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971.
Watano S Okamoto T Tsuhari M Koizumi I Osako Y 《Chemical & pharmaceutical bulletin》2002,50(3):341-345
A novel multi-functional vertical high shear kneader has been developed. Wet kneading of pharmaceutical powders was conducted under various blade components and operating conditions. Compression properties of wet kneaded mass was analyzed and dispersion of hinder liquid (water) among the mass was investigated by assaying tracer aqueous pigment. Pellets were produced through a dome type extrusion granulator with continuous extrusion pressure measurement device and a fluidized bed drier, and then the physical properties were measured. Quantitative relationship between the pellet's physical properties and the binder dispersion condition as well as the compression properties could be obtained. It was found that the newly developed kneader was very effective to uniformly disperse binder as well as impart high shear stress to the wet mass without generating obvious adhesion onto the vessel wall. It was also pointed out that the extrusion pressure could determine the physical strength of pellet. This method proposes a new methodology for continuous monitoring of kneading condition as well as predicting pellet's physical properties. 相似文献
972.
Kabashima Si Kuwata S Ueno K Shiro M Hidai M 《Angewandte Chemie (International ed. in English)》2000,39(6):1128-1131
973.
Time-resolved measurement of He (2 3S) concentration by its optical absorption after electron pulse irradiation of HeN2 mixtures confirms that the optical emission of N+2(B 2Σ+u → X 2Σ+g) is based on the energy transfer (Penning ionization) from He (2 3S) to N2. The addition of other atoms and molecules to HeN2 mixtures changes the decay rate of the optical emission N+2(B 2Σ+u → X 2Σ+g), which is a detector of He (2 3S), and gives the rate constant of He (2 3S) de-excitation by various atoms and molecules. Our results are discussed from the viewpoint of a gas-kinetic collision model. 相似文献
974.
Tsubaki K Miura M Morikawa H Tanaka H Kawabata T Furuta T Tanaka K Fuji K 《Journal of the American Chemical Society》2003,125(52):16200-16201
Synthesis of numerous optically active rod-shaped oligo(2,3-dioxyfunctionalized)naphthalenes connected at their 1,4-positions was achieved using oxidative coupling under CuCl2/alpha-methylbenzylamine conditions by second-order asymmetric transformation. We believe this method is practical and should contribute to the field of material science. 相似文献
975.
[reaction: see text] 6(A),6(D)-Bispyridinio-appended gamma-cyclodextrin effectively enhanced the excimer fluorescence of 2-naphthylacetate. This increase derived from the increase of formation of the 1:2 complex between the cation-charged gamma-cyclodextrin and 2-naphthylacetate by the electrostatic interaction between the host and the guest. 相似文献
976.
Diels-Alder reactions of acyclic oligoether-substituted quinones 1b, 1c, 2b, and 2c with cyclopentadiene were accelerated by the addition of alkali and alkaline earth metal perchlorates, and scandium trifluoromethane sulfonate (k(c)/k(f) = 1.2-23 for univalent cations, 11-1160 for divalent cations, and 1700-192 000 for Sc(3+), where k(c) and k(f) are the rate constants for the metal complexed and uncomplexed quinones, respectively). The shorter-armed 1a, 2a, and 3, however, exhibited no such acceleration effects. The rate accelerations can be rationalized by the FMO consequence in which the bound guest cation withdraws electron density from the quinone dienophile and lowers the LUMO energy suitable for the orbital interaction with the HOMO of cyclopentadiene. Despite the poor cation selectivity, these acyclic oligoether quinones showed larger rate accelerations than the relevant quinocrown ethers 4 (k(c)/k(f) = 1.3-3.0 for univalent cations, 5.0-160 for divalent cations, and 100-2020 for Sc(3+)). The effective electron withdrawal, which leads to the enhanced rate acceleration, can be caused by the direct interaction between the metal cation accommodated in the pseudo-cyclic oligoether linkage and the quinone carbonyl oxygen, as indicated by (1)H NMR spectroscopy. In addition, the larger rate enhancement is rather achieved in the complex with low binding constant K, because the strong encapsulation of metal cation by the oligoether chain diminishes the crucial interaction to the quinone carbonyl oxygen. As a whole, the smaller and higher valent cations tend to bring about notable rate acceleration due to the more enhanced ion-dipole interaction with the quinone carbonyl oxygen. Spectroscopic titration (absorption and (1)H NMR) and kinetic experiments indicated that only the longest di-armed 2c constructs 1:1, and then 1:2, host/guest complexes with Ca(2+), Sr(2+), and Ba(2+). These 1:2 complexes exhibited the most effective acceleration for the respective metal cations. 相似文献
977.
978.
Tatsuhiko Kanmera Haruhiko Aoyagi Michinori Waki Tetsuo Kato Nobuo Izumiya Kosaku Noda Tamio Ueno 《Tetrahedron letters》1981,22(37):3625-3628
Syntheses of cyclotetradepsipeptides, AM-toxin III and two analogs, were achieved, in which the Hofmann degradation method was used in order to derive a dehydroalanine residue from a 2,3-diaminopropionic acid residue in cyclodepsipeptide precursors. 相似文献
979.
H Harada Y Ueno M Kamei R Ohura N Tanabe Y Uchida F Koyama T Yamaguchi 《Biomedical chromatography : BMC》1989,3(3):110-113
Fluorescein isothiocyanate (FITC)-labelled asialotransferrin and pyridyl aminated oligosaccharides were prepared from asialotransferrin and human milk using affinity chromatography and high performance liquid chromatography (HPLC), respectively. These substances were incubated with galactosidase or sialyltransferase and then examined by lectin affinity HPLC. The elution patterns changed according to the period of incubation and amount of enzyme. This analytical method using lectin affinity HPLC with fluorescence labelled glycoprotein or oligosaccharides as the substrates has great value for detecting these enzyme under the same chromatographic conditions. In addition, differences were noted in the activity of beta-galactosidase toward oligosaccharides having the Gal beta(1----3)GlcNAc or Gal beta(1----4)GlcNAc structure at reducing termini. 相似文献
980.
Various functional group-substituted cyclopropanes were prepared in good yield starting from β-tributylstannylproprionaldehyde via homoallylstannanes or γ-hydroxypropylstannanes. 相似文献