全文获取类型
收费全文 | 207篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
化学 | 76篇 |
力学 | 4篇 |
数学 | 30篇 |
物理学 | 100篇 |
出版年
2022年 | 3篇 |
2021年 | 6篇 |
2020年 | 1篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2017年 | 7篇 |
2016年 | 5篇 |
2015年 | 4篇 |
2014年 | 6篇 |
2013年 | 12篇 |
2012年 | 13篇 |
2011年 | 20篇 |
2010年 | 8篇 |
2009年 | 11篇 |
2008年 | 14篇 |
2007年 | 12篇 |
2006年 | 6篇 |
2005年 | 7篇 |
2004年 | 7篇 |
2003年 | 3篇 |
2002年 | 27篇 |
2001年 | 7篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 5篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1984年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有210条查询结果,搜索用时 62 毫秒
61.
M.M. Cavalcanti V.N. Domingos Cavalcanti P. Martinez 《Nonlinear Analysis: Theory, Methods & Applications》2008
The linear viscoelastic equation is considered. We prove uniform decay rates of the energy by assuming a nonlinear feedback acting on the boundary, without imposing any restrictive growth assumption on the damping term and strongly weakening the usual assumptions on the relaxation function. Our estimate depends both on the behavior of the damping term near zero and on the behavior of the relaxation function at infinity. 相似文献
62.
A. S. Lodhi MD. Rashiduzzaman Khan 《Journal of Radioanalytical and Nuclear Chemistry》1979,49(1):89-94
A number of samples of whole blood, and urine from diabetic and non-diabetic persons have been analyzed for their trace elemental
contents using the proton-induced X-ray emission. The elemental contents of the diabetic and non-diabetic samples are compared. 相似文献
63.
M. M. Cavalcanti V. N. Domingos Cavalcanti J. Ferreira 《Mathematical Methods in the Applied Sciences》2001,24(14):1043-1053
This paper is concerned with the non‐linear viscoelastic equation We prove global existence of weak solutions. Furthermore, uniform decay rates of the energy are obtained assuming a strong damping Δut acting in the domain and provided the relaxation function decays exponentially. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
64.
Gil R. Cavalcanti Marco Gualtieri 《Bulletin of the Brazilian Mathematical Society》2011,42(4):537-557
We show that the blow-up of a generalized Kähler 4-manifold in a nondegenerate complex point admits a generalized Kähler metric. As with the blow-up of complex surfaces, this metric may be chosen to coincide with the original outside a tubular neighbourhood of the exceptional divisor. To accomplish this, we develop a blow-up operation for bi-Hermitian manifolds. 相似文献
65.
66.
Marcelo M. Cavalcanti Valéria N. Domingos Cavalcanti Ryuichi Fukuoka Daniel Toundykov 《Applied Mathematics and Optimization》2014,69(1):83-122
Let $\mathcal{M}\subset\mathbb{R}^{3}$ be an oriented compact surface on which we consider the system: $$\left \{ \begin{array}{l@{\quad}l} u_{tt} - \Delta_{\mathcal{M}} u + a(x)g_{0}(u_{t})=0 & \text{in } \mathcal{M}\times\mathopen{]} 0,\infty[ ,\\ \partial_{\nu_{co}}u +u + b(x)g(u_t)=0 & \text{on } \partial \mathcal {M}\times\mathopen{]}0,+\infty[. \end{array} \right . $$ If $\mathcal{M}$ along with the localizers a, b and the nonlinear feedbacks g,g 0 satisfy certain conditions then uniform (but not necessarily exponential) decay rates of the finite energy of solutions can be established. We present a unified approach that bridges and extends a number of earlier results on stabilization of 2nd-order hyperbolic equations on manifolds. The methodology captures geometric requirements for damping acting simultaneously on subsets of the interior and of the boundary, and shows how placements of these feedbacks can complement each other depending on the underlying surface. In addition, the results conveniently incorporate the existing theory that allows elimination of geometric conditions from the controlled boundary (in absence of nearby interior damping), and elimination of damping entirely from certain boundary neighborhoods. The model also admits feedbacks that grow sub- or super-linearly not only at the origin, but also at infinity and demonstrates an interplay between the regularity of solutions and asymptotic energy decay rates. 相似文献
67.
Yata Praveen Kumar C. Shobha Devi N. Deepika Nazar MD Gabra Nishant Jain A. Srishailam Kotha Laxma Reddy S. Satyanarayana 《Transition Metal Chemistry》2013,38(8):811-819
A new ligand, (2-ethoxy-6-(1H imadazo[4,5-f][1,10]phenanthroline-2-yl)phenol) (HEPIP) and its three Co(III) complexes [Co(phen)2(HEPIP)](ClO4)3 (1), [Co(bpy)2(HEPIP)](ClO4)3 (2) and [Co(dmb)2(HEPIP)](ClO4)3 (3) have been synthesized and characterized. All three Co(III) complexes exhibited antitumor activity against four human tumor cell lines. The interaction of these complexes with calf thymus DNA was studied by absorption and emission spectroscopy, viscosity measurements and DNA cleavage assays. The DNA-binding constants of complexes 1, 2 and 3 were determined as 6.13 × 105, 4.46 × 105 and 3.72 × 105 M?1, respectively. The complexes appear to interact with DNA through intercalation. Studies on the mechanism of photocleavage indicated that both superoxide anion radical and singlet oxygen may play an important role. 相似文献
68.
MD. Akhtaruzzaman Masaaki Tomura Kazuko Takahashi Jun-Ichi Nishida 《Supramolecular chemistry》2013,25(4):239-243
Hydrogen-bonding networks of π-extended 4,4′-bipyridines, 2,5-di(4-pyridyl)thiophene (1), 2,5-di(4-pyridyl)furan (2) and 1,4-di(4-pyridyl)benzene (3) with 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone (chloranilic acid, CA) have been investigated. The dipyridyl compounds afforded complexes 4 [(dication of 1)·(monoanion of CA)2], 5 [(dication of 2)·(dianion of CA)·(MeOH)] and 6 [(3)·(dication of 3)·(dianion of CA)·(H2O)6] with CA. X-ray structure analyses revealed the formation of unusual molecular tape and sheet structures involving N–H ?O, O–H ?O, C–H ?O and N–H ?N hydrogen bonds, where the aromatic spacer groups play an important role in constructing the unique crystal structures. 相似文献
69.
Nilay K. Pramanik Ramsankar Haldar Utpal K. Niyogi MD. Sarwar Alam 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(4):296-307
The non-isothermal crystallization kinetics was studied by differential scanning calorimetric analysis on nylon 66 and e-beam irradiated nylon 66 at different cooling rates. The Modified Avrami equation, the Ozawa equation and the Combined Avrami-Ozawa equation were applied to study the kinetics of non-isothermal crystallization of nylon 66. The crystallization behavior of pristine nylon 66 polymer was compared with that of e-beam irradiated nylon 66 and observed that the kinetics of non-isothermal crystallization of nylon66 was affected largely upon e-beam irradiation. E-beam irradiation not only decreased the crystallization temperature of nylon 66, but influenced the mechanism of nucleation and crystal growth and reduced the overall crystallization rate of nylon 66 also. The crystallization activation energy calculated by the Kissinger method for irradiated nylon 66 was lower than that of pristine nylon 66. 相似文献