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991.
Aniline was polymerised enzymatically in aqueous solution at pH = 4.3 and 25°C in the presence of submicrometer-sized vesicles formed from sodium bis(2-ethylhexyl)sulphosuccinate (AOT). H2O2 served as oxidant and the enzyme used was either horseradish peroxidase isoenzyme C (HRPC) or soybean peroxidase (SBP), both being class III peroxidases. From previous studies with HRPC, it is known that stable vesicle suspensions containing the emeraldine salt form of polyaniline (PANI-ES) can be obtained within 1–2 days with a 90–95 % yield, provided that optimal reaction conditions are applied. Unfortunately, HRPC becomes inactivated during polymerisation. In the present study, a linear dendritic block copolymer was added to HRPC, resulting in higher operational enzyme stability; the stabilising effect, however, was too small to afford a substantial decrease in the required amount of enzyme. Moreover, replacing HRPC with SBP was of no advantage, although SBP is known to be more stable towards inactivation by H2O2 than HRPC. By contrast, SBP was found to be much slower in oxidising aniline, and complete inactivation of SBP occurred before all the aniline monomers were oxidised, leading to low yields and the formation of over-oxidised products. The same was observed for HRP isoenzyme A2. Reactions without vesicles indicated that peroxidase inactivation was probably caused by PANI-ES. 相似文献
992.
Ivan Pavlović Ivan Ćirić Petar Djekić Vlastimir Nikolić Ratko Pavlović Žarko Ćojbašić Goran Radenković 《Meccanica》2013,48(10):2467-2477
Rheological models of tested rubber blend samples, with different ratios of smut/recycled material, were developed, analyzed and discussed according to experimental data. The experimental measurements show the dynamical behavior of these samples after a short-term axial load. The rheological model of samples was assumed as a viscoelastic Voigt-Maxwell and hyperelastic Mooney-Rivlin model. Real coded genetic algorithms were implemented for optimal model parameters identification in order to minimize the difference between the real sample behavior and dynamical model output. Numerical results obtained for analyzed mixture were compared with the original sample to verify the presented method. In purpose of predicting the dynamical characteristics for desirable rubber blends, an interrelation was formed based on the concentration of recycled material in sample blends and dynamical model parameters dependence. 相似文献
993.
Pavel Mikuška Zbyněk Večeřa Ivan Kalinichenko Josef Kellner 《International journal of environmental analytical chemistry》2013,93(10):1038-1049
A sensitive flow-injection method for the chemiluminescent determination of ultra-low concentration of nitrate in water is presented. Nitrate is on-line photolytically converted to peroxynitrite by absorption of UV light inside of 60 mm long quartz capillary (i.d. 530 µm, o.d. 720 µm). Peroxynitrite is subsequently determined by the chemiluminescent reaction with luminol. The detection limit of nitrate is 7 × 10?10 M (S/N = 3). The linear range of the method is 2 × 10?9–1 × 10?5 M nitrate. The interference of nitrite is eliminated by its conversion to nitrogen after mixing of sample with a solution of sulfamidic acid. Other common anions do not interfere. The interference of cations is eliminated by passing the sample through a cation-exchange column. The FIA procedure allows analysing of 15 samples per hour. The method was applied to the determination of nitrate in various real water samples. The results are in good agreement with a reference ion chromatographic method. 相似文献
994.
Ivan R. Pitta Claude Bosso Alexandre J. S. Góes Maria C. A. Lima Suely L. Galdino Cuong Luu-Duc 《光谱学快报》2013,46(3):419-431
In the present investigation, a study of the electron-impact mass spectrometry in positive- and negative-ion modes is reported for a series of 3-chlorobenzyl-5-benzylidene-imidazolidine-2,4-dione and -thiazolidine-2,4-dione derivatives previously synthetized. 相似文献
995.
996.
997.
The increase in the content of the alloying element in electrodeposited alloys reflects in the changes of their phase composition, when the saturation limit of the lattice of the basic metal is reached. At higher percentages, the excess amount of the alloying element forms one or more new, richer in this element phases. The coatings become multi-phase, heterogeneous and their physical–mechanical properties change. Sometimes an ordered distribution of the different phases of the heterogeneous alloy coating could be observed. Examples of self-organization phenomena during electrodeposition of different alloy systems, such as Ag-Sb, Ag-Bi, Ag-In, Ag-Sn, Ag-Cd, Cu-Sb and In-Co, resulting in pattern formation and formation of spatio-temporal structures on the surface of the obtained coatings are presented and compared. Instabilities resulting in potential or current oscillations are registered in most of the investigated systems. The phase composition of the alloy coatings and especially of the observed pattern is determined and some similarities in the structure of the phases forming the pattern are registered. The pattern formation is registered on the cathode not only in cyanide silver alloys electrolytes, but also during deposition of other alloy systems in acidic electrolytes like Cu-Sb and In-Co. The effect of the natural convection in non-agitated electrolytes on the pattern formation is discussed. The possibility of formation of periodic structured coatings without applying external electrical pulses which could result in appropriate modification of some properties of the electrodeposited alloys is demonstrated. The hypothesis that similar pattern formation could be observed in agitated electrolytes at different hydrodynamic and electrolysis conditions, when the same percentage or the same phase composition of the alloy is reached was examined for Ag-Cd, In-Co and Ag-Sb alloys in jet-plating experiments. 相似文献
998.
999.
Ivan Pan 《Bulletin of the Brazilian Mathematical Society》1999,30(1):95-98
Resumé On montre que tout ensemble de générateurs du groupe de Cremona de l'espace projectif de dimension plus grande que 2 doit contenir un nombre infini non dénombrable de transformations non triviales.
We show that any set of generators of the Cremona group ofP n withn greater than 2 contains an infinite non numerable number of non trivial transformations.相似文献
1000.
It is shown that every pseudo-effect algebra can be organized as a total algebra. In general, this total algebra is not unique,
but it always determines the original partial addition. Special attention is paid to lattice-ordered pseudo-effect algebras
for which the total operations can be defined in a unique natural way and this allows one to characterize pairs of compatible
elements. 相似文献