全文获取类型
收费全文 | 218篇 |
免费 | 40篇 |
国内免费 | 11篇 |
专业分类
化学 | 38篇 |
力学 | 2篇 |
综合类 | 2篇 |
数学 | 111篇 |
物理学 | 116篇 |
出版年
2023年 | 4篇 |
2022年 | 4篇 |
2021年 | 2篇 |
2020年 | 9篇 |
2019年 | 16篇 |
2018年 | 6篇 |
2017年 | 15篇 |
2016年 | 5篇 |
2015年 | 10篇 |
2014年 | 21篇 |
2013年 | 28篇 |
2012年 | 12篇 |
2011年 | 13篇 |
2010年 | 15篇 |
2009年 | 14篇 |
2008年 | 14篇 |
2007年 | 8篇 |
2006年 | 12篇 |
2005年 | 8篇 |
2004年 | 8篇 |
2003年 | 6篇 |
2002年 | 13篇 |
2001年 | 4篇 |
2000年 | 10篇 |
1999年 | 2篇 |
1998年 | 7篇 |
1997年 | 2篇 |
1986年 | 1篇 |
排序方式: 共有269条查询结果,搜索用时 31 毫秒
1.
2.
This paper is concerned with the following Klein–Gordon–Maxwell system where is a constant, and are periodic with respect to . By combining deformation type arguments, Lusternik–Schnirelmann theory and some new tricks, we prove that the above system admits infinitely many geometrically distinct solutions under weaker superlinear conditions instead of the common super-cubic conditions on . Our result seems new and extends the previous results in the literature. 相似文献
3.
4.
5.
Monica Roşiu 《复变函数与椭圆型方程》2015,60(2):181-190
We extend the notion and basic properties of quadratic differential divisors to a Klein surface, using the corresponding form’s divisors from the double cover of the Klein surface. 相似文献
6.
In this paper, we study the following Klein–Gordon–Maxwell system Using variational methods, we obtain the existence of ground state solutions under some appropriate assumptions on and . 相似文献
7.
《Physics letters. A》2019,383(21):2462-2466
We propose an experimental scheme to simulate and observe the Klein tunneling of relativistic Maxwell particles with trapped ions. We explore the scattering dynamics of the pseudospin-one Maxwell particles and demonstrate that the scattered state should be a superposition of a reflection state, a localization state, and a transmission state. The probabilities of these states can be analytically obtained by the approach of Landau-Zener transition. We further show that the Maxwell Hamiltonian and the associated scattering dynamics can be mimicked with two trapped ions. The Maxwell spinors are encoded by three internal states of the first ion, the position and momentum are described by those of the motional modes, and the desired linear potential barrier is built by the second ion. 相似文献
8.
提出了测定聚对苯二甲酸乙二醇酯(PEGTP)瓶装纯水中乙醛迁移量的气相色谱质谱法。水样(100mL)中乙醛用2,4-二硝基苯肼在pH 3柠檬酸盐缓冲溶液10mL中,于40℃水浴上振荡1h加热使之衍生化。冷却后用二氯甲烷萃取3次,每次10mL。萃取液于40℃旋转蒸发至1.0mL,分取1分L进样分析。采用DB-5MS毛细管柱及在70℃~280℃范围内程序升温进行分离。线性范围在300μg·L~(-1)以内,检出限(3S/N)为1μg·L~(-1),加入50μg·L~(-1)及100μg·L~(-1)标准溶液做回收试验及精密度试验,测得平均回收率为88%,相对标准偏差(n=5)依次为5.4%及4.5%。 相似文献
9.
To improve the glass transition temperature (Tg) and heat resistance of polyethylene terephthalate (PET) bottle, poly (ethylene glycol 1,4-cyclohexane dimethylene isosorbide terephthalate) (PEICT) with a unique cyclic structure was introduced into PET. The miscibility of the PET/PEICT blends and their feasibility as a heat resistant bottle were investigated. The introduction of PEICT into PET increases the Tg and the PET/PEICT blends exhibit a single Tg, indicating good miscibility between PEICT and PET. Furthermore, the Tg and crystallinity of the PET/PEICT blends can be adjusted by controlling the amount of PEICT added. The PET/PEICT blends were transparent in the visible light range (no significant change in transparency) because the blends were truly miscible as confirmed by Fox equation. As expected, the introduction of PEICT into PET bottle allows for improved heat resistance and shape stability due to the rigid molecular structure and chirality of the two tetrahydrofuran rings in the isosorbide group of PEICT. Based on our results, the as-prepared PET/PEICT blends with controllable high heat resistance can be used as a cost-effective alternative material for various hot-filling conditions in the beverage industry by adjusting the optimal ratio of PEICT to PET for each product (e.g. fruit juice, tea). 相似文献
10.