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91.
Shin-ichiro Fujita Shuhei Moribe Yoshinori Kanamori Nobutsune Takezawa 《Reaction Kinetics and Catalysis Letters》2000,70(1):11-16
The CuO crystallite size of the catalysts obtained from aurichalcite greatly depends on the heating rate of calcination for highly active and selective Cu/ZnO catalyst was prepared by reduction with methanol at 443 K for 17 h. 相似文献
92.
Roman Efremov Pavel Volynsky Dmitry Nolde Gérard Vergoten Alexander Arseniev 《Theoretical chemistry accounts》2001,106(1-2):48-54
A heterogeneous implicit membrane-mimetic model is applied to simulations of membrane proteins. The model employs atomic
solvation parameters for gas–water and gas–cyclohexane transfer. It is used to analyze structure, energetics, and orientation
with respect to the bilayer of two polypeptides with different modes of membrane binding – hydrophobic segment of human glycophorin
A (GpA) and cytotoxin II from Naja naja oxiana snake venom (CTX). The native state of GpA represents a transmembrane (TM) α helix, while CTX is a water-soluble protein,
which is able to interact with the cell membrane. The conformational space of the polypeptides was explored in Monte Carlo
simulations. The results show that the most stable conformers of GpA represent a TM α helix. They are additionally stabilized
by an applied TM voltage. The results also show that CTX inserts with its three loops, does not cross the hydrophobic layer,
and stays partially immersed in the membrane. This agrees well with the experimental data, thus confirming the validity of
the solvation model.
Received: 13 June 2000 / Accepted: 15 September 2000 / Published online: 19 January 2001 相似文献
93.
The AME 2020 atomic mass evaluation (I). Evaluation of input data,and adjustment procedures
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This is the first of two articles(Part I and Part II)that presents the results of the new atomic mass evaluation,Ame2020.It includes complete information on the experimental input data that were used to derive the tables of recommended values which are given in Part II.This article describes the evaluation philosophy and procedures that were implemented in the selection of specific nuclear reaction,decay and mass-spectrometric data which were used in a least-squares fit adjustment in order to determine the recommended mass values and their uncertainties.All input data,including both the accepted and rejected ones,are tabulated and compared with the adjusted values obtained from the least-squares fit analysis.Differences with the previous Ame2016 evaluation are discussed and specific examples are presented for several nuclides that may be of interest to Ame users. 相似文献
94.
在长30m,公称直径(Dg)分别为50、65、80和100mm的管道内,进行了C_2H_2分解爆轰实验。用O_2—C_2H_2爆轰波引爆C_2H_2,测量了管道内的爆轰压力,及在管道端面上的反射压力。与以前认为在管径500mm管道内不会出现自持的C_2H_2分解爆轰的意见相反,在这样的管道内也发生了C_2H_2分解炸轰。在管端测到了1700kg/cm~2的异常高压,并对数次异常高压的破坏威力作了记录。 相似文献
95.
An effective method for producing methyl 4-bromo-3-hydroxybutyrate enantiomers was developed using an engineered protein. Escherichia coli transformant cells containing a mutant β-keto ester reductase (KER-L54Q) from Penicillium citrinum and a cofactor-regeneration enzyme such as glucose dehydrogenase (GDH) or Leifsonia sp. alcohol dehydrogenase (LSADH) were used to produce methyl (S)-4-bromo-3-hydroxybutyrate from methyl 4-bromo-3-oxobutyrate. On the other hand, the production of methyl (R)-4-bromo-3-hydroxybutyrate was achieved by asymmetric reduction of methyl 4-bromo-3-oxobutyrate with a mutant phenylacetaldehyde reductase (PAR-HAR1) from Rhodococcus sp. ST-10. 相似文献
96.
Carlos Camacho-Camacho Maria E. Castillo-Ramos Aurora Vásquez-Badillo Angelina Flores-Parra Rosalinda Contreras 《Journal of organometallic chemistry》2010,695(6):833-9863
The syntheses of [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)amine]diphenyltin (1) and [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)amine]dichloro-phenyl-stannate (2) by template reactions using 3,5-di-tert-butylcatechol, aqueous ammonia and SnPh2Cl2 are reported. We also report the syntheses of compounds 2, [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)amine]trichloro-stannate (4), [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)methylamine]chloro-methyltin (5), and [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)-n-butylamine]n-butyl-chlorotin (6) and [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)amine]n-butyl-dichloro-stannate (7), performed by transmetallation reactions of the octahedral zinc coordination compound Zn[3,5-di-tert-butyl-1,2-quinone-(3,5-di-tert-butyl-2-hydroxy-1-phenyl)imine]2 (3) with SnPhCl3 or SnPh2Cl2, SnCl4, SnMe2Cl2, Sn(nBu)2Cl2 and Sn(nBu)Cl3, respectively. The X-ray diffraction structures of compounds 1, 2, 4 and 6 are reported. The transmetallation reactions with Sn(alkyl)2Cl2 afforded pentacoordinated tin compounds, where an alkyl group migrated from tin to nitrogen, while similar reactions with Sn-Ph compounds did not present any phenyl group migration. 相似文献
97.
The compound NaAlF4 has been obtained in the form of thin fibrous crystals or fine colorless powder by condensation at 18 °C of vapors arising over chiolite Na5Al3F14 or NaCaAlF6, heated up to 800 °C. Thermal stability has been investigated by the methods of thermal analysis and high temperature X-ray diffraction. When heated in air, NaAlF4 is stable up to 390-400 °C, then there is an exothermal solid state decay into Na5Al3F14(s) and AlF3(s). At higher temperature Na5Al3F14(s) decays into Na3AlF6(s) and NaAlF4(g). The crystal structure (space group Cmcm, a=3.6124(1) Å, b=14.9469(7) Å, c=5.2617(3) Å, V=284.10 Å3) has been determined by X-ray powder diffraction method. In the crystal structure of NaAlF4 the octahedrons [AlF6] are joined through vertices and form corrugated layers, sodium ion layers being located between them. The distances between the atoms of Al-F are in the range 1.791-1.814 Å, and those for Na…F are in the range 2.297-2.439 Å. In spite of limited thermal stability of the crystal form, the compound NaAlF4 is the main component of the gas mixture over solid and molten salts in the ternary system NaF-AlF3-CaF2 and participates in chemical transformations between the phases at high temperature. 相似文献
98.
99.
The Yb3+-doped LiGd(MoO4)2 crystal with the size up to Φ20×30 mm3 has been grown by Czochralski technique.The polarized room temperature absorption and emission spectra have been investigated.This crystal exhibits a broad absorption band centered at 975 nm with an FWHM of 43 and 59 nm for π-and σ-polarization,respectively,and the corresponding maximal absorption cross-sections are 3.36 and 2.42×10-20 cm2.The emission broadband has an FWHM of 47 and 54 nm for π-and σ-polarization,respectively,with the corresponding emission cross sections of 3.92 and 3.34 × 10-20 cm2 at 1020 nm.The measured fluorescence lifetime is 287 μs. 相似文献
100.