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51.
52.
We report the synthesis and characterisation of (S) and (R)-2′-formylcymantrenyl-17α-ethynylestradiol synthesized using the Sonogashira cross-coupling reaction between optically pure (S) and (R) 1-formyl-2-iodo cymantrenes and ethynylestradiol. (S) and (R) 1-formyl-2-iodo cymantrenes were obtained from the same precursor: (2R,4R)-4-(methoxymethyl)-2-cymantrenyl-1,3-dioxane. 相似文献
53.
54.
Influence of Coriolis coupling on excitation of some Nilsson states in155Gd,157Gd and167Er by inelastic scattering of 12·1 MeV deuterons is analysed. Expanded Nilsson potential with hexadecapolar deformation is used for the model calculations. Theoretical values of reduced transition probability,B(E2) are compared with experimental ones. 相似文献
55.
A modified Bridgman method is described, which makes it possible to prepare homogeneous BiTeI crystals using excess iodine. At room temperature the values of the electrical conductivity of the crystals range around 2000 –1 cm–1, the Hall constant value about 0·09 cm–3 coul–1, the Seebeck coefficient about 50 V K–1. In connection with the assumption of super-stoichiometric iodine content we expect there exist point defects in the crystals, where Te atoms are replaced with I atoms, which gives rise to electric conductivity. On the basis of the temperature dependence of the electron mobility one can suppose a mixed mechanism of the scattering of the free carriers by the acoustic branch of lattice vibrations and by ionized impurities. 相似文献
56.
The distribution of hydrodesulfurization (HDS) products of thiophene was compared on 9 different catalysts at different degrees
of sulfidation and at aging in H2/thiophene mixtures. The main products of HDS were C4 and Cl-C3 hydrocarbons. The effect of sulfur uptake on the productsmin distribution was similar for Co and Ni promoted, and reverse
to that on Pd and Pt promoted samples. The effect of aging was similar for all samples.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
57.
Z. Vít 《Reaction Kinetics and Catalysis Letters》1986,32(1):205-208
The catalytic activity of some solid acidic catalysts was tested in the depolymerization of paraldehyde. It was found that the activities of sulfonated ion exchange resin and mounted phosphotungstic acid strongly exceed the activity of silica-alumina and other oxide catalysts. By means of Brönsted relationship, the differences in HO of the surfaces were estimated.
. , - - . HO .相似文献
58.
The flaws in the Reply [1] to our paper [2] have been pointed out. Elber and Karplus (EK) have not disproved our irrefutable global statement that the energy average cannot be minimized which rebuts the theoretical background of EK-type calculations. Another statement of ours has shown that even a curve for which the average energy is locally minimal for all directional perturbations in the sense of classical variational calculus cannot be identical with the reaction path (RP) defined as a steepest descent path (SDP). EK found an error in the early preprint of our theoretical paper [3] and because of this error they qualified our correct variational statement as false for all the SDPs consisting of a straight line each. Mixing global and variational arguments, EK refuted our criticism in a logically incorrect manner. In this Comment we prove that both of our earlier statements invariably remain in force and the criticism included in those has been as well-established and solid as was before. 相似文献
59.
V. Kontrimavičiūtė H. Breton F. Barnay J. C. Mathieu-Daudé F. M. M. Bressolle 《Chromatographia》2006,63(11-12):533-541
A specific and sensitive liquid chromatography-electrospray ionization mass spectrometry method was developed for the determination of ibogaine and noribogaine in human urine. The work-up procedure involved a solid phase extraction of the compounds and the internal standard (fluorescein) using Oasis HLB columns. The system used a Zorbax eclipse XDB C8 analytical column packed with 5µm diameter particles as the stationary phase. The mobile phase consisted of a 20-min gradient (mobile phase A: 0.02% (v/v) trimethylamine in acetonitrile, mobile phase B: 2 mM ammonium formate buffer (pH 3)). Mass spectrometric data were acquired in single ion monitoring mode at m/z 311.1, 297.2 and 333 for ibogaine, noribogaine and fluorescein, respectively. The drug/internal standard peak area ratios were linked via a quadratic relationship to concentrations (1.78?358 μg L?1 for ibogaine; 2?400 μg L?1 for noribogaine). Precision ranged from 5.8 to 14.8% and accuracy was between 93.2 and 112.9%. Mean extraction recoveries of ibogaine, noribogaine and fluorescein were 70.0, 81.7 and 94.8%, respectively. The extraction efficiency was independent of concentration over the range studied. The lower limits of quantitation were 1.78 μg L?1 for ibogaine and 2 μg L?1 for noribogaine. In this paper, extensive stability testing was undertaken using a wide range of storage conditions. This method was found suitable for urine analysis of a poisoning involving ingestion of drink made from powdered root of shrub Tabernanthe iboga. 相似文献
60.
Anna M. Trzeciak Petr Štěpni?ka Ewa Mieczyńska 《Journal of organometallic chemistry》2005,690(13):3260-3267
The rhodium complex trans-[Rh(CO)(Hdpf-κP)(dpf-κ2O,P)] (1), (Hdpf = 1′-(diphenylphosphino)ferrocenecarboxylic acid) was used as an efficient and recyclable catalyst for 1-hexene hydroformylation producing ca. 80% of aldehydes at 10 atm CO/H2 and 80 °C. After the reaction, unchanged complex 1 was separated from the reaction mixture and used again three times with the same catalytic activity. The effect of modifying ligands, phosphines and phosphites, on the reactivity of 1 was investigated. The active catalytic systems containing 1 or trans-[Rh(CO)(L)(dpf-κ2O,P)] (2) were formed in situ from acetylacetonato rhodium(I) precursors [Rh(CO)2(acac)] (3) or [RhL(CO)(acac)] (4) and Hdpf or Medpf (L = phosphine, Medpf = methyl ester of Hdpf). 相似文献