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981.
We prepared a phenobarbital (PB) solid dispersion (SD) with phosphatidylcholine (PC). PB was present in an amorphous state in SD if its mole fraction was under 0.75. An infrared (IR) spectra study suggested a hydrogen bond between NH in PB and phosphate in PC, with a ratio of about 1:1. When the mole fraction of PB was less than 0.50, differential scanning calorimetry (DSC) curves showed endothermic peaks at 57, 90 and 145 degrees C, and an exothermic peak at 60 degrees C. The IR spectrum and X-ray diffraction pattern changed after holding at 70 degrees C, so at this point it is considered that the metastable state of SD changed into a stable state, and extra energy was released. When the mole fraction of PB was high, PB also arranged near hydrophobic group because an endothermic peak was observed at 46-52 degrees C, which was lower than fully hydrated PC. PB is similar to indomethacin (IM) in molecular shape and to phenytoin (PHT) in chemical structure. Its DSC curve and IR spectra are similar to PHT, and the limit ratio of its amorphous state is the same as IM. It is considered that the chemical structure is an important factor in its interaction to PC, and also, the molecular shape is important to arrange into PC lattice. 相似文献
982.
M. Asai J. L. Bailly H. B?ttcher F. Bruyant C. Caso Y. Chiba H. Dibon B. Epp A. Ferrando F. Fontanelli S. N. Ganguli T. Gémesy R. Hamatsu P. Hidas T. Hirose J. Hrubec T. Kageya N. Khalatyan E. Kistenev I. Kita S. Kitamura V. Kubik J. MacNaughton M. Markytan S. Matsumoto I. S. Mittra L. Montanet G. Neuhofer G. Pinter P. Porth T. Rodrigo J. Singh S. Squarcia K. Takahashi R. Tanaka L. A. Tikhonova U. Trevisan R. Wischnewski T. Yamagata S. A. Zotkin NA EHS-RCBC Collaboration 《Zeitschrift fur Physik C Particles and Fields》1990,46(4):593-598
Properties of proton diffractive dissociation have been investigated for four-prong final states in proton-proton reactions at 360 GeV/c, in particular forpp→ppπ +π? mπ 0(m=0,1,2). Mass distributions and decay angular distributions are given. The decay of the diffractive system is seen to be very anisotropic, and largep T is suppressed at higher masses. It is found that the “pomeron” couples with a single valence quark of the incident proton, but indications for a diquark-pomeron coupling are also found. Similarities with fragmentation in lepton-hadron deep inelastic scattering are underlined. 相似文献
983.
Eiichi Kobayashi Junji Furukawa Shiro Nagata 《Journal of polymer science. Part A, Polymer chemistry》1979,17(7):2093-2101
In the presence of an optical active amyloxyaluminum or menthoxyaluminum chloride the asymmetric-induction alternating copolymerization of benzofuran or 1,3-cyclooctadiene and acrylonitrile or methacrylonitrile was investigated. The sign of optical rotation of copolymers was positive or negative, depending on the kind of catalyst used. The optical activity of copolymers of benzofuran and acrylonitrile attains a maximum value at an equimolar composition. The highest specific rotation [α]D of copolymers of benzofuran and acrylonitrile prepared in the presence of stoichiometric amount of (—)-menthoxyaluminum dichloride with respect to acrylonitrile was about ?8°. The stereo-structure of acrylonitrile unit may be controlled by the optical active aluminum compound onto which a strong coordination of acrylonitrile may occur. 相似文献
984.
Shiro Hirota Takashi Fujikawa 《Journal of Electron Spectroscopy and Related Phenomena》1982,28(1):95-109
Dynamic theory developed previously by the authors is applied to photoionization from delocalized molecular orbitals. EXAFS-like oscillation is observed in any case, but the origin, period and magnitude differ from those of EXAFS usually observed in core photoionization. Numerical calcu- lations are performed in the energy range k = 3–6 a.u. for three molecules: H2O, CO and CO2. Analysis of such oscillatory behavior aids in the characterization of photoionized orbitals. 相似文献
985.
The crystal and molecular structure of [N,N′-(3,3′-dipropylamine)bis(salicyclideneaminato)-monoacetate]cobalt(III) complex has been determined by a three-dimensional X-ray diffraction study. In the complex, the cobalt ion has an octahedral coordination environment with cis-geometry for the two salicyclideneaminato moieties. An oxygen atom of the acetate ion is coordinated to cobalt ion and another oxygen atom is hydrogen-bonded to the secondary amine nitrogen atom. 相似文献
986.
Summary A numerical method for determining the distribution function of relaxation times from the decay curve of electric birefringence in macromolecular solutions has been described. The distribution function is expanded in a series of appropriate functions, and the best values of the coefficients are determined by the method of least squares. An application of this method to poly-Lglutamic acid in methanol is presented. It is shown that the distribution of molecular lengths can be obtained from the relaxation spectrum in the case of helical polypeptides in solution.
Zusammenfassung Es wird eine numerische Methode beschrieben, die die Relaxationszeit-Verteilungsfunktion aus der Abklingkurve der elektrischen Doppelbrechung bei makromolekularen Lösungen zu bestimmen erlaubt. Die Verteilungsfunktion wird in eine Reihe geeigneter Funktionen entwickelt und die besten Werte der Koeffizienten werden nach der Methode der kleinsten Quadrate bestimmt. Eine Anwendung dieser Methode zur Poly-L-glutaminsäure in Methanol-Lösung wird exemplifiziert. Es zeigt sich, daß die Verteilung von Moleküllängen im Falle helicaler Polypeptide aus dem Relaxationsspektrum gewonnen wird.相似文献
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