全文获取类型
收费全文 | 477546篇 |
免费 | 5014篇 |
国内免费 | 1072篇 |
专业分类
化学 | 245236篇 |
晶体学 | 7785篇 |
力学 | 21618篇 |
综合类 | 15篇 |
数学 | 63750篇 |
物理学 | 145228篇 |
出版年
2019年 | 3151篇 |
2018年 | 11730篇 |
2017年 | 12553篇 |
2016年 | 9882篇 |
2015年 | 5035篇 |
2014年 | 6410篇 |
2013年 | 17273篇 |
2012年 | 16004篇 |
2011年 | 26244篇 |
2010年 | 16722篇 |
2009年 | 16561篇 |
2008年 | 23084篇 |
2007年 | 26242篇 |
2006年 | 12824篇 |
2005年 | 17859篇 |
2004年 | 13579篇 |
2003年 | 12337篇 |
2002年 | 10197篇 |
2001年 | 10979篇 |
2000年 | 8647篇 |
1999年 | 6537篇 |
1998年 | 5275篇 |
1997年 | 5199篇 |
1996年 | 5292篇 |
1995年 | 4858篇 |
1994年 | 4692篇 |
1993年 | 4524篇 |
1992年 | 5414篇 |
1991年 | 5156篇 |
1990年 | 5041篇 |
1989年 | 5047篇 |
1988年 | 5025篇 |
1987年 | 5060篇 |
1986年 | 4770篇 |
1985年 | 6319篇 |
1984年 | 6358篇 |
1983年 | 5157篇 |
1982年 | 5447篇 |
1981年 | 5474篇 |
1980年 | 5164篇 |
1979年 | 5543篇 |
1978年 | 5820篇 |
1977年 | 5679篇 |
1976年 | 5461篇 |
1975年 | 5080篇 |
1974年 | 5005篇 |
1973年 | 5015篇 |
1972年 | 3330篇 |
1968年 | 3553篇 |
1967年 | 3564篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
83.
84.
V. V. Sagaradze N. V. Kataeva V. A. Zavalishin K. A. Kozlov V. V. Makarov A. R. Kuznetsov 《哲学杂志》2020,100(14):1868-1879
ABSTRACT The authors present the results of an investigation in Fe–Ni-Cr austenitic alloys of the low-temperature deformation-induced segregations of nickel that form in the micro regions being (i) located close to grain- and subgrain boundaries and (ii) characteristic of the concentration and magnetic inhomogeneities indicated by the appearance of a dark diffraction contrast at the electron diffraction patterns taken from these regions typical (at the same time) of an enhanced value of Curie temperature. The observed effects were connected with the micro distortions caused by the local change of lattice parameter because of an increase in nickel concentration, as well as in the result of a magnetostriction dilatation. Using methods of the X-ray energy dispersive spectroscopy (XEDS) and atomic-probe body-section radiography (tomography – APT) has made it possible to determine the borders of those regions of austenite that were characteristic of an enhanced concentration of nickel in the fields of the localisation of a deformation-induced segregation of nickel in the vicinity of grain (subgrain) boundaries of austenitic alloys of the types Fe–13Cr–30Ni and Fe–37Ni–3Ti. 相似文献
85.
I. F. Golovnev E. I. Golovneva L. A. Merzhievsky V. M. Fomin V. E. Panin 《Physical Mesomechanics》2015,18(3):179-186
Molecular dynamics simulation was performed to study the formation of cluster structure, interfaces, and surfaces with different curvature radii in a perfect nanocrystal passed through by a nonlinear wave. It is shown that this process is a type of nanostructure self-organization in response to an external energy flux with subsequent development of a strong rotational field. 相似文献
86.
87.
88.
Mathematical Notes - 相似文献
89.
Acoustical Physics - The problem of pulsed excitation of an acoustic waveguide with a constant cross section is considered. Absorption is ignored. As the most general model of such a waveguide,... 相似文献
90.
Sergio Ayala‐Mar Javier Donoso‐Quezada Roberto C. Gallo‐Villanueva Victor H. Perez‐Gonzalez Jos Gonzlez‐Valdez 《Electrophoresis》2019,40(23-24):3036-3049
Exosomes are nanovesicles secreted by most cellular types that carry important biochemical compounds throughout the body with different purposes, playing a preponderant role in cellular communication. Because of their structure, physicochemical properties and stability, recent studies are focusing in their use as nanocarriers for different therapeutic compounds for the treatment of different diseases ranging from cancer to Parkinson's disease. However, current bioseparation protocols and methodologies are selected based on the final exosome application or intended use and present both advantages and disadvantages when compared among them. In this context, this review aims to present the most important technologies available for exosome isolation while discussing their advantages and disadvantages and the possibilities of being combined with other strategies. This is critical since the development of novel exosome‐based therapeutic strategies will be constrained to the effectiveness and yield of the selected downstream purification methodologies for which a thorough understanding of the available technological resources is needed. 相似文献