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931.
Hyunkwon Shin 《Applied Surface Science》2010,256(9):2944-2947
We report that one-dimensional (1D) and two-dimensional (2D) metal thin film gratings can be directly fabricated by interfering Nd-YAG pulsed laser beams (wavelength = 1064 nm, pulse width = 6 ns) incident from the backside of glass substrate. This process utilizes a laser-induced thermo-elastic force which plays a role to detach the film from the substrate. Micro-scale Au transmission gratings with a minimum feature size of 1 μm could be generated by interference-driven periodic detachment. The fabrication of tube-structured patterns as well as stripes was also possible by adjusting the pulse power and this is explained with the effect of film cohesion. 相似文献
932.
We report the application of aluminum doped ZnO (ZnO:Al) layer as a buffer on ITO glass for fabrication of non-inverted polymer solar cells. The ZnO:Al thin film was deposited using DC magnetron sputtering, with the thickness being varied from 23 to 100 nm. The devices showed most discernible improvements in their efficiencies when a thin layer of ZnO:Al film of thickness ∼40 nm was introduced. The observed enhancement in short circuit current density and open circuit voltage is likely attributed to the role of the ZnO:Al film as an optical tuner and an interfacial diffusion barrier. The result suggests that a metal oxide layer inserted between ITO and polymer layers can be a route for improving both efficiency and stability of polymer solar cells. 相似文献
933.
934.
Alexander A. Pasynskii Yuri V. Torubaev Vladimir N. Grigor’ev Anton I. Blokhin Max Herberhold Pradeep Mathur 《Journal of Cluster Science》2009,20(1):193-204
The shortening of partly multiple M–Te (M = Mn, Fe, Co, Cr or W) bonds is observed for two classes of organometallic compounds:
(1) formally electron-deficient species with additional donor–acceptor interaction between Te lone pairs and half-occupied
d-orbitals of M; (2) formally electron-saturated species having additional dative interaction between M lone pairs and LUMO
of Te. These compounds could be prepared by two main methods: (a) interaction of [CpMn(CO)2PhC(O)−]Li+ with Te proceeds via formation of intermediate {[CpMn(CO)2]2Te}2− which is further transformed into binuclear complex [CpMn(CO)2]2Te(CH2Ph)2 or into trinuclear ditelluride cluster [CpMn(CO)2]3Te2 on one hand or to mixed-metal monotelluride clusters [CpMn(CO)2]2TeM(CO)5 on another hand. (b) treatment of Fe(CO)5, CpMn(CO)2(THF) or Me4C4Co(CO)2I with [PhTeI]4, PhTeI3 or PhTeI2HC = CPhI results in different PhTeI-containing complexes of Fe, Mn or Co. The molecular structures of all new compounds were
studied by means of X-ray diffraction analyses and the mechanism of M–Te bond shortening is discussed.
Proceeding of the international workshop on transition metal clusters, 3–5 July 2008, Université de Rennes 1, Campus de Beaulieu,
Rennes, France. 相似文献
935.
Noya Loew Ulla Wollenberger Frieder W. Scheller Martin Katterle 《Bioelectrochemistry (Amsterdam, Netherlands)》2009,76(1-2):28
In this contribution the substitution of the central protoporphyrin IX iron complex of horseradish peroxidase by the respective osmium porphyrin complex is described. The direct electrochemical reduction of the Os containing horseradish peroxidase (OsHRP) was achieved at ITO and modified glassy carbon electrodes and in combination with spectroscopy revealed the three redox couples OsIIIHRP/OsIVHRP, OsIVHRP/OsVHRP and OsVHRP/OsVIHRP. The midpoint potentials differ dependent on the electrode material used with E1/2 (OsIII/IV) of − 0.4 V (ITO) and − 0.25 V (GC), E1/2 (OsIV/V) of − 0.16 V (ITO) and + 0.10 V (GC), and E1/2 (OsV/VI)of + 0.18 V (ITO), respectively. Moreover, with immobilised OsHRP the direct electrocatalytic reduction of hydrogen peroxide and tert-butyl hydroperoxide was observed. In comparison to electrodes modified with native HRP the sensitivity of the OsHRP-electrode for tert-butyl hydroperoxide is higher. 相似文献
936.
A systematic study of various metal trifluoromethanesulfonates as efficient catalysts in the regioselective reductive ring opening of benzylidene acetals is described, including the effects of solvents, reducing agents, and temperature. These catalysts are found to be effective in cleaving the 4,6‐O‐acetal rings of hexopyranosides at either O4 or O6, respectively. When used in conjunction with a 1 M solution of BH3·THF in THF without extra addition of any solvent, it affects the ring fission at the O6 position to generate the corresponding primary alcohols, whereas O4‐opening takes place in acetonitrile in the presence of dimethylethylsilane as the reductant leading to the secondary hydroxyl derivatives in high selectivity and yields. These methodologies can be applied to a wide range of substrates containing various functional groups. 相似文献
937.
Heloisa França Maltez Margarita Villanueva Tagle Alfredo Sanz-Medel 《Analytica chimica acta》2009,650(2):234-6910
Metal speciation analysis in MLPs was carried out in two snails, Marisa cornuarietis and Pomacea bridgesi, in order to investigate them as possible sentinel organisms of heavy metal contamination. To carry out this study snails born in a non-contaminated environment were divided into two groups: a control group and a contaminated one with cadmium administered for 40 days. Subsequently, we investigated the speciation of the induced MLPs in exposed animals in relation to controls. In order to obtain the MLP fraction, cytosols from both snail species where subjected to size-exclusion fractionation, monitoring on-line the metal signal (Cd, Cu and Zn) by ICP-MS while protein elution was followed by on-line UV detection. MLP fraction was then separated by anion-exchange (AE)-FPLC using optimal chromatographic conditions for the separation of the different MLP isoforms in both snail species. Specific detection of separated metalloforms was carried out again by the hyphenation of the AE chromatographic system with ICP-MS. The determination of the amount of metal bound to MLPs was carried out by post-column isotope dilution analysis ICP-MS, finding that the snail M. cornuarietis accumulated higher concentrations of cadmium than P. bridgesi. Thus this first snail could therefore be a better candidate sentinel organism of pollution in natural waters. Identification and characterization of the isoforms separated in M. cornuarietis was carried out for the entire or intact isoforms by MALDI-TOF and then conventional triptic digestion was also carried out to identify the nature of the formed peptides. The presence identification of a MLP isoform of relatively low molecular weight in M. cornuarietis is reported. 相似文献
938.
A simple method, developed primarily for simultaneous determination of total nitrogen and inorganic cations by high performance ion chromatographic (HPIC), was optimized for digestion of flue‐cured tobaccos, and compared with the traditional Kjeldahl method and atomic absorption spectrometry (AAS). Nitrogen determination by either Dumas method or Kjeldahl method is time‐consuming and tedious. Metal elements determination by either inductively coupled plasma‐mass spectrometry (ICP‐MS) or AAS may be more expensive and requires specialist equipment. The use of HPIC to simultaneous determine total nitrogen as ammonium ion and metal elements as inorganic cations after sample digestion significantly improves the speed of the analysis compared with the conventional methods. The cation‐exchange column and suppressed conductivity detector was used for determination of ammonium and inorganic cations in the presence of the elevated levels of sulfuric acid found in digested sample. The propsoed digestion method was accurate and precise, and required little investment. The determination of ammonium and inorganic cations was linear from 15 pg·L?1 up to 25 ng·L?1. The results obtained by the HPIC method were compared with those for the conventional methods approach for the determination of total nitrogen and metal elements. The application of the HPIC method is also demonstrated for a variety of other plant samples matrices. 相似文献
939.
“Reverse” colorimetric DNA detection by the formation of core-shell particles upon DNA hybridization is described. Specifically,
the assay is based on a strategy to covalently link polymer reaction initiators to suspended nanoparticles upon DNA hybridization.
These initiators then prompt polymer chain growth to form a thick polymer shell outside of particles, acting as the physical
barrier to keep Au particles apart. Particles without DNA hybridization aggregate, accompanied by a pronounced solution color
change from red to blue. The focus of this report is to address reaction kinetics of two co-occurring processes: polymer growth
and particle aggregation during the reverse colorimetric DNA assay. The results show that Cu ions used as the polymerization
catalyst bind strongly to the bases in DNA molecules, resulting in crosslinking of DNA-attached gold nanoparticles and their
subsequent precipitation. Both Cu-ion-assisted particle aggregation and polymer growth are found to depend strongly on Cu
ion concentration, salt concentration, and reaction temperature. Under the optimized conditions, faster polymer chain growth
on the surface overcomes particle aggregation and preserves particle stability via steric stabilization. 相似文献
940.
Jiménez MS Gomez MT Rodriguez L Martinez L Castillo JR 《Analytical and bioanalytical chemistry》2009,393(2):699-707
An experimental approach to evaluate the capabilities and limitations of polyacrylamide gel electrophoresis (PAGE) and laser
ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for quantitative elemental speciation is presented. Two
metalloproteins (superoxide dismutase, containing Cu and Zn, and thyroglobulin, containing I) with high binding affinity for
metals, and metal-dissolved organic matter (DOM) complexes (from a compost leachate sample) which show different types of
metal binding are studied. Iodine can be quantitatively detected in thyroglobulin after PAGE-LA-ICP-MS using either sodium
dodecyl sulfate (SDS) PAGE or native PAGE. However, detection of Cu and Zn in superoxide dismutase after PAGE-LA-ICP-MS depends
on the conditions of the PAGE method because possible metal losses can occur (either with SDS-PAGE or with native PAGE). The
use of PAGE-LA-ICP-MS to study the contribution of DOM to the mobilization of metals from environmental samples is possible,
but it depends also on the PAGE separation conditions owing to disequilibrium effects of metal-DOM complexes.
Presented at the 4th International Conference on Trace Element Speciation in Biomedical, Nutritional and Environmental Sciences,
25–29 May 2008, Munich-Neuherberg, Germany. 相似文献