全文获取类型
收费全文 | 103篇 |
免费 | 7篇 |
专业分类
化学 | 59篇 |
晶体学 | 2篇 |
力学 | 1篇 |
数学 | 10篇 |
物理学 | 38篇 |
出版年
2023年 | 1篇 |
2021年 | 6篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 5篇 |
2013年 | 11篇 |
2012年 | 8篇 |
2011年 | 6篇 |
2010年 | 2篇 |
2009年 | 6篇 |
2008年 | 9篇 |
2007年 | 5篇 |
2006年 | 5篇 |
2005年 | 5篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1976年 | 4篇 |
1975年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有110条查询结果,搜索用时 31 毫秒
61.
Takashi Yasui Nozomu Komatsu Kazuki Egami Hiromichi Yamada Akio Yuchi 《Analytical sciences》2007,23(8):1011-1014
Bidentate and tridentate heterocyclic azo compounds with and without a long alkyl chain were prepared and examined for cation exchange chromatography of manganese, zinc, and cadmium; these ions could not be separated by reversed phase HPLC following precolumn derivatization with heterocyclic azo compounds owing to the dissociation of the complexes. The newly prepared azo compounds having a long alkyl chain favorably orientate in the reversed-phase stationary phase such that the coordinating parts of the ligand may make contact with metal ions in the mobile phase. Bidentate ligands showed sharp peaks but almost no resolution of manganese and cadmium. A tridentate ligand strongly retained all the three metal ions, which could be separated within 10 min by a competing ligand and by optimizing the pH. 相似文献
62.
Yamaoka H Jarrige I Tsujii N Lin JF Ikeno T Isikawa Y Nishimura K Higashinaka R Sato H Hiraoka N Ishii H Tsuei KD 《Physical review letters》2011,107(17):177203
We have investigated the temperature and pressure dependency of the electronic structure of Yb-filled skutterudites, YbFe(4)Sb(12) and Yb(0.88)Fe(4)Sb(12), using x-ray absorption and emission spectroscopies. An anomalous increase of the Yb valence, which is beyond the conventional Anderson model picture, is found to coincide with the onset of the ferromagnetic order in the x=0.88 sample below 20 K. In contrast, the nearly stoichiometric YbFe(4)Sb(12) is paramagnetic down to 2 K and the Yb valence is independent of temperature. This evidences a close interplay between the magnetic instability of the Fe 3d electrons and valence instability of the Yb 4f electrons. Under pressure, a sudden increase in the valence is found to occur around 13 GPa for YbFe(4)Sb(12) and 17 GPa for Yb(0.88)YbFe(4)Sb(12). 相似文献
63.
64.
Abstract Phase transitions in praseodymium and lanthanum under pressure have been studied using a synchrotron powder X-ray diffraction technique. A structure refinement of the distorted fcc phase of Pr using diffraction data collected with an imaging plate (IP) detector demonstrate that among some possible structures the rhombohedral structure with space group R3m best reproduces the observed diffraction pattern. The distorted fcc-fcc phase transition in La was observed as a function of the temperature at 23 GPa using a CCD-based detector. A five-minute exposure sufficiently long to measure the intensities of very weak superlattice reflections from the distorted fcc phase, which has been found to transform to the fcc phase at 550 K. The performance of the IP and a CCD-based detector are compared and their future developments discussed. 相似文献
65.
The hydrogen abstraction reactions from hydrazine and its methyl derivatives by the H atom have been investigated theoretically by using CBS-QB3//DSD-BLYP-D3(BJ)/Def2-TZVP quantum chemical calculations and transition state theory calculations coupled with various tunneling correction methods. Both the products and transition state energies of the hydrogen abstraction from the amino group were stabilized by the methyl group substitution. The substitution effect on the αN site was two times larger than that on the βN site. On the other hand, the substitution effect was negligible on the hydrogen abstraction from the methyl group. The overall rate coefficients of N2H4 + H reaction calculated by canonical variational transition state theory with the small-curvature tunneling correction agreed well with previously reported values, but those of CH3NHNH2/(CH3)2NNH2 + H were slightly lower than a previous experimental value. The product-specific rate coefficients have been proposed for the kinetics modeling of these fuels’ combustion. 相似文献
66.
Dominik Karos Nozomu Muto Shiran Rachmilevitch 《International Journal of Game Theory》2018,47(4):1169-1182
We characterize the class of weakly efficient n-person bargaining solutions that solely depend on the ratios of the players’ ideal payoffs. In the case of at least three players the ratio between the solution payoffs of any two players is a power of the ratio between their ideal payoffs. As special cases this class contains the Egalitarian and the Kalai–Smorodinsky bargaining solutions, which can be pinned down by imposing additional axioms. 相似文献
67.
Hirosuke Matsui Naoyuki Maejima Nozomu Ishiguro Yuanyuan Tan Tomoya Uruga Oki Sekizawa Tomohiro Sakata Mizuki Tada 《Chemical record (New York, N.Y.)》2019,19(7):1380-1392
Three‐dimensional imaging using X‐ray as a probe is state‐of‐the‐art for the characterization of heterogeneous materials. In addition to simple imaging of sample morphology, imaging of elemental distribution and chemical states provides advanced maps of key structural parameters of functional materials. The combination of X‐ray absorption fine structure (XAFS) spectroscopy and three‐dimensional imaging such as computed tomography (CT) can visualize the three‐dimensional distribution of target elements, their valence states, and local structures in a non‐destructive manner. In this personal account, our recent results on the three‐dimensional XAFS imaging for Pt cathode catalysts in the membrane electrode assembly (MEA) of polymer electrolyte fuel cell (PEFC) are introduced. The distribution and chemical states of Pt cathode catalysts in MEAs remarkably change under PEFC operating conditions, and the 3D XAFS imaging revealed essential events in PEFC MEAs. 相似文献
68.
We established a simple cryopreservation protocol for Arabidopsis T87 cells using an encapsulation-dehydration method. T87 cells were encapsulated into alginate beads containing 2 M glycerol and 0.4 M sucrose. Alginate beads containing T87 cells were dehydrated with silica gel for 2 h (to c. 0.7 g water per g dry weight followed by immersed in LN. After rewarming at 35 degree C for 3 min and 1-d incubation under continuous illumination at 22 degree C, cryopreserved T87 cells exhibited considerable regrowth. Exponentially-grown 7-d-old T87 cells regrew more vigorously (86% of control) than 14-d-old cells after cryopreservation without preculture in medium containing 0.3 M sucrose. Genetic stability of cryopreserved T87 cells was demonstrated by gas chromatography time-of-flight mass spectrometry (GC-TOF-MS) and principal component analysis (PCA). Transformed T87 cells were cryopreserved using established protocols, and GUS expression was maintained within a 2-fold variance. These results indicate that cryopreservation of T87 cells is useful for comprehensive metabolomics research and for the large scale collection of transformed cultured cell lines for functional genomics research. 相似文献
69.
Michihisa Koyama Riadh Sahnoun Nozomu Hatakeyama Hiromitsu Takaba Carlos A. Del Carpio 《Applied Surface Science》2008,254(23):7774-7776
Efficient development of highly functional porous materials, used as catalysts in the automobile industry, demands a meticulous knowledge of the nano-scale interface at the electronic and atomistic scale. However, it is often difficult to correlate the microscopic interfacial interactions with macroscopic characteristics of the materials; for instance, the interaction between a precious metal and its support oxide with long-term sintering properties of the catalyst. Multi-scale computational chemistry approaches can contribute to bridge the gap between micro- and macroscopic characteristics of these materials; however this type of multi-scale simulations has been difficult to apply especially to porous materials. To overcome this problem, we have developed a novel mesoscopic approach based on a porous structure simulator. This simulator can construct automatically irregular porous structures on a computer, enabling simulations with complex meso-scale structures. Moreover, in this work we have developed a new method to simulate long-term sintering properties of metal particles on porous catalysts. Finally, we have applied the method to the simulation of sintering properties of Pt on alumina support. This newly developed method has enabled us to propose a multi-scale simulation approach for porous catalysts. 相似文献
70.
The level scheme of the doubly odd nucleus 72As has been investigated by the (p, nγ) reaction up to an excitation energy of about 800 keV. Spin and parity assignments were made by measuring internal conversion coefficients and by an analysis of the (p, n) cross sections through the statistical model of the compound nuclear reaction. The level scheme obtained was interpreted by a simple model calculation based on the shell model. 相似文献