全文获取类型
收费全文 | 223篇 |
免费 | 10篇 |
专业分类
化学 | 150篇 |
晶体学 | 1篇 |
力学 | 9篇 |
数学 | 15篇 |
物理学 | 58篇 |
出版年
2023年 | 5篇 |
2022年 | 7篇 |
2021年 | 6篇 |
2020年 | 7篇 |
2019年 | 9篇 |
2018年 | 7篇 |
2017年 | 14篇 |
2016年 | 9篇 |
2015年 | 10篇 |
2014年 | 14篇 |
2013年 | 29篇 |
2012年 | 21篇 |
2011年 | 10篇 |
2010年 | 16篇 |
2009年 | 8篇 |
2008年 | 11篇 |
2007年 | 8篇 |
2006年 | 7篇 |
2005年 | 4篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 6篇 |
2001年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1982年 | 1篇 |
排序方式: 共有233条查询结果,搜索用时 15 毫秒
11.
Sahu Mukesh Kumar Matheswaran M. M. Bishnoi Pardeep 《Journal of Thermal Analysis and Calorimetry》2021,144(4):1417-1434
Journal of Thermal Analysis and Calorimetry - An exhaustive experimental investigation was carried out for the thermal performance of artificially roughened solar air heaters (SAHs) under the... 相似文献
12.
Journal of Thermal Analysis and Calorimetry - More than a decade, a numerous experimental and theoretical studies of thermophysical properties of nanofluids are conducted to reveal its heat... 相似文献
13.
Sridevi Duggirala Rakesh P. Nankar Selvakumar Rajendran Mukesh Doble 《Applied biochemistry and biotechnology》2014,174(1):283-296
Naturally occurring phytochemicals with reported antibacterial activity were screened for their ability to inhibit the bacterial cell division protein Escherichia coli FtsZ. Among the representative compounds, coumarins inhibit the GTPase and polymerization activities of this protein effectively. Further screening with ten coumarin analogs we identified two promising candidates, scopoletin and daphnetin. The former is found to inhibit the GTPase activity of the protein in a noncompetitive manner. Docking of these coumarins with the modeled protein indicate that they bind to T7 loop, which is different from the GTP-binding site (active site), thereby supporting the experimental data. Lowest binding energy is obtained with scopoletin. 3D QSAR indicates the need for groups such as hydroxyl, diethyl, or dimethyl amino in the 7th carbon for enhanced activity. None of the coumarins exhibited cytotoxicity against NIH/3T3 and human embryonic kidney cell lines. The length of Bacillus subtilis increases in the presence of these compounds probably due to the lack of septum formation. Results of this study indicate the role of coumarins in halting the first step of bacterial cell division process. 相似文献
14.
Sumita Rani Mukesh Kumar Sumit Sharma Dinesh Kumar 《Journal of Sol-Gel Science and Technology》2014,71(3):470-476
Fine powders of zirconium oxide (ZrO2) were prepared using zirconium oxychloride by combustion method. The crystalline size of pure ZrO2 was in range of 14–45 nm. Graphene was incorporated in ZrO2 using graphene oxide as precursor and reducing it with hydrazine hydrate. X-Ray diffraction, Fourier transform infra-red spectroscopy, thermogravimetric analysis and Raman spectroscopy methods were used to characterize the samples. The role of graphene in structural transformation of ZrO2 to monoclinic phase was clearly observed. 相似文献
15.
BaGd2O4, BaLa2O4 and SrLa2O4 powders doped with different concentrations of Eu3+ or Tb3+ are prepared by combustion synthesis method and the samples were further heated to 500, 700 and 900 °C to improve the crystallinity of the materials. The structure and morphology of materials have been examined by X-ray diffraction and scanning electron microscopy. It is remarkable that all the samples of BaGd2O4, BaLa2O4 and SrLa2O4 have similar morphology. The SEM images show homogeneous aggregates of varying shapes and sizes, which are composed of a large number of small elliptical shaped crystallites with an average diameter of about 0.5-3.0 μm. Photoluminescence for all materials increases with increase of temperature and shows a maximum for the samples heated to 900 °C with 4 mole% doping of Eu3+ or Tb3+ ions. The luminescence is almost same for all powders when doped with same concentration of Eu3+. 相似文献
16.
17.
Some invariant solutions for non-conformal perfect fluid plates in 5-flat form in general relativity
A set of six invariant solutions for non-conformal perfect fluid plates in 5-flat form is obtained using one-parametric Lie
group of transformations. Out of the six solutions so obtained, three are in implicit form while the remaining three could
be expressed explicitly. Each solution describes an accelerating fluid distribution and is new as far as authors are aware. 相似文献
18.
A charged analogue of Schwarzschilds interior solution has been derived by considering the non-gravitational energy density to be constant along with a special choice of electric intensity. The charged fluid sphere so obtained is seen to be more general than that of P.S. Florides and joins smoothly with the Reissner-Nordström metric at the pressure-free interface. Also the new charged fluid sphere is capable of representing a superdense star with surface density of 2×1014 g cm–3 which can occupy maximum mass 1.502408 times the solar mass. In the process of deriving the solution, the authors have also come across A. L. Mehras gaseous charged fluid model which is found to be unphysical as it has negative pressure at least at the center of the model.This revised version was published online in April 2005. The publishing date was inserted. 相似文献
19.
In the present work, single-walled carbon nanotubes (SWCNTs) were dispersed in a room temperature nematic liquid crystal 4-pentyl-4′-cyanobiphenyl at the concentration of 0.02 and 0.05 wt%. Differential scanning calorimetry and temperature-dependent dielectric studies suggest decrease in clearing temperature of the composite materials as compared to the pure material. Ionic conductivity increases by two orders of magnitude due to the dispersion of such a low concentration (0.05 wt%) of SWCNTs. Dielectric studies also show that the presence of the SWCNTs decreases the effective longitudinal as well as transverse components of the dielectric permittivity. For homeotropic aligned samples, a relaxation mechanism has been detected in the lower MHz region both for the pure as well as dispersed samples. Presence of SWCNTs increases the relaxation frequency corresponding to flip-flop motion of molecules around their short axes. From frequency-dependent dielectric studies, important dielectric parameters such as relaxation frequency, dielectric strength and distribution parameters have been determined. Electro-optical experiments show that the threshold voltage decreases and the steepness of the transmission voltage curve improves due to the dispersion of SWCNTs. 相似文献
20.
Mukesh Yadav Amita Lavania Radha Tomar G. B. K. S. Prasad Shalini Jain Hariom Yadav 《Applied biochemistry and biotechnology》2010,160(8):2388-2400
In present study, we investigated hypoglycemic and antihyperglycemic potential of five extracts (water, ethanol, methanol,
hexane, and chloroform) of four plants (i.e., seeds of Eugenia jambolana, fruits of Momordica charantia, leaves of Gymnema sylvestre, and seeds of Trigonella foenum graecum) alone and/or in combination with glimepiride in rats. Ethanol extract of E. jambolana, water extract of M. charantia, ethanol extract of G. sylvestre, and water extract of T. graecum exhibited highest hypoglycemic and antihyperglycemic activity (most active) in rats among all the extracts, while hexane
extracts exhibited least activities. Most active extracts were further studied to dose-dependent (200, 100, and 50 mg/kg body
weight (bw)) hypoglycemic and antihyperglycemic effects alone and in combination with glimepiride (20, 10, and 5 mg/kg bw).
The combination of most active extracts (200 mg/kg bw) and lower dose of glimepiride (5 mg/kg bw) showed safer and potent
hypoglycemic as well as antihyperglycemic activities without creating severe hypoglycemia in normal rats, while higher doses
(200 mg/kg bw of most active extracts, and 10 and 20 mg/kg bw of glimepiride) were generated lethal hypoglycemia in normal
rats. From this study, it may be concluded that the ethanol extract of E. jambolana seeds, water extract of M. charantia fruits, ethanol extract of G. sylvestre leaves, and water extract of T. graecum seeds have higher hypoglycemic and antihyperglycemic potential and may use as complementary medicine to treat the diabetic
population by significantly reducing dose of standard drugs. 相似文献