全文获取类型
收费全文 | 1604篇 |
免费 | 58篇 |
国内免费 | 21篇 |
专业分类
化学 | 923篇 |
晶体学 | 7篇 |
力学 | 74篇 |
数学 | 420篇 |
物理学 | 259篇 |
出版年
2023年 | 15篇 |
2022年 | 39篇 |
2021年 | 58篇 |
2020年 | 60篇 |
2019年 | 62篇 |
2018年 | 60篇 |
2017年 | 53篇 |
2016年 | 79篇 |
2015年 | 40篇 |
2014年 | 63篇 |
2013年 | 118篇 |
2012年 | 94篇 |
2011年 | 87篇 |
2010年 | 71篇 |
2009年 | 54篇 |
2008年 | 84篇 |
2007年 | 76篇 |
2006年 | 50篇 |
2005年 | 55篇 |
2004年 | 41篇 |
2003年 | 34篇 |
2002年 | 32篇 |
2001年 | 10篇 |
2000年 | 15篇 |
1999年 | 17篇 |
1998年 | 17篇 |
1997年 | 14篇 |
1996年 | 16篇 |
1995年 | 18篇 |
1994年 | 15篇 |
1993年 | 9篇 |
1992年 | 7篇 |
1991年 | 10篇 |
1990年 | 8篇 |
1989年 | 8篇 |
1988年 | 8篇 |
1987年 | 9篇 |
1985年 | 23篇 |
1984年 | 11篇 |
1983年 | 9篇 |
1982年 | 16篇 |
1981年 | 19篇 |
1980年 | 13篇 |
1979年 | 12篇 |
1978年 | 10篇 |
1977年 | 13篇 |
1976年 | 10篇 |
1975年 | 11篇 |
1973年 | 6篇 |
1972年 | 6篇 |
排序方式: 共有1683条查询结果,搜索用时 15 毫秒
101.
Pham Y. Yu Y. K. Manh T. V. Gamzatov A. Tartakovsky D. M. Yu S.-C. Yang D.-S. Kim D.-H. 《Physics of the Solid State》2020,62(5):845-850
Physics of the Solid State - Structural and magnetic properties of Sr-doped Pr0.7Ba0.3MnO3 polycrystallines prepared by solid state reaction are presented. Samples were in monoclinic structure... 相似文献
102.
Dr. Tran Quang Hung Dr. Ferial Terki Dr. Souleymane Kamara Mourad Dehbaoui Prof. Salam Charar Brajalal Sinha Prof. CheolGi Kim Dr. Philippe Gandit Il'ya A. Gural'skiy Dr. Gabor Molnar Dr. Lionel Salmon Dr. Helena J. Shepherd Dr. Azzedine Bousseksou 《Angewandte Chemie (International ed. in English)》2013,52(4):1185-1188
103.
Spin gapless semiconductor like Ti2MnAl film as a new candidate for spintronics application 下载免费PDF全文
Wuwei Feng Xiao Fu Caihua Wan Zhonghui Yuan Xiufeng Han Nguyen Van Quang Sunglae Cho 《固体物理学:研究快报》2015,9(11):641-645
A novel Heusler ferrimagnet Ti2MnAl film has been grown on Si(001) substrate using magnetron sputtering. Characteristics of its magnetic and transport properties reveal the spin‐gapless‐semiconductor (SGS) nature of the stoichiometric Ti2MnAl, in agreement with theoretical prediction. The as‐grown SGS‐like Ti2MnAl film demonstrated high Curie temperature, nearly compensated ferrimagnetic properties with small coercivity and low magnetization. It also showed semiconductor‐like behavior at room temperature allowing good compatibility with commercial Si‐based semiconductor. In this regards, Ti2MnAl film is a potential candidate material for spintronics application, especially for the minimization of energy consumption of device. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
104.
105.
106.
107.
This paper presents a novel geometric non-linear finite element formulation for the analysis of shear deformable two-layer beams with interlayer slips. We adopt the co-rotational approach where the motion of the element is decomposed into two parts: a rigid body motion which defines a local coordinate system and a small deformational motion of the element relative to this local coordinate system. The main advantage of this approach is that the transformation matrices relating local and global quantities are independent to the choice of the geometrical linear local element. The effect of transverse shear deformation of the layers is taken into account by assuming that each layer behaves as a Timoshenko beam element. The layers are assumed to be continuously connected and partial interaction is considered by considering a continuous relationship between the interface shear flow and the corresponding slip. In order to avoid curvature and shear locking phenomena, the local linear element is formulated using “exact” displacement shape functions derived from the closed-form solution of the governing equations of a two-layer beam element. Finally, three numerical applications are presented in order to assess the performance of the proposed formulation. 相似文献
108.
Nguyen Huy Dan Pham Thi ThanhNguyen Hai Yen Nguyen Thi Thanh Huyen Duong Dinh Thang Luu Tien Hung 《Journal of magnetism and magnetic materials》2012,324(7):1435-1439
We have observed magnetic anisotropy in bulk Nd55−xCoxFe30Al10B5 (x=10, 15 and 20) alloys prepared by copper mold suction casting method with a presence of external magnetic field (quenching field) μ0H=0.25 T. By changing direction of the measuring field from perpendicular to parallel one in comparison with that of the quenching field, coercive force of the alloys slightly decreases while remanent magnetization and squareness of hysteresis loop increase more clearly. It is also found that the higher Co-concentration in the alloys the larger magnetic anisotropy is induced. The structure analyses manifest nanocrystalline particles embedded in residual amorphous matrix of the alloys. The size of the particles is in range of 10-30 nm and their crystalline phases consist of Nd2(Fe,Co)14B, Nd3Co, Nd3Al, NdAl2 and Nd. 相似文献
109.
The Alperin Weight Conjecture was stated by J. Alperin in 1986 and constitutes one of the main problems in the representation
theory of finite groups. In this paper, we provide a reduction to simple groups and as an application we prove the conjecture
in several cases. 相似文献
110.
Globally solving a nonlinear UAV task assignment problem by stochastic and deterministic optimization approaches 总被引:1,自引:0,他引:1
In this paper, we consider a task allocation model that consists of assigning a set of m unmanned aerial vehicles (UAVs) to a set of n tasks in an optimal way. The optimality is quantified by target scores. The mission is to maximize the target score while
satisfying capacity constraints of both the UAVs and the tasks. This problem is known to be NP-hard. Existing algorithms are
not suitable for the large scale setting. Scalability and robustness are recognized as two main issues. We deal with these
issues by two optimization approaches. The first approach is the Cross-Entropy (CE) method, a generic and practical tool of
stochastic optimization for solving NP-hard problem. The second one is Branch and Bound algorithm, an efficient classical
tool of global deterministic optimization. The numerical results show the efficiency of our approaches, in particular the
CE method for very large scale setting. 相似文献