全文获取类型
收费全文 | 982篇 |
免费 | 6篇 |
国内免费 | 1篇 |
专业分类
化学 | 396篇 |
晶体学 | 13篇 |
力学 | 83篇 |
数学 | 168篇 |
物理学 | 329篇 |
出版年
2021年 | 13篇 |
2020年 | 17篇 |
2019年 | 18篇 |
2018年 | 31篇 |
2017年 | 28篇 |
2016年 | 35篇 |
2015年 | 12篇 |
2014年 | 21篇 |
2013年 | 42篇 |
2012年 | 44篇 |
2011年 | 42篇 |
2010年 | 33篇 |
2009年 | 40篇 |
2008年 | 29篇 |
2007年 | 52篇 |
2006年 | 34篇 |
2005年 | 27篇 |
2004年 | 19篇 |
2003年 | 27篇 |
2002年 | 14篇 |
2001年 | 17篇 |
2000年 | 14篇 |
1999年 | 8篇 |
1998年 | 18篇 |
1997年 | 18篇 |
1996年 | 16篇 |
1995年 | 14篇 |
1992年 | 17篇 |
1991年 | 14篇 |
1989年 | 12篇 |
1988年 | 10篇 |
1987年 | 12篇 |
1986年 | 14篇 |
1984年 | 13篇 |
1983年 | 11篇 |
1982年 | 9篇 |
1981年 | 12篇 |
1979年 | 9篇 |
1978年 | 15篇 |
1977年 | 11篇 |
1976年 | 10篇 |
1975年 | 11篇 |
1974年 | 13篇 |
1973年 | 10篇 |
1972年 | 8篇 |
1971年 | 13篇 |
1970年 | 9篇 |
1969年 | 9篇 |
1968年 | 6篇 |
1966年 | 6篇 |
排序方式: 共有989条查询结果,搜索用时 15 毫秒
1.
Nikitin D. Lipatova I. Naumova I. Sirotkin N. Pleskunov P. Krakovský I. Khalakhan I. Choukourov A. Titov V. Agafonov A. 《Plasma Chemistry and Plasma Processing》2020,40(1):207-220
Plasma Chemistry and Plasma Processing - The combination of an atmospheric pressure plasma afterglow operated in air with wet grafting was utilized for the immobilization of chitosan on the surface... 相似文献
2.
Rogozhkin S. V. Khomich A. A. Bogachev A. A. Nikitin A. A. Khoroshilov V. V. Kulevoy T. V. Fedin P. A. Pryanishnikov K. E. Lukyanchuk A. A. Raznitsyn O. A. Shutov A. S. Zaluzhnyi A. G. Vasiliev A. L. Presniakov M. Yu. 《Physics of Atomic Nuclei》2020,83(11):1519-1528
Physics of Atomic Nuclei - Improved mechanical properties of oxide dispersion strengthened (ODS) steels, the advanced materials for the reactor core, are due to the high density of uniformly... 相似文献
3.
4.
5.
Savchenko V. I. Ozerskii A. V. Fokin I. G. Nikitin A. V. Arutyunov V. S. Sedov I. V. 《Russian Journal of Applied Chemistry》2021,94(4):509-517
Russian Journal of Applied Chemistry - Various options for designing the direct oxidation of natural gas to methanol are considered: flow-through, with a distributed supply of the oxidizer along... 相似文献
6.
Sergey V. Nikitin Dmitriy A. Parkhomenko Mariya V. Edeleva Elena G. Bagryanskaya 《Journal of polymer science. Part A, Polymer chemistry》2015,53(21):2546-2556
Simulation on the kinetic scheme of enhanced spin capturing polymerizations (ESCP) were performed to reveal the influence of different parameters, e.g., initiation rate, spin capturing and side reactions on the properties (the monomer conversion, degree of polymerization, polydispersity index, and the fraction of “living” chains) of polymer obtained. The kinetic scheme of ESCP was solved numerically as well as the method of statistical moments of molecular weight distribution was applied to get some numerical expressions for analysis. The simulations showed that fast initiation rate can lead to decrease of living fraction and broadening of molecular weight distribution. Whereas high rate of spin capturing makes the polymer chains shorter but increases living character. And side reactions always decrease livingness of the polymer obtained. Finally in the case of absence of side reaction we were able to formulate criteria for formation of polymer with target molecular weight and quota of living chains via ESCP process. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2546–2556 相似文献
7.
8.
N. V. Nikitin 《Fluid Dynamics》2003,38(6):854-861
Turbulent flow of an incompressible fluid in a plane channel with parallel walls is considered. The three-dimensional time-dependent Navier-Stokes equations are solved numerically using the spectral finite-difference method. An artificial force which completely suppresses lateral oscillations of the velocity is introduced in the near-wall zone (10 % of the channel half-width in the neighborhood of each wall). Thus, the three-dimensional flow zone, in which turbulent oscillations can develop, is separated from the wall by a fluid layer. It is found that the elimination of three-dimensionality in the neighborhood of the walls leads to a significant reduction in the drag. However, complete laminarization does not occur. The flow in the stream core remains turbulent and can be interpreted as a turbulent flow in a channel with walls located on the boundary of the two-dimensional layer and traveling at the local mean-flow velocity. The oscillations developing inside the two-dimensional layer, which have significant amplitude, distort the flow only in the adjacent zone. Beyond this zone the distributions of the mean characteristics and the structure of instantaneous fields completely correspond to ordinary turbulent flow in a channel with rigid walls. The results obtained confirm the hypothesis of the unimportance of the no-slip boundary conditions for the fluctuating velocity component in the mechanism of onset and self-maintenance of turbulence in wall flows. 相似文献
9.
Thermal convection in an elongated parallelepiped is considered in the case when different temperatures are maintained on the short faces while the other faces are thermally insulated. On the basis of a stability analysis of the main flow in an infinite channel and of the numerical solution of the three-dimensional Navier-Stokes equations in the Boussinesq approximation in a closed channel, the spatial convection structure is studied as a function of the Grashof number, the length, and the width of the domain.Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 4, pp. 28–37, July–August, 1996. 相似文献
10.
Summary The bending of a finite-length beam that lies on a rigid, rough, flat foundation and interacts with it in accordance to the
dry friction law is considered. Loading by bending moments applied at the ends of the beam is studied in detail. The problem
is found to be a self-similar one. For small moments, the central part of the beam remains undeflected, and the problem reduces
to the solution of an infinite system of algebraic equations. Large moments deflect the entire length of the beam, and the
problem partly loses its self-similarity. In this case, the problem reduces to the solution of a successively decreasing number
of ordinary differential equations along with some algebraical equations. The solution for the latter case provides initial
conditions for the former one. This permits to obtain a solution for any value of the moment.
Received 5 November 1996; accepted for publication 27 January 1997 相似文献