全文获取类型
收费全文 | 184篇 |
免费 | 15篇 |
国内免费 | 1篇 |
专业分类
化学 | 82篇 |
晶体学 | 2篇 |
力学 | 23篇 |
数学 | 39篇 |
物理学 | 54篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 6篇 |
2018年 | 6篇 |
2017年 | 4篇 |
2016年 | 10篇 |
2015年 | 13篇 |
2014年 | 7篇 |
2013年 | 19篇 |
2012年 | 12篇 |
2011年 | 25篇 |
2010年 | 13篇 |
2009年 | 12篇 |
2008年 | 5篇 |
2007年 | 4篇 |
2006年 | 5篇 |
2005年 | 5篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1941年 | 1篇 |
排序方式: 共有200条查询结果,搜索用时 363 毫秒
21.
Mohammadi-Manesh H Alavi S Woo TK Najafi B 《Physical chemistry chemical physics : PCCP》2011,13(6):2367-2377
We perform molecular dynamics simulations (up to 6 ns) for the structure I clathrate hydrates of linear molecules CS, CS(2), OCS, and C(2)H(2) in large cages at different temperatures in the stability range to determine the angular distribution and dynamics of the guests in the large cages. The long axes of linear guest molecules in the oblate large structure I clathrate hydrate cages are primarily confined near the equatorial plane of the cage rather than axial regions. This non-uniform spatial distribution leads to well-known anisotropic lineshapes in the solid-state NMR spectra of the guest species. We use the dynamic distribution of guest orientations in the cages during the MD simulations at different temperatures to predict the (13)C NMR powder lineshapes of the guests in the large cages. The length of the guests and intermolecular interactions of the guests in the water cages determine the angular distribution and the mobility of the guests in the sI large cages at different temperatures. At low temperatures the range of motion of the guests in the cages are limited and this is reflected in the skew of the predicted (13)C lineshapes. As the guest molecules reach the fast motion limit at higher temperatures, the lineshapes for CS, OCS, and C(2)H(2) are predicted to have the "standard" powder lineshapes of guest molecules. 相似文献
22.
23.
Journal of Geometry - In [1,5 ] the authors prove that any transformation of the euclidean plane,coordinatized by the real field, which preserves a single non-zero distance is necessarily an... 相似文献
24.
Bijan K Bagchi 《Pramana》1981,17(5):405-414
We consider the effects ofη−π mixing on the violation of the |ΔI|=1/2 rule in |ΔS|=1 weak transitions. The processes considered are theK→2π,K→3π, Λ, Ξ and Λ hyperon decays. 相似文献
25.
Bijan Kumar Patel Prasanta Kumar Ray Manasi K Sahukar 《Proceedings Mathematical Sciences》2018,128(1):5
In this study, the diophantine equations \(x^2 -32B_nxy-32y^2 =\pm 32^{r}\), \(x^4 -32B_nxy-32y^2 =\pm 32^{r}\) and \(x^2 -32B_nxy-32y^4 =\pm 32^{r}\) are considered and determined when these equations have positive integer solutions. Moreover, all positive integer solutions of these diophantine equations in terms of balancing and Lucas-balancing numbers are also found out. 相似文献
26.
Muhammad Akram Saba Siddique Bijan Davvaz 《Journal of Applied Mathematics and Computing》2018,57(1-2):279-302
A neutrosophic set is a generalization of an intuitionistic fuzzy set. Neutrosophic models give more flexibility, precisions and compatibility to the system as compared to intuitionistic fuzzy models. In this research study, we apply the concept of neutrosophic sets to graphs and discuss certain concepts of single-valued neutrosophic graphs. We illustrate the concepts by several examples. We investigate some interesting properties. We describe an application of single-valued neutrosophic graph in decision making process. We also present the procedure of our proposed method as an algorithm. 相似文献
27.
In this paper by considering the notion of hyperlattice, we introduce good and s-good hyperlattices, homomorphism of hyperlattices and s-reflexives. We give some examples of them and we study their structures. We show that there exists a hyperlattice L such that ${x \vee x = \{x\}}In this paper by considering the notion of hyperlattice, we introduce good and s-good hyperlattices, homomorphism of hyperlattices
and s-reflexives. We give some examples of them and we study their structures. We show that there exists a hyperlattice L such that x úx = {x}{x \vee x = \{x\}} for all x ? L{x \in L} and there exist x, y ? L{x, y \in L} which card(x úy) 1 1{card(x \vee y) \ne 1}. Also, we define a topology on the set of prime ideals of a distributive hyperlattice L and we will call it S(L){{{\mathcal S}(L)}}, then we show that S(L){{{\mathcal S}(L)}} is a T
0-space. At the end, we obtain that each complemented distributive hyperlattice is a T
1-space. 相似文献
28.
In this note we show that if Gis a finitely generated soluble group, then every infinite subset of Gcontains two elements generating a nilpotent group of class at most kif and only if Gis finite by a group in which every two generator subgroup is nilpotent of class at most k. 相似文献
29.
30.
Chemistry of Diruthenium and Dirhodium Analogues of Pentaborane(9): Synthesis and Characterization of Metal N,S‐Heterocyclic Carbene and B‐Agostic Complexes
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
M. Sc. Dipak Kumar Roy M. Sc. Bijan Mondal M. Sc. R. S. Anju Prof. Sundargopal Ghosh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(9):3640-3648
Building upon our earlier results on the synthesis of electron‐precise transition‐metal–boron complexes, we continue to investigate the reactivity of pentaborane(9) and tetraborane(10) analogues of ruthenium and rhodium towards thiazolyl and oxazolyl ligands. Thus, mild thermolysis of nido‐[(Cp*RuH)2B3H7] ( 1 ) with 2‐mercaptobenzothiazole (2‐mbtz) and 2‐mercaptobenzoxazole (2‐mboz) led to the isolation of Cp*‐based (Cp*=η5‐C5Me5) borate complexes 5 a , b [Cp*RuBH3L] ( 5 a : L=C7H4NS2; 5 b : L=C7H4NOS)) and agostic complexes 7 a , b [Cp*RuBH2(L)2], ( 7 a : L=C7H4NS2; 7 b : L=C7H4NOS). In a similar fashion, a rhodium analogue of pentaborane(9), nido‐[(Cp*Rh)2B3H7] ( 2 ) yielded rhodaboratrane [Cp*RhBH(L)2], 10 (L=C7H4NS2). Interestingly, when the reaction was performed with an excess of 2‐mbtz, it led to the formation of the first structurally characterized N,S‐heterocyclic rhodium‐carbene complex [(Cp*Rh)(L2)(1‐benzothiazol‐2‐ylidene)] ( 11 ) (L=C7H4NS2). Furthermore, to evaluate the scope of this new route, we extended this chemistry towards the diruthenium analogue of tetraborane(10), arachno‐[(Cp*RuCO)2B2H6] ( 3 ), in which the metal center possesses different ancillary ligands. 相似文献