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111.
112.
The palladium‐catalyzed reaction of acid anhydrides with silacyclobutane gives a mixture of cyclic silyl enol ether, carboxy(propyl)silane, and 3‐(carboxysilyl)ketone. In the presence of N,N‐dicyclohexylcarbodiimido (DCC), the reaction preferentially provides a cyclic silyl enol ether in a good yield. In addition, the palladium‐catalyzed reaction of benzoic acid with silacyclobutane in the presence of two equivalents of DCC also affords a cyclic silyl enol ether in a moderate yield. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
113.
Masafumi Yano Yorichika Okino Yuji Ichihara Masakazu Tatsumi Munetaka Oyama Kazunobu Sato Takeji Takui 《Polyhedron》2009,28(9-10):1764-1767
Three highly π-extended tetraaryl-1,3-phenylenediamines for charged high-spin molecular systems were successfully synthesized using Suzuki coupling. Their electrochemical and spectroscopic properties were also examined. They showed blue fluorescence. The dications derived from highly π-extended tetraaryl-1,3-phenylenediamines were generated and characterized by electron transfer stopped-flow method. 相似文献
114.
115.
Kazuhiro Kobayashi Sunyoung Kim Masakazu Kojima 《Applied Mathematics and Optimization》2008,58(1):69-88
Exploiting sparsity has been a key issue in solving large-scale optimization problems. The most time-consuming part of primal-dual
interior-point methods for linear programs, second-order cone programs, and semidefinite programs is solving the Schur complement
equation at each iteration, usually by the Cholesky factorization. The computational efficiency is greatly affected by the
sparsity of the coefficient matrix of the equation which is determined by the sparsity of an optimization problem (linear
program, semidefinite program or second-order cone program). We show if an optimization problem is correlatively sparse, then the coefficient matrix of the Schur complement equation inherits the sparsity, and a sparse Cholesky factorization
applied to the matrix results in no fill-in.
S. Kim’s research was supported by Kosef R01-2005-000-10271-0 and KRF-2006-312-C00062. 相似文献
116.
117.
Kondo M Mates TE Fischer DA Wudl F Kramer EJ 《Langmuir : the ACS journal of surfaces and colloids》2010,26(22):17000-17012
Interfaces between phenylacetylene (PA) monolayers and two silicon surfaces, Si(111) and Si(100), are probed by X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, and the results are analyzed using ab initio molecular orbital calculations. The monolayer systems are prepared via the surface hydrosilylation reaction between PA and hydrogen-terminated silicon surfaces. The following spectral features are obtained for both of the PA-Si(111) and PA-Si(100) systems: a broad π-π* shakeup peak at 292 eV (XPS), a broad first ionization peak at 3.8 eV (UPS), and a low-energy C 1s → π* resonance peak at 284.3 eV (NEXAFS). These findings are ascribed to a styrene-like π-conjugated molecular structure at the PA-Si interface by comparing the experimental data with theoretical analysis results. A conclusion is drawn that the vinyl group can keep its π-conjugation character on the hydrogen-terminated Si(100) [H:Si(100)] surface composed of the dihydride (SiH(2)) groups as well as on hydrogen-terminated Si(111) having the monohydride (SiH) group. The formation mechanism of the PA-Si(100) interface is investigated within cluster ab initio calculations, and the possible structure of the H:Si(100) surface is discussed based on available data. 相似文献
118.
Wenjiao Wang Jinlong Zhang Feng Chen Masakazu Anpo Dannong He 《Research on Chemical Intermediates》2010,36(2):163-172
Ag nanoparticles encapsulated by TiO2 shells have the ability to catalyze redox reactions on their surface. By continually monitoring by use of UV–visible spectroscopy
it was found that the surface charge of both TiO2-coated and uncoated colloidal silver particles changed after chemical electron injection. The charging and discharging process
of Ag@TiO2 vary, depending on the different Ag content of the core–shell nanoparticles. In order to enhance the stability of Ag@TiO2 colloids, Fe3+ was doped into the lattice of the TiO2 shells. The experimental results showed that the Fe3+ ions have the capacity to store and transfer electrons. Furthermore, the charging and discharging rate can be controlled
by changing the thickness of the TiO2 shells, because they are limited by the diffusion distance of electrons through the TiO2 shells. 相似文献
119.
Kensuke Okusa Yuki Suita Yukio Otsuka Mineo Tahara Tohru Ikegami Nobuo Tanaka Masayoshi Ohira Masakazu Takahashi 《Journal of separation science》2010,33(3):348-358
The effectiveness of several basic compounds for testing silica‐based stationary phases was reviewed by applying them to recent columns for reversed‐phase HPLC. Most octadecylsilylated (C18) stationary phases, prepared as a base‐deactivated material from high‐purity silica gel with endcapping, provided excellent peak shape and column efficiency for the bases including benzylamine and amitriptyline that once caused problems and were subsequently employed for testing silanol activities. However, a cyclic tertiary amine, dextrometorphan, was eluted as an acceptable peak from only a few columns at neutral pH. Such a more sensitive probe is expected to contribute to further improvement of the stationary phase for reversed‐phase HPLC. 相似文献
120.
Kanyiva KS Kashihara N Nakao Y Hiyama T Ohashi M Ogoshi S 《Dalton transactions (Cambridge, England : 2003)》2010,39(43):10483-10494
A combination of Ni(cod)(2) and PCyp(3) is found to be an effective catalyst for chemoselective activation of the C-H bond of fluoroarenes over C-F bonds followed by insertion of alkynes to allow direct alkenylation of the electron-deficient arenes. The characteristics of the reactions are: a C-H bond ortho to a fluorine substituent is selectively activated; the reactivity of fluorobenzenes is roughly proportional to the number of fluorine atoms. The reaction conditions tolerate a broad range of both alkynes and fluoroarenes containing both electron-withdrawing and -donating groups, thus allowing efficient synthesis of a variety of substituted ethenes containing a fluoroaryl motif in high regio- and stereoselective manners. Mechanistic studies including both labeling experiments and stoichiometric reactions reveal that oxidative addition of C-H bonds in fluoroarenes to nickel(0) is kinetically highly facile whereas that of C-F bonds is thermodynamically favoured. 相似文献