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21.
Elena Eggl Martin Dierolf Klaus Achterhold Christoph Jud Benedikt Günther Eva Braig Bernhard Gleich Franz Pfeiffer 《Journal of synchrotron radiation》2016,23(5):1137-1142
While large‐scale synchrotron sources provide a highly brilliant monochromatic X‐ray beam, these X‐ray sources are expensive in terms of installation and maintenance, and require large amounts of space due to the size of storage rings for GeV electrons. On the other hand, laboratory X‐ray tube sources can easily be implemented in laboratories or hospitals with comparatively little cost, but their performance features a lower brilliance and a polychromatic spectrum creates problems with beam hardening artifacts for imaging experiments. Over the last decade, compact synchrotron sources based on inverse Compton scattering have evolved as one of the most promising types of laboratory‐scale X‐ray sources: they provide a performance and brilliance that lie in between those of large‐scale synchrotron sources and X‐ray tube sources, with significantly reduced financial and spatial requirements. These sources produce X‐rays through the collision of relativistic electrons with infrared laser photons. In this study, an analysis of the performance, such as X‐ray flux, source size and spectra, of the first commercially sold compact light source, the Munich Compact Light Source, is presented. 相似文献
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Cristiana Lofrumento Marilena Ricci Elena Platania Maurizio Becucci Emilio Castellucci 《Journal of Raman spectroscopy : JRS》2013,44(1):47-54
Micro‐Raman spectroscopy has been widely employed in the last few years for the study of artworks, allowing for the characterization of a high class of pictorial materials. However, the detection of organic dyes by conventional Raman spectroscopy is quite difficult, due to the high fluorescence provided by these compounds. Recently, remarkable improvements have been achieved by the introduction of the surface enhanced Raman spectroscopy (SERS) technique for the analysis of organic dyes. In the present work, a new method is presented, based on the use of a SERS probe made of agar‐agar coupled with silver nanoparticles, for a non‐destructive and minimally invasive micro‐extraction of dyes from textiles. Ag‐agar gel has been tested first on textile mock‐ups dyed with alizarin, purpurin and carminic acid. SERS measurements have been performed adopting laser light excitations at 514.5 and 785 nm of a micro‐Raman setup. Highly structured SERS band intensities have been obtained. After having verified the safety of the method by colorimetric, X‐ray fluorescence and attenuated total reflectance Fourier transform infrared techniques, a real case, a pre‐Columbian piece of textile, have been investigated by Ag‐agar gel. This cutting‐edge method offers new possibilities for a sensitive and non‐destructive analysis of fluorescent materials. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
25.
Abe K Abt I Ahn CJ Akagi T Ash WW Aston D Bacchetta N Baird KG Baltay C Band HR Barakat MB Baranko G Bardon O Barklow T Bazarko AO Ben-David R Benvenuti AC Bienz T Bilei GM Bisello D Blaylock G Bogart JR Bolton T Bower GR Brau JE Breidenbach M Bugg WM Burke D Burnett TH Burrows PN Busza W Calcaterra A Caldwell DO Calloway D Camanzi B Carpinelli M Cassell R Castaldi R Castro A Cavalli-Sforza M Church E Cohn HO Coller JA Cook V Cotton R Cowan RF Coyne DG D'Oliveira A Damerell CJ Dasu S 《Physical review letters》1995,74(9):1512-1516
26.
George Pitsevich Elena Shalamberidze Alex Malevich Valdas Sablinskas Vytautas Balevicius Lars G. M. Pettersson 《Molecular physics》2017,115(20):2605-2613
The frequencies and intensities of vibration–rotational transitions of water molecules in an argon matrix were calculated for temperatures of 6 and 30 K. The rigid asymmetric top approximation was used with available literature values of the effective rotational constants in the ground and excited vibrational states. The calculations were carried out by taking into account the existence of a non-equilibrium population distribution between the rotational levels of ortho- and para-water isomers. It was assumed that the temperature relaxation of the population of rotational levels is independent of the ortho- and para-isomers. Comparison of the results of the theoretical calculations with experimental literature data shows good agreement for the majority of the rotational structure lines for symmetric and antisymmetric stretching vibrations both in the frequency values and in the values of the relative intensities. 相似文献
27.
Arwen R. Pearson Reinhard Pahl Elena G. Kovaleva Victor L. Davidson Carrie M. Wilmot 《Journal of synchrotron radiation》2007,14(1):92-98
X‐ray exposure during crystallographic data collection can result in unintended redox changes in proteins containing functionally important redox centers. In order to directly monitor X‐ray‐derived redox changes in trapped oxidative half‐reaction intermediates of Paracoccus denitrificans methylamine dehydrogenase, a commercially available single‐crystal UV/Vis microspectrophotometer was installed on‐line at the BioCARS beamline 14‐BM‐C at the Advanced Photon Source, Argonne, USA. Monitoring the redox state of the intermediates during X‐ray exposure permitted the creation of a general multi‐crystal data collection strategy to generate true structures of each redox intermediate. 相似文献
28.
Solid-Phase Luminescence Determination of Ciprofloxacin and Norfloxacin in Biological Fluids 总被引:1,自引:0,他引:1
Svetlana Beltyukova Olga Teslyuk Alla Egorova Elena Tselik 《Journal of fluorescence》2002,12(2):269-272
A simple, rapid, and sensitive luminescence test method for the determination of ciprofloxacin (CIP) and norfloxacin (NOR) has been described. The method is based on the intramolecular energy transfer from organic acid to terbium (Tb3+) ion. Luminescence of terbium (III) complex with CIP (NOR), sorbed on the zeolite has been studied. Under optimized conditions the detection limit is 1 g/mL in urine and human plasma. 相似文献
29.
Eric Jourdanneau Tony Gabard Frdric Chaussard Robert Saint-Loup Hubert Berger Elena Bertseva Frdric Grisch 《Journal of Molecular Spectroscopy》2007,246(2):167-179
CARS laboratory experiments were done in the 2905–2925 cm−1 range, in the vicinity of the ν1 band of the methane molecule, for pressures ranging from 1 to 50 bar, and temperatures up to 1100 K. These experiments were carried out in order to retrieve the pressure evolution of the CH4 spectrum, as well as to confirm its temperature dependance. After a brief recall on the theory used to compute pressure broadening coefficients and relaxation rates, we consider the ν3 and ν4 infrared bands of methane for benchmark calculations purposes. Next, we present recent experimental CARS spectra and calculated ones. Lastly, we discuss flame experiments as well as comparisons of temperature retrieval using N2 and CH4 as probe molecules. 相似文献
30.
Viktor S. Burakov Andrey V. Butsen Volker Brüser Falk Harnisch Pulat Y. Misakov Elena A. Nevar Miriam Rosenbaum Natalie A. Savastenko Nikolai V. Tarasenko 《Journal of nanoparticle research》2008,10(5):881-886
Tungsten carbide nanopowder was prepared via pulsed discharge of bulk tungsten and graphite rods immersed in pure ethanol.
The effect of discharge parameters on the characteristics of final products was investigated. Structural and morphological
characterization of nanopowder was performed by means of X-ray diffraction analysis and transmission electron microscopy.
In order to determine the feasibility of using synthesized material as an electrocatalyst, tungsten carbide nanopowder was
tested for hydrogen evolution. A correlation was found between morphology of nanoparticles, their phase composition and electrocatalytic
activity. 相似文献