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771.
Éva Jeszenszky László Kocsányi Attila Barócsi Péter Richter 《Macromolecular Symposia》2008,265(1):233-240
Summary: Determining the thickness or identification of polymer materials with building a multivariate calibration model is based on the near infrared spectral information of the material. The spectrum of a thin plastic sheet is modulated by the interference of multiply reflected beams from the boundary surfaces and causes a disturbing signal component. On one hand, this yields unidentifiable samples or introduces large errors in the sample prediction set. On the other hand, interference-patterned spectra have to be excluded from the calibration set. Fourier-transformation of an interference-patterned spectrum vs. wave number leads to a Fourier-spectrum as a function of the optical path length (OPL) containing a well recognizable interference peak. After replacing these interference-components and performing an inverse Fourier-transformation, the spectra can be used for calibration or prediction. Two types of replacing were studied: the spline-interpolation on Fourier- spectrum vs. OPL and a novel method based on linear approximation between Fourier-spectra and thickness values. The effectiveness of each filtering method was tested on low-density polyethylene and polypropylene sheets. 相似文献
772.
Éverton Berwanger Balbom Fabiane Gritzenco Adriane Sperança Marcelo Godoi Diego Alves Thiago Barcellos Benhur Godoi 《Tetrahedron》2019,75(30):4017-4023
This work describes the copper-catalyzed Csp-chalcogen bond formation through cross-coupling reactions of propynylbenzamides and diorganyl dichalcogenides at room temperature, under open atmosphere. Generally, the reactions have proceeded very smoothly, affording the new class of organochalcogen-containing propynylbenzamides in good yields. Notably, this protocol showed to be tolerant to neutral, electron-donating and electron-withdrawing substituents present in both reaction substrates. In addition, the applicability of the carbon-chalcogen bond as a reactive site has been proved by successfully employment of the N-methyl-N-(3-(butylselanyl)prop-2-yn-1-yl)benzamide as a precursor in palladium-catalyzed Suzuki and Sonogashira type reactions. 相似文献
773.
774.
Yu. I. Blokhin L. K. Vasyanina M. Ya. Érgashev É. E. Nifant'ev 《Russian Chemical Bulletin》1992,41(12):2205-2210
Starting from 2,2-di-(p-hydroxyphenyl)propane and phenylphosphonic acid tetraethylamide we have prepared the first oligoarylenephosphonites with spatially separated phosphorus functionalities. We have studied the principal chemical properties of these compounds. We have shown the capacity of oligoarylenediphosphonites to coordinate with transition metals through one or all phosphorus atoms with formation of mono- and oligo complexes. We have found that monocomplexes can undergo degenerated metallotropic rearrangements.V. I. Lenin Moscow Pedagogical State University, 119883 Moscow, Russia. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 12, pp. 2777–2784, December, 1992. 相似文献
775.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 55, No. 2, pp. 225–229, August, 1991. 相似文献
776.
R. A. Vafin M. I. Bashmakova V. A. Romanchenko E. V. Borovko L. A. Levshuk E. V. Chikin D. N. Kachevskii V. I. Berezin Yu. I. Nedranets V. P. Sevost'yanov G. M. Ikonnikova O. M. Ivleva L. E. Popov N. A. Koneva L. A. Teplyakova V. Ya. Épp A. F. Medvedev M. M. Nikitin V. P. Umbras B. F. Minaev D. M. Kizhner Kh. T. Akhmetov I. A. Moroz A. A. Bryukhanov N. G. Nechiporenko V. S. Ivanii Yu. A. Gnedov Yu. I. Romanov 《Russian Physics Journal》1976,19(10):1385-1390
777.
778.
779.
V. P. Martynova N. E. Shelepin N. S. Loseva É. R. Zakhs L. E. Nivorozhkin V. I. Minkin L. S. Éfros 《Chemistry of Heterocyclic Compounds》1971,7(2):152-154
The corresponding merocyanins (II and III), which are not capable of intramolecular cyclization to form spiropyrans, were obtained by the condensation of quaternary salts of 2- and 4-methylquinoline with o-hydroxyaryl aldehydes. In contrast to II and III, the products of the condensation of 5, 6-dimethylphenanthridinium salts with o-hydroxyaryl aldehydes (IV and V) exist, under the usual conditions, in the spiropyran form, while the derivative of 5-nitrosali-cylaldehyde can be isolated in both the cyclic and merocyanin forms. These differences are associated with the magnitude of the positive charge on the carbon atom which participates in closing the pyran ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 167–170, February, 1971. 相似文献
780.