全文获取类型
收费全文 | 1884篇 |
免费 | 97篇 |
国内免费 | 6篇 |
专业分类
化学 | 1506篇 |
晶体学 | 15篇 |
力学 | 24篇 |
数学 | 87篇 |
物理学 | 355篇 |
出版年
2023年 | 11篇 |
2022年 | 35篇 |
2021年 | 59篇 |
2020年 | 47篇 |
2019年 | 52篇 |
2018年 | 24篇 |
2017年 | 29篇 |
2016年 | 70篇 |
2015年 | 68篇 |
2014年 | 74篇 |
2013年 | 123篇 |
2012年 | 166篇 |
2011年 | 180篇 |
2010年 | 110篇 |
2009年 | 92篇 |
2008年 | 130篇 |
2007年 | 104篇 |
2006年 | 93篇 |
2005年 | 93篇 |
2004年 | 87篇 |
2003年 | 58篇 |
2002年 | 68篇 |
2001年 | 37篇 |
2000年 | 26篇 |
1999年 | 31篇 |
1998年 | 18篇 |
1997年 | 12篇 |
1996年 | 14篇 |
1995年 | 8篇 |
1994年 | 12篇 |
1993年 | 7篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 5篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有1987条查询结果,搜索用时 0 毫秒
81.
Park Hye Min Kim Jeong Ho Kim Young Seok Kang Sung Won Oh Dae Min Lee Un Jang Kim Do Hyung Joo Koan Sik 《Journal of Radioanalytical and Nuclear Chemistry》2018,317(2):1051-1057
Journal of Radioanalytical and Nuclear Chemistry - An in situ detector for radiological assessments of strontium-90 (90Sr) in river and lake water is developed, based on a CaF2(Eu) scintillator,... 相似文献
82.
Chung Won Sang Hassanabadi Hassan 《International Journal of Theoretical Physics》2019,58(6):1791-1802
In this paper we show that the position representation of the higher order generalized uncertainty principle (HGUP) is also well defined without approximation. We find the simpler form of this representation with a help of the signature of the discriminant of the cubic equation. Using this we discuss the HGUP derivative, HGUP exponential and HGUP trigonometric functions and HGUP-corrected Bohr atom model. Finally we discuss the D-dimensional HGUP algebra and compute the cosmological constant.
相似文献83.
Sung Hwan Hwang Gye Won Kim Woo-Jin Lee Myoung Jin Kim Eun Joo Jung Jong Bae An Byung Sup Rho 《Optical and Quantum Electronics》2014,46(10):1321-1327
A compact, highly efficient, and passively assembled parallel optical-electrical convertor module (POECM) for active optical cable application is proposed. This paper presents our POECM structure, optical design simulation results, fabrication process, and data transmission test results, in sequence. The POECM has a compact size of \(18.5\hbox {mm} \times 10\hbox {mm} \times 2.8\hbox {mm}\) . We confirm a data rate of total throughput at 21.6 Gbps ( \(5.4\hbox {Gbps} \times 4\) channels) with a bit error rate of less than \(10^{-12}\) . 相似文献
84.
In the asymptotically flat two-dimensional dilaton gravity, we present an N-body particle action which has a dilaton coupled mass term for the exact solubility. This gives nonperturbative exact solutions for the N-body self-gravitating system, so the infalling particles form a black hole and their trajectories are exactly described. In our two-dimensional case, the critical mass for the formation of black holes does not exist, so even a single particle forms a black hole. The infalling particles give additional time-like singularities in addition to the space-like black hole singularity. However, the latter singularities can be properly cloaked by the future horizons within some conditions. 相似文献
85.
Ultrafine particles of BaMgAl10O17:Eu2+ (BAM) phosphor were synthesized by a solid-state combustion reaction in a powder bed of 0.9BaCO3+MgO+5Al2O3+0.05Eu2O3+k(KClO3+1.5C) composition. A large exothermic reaction of the mixture (KClO3+1.5C) leads to a self-sustaining combustion mode. Under optimized combustion conditions, the product consisted of BAM powder and KCl was obtained. BAM ultrafine particles resulting from the combustion process were easily obtained by simply washing the salt by-product with water. Combustion-processed BAM phosphor shows a homogeneous grain size of 100-500 nm, good dispersity, regular morphology, and improved luminescence properties. 相似文献
86.
87.
本文研究了活动轮廓模型初始化的问题.利用EM算法和小波多尺度边缘检测的方法,获得了活动轮廓模型的外部能量函数和初始曲线,并对于具体的X射线图像给出了实验结果和该算法的有效性. 相似文献
88.
In this paper,we consider a possible modification of the de Sitter and anti-de Sitter space for the extended uncertainty principle.For the modified anti-de Sitter model we discuss the representation and wave functions of the momentum operator for a one-dimensional box problem.Also,we consider modified Snyder and anti-Snyder models for the generalized uncertainty principle.Then,we assume the Hamiltonian with different potential and solve the Heisenberg algebra for the modified(anti)-de Sitter and(anti)-Snyder models in both position and in the momentum space. 相似文献
89.
This paper considers the problem of passivity-based controller design for Hopfield neural networks. By making use of a convex representation of nonlinearities, a feedback control scheme based on passivity and Lyapunov theory is presented. A criterion for existence of the controller is given in terms of linear matrix inequality (LMI), which can be easily solved by a convex optimization problem. An example and its numerical simulation are given to show the effectiveness of the proposed method. 相似文献
90.
R. Nirmala R. Navamathavan Jeong Jin Won Kyungsoo Jeon R. Afeesh Hak Yong Kim 《Journal of Physics and Chemistry of Solids》2012,73(11):1326-1330
The electrical characteristics of nylon-6 nanofibers incorporated with TiO2 and Fe3O4 nanoparticles were investigated. The resultant nanofibers exhibited good incorporation of nanoparticles. The impregnated TiO2 and Fe3O4 nanoparticles into the nylon-6 nanofibers were confirmed by high resolution transmission electron microscopy (HR-TEM) and energy dispersive X-ray (EDX) spectroscopy studies. The electrical conductivity of the nylon-6 incorporated with TiO2 and Fe3O4 composite nanofibers were higher than that of the pristine nylon-6 nanofibers. The impregnation of TiO2 and Fe3O4 nanoparticles significantly enhanced the electrical property of the composite nanofibers. These polymeric/nanoparticles composite nanofibers structure may open a new direction for future organic electronics. 相似文献