全文获取类型
收费全文 | 142篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
化学 | 106篇 |
晶体学 | 2篇 |
数学 | 10篇 |
物理学 | 28篇 |
出版年
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 2篇 |
2020年 | 10篇 |
2019年 | 6篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2015年 | 1篇 |
2014年 | 6篇 |
2013年 | 10篇 |
2012年 | 19篇 |
2011年 | 19篇 |
2010年 | 12篇 |
2009年 | 2篇 |
2008年 | 3篇 |
2007年 | 4篇 |
2006年 | 4篇 |
2005年 | 5篇 |
2004年 | 4篇 |
2003年 | 1篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有146条查询结果,搜索用时 31 毫秒
141.
V. Alagarsamy P. Parthiban V. Raja Solomon K. Dhanabal S. Murugesan G. Saravanan G. V. Anjana 《Journal of heterocyclic chemistry》2008,45(3):709-715
142.
Vinu A Krithiga T Balasubramanian VV Asthana A Srinivasu P Mori T Ariga K Ramanath G Ganesan PG 《The journal of physical chemistry. B》2006,110(24):11924-11931
Iron substituted cubic cage type mesoporous molecular sieves (FeSBA-1) were synthesized for the first time in a highly acidic media using cetyltriethylammonium bromide as a template. The amount of Fe incorporation in SBA-1 can easily be controlled by the simple adjustment of the molar hydrochloric acid-to-silicon ratio. All the materials were unambiguously characterized by AAS, XRD, N2 adsorption, UV-Vis DRS, XPS, and ESR spectroscopy. The results from AAS, XRD, and N2 adsorption reveal that the iron atom can be incorporated in the framework of SBA-1 matrix without altering the structural order and the textural parameters. The nature and the coordination of iron atoms were extensively studied by XPS spectroscopy, and the results revealed that most of the iron atoms in FeSBA-1 are in +3 coordination state. UV-Vis DRS and ESR studies confirmed that the majority of the Fe atoms in FeSBA-1 exist in a tetrahedral coordination environment (most probably occupying framework positions). tert-Butylation of phenol employing tert-butanol as the alkylation agent was carried out over FeSBA-1 catalysts with different iron content and the results are compared with one-dimensional mesoporous catalysts. The influence of various reaction parameters such as reaction temperature, reactant feed ratio, weight hourly space velocity, and time-on-stream affecting the activity and selectivity of FeSBA-1 were also studied. Under the optimized reaction conditions, the FeSBA-1(36) catalyst showed superior catalytic performance for the tert-butylation of phenol as compared to the uni-dimensional mesoporous catalysts. 相似文献
143.
Naresh B. Kotadiya Anjana J. Kothari Devendra Tiwari Tapas K. Chaudhuri 《Applied Physics A: Materials Science & Processing》2012,108(4):819-824
A chemical bath deposition method of preparing photoconducting nanocrystalline lead sulphide (PbS) thin films at room temperature (RT) is described. The aqueous bath of lead acetate, thiourea, and ammonium hydroxide produce films of about 100?nm thicknesses in 45?minutes. X-ray diffraction (XRD) studies show that these films are nanocrystalline cubic PbS with 10?nm crystallite size. Atomic Force Microscope (AFM) and Scanning Electron Microscope (SEM) revealed that the films consist of spherical grains of sizes 100 to 200?nm. The transmission spectra of the films show onset of absorption edge around 850?nm and the bandgap is around 1.65?eV. The films are p-type with dark conductivity of 2.5×10?3?S/cm and mobility of 0.07?cm2/V?s. The photosensitivity is 6–7 for an illumination of 80?mW/cm2 from a halogen lamp (50?W, 12?V). Transient photoconductivity measurements reveal short and long life times of minority carriers. Thermoelectric and photothermoelectric studies show that photoconductivity in these films is mainly due to photogenerated majority carriers. 相似文献
144.
Kasra Momeni Anjana Asthana Abhishek Prasad Yoke K. Yap Reza Shahbazian-Yassar 《Applied Physics A: Materials Science & Processing》2012,109(1):95-100
In this work, piezoelectricity of individual ZnO nanobelts grown along the [0?1????0] direction is studied using piezoresponse force microscopy (PFM). It is found that the effective piezoelectric coefficient of these NBs, $d_{33}^{\mathrm{eff}}$ , is increasing from 2.7?pm/V at 30?kHz to 44?pm/V at 150?kHz. The results were explained by the Debye model, where structural inhomogeneity in our NBs was shown to be responsible for piezoelectric enhancement. 相似文献
145.
Anjana Baby Athira Maria John Dr. Sreeja Puthenveetil Balakrishnan 《Chemphyschem》2023,24(6):e202200676
Advancements in renewable energy technology have been a hot topic in the field of photoresponsive materials for a sustainable community. Organic compounds that function as photoswitches is being researched and developed for use in a variety of energy storage systems. Azobenzene photoswitches can be used to store and release solar energy in solar thermal fuels. This review draws out the significance of azobenzene as photoswitches and its recent advances in solar thermal fuels. The recent developments of nano carbon templated azobenzene, their interactions and the effect of substituents are highlighted. The review also introduces their applications in solar thermal fuels and concludes with the challenges and future scope of the material. The advancements of solar thermal fuels with cost effective and desired optimal properties can be explored by scientists and engineers from different technological backgrounds. 相似文献
146.
Varsha Lisa John A. R. Nayana T. R. Keerthi Athira Krishnan K. A. B. C. P. Sasidharan Vinod T. P. 《Macromolecular bioscience》2023,23(9):2300081
Silk fibers (SF) reeled from silkworms are constituted by natural proteins, and their characteristic structural features render them applicable as materials for textiles and packaging. Modification of SF with functional materials can facilitate their applications in additional areas. In this work, the preparation of functional SF embedded with carbon dots (CD) is reported through the direct feeding of a CD-modified diet to silkworms. Fluorescent and mechanically robust SF are obtained from silkworms (Bombyx mori) that are fed on CDs synthesized from the Morus rubra variant of mulberry leaves (MB-CDs). MB-CDs are introduced to silkworms from the third instar by spraying them on the silkworm feed, the mulberry leaves. MB-CDs are synthesized hydrothermally without adding surface passivating agents and are observed to have a quantum yield of 22%. With sizes of ≈4 nm, MB-CDs exhibited blue fluorescence, and they can be used as efficient fluorophores to detect Dopamine (DA) up to the limit of 4.39 nM. The nanostructures and physical characteristics of SF weren't altered when the SF are infused with MB-CDs. Also, a novel DA sensing application based on fluorescence with the MB-CD incorporated SF is demonstrated. 相似文献