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311.
Sourov Chandra Sourav Bag Radhaballav Bhar Panchanan Pramanik 《Journal of nanoparticle research》2011,13(7):2769-2777
Abstract
Highly water dispersible rhodium–graphene nanocomposite have been successfully synthesized by the simple reduction of Rh3+ salt on poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) (PEO/PPO/PEO) triblock copolymer or pluronic-stabilized graphene oxide (GO) nanosheets with borohydride. Rhodium nanoparticles, having average size of 1–3 nm, are homogeneously distributed through out the graphene sheets. Some porous structures of graphene sheets have also been observed after the reduction of pluronic-stabilized GO in the presence of metal ions. The material is very effective for hydrogenation of arenes, especially for benzene as the substrate material at the room temperature and 5 atm pressure of hydrogen. 相似文献312.
M. K. Sen A. Baura B. C. Bag 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,83(3):381-389
We have studied work fluctuation behaviour in the presence of internal thermal noise as
well as external coloured noise. The external coloured noise may have both Gaussian or
non-Gaussian characteristics. We have investigated the dependence of position and work
fluctuations on the properties of both the environments. For thermal noise driven systems,
there is a maximum in the variation of mean square fluctuation of work (MSFW) as a
function of damping strength at intermediate times, while at asymptotic long times MSFW
monotonically increases in the same damping regime. But for external noise, MSFW
monotonically decreases as a function of damping strength at intermediate times, whereas
at long times it becomes almost independent of damping strength.Another interesting
observation is that for the external noise driven systems, noise correlation time and
damping strength have similar roles in the dynamics. 相似文献
313.
N-Phenylacetylphenylhydroxylamine complexes of titanium(IV), yellow in color and extractable into chloroform, with metal:ligand ratios 1:2, 1:3, and 1:4, exist in the acidity ranges of 1–3, 4–7, and 7.5–9.0 N HCl, respectively. The compositions of the complexes were found out by Job's and molar ratio methods. The stepwise and overall formation constants were evaluated following extensions of Yatsimirskii's, Leden's and Harvey and Manning's methods. A computer was used for evaluation of the formation constants of the 1:3 system following the first method. A spectrophotometric method based on solvent extraction technique, for determination of trace amounts of titanium in the presence of diverse ions, has also been described. 相似文献
314.
Atanu Kumar Das Biprajit Sarkar Dr. Carole Duboc Dr. Sabine Strobel Dr. Jan Fiedler Dr. Stanislav Záliš Dr. Goutam Kumar Lahiri Prof. Dr. Wolfgang Kaim Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(23):4242-4245
Six combinations of oxidation states are conceivable for the paramagnetic title complex. Single‐crystal X‐ray diffraction, spectroscopic analysis (IR, EPR at conventional and high frequency), and DFT calculations establish that it is the iminosemiquinone radical structure that is formed: [Ruk(NOm)(Qn)(terpy)]2+ (k=2+, m=1+, n=1?).
315.
Very high electrical conductivity of ~0.021 S/cm at 600 °C is obtained in Ce0.79Gd0.20Co0.01O2?δ. Corresponding activation energy of conduction ~0.43 eV measured in the temperature range of 400–700 °C is found to be notably low. Improved electrical properties with 99% of the theoretical density as obtained for these specimens, prepared using powder of average particle size ~20 nm and subsequent sintering at 1100 °C, is considered to be a significant step to reduce the processing temperature. The measured electrical potential of ~1 V indicates the suitability of its use as an electrolyte in electrochemical devices. 相似文献
316.
Cyclopentanoids are omnipresent in natural products and pharmaceutically relevant compounds. Among them, cyclopenta‐fused arenes and heteroarenes possess impressive biological properties and play significant role in materials science. Consequently, several notable methods have been developed for their synthesis over the years. In this review, we mainly described metal‐free and organocatalytic approaches that led to the construction of pentannulated arenes and heteroarenes. 相似文献
317.
Atanu Biswas Sanghoon Kim Roselayne Ferro Furtado Carlucio Roberto Alves Megan Buttrum Veera Boddu 《International Journal of Polymer Analysis and Characterization》2018,23(6):577-589
Acylation of polysaccharides is a commercially important reaction and is usually performed in a process involving the polysaccharide, an acid anhydride, and an inorganic acid. As an alternative to inorganic acid, many catalysts, including some metal chlorides, have been previously reported as catalysts. In this work, we took a more comprehensive look at several metal chlorides to observe trends and reactivities among them, particularly relating to reaction temperature, time, and amount of acetic anhydride used. Iodine was also included for comparison. Almost all the metal chlorides studied were found to be active as catalysts for the acetylation of starch under suitable reaction conditions. However, each metal chloride had a somewhat different reactivity with a different optimal temperature needed for satisfactory reactions to take place. The molecular weight of the starch acetate products decreased in all cases observed. The reactivity trends among the metal halides seemed to correlate both with the ease of complexation between the halide and the substrate and with the acidity of the metal chloride. Characterization was achieved through 13?C NMR, FT-IR, thermogravimetric analysis and size exclusion chromatography. 相似文献
318.
Durba Roy Samrajnee Dutta Shyam Sundar Maity Sanjib Ghosh Atanu Singha Roy Kalyan Sundar Ghosh Swagata Dasgupta 《Journal of luminescence》2012,132(6):1364-1375
The interactions of two stereoisomeric antioxidant flavonoids, catechin (C) and epicatechin (EC) with bovine serum albumin (BSA) and human serum albumin (HSA), have been investigated by steady state and time resolved fluorescence, phosphorescence, circular dichroism (CD), FTIR and protein–ligand docking studies. The steady-state fluorescence studies indicate a single binding site for both the ligands. FTIR spectra suggest that in both the albumins, C and EC stabilize the α-helix at the cost of a corresponding loss in the β-sheet structure. CD studies have been carried out using (±)C, and both the epimers (+)C and (?)C. The low temperature phosphorescence and protein–ligand [(+), (?) and (±) forms of C and EC] docking studies indicate that the ligands bind in the proximity of Trp 134 of BSA and Trp 214 of HSA, thereby changing their solvent accessible surface areas (ASA). Asn 158 and Glu 130 side chains are found to be within the hydrogen bonding distance from the phenolic –OH groups of C and EC in the case of BSA complex. C and EC are located within the binding pocket of sub-domain IIa of HSA. 相似文献