全文获取类型
收费全文 | 121篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
化学 | 81篇 |
力学 | 1篇 |
数学 | 3篇 |
物理学 | 13篇 |
无线电 | 25篇 |
出版年
2024年 | 5篇 |
2023年 | 9篇 |
2022年 | 15篇 |
2021年 | 7篇 |
2020年 | 13篇 |
2019年 | 14篇 |
2018年 | 5篇 |
2017年 | 3篇 |
2016年 | 3篇 |
2015年 | 3篇 |
2014年 | 7篇 |
2013年 | 6篇 |
2012年 | 4篇 |
2011年 | 5篇 |
2010年 | 5篇 |
2009年 | 4篇 |
2008年 | 5篇 |
2007年 | 1篇 |
2006年 | 2篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2001年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有123条查询结果,搜索用时 15 毫秒
101.
Tanwar Anand Sharma Ajay K. Pandey R. Vinay Shankar 《Wireless Personal Communications》2020,113(1):399-422
Wireless Personal Communications - The progression in wireless sensor network (WSN) has been increased and gained immense attention in computer vision. In WSN, a large number of sensors are... 相似文献
102.
Samiappan Dhanalakshmi Kesarikiran A. V. S. Chakravartula Venkatesh Kumari C. R. Uma Shubham Kumar Aakash Bolisetty Kumar R. 《Wireless Personal Communications》2020,110(2):593-604
Wireless Personal Communications - As global warming and climate change persistently threaten our planet, especially in developing countries, environmental monitoring becomes more and more... 相似文献
103.
Shubham Duttagupta Fen Lin Kishan Devappa Shetty Armin G. Aberle Bram Hoex 《Progress in Photovoltaics: Research and Applications》2013,21(4):760-764
Excellent passivation of boron emitters is realised using AlOx/SiNx dielectric stacks deposited in an industrial inline plasma‐enhanced chemical vapour deposition reactor. Very low emitter saturation current density (J0e) values of 10 and 45 fA/cm2 are obtained for 180 and 30 Ω/sq planar p+ emitters, respectively. For textured p+ emitters, the J0e was found to be 1.5–2 times higher compared with planar emitters. The required thermal activation of the AlOx films is performed in a standard industrial fast‐firing furnace, making the developed passivation stack industrially viable. We also show that an AlOx thickness of 5 nm in the AlOx/SiNx stack is sufficient for obtaining a J0e of 18 fA/cm2 for planar 80 Ω/sq p+ emitters, which corresponds to a 1‐sun open‐circuit voltage limit of the solar cell of 736 mV at 25 °C. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
104.
Rastogi VK Alcolea Palafox M Tanwar RP Mittal L 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2002,58(9):1987-2004
Geometry, vibrational wavenumbers and several thermodynamic parameters were calculated using ab initio quantum chemical methods for the 3,5-difluorobenzonitrile molecule. The results were compared with the experimental values. With the help of three specific scaling procedures, the observed vibrational wavenumbers in FTIR and Raman spectra were analysed and assigned to different normal modes of the molecule. Most of the modes have wavenumbers in the expected range and the error obtained was in general very low. Using PEDs the contributions were determined for the different modes to each wavenumber. From the PED, it is apparent that the frequency corresponding to C[triple bond]N stretching contains 87% contribution from the C[triple bond]N stretching force constant and it mixes with the C-CN stretching mode 13 to the extent of 12%. Other general conclusions were also deduced. 相似文献
105.
Shubham Agarwal Diptesh Ghosh Anindya S. Chakrabarti 《The European Physical Journal B - Condensed Matter and Complex Systems》2016,89(12):266
In this paper, we consider a distributed coordination game played by a large number ofagents with finite information sets, which characterizes emergence of a single dominantattribute out of a large number of competitors. Formally, N agents play acoordination game repeatedly, which has exactly N pure strategy Nash equilibria, and all of theequilibria are equally preferred by the agents. The problem is to select one equilibriumout of Npossible equilibria in the least number of attempts. We propose a number of heuristicrules based on reinforcement learning to solve the coordination problem. We see that theagents self-organize into clusters with varying intensities depending on the heuristicrule applied, although all clusters but one are transitory in most cases. Finally, wecharacterize a trade-off in terms of the time requirement to achieve a degree of stabilityin strategies versus the efficiency of such a solution. 相似文献
106.
107.
Shubham Singh Negi Suneyana Rawat Pramod K. Singh Shri Prakash Pandey Tarun Yadav Monika Srivastava Ram Chandra Singh 《Macromolecular Symposia》2024,413(1):2300104
The potential applications of carbon black are expected to grow as science and technology improve offering up new possibilities for innovation throughout disciplines included in the field of energy storage. The present work shows the influence of carbon black to improve the ionic conductivity of the polymer electrolyte. The synthesis of polyethylene oxide: ammonium iodide based polymer electrolyte incorporated with carbon black varying from 0.01 to 0.06 wt% with respect to PEO: NH4I system by solution casting method. Different characterizations like polarized optical microscopy (POM), impedance spectroscopy, and ionic transference number (tion) are studied in detail. The maximum ionic conductivity is achieved at 0.05 wt% carbon black shows 1.20 × 10−5 S cm−1 at ambient temperature. In accordance with POM data, the amorphous region has increased whereas the crystalline region has shrunk which further indicated the increase in ionic conductivity . The value of (tion) is calculated to be 0.97 which shows the system is ionic in nature. PEO based polymer electrolyte doped carbon black can be used for the fabrication of energy storage devices. 相似文献
108.
Neeraj Soni Shivendra Singh Shubham Sharma Gayatri Batra Kush Kaushik Chethana Rao Navneet C. Verma Bhaskar Mondal Aditya Yadav Chayan K. Nandi 《Chemical science》2021,12(10):3615
The structure–function relationship, especially the origin of absorption and emission of light in carbon nanodots (CNDs), has baffled scientists. The multilevel complexity arises due to the large number of by-products synthesized during the bottom-up approach. By performing systematic purification and characterization, we reveal the presence of a molecular fluorophore, quinoxalino[2,3-b]phenazine-2,3-diamine (QXPDA), in a large amount (∼80% of the total mass) in red emissive CNDs synthesized from o-phenylenediamine (OPDA), which is one of the well-known precursor molecules used for CND synthesis. The recorded NMR and mass spectra tentatively confirm the structure of QXPDA. The close resemblance of the experimental vibronic progression and the mirror symmetry of the absorption and emission spectra with the theoretically simulated spectra confirm an extended conjugated structure of QXPDA. Interestingly, QXPDA dictates the complete emission characteristics of the CNDs; in particular, it showed a striking similarity of its excitation independent emission spectra with that of the original synthesized red emissive CND solution. On the other hand, the CND like structure with a typical size of ∼4 nm was observed under a transmission electron microscope for a blue emissive species, which showed both excitation dependent and independent emission spectra. Interestingly, Raman spectroscopic data showed the similarity between QXPDA and the dot structure thus suggesting the formation of the QXPDA aggregated core structure in CNDs. We further demonstrated the parallelism in trends of absorption and emission of light from a few other red emissive CNDs, which were synthesized using different experimental conditions.Herein we unveil the presence of a molecular fluorophore quinoxalino[2,3-b]phenazine-2,3-diamine (QXPDA) in a colossal amount in red emissive CNDs synthesized from o-phenylenediamine, a well-known precursor molecule used for CND synthesis. 相似文献
109.
Malcolm H. Chisholm Christopher M. Hadad Katja Heinze Klaus Hempel Namrata Singh Shubham Vyas 《Journal of Cluster Science》2008,19(1):209-218
The homoleptic compound Ru(II)(L)2 where L = 4′-carboxylato-2,2′:6′,2″-terpyridine was employed as a bridge to link two [Mo2(O2CBu
t
)3]+ units in the formation of the title complex: [Mo2(O2CBu
t
)3]2-μ-Ru(II)L2] (2+) [BF4−]2, which has been characterized by 1H-NMR, UV–vis and emission spectroscopy, MALDI-TOF-MS and cyclic voltammetry. The electronic structure of the complex has
been investigated by density functional theory employing Turbomole on the model complex cation [Mo2(O2CH)3]2-μ-(Ru(II)L2)2+. The intense blue color of the cation arises from M2 δ to bridge/terpyridine charge transfer.
This paper is dedicated to Prof. F. A. Cotton in memoriam. 相似文献
110.
Shubham Sharma Virender Singh Vaishali Rakesh Kumar Rahul Jamra Naveen Banyal Jyoti 《Journal of heterocyclic chemistry》2024,61(2):232-284
The synthesis of pyrazole derivative using α,β-unsaturated carbonyl compounds has attracted increasing attention of the synthetic organic chemist community. Interestingly, the simplicity of the synthetic method, high reactivity, and ease of incorporating diversity into the desired prototype have contributed a lot toward the exploration of α,β-unsaturated carbonyl compounds by various research groups. Due to the tremendous pharmacological significance of pyrazole derivatives, their synthesis has been one of the leading research frontiers in recent years. As prime examples, sildenafil, zometapin, Celebrex, and rimonabant have been successfully commercialized in the market to treat various life-challenging diseases. Considering the great profile of α,β-unsaturated carbonyl compound in the synthesis of biologically active pyrazole derivatives, this review incorporates contemporary literature (2011–2022) on the synthesis of pyrazole and its derivatives using α,β-unsaturated carbonyl compound as a starting precursor. 相似文献