全文获取类型
收费全文 | 93篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
化学 | 20篇 |
力学 | 4篇 |
数学 | 38篇 |
物理学 | 33篇 |
出版年
2018年 | 2篇 |
2015年 | 1篇 |
2013年 | 3篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2008年 | 2篇 |
2007年 | 1篇 |
2006年 | 1篇 |
2005年 | 1篇 |
2004年 | 3篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1982年 | 4篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 3篇 |
1968年 | 1篇 |
1959年 | 1篇 |
1958年 | 1篇 |
1957年 | 1篇 |
1948年 | 5篇 |
1947年 | 2篇 |
1946年 | 1篇 |
1945年 | 6篇 |
1944年 | 1篇 |
1943年 | 1篇 |
1942年 | 1篇 |
1941年 | 7篇 |
1940年 | 3篇 |
1939年 | 2篇 |
1938年 | 1篇 |
排序方式: 共有95条查询结果,搜索用时 15 毫秒
1.
CV Tomy D Pal SS Banerjee S Ramakrishnan AK Grover S Bhattacharya MJ Higgins G Balakrishnan McK Paul 《Pramana》2002,58(5-6):925-935
The weakly pinned single crystals of the hexagonal 2H-NbSe2 compound have emerged as prototypes for determining and characterizing the phase boundaries of the possible order-disorder
transformations in the vortex matter. We present here a status report based on the ac and dc magnetization measurements of
the peak effect phenomenon in three crystals of 2H-NbSe2, in which the critical current densities vary over two orders of magnitude. We sketch the generic vortex phase diagram of
a weakly pinned superconductor, which also utilizes theoretical proposals. We also establish the connection between the metastability
effects and pinning. 相似文献
2.
K. Premchand B. Seetharami Reddy B. Mallikarjuna Rao K. Parthasaradhi M. V. R. Murti K. S. Rao 《Il Nuovo Cimento D》1993,15(1):73-76
Summary An attempt is made to study theK
α
L
1 satellite multiplet structure of chlorine atoms in different compounds by photon excitation. A comparison of the averageK
α
L
1 group energy shift from the diagram line with those based on Dirac-Fock evaluations with different number ofM-shell electrons shows a reasonable agreement. The
intensity ratios are found to be higher than those studied in Mg compounds in general. 相似文献
3.
Some procedures for the gravimetric determination of silica in lead-bearing samples involve the extraction of lead sulphate with ammonium acetate. Results for silica are then low because some silica is dissolved in ammonium acetate solution. Correct results can be obtained only by avoiding fuming with sulphuric acid. If samples contain a large proportion of insoluble silica, preliminary fusion with sodium hydroxide is recommended. 相似文献
4.
Excipient compatibility of a new chemical entity was assessed using an isothermal microcalorimeter. Mixtures of an active
pharmaceutical ingredient with a primary amine group and excipients were prepared in a 1:1 ratio and compatibility monitored
by exposing to 50, 60 and 70°C in presence of 200 mL of water. The new chemical entity, a primary amine, reacted with reducing
sugars such as lactose and resulted in a brown discoloration. This reaction is the Maillard type condensation reaction between
amines and reducing sugars. The rate of reaction was dependent on the temperature with rapid degradation at higher temperatures.
No other incompatibility was apparent between the primary amine and other excipients
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
6.
7.
8.
9.
The analysis of slope failure is complicated due to its mechanism as well as the geological history of the slope. In classical slope stability analysis, the slope failure is assessed using the basic continuum mechanics or the limit equilibrium approach. This analysis, however, must be slightly modified when tension cracks exist at the upper edge of the slope. From post-mortem analyses of slope failures in the past, it was found that tension cracks had some considerable importance affecting the failure mechanism of the slope.Some attempts had also been directed in the past towards simple vertical cut slopes with tension cracks. Terzaghi [40]. Using an elasto-plastic model and a few analytical assumptions, Terzaghi [40] obtained an expression for a critical height of a vertical cut slope. However, since the stress distribution is changing during crack propagation, the failure mechanism cannot in principle conjecture from a static (undisturbed) stress field alone. In this report, a unified numerical approach combining Finite Element Method (FEM), fracture mechanics and remeshing technique is used to model the failure analysis of vertical cut slopes with tension cracks. Using this approach, the crack can be extended incrementally under a certain energy based failure criterion (Strain Energy Density criterion - SED) while taking into account the existing stress singularity field in the vicinity of the crack-tip.The use of fracture mechanics in soils, however, poses some difficulties in obtaining its relevant parameters due to the granular structure of soil. Because of its granular structure, the shear strength of soil depends on cohesion and the applied confining pressure making the determination of fracture parameters in soil difficult. These relevant parameters are not yet available in literature and hence, certain assumptions and interpolations had to be made in obtaining these parameters. Future research direction in this area is badly needed. Using a certain set of soil properties and crack geometry, a series of curves relating parameters S (Strain Energy Density Factor) and a non-dimensional variable N ( = H/C - slope height vs. crack distance from edge ratio) for vertical cut slopes can be constructed through numerous parametric studies. These curves can serve as a quick guide to obtain the critical height for a given vertical cut slope geometry with tension cracks. 相似文献
10.
In subnormal glow discharge under d.c. excitation at different pressure in a varying transverse magnetic field (0 to 30 G)
some measurements have been carried out for various initial average tube currents. The voltage across the discharge increases
and average tube current and residual current decreases in the magnetic field. With the help of Beckman’s expression [4] for
the axial field and the electron density distribution in a transverse magnetic field the observed variation of current and
voltage can be satisfactorily explained. The variation of axial electric field with transverse magnetic field can be represented
to a fair degree of accuracy by the derived equation. The behaviour of residual current with magnetic field has been observed
in these oscillations. 相似文献