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81.
Milan Kanti Naskar Debtosh Kundu Minati Chatterjee 《Journal of Sol-Gel Science and Technology》2012,64(1):117-123
The support substrates were modified with sol?Cgel-based silica coating as intermediate buffer layer followed by NaA zeolite seed (prepared hydrothermally at 85?°C for 3?h) coating with 2?wt% aqueous dispersion. The secondary crystallization of NaA zeolite in the silica-seed-coated supports was carried out hydrothermally through crystal growth process at 65?°C for 4 and 8?h (single-stage each), (6?+?4) and (6?+?6)?h (double-stage each), and (6?+?4?+?2) and (6?+?4?+?4)?h (triple-stage each). The crystallization behaviours of the prepared NaA membranes were studied by X-ray diffraction, and the microstructures of the same films were observed by field emission scanning electron microscope. The efficiency of the membranes was tested with gas permeation study. The double-stage secondary crystallization at 65?°C for (6?+?4)?h showed highly interlocked NaA grains in the membrane and it rendered the permeance values of 3.7?×?10?8?mol?m?2?s?1?Pa?1 and 15.9?×?10?8 for single gas, nitrogen (N2) and hydrogen (H2) respectively with the ideal selectivity of 4.3. 相似文献
82.
83.
Subhendu Naskar Sumita Naskar Hake M. Figgie William S. Sheldrick Shyamal Kumar Chattopadhyay 《Polyhedron》2010
Two mononuclear zinc(II) complexes, [ZnL1H2Cl]Cl·2H2O (1·Cl·2H2O) and [ZnL2HCl]·H2O (2·H2O) (L1H2 and L2H2 are N,N′-bis(pyridoxylidene)ethylenediamine and N,N′-bis(pyridoxylidene)1,3-propanediamine, respectively) have been synthesized and characterized by elemental analysis, FT-IR, fluorescence spectroscopy, TG–DTA and single crystal X-ray diffraction studies. The Zn(II) ion in complex 1 have a square pyramidal geometry with appreciable distortion towards trigonal bipyramid, whereas in 2 it has a geometry which is near the midpoint of square pyramid and trigonal bipyramid. The zinc atom is coordinated by two imine nitrogens, two phenolic oxygens and one chloride ion. The Zn(II) complexes show emission at 462 nm when excited at their lowest energy absorption at 372 nm. 相似文献
84.
85.
Jahangir Mondal Amit K. Manna Kalyani Rout Sunil K. Singh Jnan P. Naskar 《International journal of environmental analytical chemistry》2013,93(12):1160-1174
ABSTRACTA new fluorescent-colorimetric chemosensor L has been synthesised by Schiff base condensation reaction between 1,8-diaminooctane and 4-nitro-benzaldehyde in very good yields. Its photo-luminescent properties and selective detection properties for hydrazine have been examined. The synthesised chemosensor exhibited highly selective fluorescence on-off response for hydrazine amongst a wide range of different metal cations, anions and amines, along with the bare eye colour change from colourless to yellow based on intermolecular hydrogen-bond interaction. The limit of detection of the chemosensor L was estimated as 9.77 × 10?8 M or 3.12 × 10?6 g L?1 for hydrazine which is extremely below the limit set by the World Health Organization (WHO) and the binding stoichiometry was proposed to be 1 : 2 based on 1H NMR spectroscopic techniques and the Job’s plot analysis. The proposed sensing mechanism is the hydrogen-bonding interaction which has further been established by Density Functional Theory (Functional Density Theory (DFT)) studies. This recognition feature of sensor L makes it an efficient chemosensor for hydrazine detection in different water samples. 相似文献
86.
Manuela Weber Dr. Simon Grabowsky Dr. Abhijit Hazra Subhendu Naskar Dr. Sukdeb Banerjee Dr. Nirup B. Mondal Prof. Peter Luger 《化学:亚洲杂志》2011,6(6):1390-1397
For two indole and oxindole bioactive molecules, low‐order room‐temperature X‐ray data were used to generate aspherical electron density (ED) distributions by application of the invariom formalism. An analysis of the ED using the quantum theory of atoms in molecules (QTAIM) was carried out, which allowed for quantitatively examining bond orders and charge separations in various parts of the molecules. The inspection of electrostatic potentials (ESPs) and Hirshfeld surfaces provided additional information on the intermolecular interactions. Thus, reactive regions of the molecules could be identified, covalent and electrostatic contributions to interactions could be visualized, and the forces causing the crystal packing scheme could be rationalized. As the used invariom formalism needs no extra experimental effort compared to routine X‐ray analysis, its wide application is recommended because it delivers information far beyond the normally obtained steric properties. In this way, complementary contributions to drug design can be given as is demonstrated for indoles in this study, which are involved in the metabolism of plants and animals as well as in cancer therapy. 相似文献
87.
Pritam Saha Shyamal Mondal Abhijit Hazra Subhendu Naskar Arindam Maity Krishnendu B. Sahu 《合成通讯》2013,43(21):3166-3176
The Heck cross-coupling reaction has been employed for efficient conversion of quinolines to benzoxocinoquinoline through a microwave-assisted palladium-catalyzed intramolecular cyclization in the presence of basic alumina. 相似文献
88.
Kinsuk DasTarak Nath Mandal Somnath RoyAtanu Jana Saugata KonarCai-Ming Liu Anil Kumar BarikSusanta Kumar Kar 《Polyhedron》2011,30(5):715-724
Two new dinuclear copper compounds, [Cu2(pypz)2(N3)2(NO3)2] (1) and [Cu2(pypz)2(OH)2(NO3)2] (2), and one 1-D polymeric Cu(II) complex, [Cu(pypz)(dca)3]n (3) [‘pypz’ = (3,5dimethyl-1-(2′-pyridyl)pyrazole) and dca = (dicyanamide)], have been synthesized and characterized crystallographically and spectroscopically. Complex 1 is pseudo-octahedral, adjacent Cu atoms are connected by a pair of μ(1,1) azido groups and the structure is stabilized by π-π interactions between two pyridyl moieties from two different neighboring complex molecules. Complexes 2 and 3 are square pyramidal. The hydroxo bridged complex 2 is further stabilized through H-bonding. The 1-D polymeric chain of 3 is bridged by an end-to-end dicyanamide bridge and it propagates along the crystallographic b axis, whilst the polymer chains are stacked one upon another along the crystallographic c axis. Low temperature magnetic measurement shows that complexes 1 and 2 are ferromagnetic (J values are 30.81 and 14.79 cm−1, respectively), whereas due to larger Cu-Cu distances, complex 3 shows weak ferromagnetism. 相似文献
89.
Sayani Nandy Debtosh Kundu Milan Kanti Naskar 《Journal of Sol-Gel Science and Technology》2014,72(1):49-55
The effect of secondary (diethanolamine) and tertiary (triethanolamine) alkanolamines as catalysts on the formation of mesoporous Stöber silica nanoparticles by sol–gel method was studied. The particles were characterized by thermogravimetry and differential thermal analysis, Fourier transform infrared spectroscopy, N2 physisorption measurements, and field emission scanning electron microscopy. By using ammonia and different alkanolamines as catalysts, the Brunauer–Emmet–Teller (BET) surface area and pore volume increased in the order of ammonia < diethanolamine < triethanolamine. A maximum BET surface area of 140.1 m2 g?1 and pore volume of 0.66 cm3 g?1 were obtained from triethanolamine catalyzed silica particles. The average particle size of silica prepared by ammonia and different alkanolamines as catalysts decreased in the order of ammonia > diethanolamine > triethanolamine. The role of different alkanolamines on the textural properties and particle size of silica is explained in terms of their relative steric hindrance and basicity. 相似文献
90.
Deb Argha Gazi Mahasin Bhoumik Gopa Naskar Arindam Barman Chiranjib 《Journal of Radioanalytical and Nuclear Chemistry》2017,311(1):375-384
Air radon survey was carried out at different underground locations at Kolkata using radon monitor. Average radon concentration for basements was found to be 22.70 ± 1.12 Bq/m3 with maximum 59.00 ± 7.18 Bq/m3 and minimum 8.50 ± 3.14 Bq/m3. Average level for sub-ways was 23.05 ± 2.59 Bq/m3 fluctuating between maximum 39.00 ± 1.24 Bq/m3 and minimum 13.50 ± 1.78 Bq/m3. In comparison, open air background at basement entrance was 19.44 ± 1.06 Bq/m3 and subway entrance was 18.58 ± 1.14 Bq/m3. Annual effective dose was calculated to assess probable health risk. Radon concentration level and annual effective dose were found well below safe levels recommended by International Agencies WHO and UNSCEAR.
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