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241.
Electrospraying/electrospinning of poly(γ-stearyl-L-glutamate) (PSLG) was investigated on a series solutions with different concentrations in chloroform. Field emission scanning electron microscopy (FESEM) and attenuated total reflectance Fourier transform infrared spectroscopy (FT-IR/ATR) were used to characterize the morphology and structure of the electrosprayed/electrospun polypeptide mats. It was found that electrospraying of PSLG with concentrations lower than 16 wt% afforded beads, while microfibers could be electrospun at the concentration of 22 wt%. The hydrophobicity of the electrosprayed/electrospun PSLG mats was investigated with static water contact angle (WCA) and tilt angle measurements. It was demonstrated that the superhydrophobic surfaces of PSLG with WCAs and tilt angles in the ranges of 150°-170° and 16.5°-4.2°, respectively, were obtained through electrospraying/electrospinning process. 相似文献
242.
B. L. Tumanskii V. V. Bashilov N. N. Bubnov S. P. Solodovnikov V. I. Sokolov 《Russian Chemical Bulletin》1994,43(5):884-886
Using ESR spectroscopy, the reaction of P(O)(OPri)2 phosphoryl radicals with C60ML2 (M=Pd, Pt) was studied and the spin-adducts formed were shown to be unstable under the reaction conditions. The 5-addition of Pt(PPh3)4 to the dimer of phosphorylfullerenyl radicals results in metal-containing dimers (RO)2(O)PL2MC60-C60ML2P(O)(OR)2, which dissociate when exposed to visible light to afford C60ML2P(O)(OR)2 radicals; ML2 in these complexes is located in different positions in relation to the radical center. As a result, the ESR spectra contain the superposition of at least five signals of radicals that differ in HFS constants andg-factors.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 938–940, May, 1994.The present work was supported by the Russian Foundation for Basic Research (Projects 93-03-18725 and 93-03-4101). 相似文献
243.
E. Tomaszewicz 《Thermochimica Acta》2006,447(1):69-74
Reactivity in the solid state between CoWO4 and some rare-earth metal tungstates RE2WO6 (RE = Sm, Eu, Gd) was investigated by the XRD method. Two families of new isostructural cobalt and rare-earth metal tungstates, Co2RE2W3O14 and CoRE4W3O16, were synthesized. The Co2RE2W3O14 phases are formed by heating in air the CoWO4 and RE2WO6 compounds mixed at the molar ratio 2:1, while the CoRE4W3O16 phases are synthesized at the molar ratio of CoWO4/RE2WO6 equals to 1:2. The Co2RE2W3O14 phases as well as the CoRE4W3O16 compounds crystallize in the orthorhombic system. The Co2RE2W3O14 and CoRE4W3O16 compound melt above 1150 °C. A melting manner of the Co2RE2W3O14 and CoRE4W3O16 compounds was determined in an inert atmosphere. The formation of CoWO4−x phase was observed during heating in an inert atmosphere. 相似文献
244.
245.
Carbonate Isostructural Anions [SnX3]5? in the Compounds Rb6[SnX3]O0.5 and Cs6[SnX3]O0.5 with X = As, Sb, and Bi The metallic shining compounds Rb6[SnX3]O0.5 and Cs6[SnX3]O0.5 with X = As, Sb, and Bi were prepared from the melt starting from adequate mixtures of the elements and SnO2. They crystallize in the hexagonal system (space group P63/mmc, No. 194, Z = 2) with the lattice constants mentioned in ?Inhaltsübersicht”?. In the structures of the isotypic compounds tin and the main group(V) elements build up trigonal planar anions [SnX3]5? with X = As, Sb, and Bi isostructural to the carbonate anion, oxygen forms isolated O2? ions. The bond lengths Sn? X are significantly shortened with respect to the sums of Pauling covalent radii. The atoms of the units [SnX3]5? are coordinated by alkali metal cations forming trigonal prisms and the O2? anions occupy octahedral holes. 相似文献
246.
Jerald S. Bradshaw Reed M. Izatt James J. Christensen Krzystof E. Krakowiak Bryon J. Tarbet Ronald L. Bruening S. Lifson 《Journal of inclusion phenomena and macrocyclic chemistry》1989,7(2):127-136
Silica gel-bound crown ethers and aza macrocycles have been synthesized with the attaching arm connected to the carbon framework of the macrocycles. The interactions of these bound macrocycles with cations are almost identical to those involving the analogous free macrocycles. This has allowed for predictable cation separation, concentration, and removal processes to be performed on a small scale. Quantum mechanical calculations and NMR measurements indicate that similarly bound chiral macrocycles will be capable of use in separating chiral organic amines.Dedicated to the memory of Professor James J. Christensen who died on 5 September 1987. 相似文献
247.
D-72 resin supported nickel-copper catalysts prepared by solvated metal atom impreg-nation (SMAI) were studied by magnetic measurements and X-ray photoelectron spectro-scopy (XPS). The Ni particles on the catalysts are very highly dispersed and displaysuperparamagnetic behaviour. Ni-Cu alloy clusters were found to be formed. The sur-face compositions are different from the bulk concentrations. In contrast with the surfaceenrichment in copper generally observed on conventional Ni-Cu catalysts, the surfaces ofthese catalysts are enriched in nickel. The nickel is in both zero and valent states, whilecopper is mainly in metallic state. Catalytic data show that the formation of Ni-Cu alloyclusters has a profound effect on the catalytic activities of the catalysts in the hydrogena-tion of furfural. The activity of the Ni:Cu ratio of one bimetallic catalysts is much higherthan that of the Ni or Cu monometallic catalyst. 相似文献
248.
The goal of this work was the development of a novel type of heterogeneous catalyst, consisting of bare metal nanoparticles
on stainless steel foils, which can be shaped to any kind of architecture and, if necessary, heated electrically. Solutions
of pre-prepared, ligand protected and monodispersed gold, palladium, platinum and rhodium nanoparticles were sprayed onto
stainless steel foils, followed by the careful removal of the ligand molecules by an oxygen plasma treatment. Due to this,
bare particles become irreversibly fixed on the steel support. It could be shown that the original particle sizes do not change
during the plasma treatment. Foils, densely coated with the nanoparticles, were used for gas phase catalyses in a self-made
reactor at room temperature or at 60 °C. Hydrogenation of 1,3-butadiene at 15 nm Pd and 2 nm Pt, CO oxidation at 16 nm, 8 nm
and 1.4 nm gold and NO reduction with NH3 at 2 nm Rh particles were performed, indicating that the novel catalysts might in principle be applicable in technical processes
if the experimental conditions like form and temperature would be optimized.
Dedicated to Professor Dieter Fenske on the occassion of his 65th birthday. 相似文献
249.
A sensitive ion-pair liquid-liquid extraction-spectrophotometric method has been developed for the determination of copper, palladium, iron and cobalt, based on the formation of metal complexes with 1-nitroso-2-naphthol-6-sulphonic acid or 2-nitroso-1-naphthol-6-sulphonic acid as primary ligand, and zephiramine as counter-ion. The coloured metal complexes obtained over different pH ranges are easily and quantitatively extracted into dichloromethane. The method has been tested with samples containing known amounts of copper, palladium, iron and cobalt in ultrapure water. The reagents provide a sensitive spectrophotometric method for determining these metals. 相似文献
250.
Conductance measurements for fifteen uni-univalent salts in 2-methylpyridine-N-oxide (2-MPO) were made over the concentration range of 2–120×10–4 mol-dm–3 at 55°C. All conductance data were evaluated by the Lee-Wheaton equation. The results indicate that all of the salts studied are slightly associated in 2-MPO, which is, nevertheless, a reasonably good ionizing solvent compared to other solvents having a similar value for the dielectric constant. The tetraalkylammonium halides are weaker electrolytes than the tetraphenylborate salts in 2-MPO. Ionic limiting molar conductances were obtained by using as a reference electrolyte tris(iso-pentyl)butylammonium tetraphenylborate. Anions appear to be poorly solvated in this solvent but certain cations, particularly Na+ and K+, show evidence of specific ion-solvent interaction.This study was presented, in part, at the 6th Central Regional Meeting of the American Chemical Society, Detroit, Michigan, April 1974. 相似文献