全文获取类型
收费全文 | 145篇 |
免费 | 0篇 |
国内免费 | 11篇 |
专业分类
化学 | 19篇 |
力学 | 6篇 |
数学 | 31篇 |
物理学 | 100篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 4篇 |
2018年 | 2篇 |
2017年 | 7篇 |
2016年 | 22篇 |
2015年 | 3篇 |
2014年 | 33篇 |
2013年 | 28篇 |
2012年 | 22篇 |
2011年 | 11篇 |
2010年 | 2篇 |
2009年 | 4篇 |
2007年 | 1篇 |
2006年 | 2篇 |
2004年 | 1篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1987年 | 2篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1967年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有156条查询结果,搜索用时 15 毫秒
131.
132.
REKHA Dasari SUVARDHAN Kanchi KUMAR Kailasa Suresh JAYARAJ Bellum CHIRANJEEVI Pattium 《中国化学》2006,24(8):1095-1100
A facile,rapid and sensitive spectrophotometric method was developed for the determination of carbaryl in itsformulations,water and grain(rice and wheat)samples with newly synthesised reagent.The proposed method wasbased on the alkaline hydrolysis of carbaryl pesticide and thus resulted 1-naphthol was coupled with diazotised4,4'-methylene-bis-m-nitroaniline in basic medium(pH 9)to give red colored product having λ_(max)480 nm for dia-zonium method(DM)or 1-naphthol reacts with 4,4'-methylene-bis-m-nitroaniline in the presence of oxidising agentpotassium dichromate(K_2Cr_2O_7)to give red colored product having λ_(max)510 nm for oxidation method(OM).Theformation of colored derivatives with the coupling agent is instantaneous and stable for 48 h(DM)and 32 h(OM)respectively.Beer's law was obeyed in the concentration range of 0.2—10.0 μg·mL~(-1)for DM and 0.2—0,150μg·mL~(-1)for OM.The proposed methods are sensitive,easy to operate and permitted for the determination of car-baryl with detection limits of 0.028 μg·mL~(-1)for DM and 0.024 μg·mL~(-1)for OM respectively.The experimentalresults indicate that the procedure can eliminate the fundamental interferences caused by other pesticides andnon-target ions,which made the methods more sensitive and selective.The method was applicable to the determina-tion of carbaryl residue in water and food grain samples up to μg level. 相似文献
133.
SYAMALA Vardhana RAJA SEKHAR Damaramadugu SIVA KUMAR Kasibhatta VENKATESWARLU Ponneri 《中国化学》2007,25(1):32-43
Excess volumes (v^E), ultrasonic velocities (u), isentropic compressibility (△Ks) and viscosities (η) for the binary mixtures of dimethyl formamide (DMF) with 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,2,4-trichlorobenzene, o-chlorotoluene, m-chlorotoluene, p-chlorotoluene, o-nitrotoluene and m-nitrotoluene at 303.15 K were studied. Excess volume data exhibit an inversion in sign for the mixtures of dimethyl formamide with 1,2- and 1,3-dichlorobenzenes and the property is completely positive over the entire composition range for the mixtures of dimethyl formamide with 1,2,4-trichlorobenzene, o-nitrotoluene and m-nitrotoluene. On the other hand, the quantity is negative for the mixtures of dimethyl formamide with chlorotoluenes. Isentropic compressibility (Ks) has been computed for the same systems from precise sound velocity and density data. Further, deviation of isentropic com- pressibility (△Ks) from ideal behavior was also calculated. AKs values are negative over the entire volume fraction range in all the binary mixtures. The experimental sound velocity data were analysed in terms of Free Length Theory (FLT) and Collision Factor Theory (CFT). The viscosity data were analysed on the basis of corresponding state approach. The measured data were discussed on the basis of intermolecular interactions between unlike molecules. 相似文献
134.
BINOD KUMAR SAHOO 《Proceedings Mathematical Sciences》2016,126(2):143-151
In [5], a new combinatorial model with four types of points and nine types of lines of the slim dense near hexagon Q(5,2)?Q(5,2) was provided and it was then used to construct a non-abelain representation of Q(5,2)?Q(5,2) in the extraspecial 2-group \(2_{-}^{1+18}\). In this paper, we give a direct proof for the existence of a non-abelian representation of Q(5,2)?Q(5,2) in \(2_{-}^{1+18}\). 相似文献
135.
In this paper, we have considered the generalized bi-axially symmetric Schr\"{o}dinger equation $$\frac{\partial^2\varphi}{\partial x^2}+\frac{\partial^2\varphi}{\partial y^2} + \frac{2\nu} {x}\frac{\partial \varphi} {\partial x} + \frac{2\mu} {y}\frac{\partial \varphi} {\partial y} + \{K^2-V(r)\} \varphi=0,$$ where $\mu,\nu\ge 0$, and $rV(r)$ is an entire function of $r=+(x^2+y^2)^{1/2}$ corresponding to a scattering potential $V(r)$. Growth parameters of entire function solutions in terms of their expansion coefficients, which are analogous to the formulas for order and type occurring in classical function theory, have been obtained. Our results are applicable for the scattering of particles in quantum mechanics. 相似文献
136.
The Nie expression is amended in such a way that the expression follows the infinite pressure behaviour, i.e., \(P\to \infty \) or V → 0. A new empirical relationship is developed to predict the values of volume dependence of Grüneisen parameter. NaCl and ε-Fe have been employed to test the suitability of the expression. The results obtained reveal that the relationship is reliable as there is a good agreement between the calculated and the experimental data. 相似文献
137.
In this paper, we obtain exact soliton solutions of the modified KdV equation, inhomogeneous nonlinear Schrödinger equation and G(m, n) equation with variable-coefficients using solitary wave ansatz. The constraint conditions among the time-dependent coefficients turn out as necessary conditions for the solitons to exist. Numerical simulations for dark and bright soliton solutions for the mKdV equation are also given. 相似文献
138.
A three-level atom in a Λ configuration trapped in an optical cavity forms a basic unit in a number of proposed protocols
for quantum information processing. This system allows for efficient storage of cavity photons into long-lived atomic excitations,
and their retrieval with high fidelity, in an adiabatic transfer process through the ‘dark state’ by a slow variation of the
control laser intensity. We study the full quantum mechanics of this transfer process with a view to examine the non-adiabatic
effects arising from inevitable excitations of the system to states involving the upper level of Λ, which is radiative. We
find that the fidelity of storage is better, the stronger the control field and the slower the rate of its switching off.
On the contrary, unlike the adiabatic notion, retrieval is better with faster rates of switching on of an optimal control
field. Also, for retrieval, the behaviour with dissipation is non-monotonic. These results lend themselves to experimental
tests. Our exact computations, when applied to slow variations of the control intensity for strong atom–photon couplings,
are in very good agreement with Berry’s superadiabatic transfer results without dissipation. 相似文献
139.
SANJIVA KUMAR AMRITA DEBNATH R B TOKAS K DIVAKAR RAO D V UDUPA N K SAHOO 《Pramana》2014,82(2):289-294
The formations of sinusoidal surface relief structures recorded in positive photoresist (Allresist AR-P 3120) have been studied and optimized for different recording parameters of gratings with spatial frequency of ~1200 grooves/mm. A stable sinusoidal pattern generated using a two-beam laser interferometric technique was recorded in thin films of positive photoresist deposited on glass substrates. Several gratings were generated by varying the exposure time of interference pattern and time of chemical development of exposed media. Time duration of exposure for 90 s and chemical development for 15 s were observed to be optimum for the translation of the sinusoidal interference pattern into nearly-sinusoidal profiled grooves in the gratings for a developer AR-300-26 of dilution of 2:1 (developer:de-ionized water). 相似文献
140.
This paper reports the study on development of tilted fibre Bragg gratings using highly coherent 255 nm radiation, obtained from the second harmonic generation (SHG) of copper vapour laser (CVL). The transmission and reflection spectra of the tilted fibre Bragg gratings (TFBG) were studied for the tilt angles of 0° (normal FBG), 1°, 3° and 4° between the fibre axis and the interference fringe plane. It was observed that as the angle of fibre axis and phase mask increased, the main Bragg peak shifted towards the higher wavelength and transmission dip decreased. The transmission dip of the cladding mode first increased and then decreased after reaching a maximum with the increase in the tilt angle. 相似文献