全文获取类型
收费全文 | 260篇 |
免费 | 4篇 |
专业分类
化学 | 91篇 |
晶体学 | 3篇 |
力学 | 21篇 |
数学 | 14篇 |
物理学 | 88篇 |
无线电 | 47篇 |
出版年
2022年 | 1篇 |
2020年 | 7篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 2篇 |
2013年 | 11篇 |
2012年 | 5篇 |
2011年 | 12篇 |
2010年 | 5篇 |
2009年 | 3篇 |
2008年 | 16篇 |
2007年 | 8篇 |
2006年 | 23篇 |
2005年 | 18篇 |
2004年 | 10篇 |
2003年 | 7篇 |
2002年 | 6篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 7篇 |
1995年 | 6篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 9篇 |
1984年 | 9篇 |
1983年 | 8篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 8篇 |
1979年 | 4篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 5篇 |
1973年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有264条查询结果,搜索用时 15 毫秒
71.
Gonuguntla M Sharma A Sarkar J Subramanian SA Ghosh M Shenoy V 《Physical review letters》2006,97(1):018303
Based on experiments and 3D simulations, we show that a soft elastic film during adhesion and debonding from a rigid flat surface undergoes morphological transitions to pillars, labyrinths, and cavities, all of which have the same lateral pattern length scale, lambda close to lambda/H approximately 3 for thick films, H > 1 microm . The linear stability analysis and experiments show a new thin film regime where lambda/H approximately equal to 3 + 2pi(lambda/3 muH)1/4 (gamma is surface tension, mu is shear modulus) because of a significant surface energy penalty (for example, lambda/H approximately equal to 6 for H = 200 nm; mu = 1 MPa). 相似文献
72.
Mixtures of truncated exponentials (MTE) potentials are an alternative to discretization for representing continuous chance variables in influence diagrams. Also, MTE potentials can be used to approximate utility functions. This paper introduces MTE influence diagrams, which can represent decision problems without restrictions on the relationships between continuous and discrete chance variables, without limitations on the distributions of continuous chance variables, and without limitations on the nature of the utility functions. In MTE influence diagrams, all probability distributions and the joint utility function (or its multiplicative factors) are represented by MTE potentials and decision nodes are assumed to have discrete state spaces. MTE influence diagrams are solved by variable elimination using a fusion algorithm. 相似文献
73.
Kalagouda?B.?GudasiEmail author Siddappa?A.?Patil Ramesh?S.?Vadavi Rashmi?V.?Shenoy Manjula?S.?Patil 《Transition Metal Chemistry》2005,30(8):1014-1019
A new Schiff base, 2,6-diacetylpyridine bis(3-methylsulfhydryl-4-amino-5-mercapto-1,2,4-triazole) (DPMAMT) is designed and
synthesized by the condensation of 2,6-diacetylpyridine with 3-methylsulfhydryl-4-amino-5-mercapto-1,2,4-triazole, and structurally
characterized. Copper(II), cobalt(II), nickel(II), manganese(II), zinc(II), cadmium(II) and oxovanadium(IV) complexes of DPMAMT
have been prepared for the first time, and characterized on the basis of elemental analyses, conductance measurements, magnetic
properties, spectral (i.r., 1H-n.m.r., u.v.–vis., e.p.r. and FAB-mass) and thermal studies. The complexes exhibit an octahedral geometry around the metal
center. The pentadentate behavior of the ligand was confirmed on the basis of spectral studies. 相似文献
74.
Lagugné-Labarthet F An YQ Yu T Shen YR Dalcanale E Shenoy DK 《Langmuir : the ACS journal of surfaces and colloids》2005,21(16):7066-7070
The conformational changes of quinoxaline-bridged cavitands deposited as Langmuir films were monitored at different pH values of the subphase using surface second harmonic generation during the compression of the monolayer at the water surface. A quantitative analysis of the susceptibility tensor elements was performed for methylene (MeCav)- and quinoxaline (QxCav)-bridged cavitands for pH values varying between 5.7 and 0.1. For MeCav (reference compound), no significant changes were observed for different pHs, confirming that the cavity does not undergo protonation or a drastic conformational change. For the QxCav, however, the results suggest a partial opening of the cavity on the basis of analysis of the compression curves. 相似文献
75.
S. Narayanaswami S. Rajeswari B. R. Pai K. Nagarajan W. J. Richter S. J. Shenoy 《Journal of Chemical Sciences》1984,93(2):145-155
Solutions of 3,4-dihydro-6,7-methylenedioxyisoquinoline (1) and analogues2–5 and9 as well as isoquinolines7 and8 in certain samples of CDCl3, CCl4, DMSO-d6 or acetone-d6 gave rise to anomalous1Hnmr spectra with extreme line broadening, signals due to protons at C-l and C-3 most often not being seen. The spectra of1 and3 were most striking in this respect.1Hnmr spectra of the quaternary salt10 and the model schiff base11 were normal. Several hypotheses for the observed line broadening have been considered and rejected, a slow equilibrium1 ⇆13 being one of them. NaBH4 reduction of1 and2 followed by mass spectrometric analysis of the crude tetrahydroisoquinolines16 and17 ruled out a slow equilibrium1 ⇆14 and2 ⇆15 as contributory cause for line broadening. The crude reduction products unexpectedly contained N-ethyl species22 and25. Their formation is rationalised 相似文献
76.
Tiwari Ashutosh Prasad Sridhar B. Boshoff Helena I. Arora Kriti Gautham Shenoy G. Vandana K. E. Varadaraj Bhat G. 《Molecular diversity》2020,24(4):1265-1279
Molecular Diversity - Diphenyl ether derivatives inhibit mycobacterial cell wall synthesis by inhibiting an enzyme, enoyl-acyl carrier protein reductase (InhA), which catalyses the last step in the... 相似文献
77.
A novel planar accumulation channel SiC MOSFET structure is reported in this paper. The problems of gate oxide rupture and poor channel conductance previously reported in SiC UMOSFETs are solved by using a buried P+ layer to shield the channel region. The fabricated 6H-SiC unterminated devices had a blocking voltage of 350 V with a specific on-resistance of 18 mΩ.cm2 at room temperature for a gate bias of only 5 V. This measured specific on-resistance is within 2.5× of the value calculated for the epitaxial drift region (1016 cm-3, 10 μm), which is capable of supporting 1500 V 相似文献
78.
Mössbauer spectra of dilute : Er alloys indicate that only a fraction of the impurity ions are in isolated cubic symmetry sites of the host lattice. From the spectrum of the isolated 166Er impurities the hyperfine coupling constant of + 3.80 ± 0.05 mm/sec characteristic of the Γ7 ground state has been deduced. Clusters of rare earth atoms give a quite different contribution to the hyperfine spectrum which is easily identified. The influence of such clusters on the relaxation times and the EPR residual linewidth of isolated rare earth impurities is pointed out. 相似文献
79.
F.W. Kutzler D.E. Ellis T.I. Morrison G.K. Shenoy P.J. Viccaro P.A. Montano E.H. Appelman L. Stein M.J. Pellin D.M. Gruen 《Solid State Communications》1983,46(11):803-806
X-ray absorption near edge structure (XANES) spectra of gaseous Kr, solid Kr and solid KrF2 have been obtained and compared to differentiate between continuum resonances near the edge and bound state transitions. By comparing experimental and ab initio (MSW-Xα) calculated spectra the influence of environment as well as molecular bonding on XANES is demonstrated. 相似文献
80.
Prakash P. Shenoy 《Applied Mathematical Modelling》1980,4(4):295-300
The world oil market is modelled as a two-person non-zero-sum game in normal form with each player having a continuum of strategies. The two players are the oil importing nations (OPIC) and the oil exporting nations (OPEC). The game is solved in the noncooperative sense using the equilibrium point solution concept due to Nash. The Nash equilibrium point solution yields an analytic expression for the optimal price per barrel of oil for OPEC and the optimal level of imports of oil for OPIC assuming noncooperation between the players. The cooperative solution to the game is also investigated using the von Neumann-Morgenstern negotiation set solution and Nash's bargaining point solution. Again, we give analytic expressions for the optimal price of a barrel of oil and the optimal level of imports of oil assuming that the players cooperate (negotiate, bargain, etc., for a binding agreement) in arriving at a solution. 相似文献