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151.
Segregation and selective oxidation phenomena of minor alloying elements during annealing of steel sheets lead to the formation of bare spots after hot dip galvanizing. In order to understand the influence of common alloying elements on the surface chemistry after annealing, model alloys of binary (Fe-2Si, Fe-2Mn and Fe-0.8Cr), ternary (Fe-2Mn-2Si, Fe-2Mn-0.8Cr and Fe-2Si-0.8Cr) and quarternary (Fe-2Mn-2Si-0.8Cr) systems were investigated. The specimens were annealed for 60 s at 820 °C in N2-5% H2 gas atmospheres with different dew points −80 and −40 °C, respectively. Surface chemistry of the annealed specimens was obtained by using X-ray photoelectron spectroscopy (XPS). The field emission scanning electron microscopy (FE-SEM) was used to view surface morphology. At low dew point −80 °C, apart from the thermodynamical calculations such as solubility product of oxides and their critical solute concentrations, kinetics play a decisive role on the selective oxidation, i.e. oxygen competition. As expected, the amount of external selective oxidation of alloying elements are well pronounced at higher dew point −40 °C. An attempt has been made to explain the dominant process of Si and Mn on Cr-oxidation and segregation. It is observed that annealing of quarternary system at higher dew point shifts the Cr-oxidation from external to internal. 相似文献
152.
J.A. Sans J.F. Snchez-Royo J. Pellicer-Porres A. Segura E. Guillotel G. Martinez-Criado J. Susini A. Muoz-Pez V. Lpez-Flores 《Superlattices and Microstructures》2007,42(1-6):226
In this paper, we investigate the Co site configuration in Zn1−xCoxO thin films by means of different spectroscopic techniques. Thin films were prepared by pulsed laser deposition with Co proportion from 1% to 30%. The Co 2p doublet observed in the X-ray photoelectron spectra exhibits the spin–orbit splitting and shake-up satellites typical of Co+2 ionization states. X-ray absorption spectra at the Co K-edge, taken in fluorescence mode, unambiguously show that Co atoms are in tetrahedral configuration substituting for Zn over the whole composition range. Optical absorption spectra provide further evidence of the tetrahedral coordination of Co cations, both through the internal transitions in the Co 3d shell and through the shift to higher energies of the band-to-band absorption edge with the increase of the Co proportion. 相似文献
153.
E. Coetsee 《Journal of luminescence》2007,126(1):37-42
The degradation of the cathodoluminescence (CL) intensity of cerium-doped yttrium silicate (Y2SiO5:Ce) phosphor powders was investigated for possible application in low voltage field emission displays (FEDs). Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and CL spectroscopy were used to monitor changes in the surface chemical composition and luminous efficiency of commercially available Y2SiO5:Ce phosphor powders. The degradation of the CL intensity for the powders is consistent with a well-known electron-stimulated surface chemical reaction (ESSCR) model. It was shown with XPS and CL that the electron stimulated reaction led to the formation of a luminescent silicon dioxide (SiO2) layer on the surface of the Y2SiO5:Ce phosphor powder. XPS also indicated that the Ce concentration in the surface layer increased during the degradation process and the formation of CeO2 and CeH3 were also part of the degradation process. The CL intensity first decreased until about 300 C cm−2 and then increased due to an extra peak arising at a wavelength of 650 nm. 相似文献
154.
B.-E. Schuster A. Haug M. Häffner M. M. Blideran M. Fleischer H. Peisert D. P. Kern T. Chassé 《Analytical and bioanalytical chemistry》2009,393(8):1899-1905
We present a spectroscopic and microscopic characterization of the chemical composition, structure, and morphology of two
commercial negative resists using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS),
and atomic force microscopy (AFM). For this purpose, films of a novolak-based resist (ma-N 2400) and hydrogen silsesquioxane
(HSQ) are treated under different conditions (temperature, deep ultraviolet (DUV) exposure, CHF3 plasma). Topographic AFM images show that both heating and DUV exposure strongly affect the surface morphology of as-prepared
ma-N 2400 resist films. These different treatment conditions also lead to decreasing roughnesses, which indicates structural
reorganization. Furthermore, the decrease of the photoactive compound (bisazide) in the ma-N 2400 resist films, observed in
FTIR spectra, suggests cross-linking of the resist after CHF3 plasma treatment, heating, or DUV exposure. XPS measurements on different CHF3 plasma-treated surfaces reveal that a structurally homogeneous fluorine-containing polymer is generated that is responsible
for an enhanced etch resistance. FTIR measurements of HSQ films show a correlation between the degree of HSQ cross-linking
and baking time. 相似文献
155.
C.-M. Tg M. Pyknen J.B. Rosenholm K. Backfolk 《Journal of colloid and interface science》2009,330(2):428-436
The surface chemical and physical character of offset paper was studied before and after application of model fountain solutions based on isopropyl alcohol and an alcohol-free surfactant solution. The paper surface features were characterised with atomic force microscopy and the surface energies were determined by contact angle measurements. Changes in the surface chemical properties induced by the fountain solutions were investigated with X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectroscopy. Coated papers wetted with the surfactant solution revealed a slight increase in the root mean square roughness, but the isopropyl alcohol solution led to no observable changes. The change in sub-micro roughness is ascribed not only to substrate swelling or migration of coating constituents but also to the presence of surfactant on the surface. A change in the surface energy and particularly the polar contribution was observed after application of the surfactant solution. The X-ray photoelectron spectroscopy showed an increase in the oxygen-to-carbon ratio, which confirms the presence of surfactant on the surface. Time-of-flight secondary ion mass spectroscopy showed that the isopropyl alcohol solution did not change the elemental composition of the surface whereas the surfactant solution clearly did so. The distribution of surfactant on the surface was confirmed by mapping the characteristic fragments of the molecule. 相似文献
156.
157.
158.
G. Fonder J. Delhalle M. Essahli B. Ameduri Z. Mekhalif 《Surface and interface analysis : SIA》2008,40(2):85-96
Self‐assembly on a polycrystalline aluminum substrate of two sulfur‐containing alkylphosphonic acids, CH3? (CH2)11? S? (CH2)2? PO(OH)2, and CF3? (CF2)7? (CH2)2? S? (CH2)2? PO(OH)2, has been compared with CH3? (CH2)15? PO(OH)2. The reaction of the phosphonic head groups with the hydroxyls at the alumina surface to form phosphonates was studied with X‐ray photoelectron spectroscopy (XPS) and polarization modulation infrared reflection‐absorption spectroscopy (PM‐IRRAS). Barrier effects of the resulting layers was assessed by electrochemical polarization curves. With the conditions used in the present work for the self‐assembly reaction, it appears that the sulfur‐containing molecules do not perform as well as CH3? (CH2)15? PO(OH)2 in terms of film quality. Questions are raised about the possibility that the sulfur‐containing molecules could undergo cleavage during surface modification. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
159.
160.
S. G. Kokoreva L. V. Shirshova N. V. Kir'yakov Yu. M. Shul'ga I. P. Lavrent'ev 《Russian Chemical Bulletin》2000,49(10):1722-1725
The products of interaction of components in the donor-acceptor electron-transport (DAET) DMSO−HBr system and their complex
formation with the metallic palladium surface were studied. H2O and Me2S (main reaction products) and CO, CS2, C2H6, MeBr, H, and CH4 (minor reaction products) were found in the gas phase by mass spectrometry (MS). The samples of metallic palladium treated
with the DAET system with a components ratio corresponding to the minimum and maximum rates of metal dissolution were studied
by the methods of thermoprogrammed desorption with MS detection (TPD-MS) and XPS. According to the TPD-MS data, two forms
of Me2S are present on the metal surface, whereas the XPS method detected two complexes with the molecular compositions PdIIBr4S1.26 and PdIIBr3.86S1.42. The addition of an aqueous solution of NaOH to the system results in the formation of HCOONa, which indicates that compounds
(CH2O, HCOOH) capable of reducing the palladium complexes are present in the DAET system.
Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1740–1743, October, 2000. 相似文献