全文获取类型
收费全文 | 677篇 |
免费 | 33篇 |
国内免费 | 3篇 |
专业分类
化学 | 547篇 |
晶体学 | 6篇 |
力学 | 24篇 |
数学 | 25篇 |
物理学 | 111篇 |
出版年
2023年 | 5篇 |
2022年 | 21篇 |
2021年 | 19篇 |
2020年 | 20篇 |
2019年 | 20篇 |
2018年 | 33篇 |
2017年 | 11篇 |
2016年 | 24篇 |
2015年 | 23篇 |
2014年 | 33篇 |
2013年 | 43篇 |
2012年 | 72篇 |
2011年 | 54篇 |
2010年 | 38篇 |
2009年 | 29篇 |
2008年 | 34篇 |
2007年 | 36篇 |
2006年 | 26篇 |
2005年 | 27篇 |
2004年 | 25篇 |
2003年 | 19篇 |
2002年 | 11篇 |
2001年 | 14篇 |
2000年 | 13篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 8篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 6篇 |
1984年 | 3篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有713条查询结果,搜索用时 15 毫秒
91.
Pradeep R. Varadwaj 《Journal of Molecular Spectroscopy》2006,236(1):70-74
The ground state (ν = 0) rotational spectrum of 2-fluorobenzonitrile has been reinvestigated in the frequency range 40.0-99.0 GHz. The millimeter-wave spectrometer used is a source-modulated system combined with a free space glass cell. Millimeter-wave radiation has been produced using a Gunn diode and frequency doubler combination. High J and K−1 (J ? 49 and K−1 ? 18) transitions have been measured and accurate rotational and centrifugal distortion constants have been determined. Finally, the experimental values were compared with the corresponding values calculated at the HF/DFT-B3PW91/6-31g(d,p) level of theory. A very good agreement has been found. 相似文献
92.
Hrishikesh E. Patel T. Sundararajan T. Pradeep A. Dasgupta N. Dasgupta Sarit K. Das 《Pramana》2005,65(5):863-869
Increase in the specific surface area as well as Brownian motion are supposed to be the most significant reasons for the anomalous
enhancement in thermal conductivity of nanofluids. This work presents a semi-empirical approach for the same by emphasizing
the above two effects through micro-convection. A new way of modeling thermal conductivity of nanofluids has been explored
which is found to agree excellently with a wide range of experimental data obtained by the present authors as well as the
data published in literature 相似文献
93.
In Part I of this paper we introduced extensive games with a non-atomic continuum of players. It was shown that the Nash plays (outcomes) are invariant of the information patterns on the game, provided that no player's unilateral change in moves can be observed by others. This led to an enormous reduction in the Nash plays of the these games, as exemplified in the anti-folk theorem. Our concern in this sequel is to develop a finite version of these results. 相似文献
94.
95.
Copper sulphide films prepared by reactive evaporation, when heated in air at 500 K, oxidized to Cu2O after a series of intermediate chemical transitions. Golden yellow coloured Cu2O films showed a large absorption before the fundamental absorption edge. The optical band gap was found to be (2.29±0.02)eV.
When these Cu2O films were further heated they got converted to CuO and the optical band gap was found to be (2.17±0.02)eV. 相似文献
96.
97.
98.
Pradeep Kumar 《Physics letters. A》1978,66(6):487-488
The contribution of the textures in the B-phase of superfluid 3He to the specific heat has been calculated. The specific heat is found to be divergent near Tc. 相似文献
99.
Investigation of the role of NaBH<Subscript>4</Subscript> in the chemical synthesis of gold nanorods
Akshaya K. Samal Theruvakkattil S. Sreeprasad Thalappil Pradeep 《Journal of nanoparticle research》2010,12(5):1777-1786
An improvement in the previously reported seed-mediated chemical synthesis of gold nanorods (GNRs) is reported. Monodisperse
GNRs have been synthesized in a one-step protocol. The addition of controlled quantity of sodium borohydride (NaBH4) directly into the growth solution produced uniform GNRs, formed by in situ nucleation and growth. In order to arrive at
the conclusion, we studied the formation of GNRs with various seeds, of metals of widely differing crystal structures, and
there were no variations in the properties of the GNRs formed. The role of NaBH4 in the growth of GNR, which has not been covered in previous reports, is discussed in detail. The dependence of longitudinal
plasmon peak on the concentration of NaBH4 is compared with the dependence of residual concentration of NaBH4 in the seed solution, which is added to the growth solution in seed-mediated synthesis. The study shows that NaBH4 plays an important role in the formation of GNRs. This proposed protocol offers a number of advantages: one-step preparation
of GNRs, significant reduction in the preparation time to 10 min, high monodispersity of GNRs, and tailorability of the aspect
ratio depending on NaBH4 concentration. It is suggested that NaBH4 added to the growth solution leads to in situ formation of the seed particles of the size of 3–5 nm which enables the growth
of GNRs. The growth of GNRs suggested here is likely to have an impact on the preparation of other anisotropic structures.
Our single-pot methodology makes the procedure directly adaptable for commercial-scale production of GNRs and for their synthesis
even in undergraduate laboratories. 相似文献
100.
Kumar P Yan Z Xu L Mazza MG Buldyrev SV Chen SH Sastry S Stanley HE 《Physical review letters》2006,97(17):177802
Using molecular dynamics simulations, we investigate the relation between the dynamic transitions of biomolecules (lysozyme and DNA) and the dynamic and thermodynamic properties of hydration water. We find that the dynamic transition of the macromolecules, sometimes called a "protein glass transition," occurs at the temperature of dynamic crossover in the diffusivity of hydration water and also coincides with the maxima of the isobaric specific heat C_{P} and the temperature derivative of the orientational order parameter. We relate these findings to the hypothesis of a liquid-liquid critical point in water. Our simulations are consistent with the possibility that the protein glass transition results from crossing the Widom line, which is defined as the locus of correlation length maxima emanating from the hypothesized second critical point of water. 相似文献