全文获取类型
收费全文 | 292628篇 |
免费 | 2771篇 |
国内免费 | 825篇 |
专业分类
化学 | 138213篇 |
晶体学 | 4099篇 |
力学 | 15172篇 |
综合类 | 16篇 |
数学 | 45263篇 |
物理学 | 93461篇 |
出版年
2021年 | 1319篇 |
2020年 | 1424篇 |
2019年 | 1386篇 |
2018年 | 10724篇 |
2017年 | 11667篇 |
2016年 | 7025篇 |
2015年 | 3272篇 |
2014年 | 3100篇 |
2013年 | 8616篇 |
2012年 | 11749篇 |
2011年 | 21896篇 |
2010年 | 13025篇 |
2009年 | 13141篇 |
2008年 | 19139篇 |
2007年 | 22717篇 |
2006年 | 8031篇 |
2005年 | 15112篇 |
2004年 | 10823篇 |
2003年 | 9414篇 |
2002年 | 6942篇 |
2001年 | 6602篇 |
2000年 | 5290篇 |
1999年 | 3768篇 |
1998年 | 2872篇 |
1997年 | 2851篇 |
1996年 | 3050篇 |
1995年 | 2621篇 |
1994年 | 2498篇 |
1993年 | 2386篇 |
1992年 | 2670篇 |
1991年 | 2583篇 |
1990年 | 2259篇 |
1989年 | 2241篇 |
1988年 | 2252篇 |
1987年 | 2176篇 |
1986年 | 2081篇 |
1985年 | 3034篇 |
1984年 | 3010篇 |
1983年 | 2436篇 |
1982年 | 2618篇 |
1981年 | 2496篇 |
1980年 | 2448篇 |
1979年 | 2400篇 |
1978年 | 2491篇 |
1977年 | 2343篇 |
1976年 | 2294篇 |
1975年 | 2262篇 |
1974年 | 2185篇 |
1973年 | 2295篇 |
1972年 | 1271篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
S. Q. Hou W. Wang Z. Y. Wang Z. W. Hu K. Liu 《Journal of Applied Mechanics and Technical Physics》2018,59(1):153-162
In order to investigate the characteristics of force chains in a granular flow system, a parallel plate shear cell is constructed to simulate the shear movement of an infinite parallel plate and observe variations in relevant parameters. The shear dilatancy process is divided into three stages, namely, plastic strain, macroscopic failure, and granular recombination. The stickslip phenomenon is highly connected with the evolution of force chains during the shear dilatancy process. The load–distribution rate curves and patterns of the force chains are utilized to describe the load-carrying behaviors and morphologic changes of force chains separately. Force chains, namely, “diagonal gridding,” “tadpole-shaped,” and “pinnate” are defined according to the form of the force chains in the corresponding three stages. 相似文献
52.
53.
54.
55.
Thalia Tsiaka Panagiotis Zoumpoulakis Vassilia J. Sinanoglou Constantinos Makris Georgios A. Heropoulos Antony C. Calokerinos 《Analytica chimica acta》2015
High-energy assisted extraction techniques, like ultrasound assisted extraction (UAE) and microwave assisted extraction (MAE), are widely applied over the last years for the recovery of bioactive compounds such as carotenoids, antioxidants and phenols from foods, animals and herbal natural sources. Especially for the case of xanthophylls, the main carotenoid group of crustaceans, they can be extracted in a rapid and quantitative way with the use of UAE and MAE. 相似文献
56.
57.
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
58.
A model with 16 moments is here presented in the framework of RET of polyatomic gases. It furnishes as principal subsystem the relativistic counterpart of a work by Arima T., Ruggeri T., Sugiyama M.; this is present in literature and treats the non relativistic case which incorporates relaxation processes of molecular rotation and vibration. Another principal subsystem is the natural extension of the 14 moments model by Pennisi S. and Ruggeri T.; this is also present in literature in the relativistic framework but where the trace of the third balance equation is neglected. Its extension is found here for the case when this trace isn’t neglected.
相似文献59.
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
60.
Application of TiO2-nanotubes/PbO2 as an anode for the electrochemical elimination of Acid Red 1 dye
Santos José Eudes L. de Moura Dayanne Chianca da Silva Djalma Ribeiro Panizza Marco Martínez-Huitle Carlos A. 《Journal of Solid State Electrochemistry》2019,23(2):351-360
Journal of Solid State Electrochemistry - In this study, galvanostatic electrolysis, through the use of the platinum supported on Ti (Ti/Pt) and Ti/TiO2-nanotubes/PbO2 anodes, was conducted in an... 相似文献