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991.
In order to check if the parametrized crystal field approach is efficient in the analysis of an EPR powder spectrum we study defects of known geometry as if we did not know it. The g tensor of an interstitial V4+ ion in a single crystal of rutile TiO2 can be interpreted without ambiguity, and the optimized parameters compare well with their theoretical values. For an interstitial Ti3+ ion, two solutions are found: both of them correspond to interstitial positions, but they differ in the principal axis orientation. 相似文献
992.
[reaction: see text] N-Acylsulfonamides usually react with nucleophiles by acyl transfer and C-N bond fission. However, the hydrolysis of N-acyl beta-sultams is a sulfonyl transfer reaction that occurs with S-N fission and opening of the four-membered ring. Similar to other beta-sultams, the N-acyl derivatives are at least 10(6)-fold more reactive than N-acyl sulfonamides. 3-Oxo-beta-sultams are both beta-lactams and beta-sultams but also hydrolyze with preferential S-N bond fission. 相似文献
993.
994.
Hamdi N. Feutelais Y. Yagoubi N. de Girolamo D. Legendre B. 《Journal of Thermal Analysis and Calorimetry》2004,76(3):985-1001
Indomethacin is known to exhibit polymorphism and solvates, the different forms obtained do not exhibit the same solubility
and their bioavailabilities are different. It is of a prime importance to identify the various polymorphic and solvated forms.
This study was carried out by: DSC (different scanning calorimetry), TG (thermogravimetric analysis), X-ray diffraction and
thermomicroscopy. Seven solvates, with acetone, benzene, dichloromethane, tetrahydrofurane, propanol, chloroform and diethylether,
were isolated and studied. Their formulae have been determined by thermogravimetric analysis and their X-ray patterns on powder
are presented, by DSC their behaviour after desolvation is recorded, the temperature and the enthalpy of fusion are measured
and by this way the form obtained is deduced.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
995.
Kinoshita M Murakami E Oda Y Funakubo T Kawakami D Kakehi K Kawasaki N Morimoto K Hayakawa T 《Journal of chromatography. A》2000,890(2):261-271
Frontal affinity chromatography is a method for quantitative analysis of biomolecular interactions. We reinforced it by incorporating various merits of a contemporary liquid chromatography system. As a model study, the interaction between an immobilized Caenorhabditis elegans galectin (LEC-6) and fluorescently labeled oligosaccharides (pyridylaminated sugars) was analyzed. LEC-6 was coupled to N-hydroxysuccinimide-activated Sepharose 4 Fast Flow (100 μm diameter), and packed into a miniature column (e.g., 10×4.0 mm, 0.126 ml). Twelve pyridylaminated oligosaccharides were applied to the column through a 2-ml sample loop, and their elution patterns were monitored by fluorescence. The volume of the elution front (V) determined graphically for each sample was compared with that obtained in the presence of an excess amount of hapten saccharide, lactose (V0); and the dissociation constant, Kd, was calculated according to the literature [K. Kasai, Y. Oda, M. Nishikawa, S. Ishii, J. Chromatogr. 376 (1986) 33]. This system also proved to be useful for an inverse confirmation; that is, application of galectins to an immobilized glycan column (in the present case, asialofetuin was immobilized on Sepharose 4 Fast Flow), and the elution profiles were monitored by fluorescence based on tryptophan. The relative affinity of various galectins for asialofetuin could be easily compared in terms of the extent of retardation. The newly constructed system proved to be extremely versatile. It enabled rapid (analysis time 12 min/cycle) and sensitive (20 nM for pyridylaminated derivatives, and 1 μg/ml for protein) analyses of lectin–carbohydrate interactions. It should become a powerful tool for elucidation of biomolecular interactions, in particular for functional analysis of a large number of proteins that should be the essential issues of post-genome projects. 相似文献
996.
The concentration of cobalt in 2 solid matrices was determined by neutron activation analysis (NAA) using standard solutions which were prepared by dissolving pure cobalt in nitric acid. The matrices assayed were a cobalt-aluminium wire and an iron foil and the respective Co concentrations found were 0.488% and 0.138%. Both solid materials can equally be used as standard references of cobalt in NAA. Subcadmium and epicadmium neutron fluxes in the reactor core were determined using Co?Al and Au?Al alloy wires. Very good agreement was obtained for all irradiation configurations of the target monitors cobalt and gold. 相似文献
997.
Sinomenine, an alkaloid of the Japanese plant Sinomenium acutum, was converted to the 4-phenylether by the Ullmann reaction in a good yield. The Clemmensen reduction of sinomenine-phenylether and of its derivatives gave (+)-3-methoxy-4-phenoxy-N-methyl-Δx-morphinan.
Hydrogenation and successive sodium-liquid ammonia reduction of (+)-3-methoxy-4-phenoxy-N-methyl-Δx-morphinan gave (+)-3-methoxy-N-methylmorphinan. 相似文献
998.
The room-temperature phosphorescence (r.t.p.) and fluorescence spectra of benzoquinoline isomers are investigated. The isomers can be resolved into the linear or angular subgroups on the basis of their fluorescence and r.t.p. spectra by using conventional fixed excitation. Second-derivative and synchronous scanning techniques can be combined to improve the selectivity of the r.t.p. and fluorescence methods. These simple luminescence techniques were used to estimate three benzoquinoline isomers in a coal tar fraction. Direct analysis of this complex sample allowed acridine to be estimated and upper limits to be provided for benzo(h)quinoline and phenanthridine; the presence of three other isomers was not detected. Comparative studies with data obtained by high-performance liquid chromatography are reported. 相似文献
999.
A set of seven bituminous coal chars has been characterised by IR spectroscopy (FTIR), thermogravimetry (TG) and elemental analysis. FTIR study provided suitable information to establish differences between coal samples according to their chemical compositions. The reactivity of these samples was also studied and correlated with the coal parameters of mean vitrinite reflectance, fuel ratio and H/C ratio. The data suggest that reactivity as determined can be correlated with the mean vitrinite reflectance, fuel ratio and H/C ratio (0.90). The order of reactivity of samples were; Amasra (S1) (R m= 0.65)>Azdavay (S4) (R m=0.99)»Armutcuk (S2) (R m=0.81)»Acenta (S3) (R m=0.92)>Ac2l2k (S6) (R m=1.11) Cay (S5) (R m=1.03)>Sogutozu (S7) (R m=2.14). 相似文献
1000.
Y. Kamino 《Radiation Physics and Chemistry》1998,52(1-6):469-473
A 10MeV 25KW plus class electron LINAC was developed for sterilisation of medical devices. The LINAC composed of a standing wave type single cavity prebuncher and a 2m electro-plated travelling wave guide uses a 5MW 2856MHz pulse klystron as an RF source and provides 25KW beam power at the Ti alloy beam window stably after the energy analysing magnet with 10MeV plus-minus 1 MeV energy slit. The practical maximum beam power reached 29 KW and this demonstrated the LINAC as one of the most powerful S-band electron LINACs in the world. The control of the LINAC is fully automated and the “One-Button Operation” is realised, which is valuable for easy operation as a plant system. 2 systems have been delivered and are being operated stably. 相似文献