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排序方式: 共有747条查询结果,搜索用时 15 毫秒
721.
Toshihiro Kuzuya Yasushi HamanakaKeiichi Itoh Takamitsu KinoKenji Sumiyama Yasuhiro FukunakaShinji Hirai 《Journal of colloid and interface science》2012,388(1):137-143
CuInS2 nanoparticles (NPs) usually take chalcopyrite-(CP) structure. Recently, CuInS2 NPs with pseudo-wurtzite (WZ) structure, which is thermodynamically less favored, have been synthesized. However, the formation mechanism of this metastable-phase has not been understood yet. In this report, the key issue of phase selectivity of CuInS2 (CIS) NPs has been investigated using various metal sources and ligands. Experimental results suggested that the crystalline structure and morphology of CIS NPs were decided by the stability of indium ligand complex; the active ligand reduces the precipitation rate of In2S3, resulting in pre-generation of Cu2S seed NPs. Crystallographic analogy and superionic conductivity of Cu2S remind us that the formation of WZ CIS NPs is attributed to the pre-generation of Cu2S seed NPs and the following cation exchange reaction. In order to confirm this hypothesis, Cu2-xS seed NPs with various structures have been annealed in indium-ligand solution. This experiment revealed that the crystalline structure of CIS NP was determined by that of pre-generation Cu2-xS NPs. Our results provide the important information for the phase control and synthesis of ternary chalcogenide NPs with a novel crystalline structure. 相似文献
722.
Antonio?De?Nicola Ying?Zhao Toshihiro?Kawakatsu Danilo?Roccatano Giuseppe?MilanoEmail author 《Theoretical chemistry accounts》2012,131(3):1167
In the framework of a recently developed scheme for a hybrid particle-field simulation technique where self-consistent field
theory and molecular dynamics simulation method are combined, specific coarse-grained models for aqueous solutions of phospholipids
have been validated. In particular, the transferability of the model in the correct reproduction of non-lamellar phases has
been validated against reference particle–particle simulations. By varying the water content, the proposed model is able to
correctly describe the different morphologies that are experimentally observed such as micelles and reverse micelles. The
lower computational costs of the hybrid techniques allow us to perform simulations of large-scale systems that are needed
to investigate the applications of self-assembled structures of lipids in nanotechnologies. 相似文献
723.
Y Funasako T Mochida K Takahashi T Sakurai H Ohta 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(38):11929-11936
Vapor- and gas-responsive ionic liquids (ILs) comprised of cationic metal-chelate complexes and bis(trifluoromethanesulfonyl)imide (Tf(2) N) have been prepared, namely, [Cu(acac)(BuMe(3) en)][Tf(2) N] (1?a), [Cu(Bu-acac)(BuMe(3) en)][Tf(2) N] (1?b), [Cu(C(12) -acac)(Me(4) en)][Tf(2) N] (1?c), [Cu(acac)(Me(4) en)][Tf(2) N] (1?d), and [Ni(acac)(BuMe(3) en)][Tf(2) N] (2?a) (acac=acetylacetonate, Bu-acac=3-butyl-2,4-pentanedionate, C(12) -acac=3-dodecyl-2,4-pentanedionate, BuMe(3) en=N-butyl-N,N',N'-tetramethylethylenediamine, and Me(4) en=N,N,N',N'-trimethylethylenediamine). These ILs exhibited reversible changes in color, thermal properties, and magnetic properties in response to organic vapors and gases. The Cu(II) -containing ILs are purple and turn blue-purple to green when exposed to organic vapors, such as acetonitrile, methanol, and DMSO, or ammonia gas. The color change is based on the coordination of the vapor molecules to the cation, and the resultant colors depend on the coordination strength (donor number, DN) of the vapor molecules. The vapor absorption caused changes in the melting points and viscosities, leading to alteration in the phase behaviors. The IL with a long alkyl chain (1?d) transitioned from a purple solid to a brown liquid at its melting point. The Ni(II) -containing IL (2?a) is a dark red diamagnetic liquid, which turned into a green paramagnetic liquid by absorbing vapors with high DN. Based on the equilibrium shift from four- to six-coordinated species, the liquid exhibited thermochromism and temperature-dependent magnetic susceptibility after absorbing methanol. 相似文献
724.
Evolved gas analysis?Cion-attachment mass spectrometry (EGA?CIAMS) indicates that Mn(CO)5 and Mn2(CO)9 free radicals are produced in the gas phase by pyrolysis of Mn2(CO)10 in an infrared image furnace. The Li+-adduct mass spectra of the pyrolysis products contained peaks at m/z 202 and 369 for Mn(CO)5Li+ and Mn2(CO)9Li+, respectively, providing direct evidence that d-metal complex radicals were formed in the furnace. We studied the effect of temperature on the rate of production of the radicals, and confirmed the presence of the compounds Mn(CO)5 and Mn2(CO)9, which were reported in earlier studies based on electron-impact mass spectrometry, electron spin resonance spectroscopy, and Fourier transform infrared spectroscopy. 相似文献
725.
Yusuke Funasako Prof. Dr. Tomoyuki Mochida Prof. Dr. Kazuyuki Takahashi Dr. Toshihiro Sakurai Dr. Hitoshi Ohta 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(38):11929-11936
Vapor‐ and gas‐responsive ionic liquids (ILs) comprised of cationic metal‐chelate complexes and bis(trifluoromethanesulfonyl)imide (Tf2N) have been prepared, namely, [Cu(acac)(BuMe3en)][Tf2N] ( 1 a ), [Cu(Bu‐acac)(BuMe3en)][Tf2N] ( 1 b ), [Cu(C12‐acac)(Me4en)][Tf2N] ( 1 c ), [Cu(acac)(Me4en)][Tf2N] ( 1 d ), and [Ni(acac)(BuMe3en)][Tf2N] ( 2 a ) (acac=acetylacetonate, Bu‐acac=3‐butyl‐2,4‐pentanedionate, C12‐acac=3‐dodecyl‐2,4‐pentanedionate, BuMe3en=N‐butyl‐N,N′,N′‐tetramethylethylenediamine, and Me4en=N,N,N′,N′‐trimethylethylenediamine). These ILs exhibited reversible changes in color, thermal properties, and magnetic properties in response to organic vapors and gases. The CuII‐containing ILs are purple and turn blue‐purple to green when exposed to organic vapors, such as acetonitrile, methanol, and DMSO, or ammonia gas. The color change is based on the coordination of the vapor molecules to the cation, and the resultant colors depend on the coordination strength (donor number, DN) of the vapor molecules. The vapor absorption caused changes in the melting points and viscosities, leading to alteration in the phase behaviors. The IL with a long alkyl chain ( 1 d ) transitioned from a purple solid to a brown liquid at its melting point. The NiII‐containing IL ( 2 a ) is a dark red diamagnetic liquid, which turned into a green paramagnetic liquid by absorbing vapors with high DN. Based on the equilibrium shift from four‐ to six‐coordinated species, the liquid exhibited thermochromism and temperature‐dependent magnetic susceptibility after absorbing methanol. 相似文献
726.
Igor Maksimov Masaki Ohata Toshiaki Asakai Toshihiro Suzuki Tsutomu Miura Akiharu Hioki Koichi Chiba 《Accreditation and quality assurance》2012,17(5):529-533
The four-year evolution of standard potential of a silver?Csilver chloride reference electrode (denoted further in the text as an Ag/AgCl electrode) is presented together with some suggestions for the improvement of pH primary measurement procedure. 相似文献
727.
Takashima T Yamaguchi A Hashimoto K Nakamura R 《Chemical communications (Cambridge, England)》2012,48(24):2964-2966
Using carbon monoxide as a probe molecule for the oxidation state of Cu ions, we demonstrated that anchored polynuclear charge-transfer complexes consisting of Ce(III) ions and Cu(II)-substituted Keggin-type polyoxotungstates function as efficient visible-light-driven multielectron-transfer catalysts. 相似文献
728.
Dr. Toshihiro Okamoto Tsuyoshi Suzuki Dr. Hideyuki Tanaka Dr. Daisuke Hashizume Prof. Yutaka Matsuo 《化学:亚洲杂志》2012,7(1):105-111
We have designed and synthesized a new donor/acceptor‐type tetracene derivative by the introduction of dicarboxylic imide and disulfide groups as electron‐withdrawing and ‐donating units, respectively. The prepared compounds, tetracene dicarboxylic imide (TI) and its disulfide (TIDS) have high chemical and electrochemical stability as well as long‐wavelength absorptions of up to 886 nm in the thin films. The crystal packing structure of TIDS molecules features face‐to‐face π‐stacking, derived from dipole–dipole interactions. Notably, TIDS exhibited ambipolar properties of both electron‐donating and ‐accepting natures in p–n and p–i–n heterojunction organic thin‐film photovoltaic devices. Accordingly, TI and TIDS are expected to be promising compounds for designing new organic semiconductors. 相似文献
729.
Zhenjun Du Toshihiro Kawatani Kazuhide Kataoka Rikiya Omatsu Junzo Nokami 《Tetrahedron》2012,68(11):2471-2480
Isopropyl, ethyl, and methyl 2-(2-benzothiazolylsulfinyl)acetates have been found to be useful synthetic reagents for sulfinyl-Knoevenagel reaction with various aldehydes to give directly the corresponding 4-hydroxyalk-2-enoates [R′CH(OH)CHCHCO2R], which are ubiquitous structures in biologically active natural products and useful building blocks for organic synthesis of chiral compounds. From the optically pure (R)-2-(2-benzothiazolylsulfinyl)acetates (>99% ee) prepared by the enzymatic kinetic resolution of (±)-2-(2-benzothiazolylsulfinyl)acetates, optically active 4-hydroxyalk-2-enoates (up to 91% ee) have been obtained in good yields. 相似文献
730.
Otake K Shimomura T Goto T Imura T Furuya T Yoda S Takebayashi Y Sakai H Abe M 《Langmuir : the ACS journal of surfaces and colloids》2006,22(9):4054-4059
High-pressure carbon dioxide in contact with water dissolves to form carbonic acid, causing a decrease in pH. By use of these characteristics of a CO2/H2O biphasic system, chitosan-coated cationic liposomes of l-alpha-dipalmitoylphosphatidylcholine were successfully prepared by an improved supercritical reverse-phase evaporation (ISCRPE) method. Liposome-chitosan complexes carrying a positive charge were prepared in a single-step procedure without the use of acid or organic solvent, including ethanol. The maximum trapping efficiency of liposomes prepared by the ISCRPE method was 17%, with or without the addition of chitosan, compared to only 2% for liposomes prepared by the Bangham method. Furthermore, the liposomal dispersion was stable at room temperature in a sealed tube for over 30 days. 相似文献