全文获取类型
收费全文 | 116篇 |
免费 | 13篇 |
专业分类
化学 | 72篇 |
力学 | 2篇 |
数学 | 17篇 |
物理学 | 38篇 |
出版年
2024年 | 3篇 |
2023年 | 5篇 |
2022年 | 5篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 4篇 |
2017年 | 6篇 |
2016年 | 7篇 |
2015年 | 4篇 |
2014年 | 5篇 |
2013年 | 10篇 |
2012年 | 9篇 |
2011年 | 17篇 |
2010年 | 1篇 |
2009年 | 4篇 |
2008年 | 4篇 |
2007年 | 8篇 |
2006年 | 4篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 4篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1990年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有129条查询结果,搜索用时 15 毫秒
41.
Using fuzzy points the notions of prime fuzzy ideals and weakly prime fuzzy ideals of a Γ-semigroup have been introduced. Some important properties and characterizations of these ideals have been obtained. The concluding result shows that our work sharpens previous works on prime fuzzy ideals of Γ-semigroups. 相似文献
42.
Zhen Fan Dr. Dulal Senapati Sadia Afrin Khan Dr. Anant Kumar Singh Prof. Ashton Hamme Dr. Brian Yust Prof. Dhiraj Sardar Prof. Paresh Chandra Ray 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(8):2839-2847
Over the last few years, one of the most important and complex problems facing our society is treating infectious diseases caused by multidrug‐resistant bacteria (MDRB), by using current market‐existing antibiotics. Driven by this need, we report for the first time the development of the multifunctional popcorn‐shaped iron magnetic core–gold plasmonic shell nanotechnology‐driven approach for targeted magnetic separation and enrichment, label‐free surface‐enhanced Raman spectroscopy (SERS) detection, and the selective photothermal destruction of MDR Salmonella DT104. Due to the presence of the “lightning‐rod effect”, the core–shell popcorn‐shaped gold‐nanoparticle tips provided a huge field of SERS enhancement. The experimental data show that the M3038 antibody‐conjugated nanoparticles can be used for targeted separation and SERS imaging of MDR Salmonella DT104. A targeted photothermal‐lysis experiment, by using 670 nm light at 1.5 W cm?2 for 10 min, results in selective and irreparable cellular‐damage to MDR Salmonella. We discuss the possible mechanism and operating principle for the targeted separation, label‐free SERS imaging, and photothermal destruction of MDRB by using the popcorn‐shaped magnetic/plasmonic nanotechnology. 相似文献
43.
Impact of Metal Ions in Porphyrin‐Based Applied Materials for Visible‐Light Photocatalysis: Key Information from Ultrafast Electronic Spectroscopy
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Prasenjit Kar Samim Sardar Dr. Erkki Alarousu Dr. Jingya Sun Prof. Zaki S. Seddigi Prof. Saleh A. Ahmed Dr. Ekram Y. Danish Dr. Omar F. Mohammed Prof. Samir Kumar Pal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(33):10475-10483
Protoporphyrin IX‐zinc oxide (PP‐ZnO) nanohybrids have been synthesized for applications in photocatalytic devices. High‐resolution transmission electron microscopy (HRTEM), X‐ray diffraction (XRD), and steady‐state infrared, absorption, and emission spectroscopies have been used to analyze the structural details and optical properties of these nanohybrids. Time‐resolved fluorescence and transient absorption techniques have been applied to study the ultrafast dynamic events that are key to photocatalytic activities. The photocatalytic efficiency under visible‐light irradiation in the presence of naturally abundant iron(III) and copper(II) ions has been found to be significantly retarded in the former case, but enhanced in the latter case. More importantly, femtosecond (fs) transient absorption data have clearly demonstrated that the residence of photoexcited electrons from the sensitizer PP in the centrally located iron moiety hinders ground‐state bleach recovery of the sensitizer, affecting the overall photocatalytic rate of the nanohybrid. The presence of copper(II) ions, on the other hand, offers additional stability against photobleaching and eventually enhances the efficiency of photocatalysis. In addition, we have also explored the role of UV light in the efficiency of photocatalysis and have rationalized our observations from femtosecond‐ to picosecond‐resolved studies. 相似文献
44.
Gallium nitride nanoparticles for solar-blind detectors 总被引:1,自引:0,他引:1
We investigate the properties of GaN semiconducting nanoparticles as a potential candidate for photodetection in the solar-blind
region. The photocurrent spectral response is studied spanning the range 1.6-5.5 eV. A significant fraction of the response
is in the range 4–5.5 eV. The results are compared to other optical properties and the origins of the features observed in
the spectra are speculated upon.
Dedicated to Professor C N R Rao on his 70th birthday 相似文献
45.
Sardar PS Samanta S Maity SS Dasgupta S Ghosh S 《The journal of physical chemistry. B》2008,112(11):3451-3461
The steady-state and time-resolved studies of the sensitized emission of the excited-state proton transfer (ESIPT) probe 3-hydroxy-2-naphthoic acid (3HNA) when bound to bovine serum albumin (BSA) and human serum albumin (HSA) indicate that the nonradiative dipole-dipole F?rster type energy transfer from Trp singlet state of proteins to the ESIPT singlet state of 3HNA is greater in the case of HSA. This is supported by the distance and the orientation of the donor-acceptor pair obtained from the protein-ligand docking studies. The docking studies of the complex of BSA-3HNA also indicate that Trp 134 rather than Trp 213 is involved in the energy transfer process. The local environment of Trp 134 in BSA rather than that of Trp 213 is perturbed because of interaction with 3HNA as revealed by the optical resolution of Trp 134 phosphorescence in the complex at 77 K. Docking studies support the larger rotational correlation time, thetac (approximately 50 ns), observed for Trp residue/residues in the complexes of HSA and BSA compared with that in the free proteins. 相似文献
46.
G. G. Demirkhanyan E. P. Kokanyan H. G. Demirkhanyan D. Sardar M. Aillerie 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2016,51(1):28-34
The possibilities of LiNbO3-Ho3+ crystals for optical cooling based on the anti-Stokes luminescence in the wavelength range 2000-2200 nm are investigated. The efficiency and cooling temperature under the continuous wave (CW) excitation at the wavelengths 2035-2071 nm by ~100 W power are estimated. It is shown that under the CW excitation at 2035 nm wavelength the maximum cooling temperature is equal to 2.5 K, and at 2071 nm wavelength is equal to 10.9 K. 相似文献
47.
Photoinduced Dynamics and Toxicity of a Cancer Drug in Proximity of Inorganic Nanoparticles under Visible Light
下载免费PDF全文
![点击此处可从《Chemphyschem》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Siddhi Chaudhuri Samim Sardar Damayanti Bagchi Dr. Shreyasi Dutta Dr. Sushanta Debnath Prof. Partha Saha Prof. Peter Lemmens Prof. Samir Kumar Pal 《Chemphyschem》2016,17(2):270-277
Drug sensitization with various inorganic nanoparticles (NPs) has proved to be a promising and an emergent concept in the field of nanomedicine. Rose bengal (RB), a notable photosensitizer, triggers the formation of reactive oxygen species under green‐light irradiation, and consequently, it induces cytotoxicity and cell death. In the present study, the effect of photoinduced dynamics of RB upon complexation with semiconductor zinc oxide NPs is explored. To accomplish this, we successfully synthesized nanohybrids of RB with ZnO NPs with a particle size of 24 nm and optically characterized them. The uniform size and integrity of the particles were confirmed by high‐resolution transmission electron microscopy. UV/Vis absorption and steady‐state fluorescence studies reveal the formation of the nanohybrids. ultrafast picosecond‐resolved fluorescence studies of RB–ZnO nanohybrids demonstrate an efficient electron transfer from the photoexcited drug to the semiconductor NPs. Picosecond‐resolved Förster resonance energy transfer from ZnO NPs to RB unravel the proximity of the drug to the semiconductor at the molecular level. The photoinduced ROS formation was monitored using a dichlorofluorescin oxidation assay, which is a conventional oxidative stress indicator. It is observed that the ROS generation under green light illumination is greater at low concentrations of RB–ZnO nanohybrids compared with free RB. Substantial photodynamic activity of the nanohybrids in bacterial and fungal cell lines validated the in vitro toxicity results. Furthermore, the cytotoxic effect of the nanohybrids in HeLa cells, which was monitored by MTT assay, is also noteworthy. 相似文献
48.
Sardar R Park JW Shumaker-Parry JS 《Langmuir : the ACS journal of surfaces and colloids》2007,23(23):11883-11889
A simple, inexpensive, single-step synthesis of gold and silver nanoparticles using poly(allylamine) (PAAm) as a reducing and stabilizing agent is reported. The synthetic process was carried out in aqueous solution, making the method versatile and environmentally friendly. The synthesized polymer-stabilized nanoparticles are stable in water without particle aggregation at room temperature for at least a month. We demonstrate successful ligand exchange on the polymer-stabilized gold nanoparticles (AuNPs) with a variety of omega-functionalized acid-, alcohol-, amine-, and biotin-terminated alkylthiols. The methodologies, including ligand exchange, also are applicable for the generation of finely dispersed silver nanoparticles. The synthesized gold and silver nanoparticles are characterized by UV-visible absorption spectroscopy and transmission electron microscopy (TEM). The different ligand-stabilized AuNPs are also analyzed by Fourier transform infrared (FTIR) spectroscopy. 相似文献
49.
Tripathi S Roy BG Drew MG Achari B Mandal SB 《The Journal of organic chemistry》2007,72(19):7427-7430
Carbohydrate-derived substrates having (i) C-5 nitrone and C-3-O-allyl, (ii) C-4 vinyl and a C-3-O-tethered nitrone, and (iii) C-5 nitrone and C-4-allyloxymethyl generated tetracyclic isoxazolidinooxepane/-pyran ring systems upon intramolecular nitrone cycloaddition reactions. Deprotection of the 1,2-acetonides of these derivatives followed by introduction of uracil base via Vorbrüggen reaction condition and cleavage of the isooxazolidine rings as well as of benzyl groups by transfer hydrogenolysis yielded an oxepane ring containing bicyclic and spirocyclic nucleosides. The corresponding oxepane based nucleoside analogues were prepared by cleavage of isoxazolidine and furanose rings, coupling of the generated amino functionalities with 5-amino-4,6-dichloropyrimidine, cyclization to purine rings, and finally aminolysis. 相似文献
50.
U. V. Valiev J. B. Gruber D. K. Sardar A. K. Mukhammadiev Sh. A. Rakhimov V. Yu. Sokolov 《Optics and Spectroscopy》2007,102(6):910-917
The spectra of magnetic circular dichroism in the range of the 7 F 6→5 D 4 absorption band and the spectra of magnetic circular polarization of luminescence in the range of the 5 D 4→7 F 5 band in the terbium-gallium garnet Tb3Ga5O12 are studied at a temperature of 80 K. The optical transitions between the Stark sublevels of the 7 F 6, 7 F 5, and 5 D 4 multiplets are identified based on the analysis of the magneto-optical and optical spectra. It is shown that the experimentally determined symmetry and energy of the Stark sublevels of these multiplets confirm the results of numerical calculations of the energy spectrum of the Tb3+ rare-earth ion in terbium-gallium garnet. 相似文献