全文获取类型
收费全文 | 219篇 |
免费 | 6篇 |
国内免费 | 4篇 |
专业分类
化学 | 129篇 |
力学 | 1篇 |
综合类 | 1篇 |
数学 | 45篇 |
物理学 | 53篇 |
出版年
2023年 | 2篇 |
2022年 | 5篇 |
2021年 | 3篇 |
2020年 | 1篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 1篇 |
2015年 | 4篇 |
2014年 | 5篇 |
2013年 | 24篇 |
2012年 | 10篇 |
2011年 | 13篇 |
2010年 | 12篇 |
2009年 | 17篇 |
2008年 | 13篇 |
2007年 | 6篇 |
2006年 | 15篇 |
2005年 | 7篇 |
2004年 | 11篇 |
2003年 | 10篇 |
2002年 | 4篇 |
2001年 | 8篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1987年 | 2篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有229条查询结果,搜索用时 15 毫秒
131.
Xiwei Liu 《Physica A》2008,387(12):2952-2962
In this paper, we investigate the global robust stability for uncertain stochastic neural networks with unbounded time-varying delays and norm-bounded parameter uncertainties. A new concept of global robust μ-stability in the mean square for neural networks is given first, then by means of the linear matrix inequality (LMI) approach, stability criteria are presented. Several corollaries are also derived. A simple example is presented to demonstrate the effectiveness of the main result. 相似文献
132.
Yeon-Seop Jung Yun-Jeong Jeong Joung-Hee Kim Chang-Hwan Jeon Syng-Ook Lee 《Molecules (Basel, Switzerland)》2022,27(15)
Recent studies have shown that Nur77 and AMPKα play an important role in regulating adipogenesis and isoalantolactone (ISO) dual-targeting AMPKα and Nur77 inhibits adipogenesis. In this study, we hypothesized that Inula helenium (elecampane) root extract (IHE), which contains two sesquiterpene lactones, alantolactone (ALA) and ISO, as major compounds, might inhibit adipogenesis. Here, we found that ALA and IHE simultaneously target AMPKα and Nur77 and inhibited adipogenic differentiation of 3T3-L1 cells, accompanied by the decreased expression of adipocyte markers. Further mechanistic studies demonstrated that IHE shares similar mechanisms of action with ISO that reduce mitotic clonal expansion during the early phase of adipogenic differentiation and decrease expression of cell cycle regulators. These results suggest that IHE inhibits adipogenesis, in part, through co-regulation of AMPKα and Nur77, and has potential as a therapeutic option for obesity and related metabolic dysfunction. 相似文献
133.
Noé Zúñiga-Villarreal Juan Manuel Germán-Acacio Ana Adela Lemus-Santana Marisol Reyes-Lezama Rubén A. Toscano 《Journal of organometallic chemistry》2004,689(17):2827-2832
The halocarbonyls BrM(CO)5, M = Mn and Re, were reacted with the KN(SePPh2)2 salt in equimolar amounts; the reactions were thermally carried out and resulted in the generation of the hexacoordinated isostructural complexes [M(CO)4{Ph2P(Se)NP(Se)Ph2-Se,Se′}] with a twist MSePNPSe ring conformation. Complexes’ characterizations were achieved by IR, mass, NMR (1H, 13C, 31P, 77Se) spectroscopies, and by single-crystal X-ray diffraction. 相似文献
134.
The well-posedness of the data assimilation problem for the Navier–Stokes-α equations on a bounded three-dimensional domain is investigated. The data assimilation procedures under consideration are the adjoint method of variational data assimilation (4D-Var) and the method of continuous data assimilation. Concerning the adjoint method the existence of optimal initial conditions with respect to an observation-dependent cost functional is proven, the optimizers are characterized by a first-order necessary condition involving the adjoint linearized Navier–Stokes-α equations and conditions for the uniqueness of the initial conditions are given. Well-posedness of the continuous data assimilation problem is proven and convergence rates in terms of observational resolution are provided. 相似文献
135.
Chun LiZeng-Qi Ou Chun-Lei Tang 《Nonlinear Analysis: Theory, Methods & Applications》2012,75(4):2262-2272
Some existence theorems are obtained for periodic and subharmonic solutions of a class of non-autonomous Hamiltonian systems. Our technical approach is based on a version of the Local Linking Theorem, and the Generalized Mountain Pass Theorem. 相似文献
136.
Pradipta Bandyopadhyay Tanmoy Paul 《Journal of Mathematical Analysis and Applications》2010,369(2):525-536
In this paper, we continue our study of ball remotality of subspaces of Banach spaces. In particular, we study the problem in classical sequence spaces c0, c, ?1 and ?∞; and also ball remotality of a Banach space in its bidual. 相似文献
137.
Chi-Wai Leung 《Journal of Mathematical Analysis and Applications》2006,322(2):699-711
In this article, we define a natural Banach ∗-algebra for a C∗-dynamical system (A,G,α) which is slightly bigger than L1(G;A) (they are the same if A is finite-dimensional). We will show that this algebra is ∗-regular if G has polynomial growth. The main result in this article extends the two main results in [C.W. Leung, C.K. Ng, Functional calculus and ∗-regularity of a class of Banach algebras, Proc. Amer. Math. Soc., in press]. 相似文献
138.
利用大肠杆菌启动子探测质粒pKK232-8为载体,经HindⅢ-BamHⅠ完全消化后与HindⅢ-BamHⅠ部分消化的嗜麦芽假单胞菌染色休DNA进行体外连接,转化E.coliHB101感受态细胞,在含氨苄青霉素(Ap)和氯霉素(Cm)的选择平板上筛选转化子.从随机挑选的54株转化子中,获得一株抗氯霉素水平达1000mg/L的转化子E.coliPASI,所含重组质粒被命名为pASI.经限制性酶切分析和杂交分析表明,pASI质粒上插入了一段来源于嗜麦芽假单胞菌染色体的DNA片段,其大小为1.4kb.SDS-PAGE分析表明转化子E.coliPASI在含Cm的培养基上,额外表达了一条22×103的CAT蛋白质带.将重组质粒pWSY上的嗜麦芽假单胞菌mel基因亚克隆到pASI上1.4kb启动子功能片段下游,构建成E.coliAWS工程菌株,使黑色素产率提高了70.6%. 相似文献
139.
Erkki Kolehmainen 《Russian Chemical Bulletin》1994,43(4):563-565
Results of multinuclear NMR studies of some heteroorganic compounds have been presented.According to a report at the conference «Current problems of organometallic chemistry» (May 8–13,1994, Moscow).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 614–616, April, 1994. 相似文献
140.
Erich Ziegler Helga Wittmann Otto S. Wolfbeis Heinz Sterk 《Monatshefte für Chemie / Chemical Monthly》1984,115(10):1165-1170
When quinoline is treated with ethyl bromoacetate in ethanol at a molar ratio of 1.5:1, a highly fluorescent pyrrolodiquinolinium ion (2a) is formed along with quarternized quinoline (1a). The structure of2a has been established by infrared, proton magnetic resonance and mass spectroscopy as well as by its characteristic ultraviolet absorption spectrum.
Herrn Prof. Dr.K. Schlögl, Universität Wien, zur Vollendung des 60. Lebensjahres mit besten Wünschen gewidmet. 相似文献