全文获取类型
收费全文 | 331篇 |
免费 | 12篇 |
国内免费 | 1篇 |
专业分类
化学 | 258篇 |
晶体学 | 2篇 |
力学 | 13篇 |
数学 | 13篇 |
物理学 | 58篇 |
出版年
2023年 | 1篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 5篇 |
2018年 | 11篇 |
2017年 | 10篇 |
2016年 | 19篇 |
2015年 | 12篇 |
2014年 | 18篇 |
2013年 | 65篇 |
2012年 | 17篇 |
2011年 | 17篇 |
2010年 | 22篇 |
2009年 | 19篇 |
2008年 | 18篇 |
2007年 | 16篇 |
2006年 | 14篇 |
2005年 | 5篇 |
2004年 | 6篇 |
2003年 | 9篇 |
2002年 | 14篇 |
2001年 | 6篇 |
1999年 | 1篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1990年 | 2篇 |
1984年 | 1篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 4篇 |
1975年 | 1篇 |
排序方式: 共有344条查询结果,搜索用时 15 毫秒
71.
72.
73.
74.
Arash Yavari Jerrold E. Marsden 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2012,63(5):921-927
In this paper we make a connection between covariant elasticity based on covariance of energy balance and Lagrangian field theory of elasticity with two background metrics. We use Kucha?’s idea of reparametrization of field theories and make elasticity generally covariant by introducing a “covariance field”, which is a time-independent spatial diffeomorphism. We define a modified action for parameterized elasticity and show that the Doyle-Ericksen formula and spatial homogeneity of the Lagrangian density are among its Euler–Lagrange equations. 相似文献
75.
76.
Boyd's iterative force-field has been used to investigate the conformational energy surface of 1,2-cyclooctadiene. Two energy-minimum conformations with similar strain energies have been found; one has a two-fold axis of symmetry, whereas the other lacks symmetry. The calculated strain-energy barrier for interconversion of the two conformations is 8.8 kcal mol?1. 相似文献
77.
A novel polyoxometalate-cation exchanger, titanium(IV) molybdophosphate (TMP) has been synthesized under varying conditions. The material was characterized by X-ray diffraction, infrared spectroscopy, inductively coupled plasma and thermogravimetry techniques. Its stability was investigated in water, dilute acids, alkaline solutions, and high temperature up to 750 °C. Ion-exchange capacity and distribution coefficients (Kd) for twenty-nine radionuclides and metal ions have been determined. It was found that the TMP has high affinity for Cs+, Sr2+, UO22+, Ba2+, Pb2+, Tl+, Zn2+, Rb2+ and Zr4+ ions. The results of binary separation of metal ions showed that TMP can be potentially useful for analytical applications. 相似文献
78.
Issa Yavari Mohammad J. Bayat Sanaz Souri Mehdi Sirouspour 《Helvetica chimica acta》2009,92(9):1903-1907
A one‐pot synthesis of 2‐(4‐oxo‐1,3‐thiazinan‐5‐yl)acetic acids is described via a three‐component reaction between primary alkylamines and ithaconic anhydride and phenyl isothiocyanate or benzoyl isothiocyanate. 相似文献
79.
Formation of Dialkyl 2‐[3‐Alkoxy‐1‐(alkylimino)‐1‐chloro‐3‐oxopropan‐2‐ylidene]hydrazine‐1,1‐dicarboxylates of α‐(Alkoxycarbonyl)imidoyl Chlorides from PhosphineDiazo Ester Zwitterions and Nef‐Isocyanide Adducts 下载免费PDF全文
A novel transformation involving phosphine? diazo ester zwitterions (generated from dialkyl azodicarboxylates with Ph3P) and α‐(alkoxycarbonyl)imidoyl chlorides (prepared from α‐addition of acyl chlorides to alkyl isocyanides) to afford dialkyl 2‐[3‐alkoxy‐1‐(alkylimino)‐1‐chloro‐3‐oxopropan‐2‐ylidene]hydrazine‐1,1‐dicarboxylates in moderate yields, is described. 相似文献
80.
Issa Yavari S. Zahra Sayyed-Alangi Rahimeh Hajinasiri Hadi Sajjadi-Ghotbabadi 《Monatshefte für Chemie / Chemical Monthly》2009,140(2):209-211
Abstract A simple one-pot synthesis of functionalized ethyl 1,3-thiazole-5-carboxylates from the reaction of 2-chloro-1,3-dicarbonyl
compounds with thioureas or thioamides in the presence of 1-butyl-3-methylimidazolium trifluoromethanesulfonate is described.
Graphical abstract
相似文献