinium (2S,3S)‐tartrate dihydrate, C5H14N22+·C4H4O62−·2H2O, (I), and (R)‐2‐methylpiperazinium (2S,3S)‐tartrate dihydrate, C5H14N22+·C4H4O62−·2H2O, (II), which reveal the formation of well defined ammonium carboxylate salts linked via strong intermolecular hydrogen bonds. Unlike the situation in the more soluble salt (II), the alternating columns of tartrate and ammonium ions of the less soluble salt (I) are packed neatly in a grid around the a axis, which incorporates water molecules at regular intervals. The increased efficiency of packing for (I) is evident in its lower `packing coefficient', and the hydrogen‐bond contribution is stronger in the more soluble salt (II). 相似文献