全文获取类型
收费全文 | 141篇 |
免费 | 5篇 |
专业分类
化学 | 50篇 |
晶体学 | 3篇 |
力学 | 2篇 |
数学 | 52篇 |
物理学 | 39篇 |
出版年
2023年 | 1篇 |
2022年 | 6篇 |
2021年 | 3篇 |
2020年 | 6篇 |
2019年 | 10篇 |
2018年 | 14篇 |
2017年 | 11篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 2篇 |
2013年 | 15篇 |
2012年 | 10篇 |
2011年 | 7篇 |
2010年 | 4篇 |
2009年 | 6篇 |
2008年 | 5篇 |
2007年 | 2篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 4篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有146条查询结果,搜索用时 31 毫秒
51.
52.
Doan The Hieu 《Archiv der Mathematik》2005,85(5):481-484
We extend Choe’s idea in [1] to nonpolyhedral calibrated surfaces and give some examples of polyhedral sets over right prisms
and nonpolyhedral calibrated surfaces.
Received: 4 October 2004 相似文献
53.
Nelsen SF Li G Schultz KP Tran HQ Guzei IA Evans DH 《Journal of the American Chemical Society》2008,130(35):11620-11622
One and two electron oxidation of N,N',N',N'-tetramethyl-1,5,12,16-tetraaza[5,5]paracyclophane (Me3C), a bis-trimethylene bridged bis-p-phenylene diamine (PD), and its ethyl and isopropyl analogues are discussed. The monocation and dication are both stable, as demonstrated by optical studies that show they are in equilibrium in solution, with an especially small difference in first and second oxidation potentials for Me3C in MeCN (+23 to -20 mV, measured by simulation of the optical spectrum and of the cyclic voltammogram, respectively). The monocations have charge localized in one PD unit and show a Hush-type mixed valence transition between their PD0 and PD.+ groups. The dications Me3C2+ and Et3C2+ have optical spectra that appear to show large splittings between their PD.+ groups and have a weak ESR spectrum, and 1H NMR data show that the former is a ground-state singlet. iPr3C2+ has a very different optical spectrum and exhibits a triplet ESR spectrum at 120 K. X-ray crystal structures show that for Me3C0 the N(CH2)3N units on each side are in doubly anti (aa) conformations that put the aryl rings as far apart as possible, but Me3C2+ has doubly gg N(CH2)3N trimethylene bridges and both N,N and C,C distances between the PD.+ groups that are significantly below van der Walls contact. In contrast, iPr3C0 is in a doubly ag conformation, and its diradical dication is suggested to be a triplet because it does not attain the doubly gg conformation. 相似文献
54.
Thuy Bui Thi Phuong My Tran Thi Ai Hai Nguyen Thi Thanh Loan Huynh Thi Phuong Hieu Le Trung Hoa Tran Thai Bui Thanh Q. Tuong Ho Nhat Thuy Nguyen Thi Thu Dung Doan Kim Van Tat Pham Quy Phan Tu Nhung Nguyen Thi Ai 《Structural chemistry》2021,32(1):135-148
Structural Chemistry - Rice, well known as the most important staple food source worldwide, is highly susceptible to many infectious diseases, especially rice sheath blight caused by fungus... 相似文献
55.
Pham Sy Hieu Pham Minh Doan Sane Abdoul Razac Nguyen Xuan Hoan Semlal Nawal Boulif Rachid Germeau Alain Toussaint Claudia Sharrock Patrick Nzihou Ange 《Journal of Thermal Analysis and Calorimetry》2021,146(5):2027-2033
Journal of Thermal Analysis and Calorimetry - Up-to-date, solar salt (a mixture of 60 mass% NaNO3 and 40 mass% KNO3) is practically the only media for thermal energy storage (TES) in concentrated... 相似文献
56.
In this paper we propose several modified hybrid projection methods for solving common solutions to variational inequality problems involving monotone and Lipschitz continuous operators. Based on differently constructed half-spaces, the proposed methods reduce the number of projections onto feasible sets as well as the number of values of operators needed to be computed. Strong convergence theorems are established under standard assumptions imposed on the operators. An extension of the proposed algorithm to a system of generalized equilibrium problems is considered and numerical experiments are also presented. 相似文献
57.
Dang Van Hieu 《Computational Optimization and Applications》2017,67(3):571-594
In this paper, three parallel hybrid subgradient extragradient algorithms are proposed for finding a common solution of a finite family of equilibrium problems in Hilbert spaces. The proposed algorithms originate from previously known results for variational inequalities and can be considered as modifications of extragradient methods for equilibrium problems. Theorems of strong convergence are established under the standard assumptions imposed on bifunctions. Some numerical experiments are given to illustrate the convergence of the new algorithms and to compare their behavior with other algorithms. 相似文献
58.
59.
Christopher John Nuttall Yasuhira Inada Yoshihiro Watanabe Kiyoe Nagai Tsunehiro Muro Dam Hieu Chi 《Molecular Crystals and Liquid Crystals》2013,570(1):635-638
Abstract We report the structural and magnetic properties of the endohedral metallofullerene Ce@C82. A hexagonal close packing phase [P63/mmc [a=11.1544Å, c=18.2256Å] is formed exclusively after vacuum annealing of the solvent precipitated compound. In contrast, sublimed Ce@C82 was found to be dominantly face-centred cubic close packed [Fm-3m; a=15.766Å]. X-ray powder profile calculations revealed that the endohedral cerium atom lies close to 1.8Å from the C82 cage centre in both phases. Hexagonal Ce@C82 has been investigated by magnetic susceptibility measurements. Paramagnetic behaviour is maintained down to 2K attributable to Ce3+ ions. Towards lower temperatures, the observed paramagnetic moment falls from the free ion Ce3+(μeff =2.54μB) value, monotonically approaching 1μB at 2K. 相似文献
60.
Nguyen Thi Thuy Phuong Dinh Tam Mai Anh Tuan Anh-Tuan Le Le Thi Tam Vu Van Thu Nguyen Van Hieu Nguyen Duc Chien 《Current Applied Physics》2012,12(6):1553-1560
The present paper introduces a facile and cost-effective route for the direct dispersion of multi-walled carbon nanotubes (MWCNTs) in DNA solution. Their application in detecting Escherichia coli O157:H7 using DNA biosensor was demonstrated. The dispersion state of the MWCNTs was characterized via UV–Vis spectroscopy, transmission electron microscopy, and field emission scanning electron microscopy. The interaction between DNA sequence and the MWCNTs was investigated using Raman spectroscopy and Fourier transform infrared spectroscopy. As-obtained MWCNT solution was used in the preparation of DNA sensor. Results revealed that the developed DNA sensor can detect a DNA target as low as 1 nM in a buffer solution. The sensitivity of the DNA sensor reached approximately 0.19 nM/mV. The effect of dispersion parameters, including pH values, DNA concentration, ion strength, and sonication time, on sensor response was also studied. The DNA sensor can respond well to 120 min of sonication time, a pH value of 9, and 20 μM of DNA sequence concentration. The results of the present study showed a potential application of the DNA sensor in the detection of Escherichia coli O157:H7. 相似文献