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51.
Subhendu Naskar Priyankar Paira Rupankar Paira Shyamal Mondal Arindam Maity Abhijit Hazra Krishnendu B. Sahu Pritam Saha Sukdeb Banerjee Peter Luger Manuela Webe Nirup B. Mondal 《Tetrahedron》2010,66(27-28):5196-5203
An environmentally benign protocol has been described for the synthesis of novel 2-(1′,3′-dihydro-1H-[2,3′]biindolyl-2′-ylidene)-indan-1,3-diones/bis-indolylindane-1,3-diones from ninhydrin and 3-substituted/unsubstituted indoles. It uses montmorillonite K-10 as catalyst in a solvent-free condition under microwave irradiation. The method was also used for the synthesis of novel bisindolylindeno[1,2-b]quinoxaline derivatives. 相似文献
52.
Sulata Kumari Sahu Rajesh Ganesan T. Gnanasekaran 《The Journal of chemical thermodynamics》2010,42(1):1-7
Standard molar Gibbs free energy of formation of ternary oxides Pb5CrO8(s), Pb2CrO5(s), and PbCrO4(s) were determined by measuring equilibrium oxygen partial pressures over relevant phase fields using manometry and solid oxide electrolyte based emf methods and are given by: 相似文献
53.
Ronhovde P Chakrabarty S Hu D Sahu M Sahu KK Kelton KF Mauro NA Nussinov Z 《The European physical journal. E, Soft matter》2011,34(9):105
We elaborate on a general method that we recently introduced for characterizing the “natural” structures in complex physical
systems via multi-scale network analysis. The method is based on “community detection” wherein interacting particles are partitioned into an “ideal
gas” of optimally decoupled groups of particles. Specifically, we construct a set of network representations (“replicas”)
of the physical system based on interatomic potentials and apply a multiscale clustering (“multiresolution community detection”)
analysis using information-based correlations among the replicas. Replicas may i) be different representations of an identical
static system, ii) embody dynamics by considering replicas to be time separated snapshots of the system (with a tunable time
separation), or iii) encode general correlations when different replicas correspond to different representations of the entire
history of the system as it evolves in space-time. Inputs for our method are the inter-particle potentials or experimentally
measured two (or higher order) particle correlations. We apply our method to computer simulations of a binary Kob-Andersen
Lennard-Jones system in a mixture ratio of A80B20 , a ternary model system with components “A”, “B”, and “C” in ratios of A88B7C5 (as in Al88Y7Fe5 , and to atomic coordinates in a Zr80Pt20 system as gleaned by reverse Monte Carlo analysis of experimentally determined structure factors. We identify the dominant
structures (disjoint or overlapping) and general length scales by analyzing extrema of the information theory measures. We
speculate on possible links between i) physical transitions or crossovers and ii) changes in structures found by this method
as well as phase transitions associated with the computational complexity of the community detection problem. We also briefly
consider continuum approaches and discuss rigidity and the shear penetration depth in amorphous systems; this latter length
scale increases as the system becomes progressively rigid. 相似文献
54.
Dipsikha Bhattacharya Sumanta K. Sahu Indranil Banerjee Manasmita Das Debashish Mishra Tapas K. Maiti Panchanan Pramanik 《Journal of nanoparticle research》2011,13(9):4173-4188
In this article, we report the design and synthesis of a series of well-dispersed superparamagnetic iron oxide nanoparticles
(SPIONs) using chitosan as a surface modifying agent to develop a potential T
2 contrast probe for magnetic resonance imaging (MRI). The amine, carboxyl, hydroxyl, and thiol functionalities were introduced
on chitosan-coated magnetic probe via simple reactions with small reactive organic molecules to afford a series of biofunctionalized
nanoparticles. Physico-chemical characterizations of these functionalized nanoparticles were performed by TEM, XRD, DLS, FTIR,
and VSM. The colloidal stability of these functionalized iron oxide nanoparticles was investigated in presence of phosphate
buffer saline, high salt concentrations and different cell media for 1 week. MRI analysis of human cervical carcinoma (HeLa)
cell lines treated with nanoparticles elucidated that the amine-functionalized nanoparticles exhibited higher amount of signal
darkening and lower T
2 relaxation in comparison to the others. The cellular internalization efficacy of these functionalized SPIONs was also investigated
with HeLa cancer cell line by magnetically activated cell sorting (MACS) and fluorescence microscopy and results established
selectively higher internalization efficacy of amine-functionalized nanoparticles to cancer cells. These positive attributes
demonstrated that these nanoconjugates can be used as a promising platform for further in vitro and in vivo biological evaluations. 相似文献
55.
Wolfgang G. Kreyling Pratim Biswas Maria E. Messing Neil Gibson Marianne Geiser Alexander Wenk Manoranjan Sahu Knut Deppert Izabela Cydzik Christoph Wigge Otmar Schmid Manuela Semmler-Behnke 《Journal of nanoparticle research》2011,13(2):511-524
The intensive use of nano-sized titanium dioxide (TiO2) particles in many different applications necessitates studies on their risk assessment as there are still open questions on their safe handling and utilization. For reliable risk assessment, the interaction of TiO2 nanoparticles (NP) with biological systems ideally needs to be investigated using physico-chemically uniform and well-characterized NP. In this article, we describe the reproducible production of TiO2 NP aerosols using spark ignition technology. Because currently no data are available on inhaled NP in the 10?C50 nm diameter range, the emphasis was to generate NP as small as 20 nm for inhalation studies in rodents. For anticipated in vivo dosimetry analyses, TiO2 NP were radiolabeled with 48V by proton irradiation of the titanium electrodes of the spark generator. The dissolution rate of the 48V label was about 1% within the first day. The highly concentrated, polydisperse TiO2 NP aerosol (3?C6 × 106 cm?3) proved to be constant over several hours in terms of its count median mobility diameter, its geometric standard deviation, and number concentration. Extensive characterization of NP chemical composition, physical structure, morphology, and specific surface area was performed. The originally generated amorphous TiO2 NP were converted into crystalline anatase TiO2 NP by thermal annealing at 950 °C. Both crystalline and amorphous 20-nm TiO2 NP were chain agglomerated/aggregated, consisting of primary particles in the range of 5 nm. Disintegration of the deposited TiO2 NP in lung tissue was not detectable within 24 h. 相似文献
56.
The enantiospecific synthesis of angular triquinanes has been developed starting from the readily available (S)-campholenaldehyde. Two alternate strategies have been used, one employing a Johnson’s orthoester Claisen rearrangement followed by an intramolecular cyclopropanation and regioselective cyclopropane ring cleavage, and a second one based on a RCM reaction. 相似文献
57.
Adusumilli Srikrishna Vijendra H. Pardeshi Konda Mahesh 《Tetrahedron: Asymmetry》2010,21(20):2512-2516
The enantiospecific total synthesis of two epimers of the sesquiterpene isocalamusenone has been accomplished starting from the readily available monoterpene (R)-limonene, which of the natural product established the stereostructure and the absolute configuration. 相似文献
58.
Debajyoti Choudhury Saurabh D. Rindani B. Ananthanarayan K. R. S. Balaji Debajyoti Choudhury Manuel Drees Shashikant Dugad Gautam Dutta Sukanta Dutta Naveen Gaur Ambar Ghosal Walter Grimus Ernest Ma Shubhendra Mohanty P. N. Pandita M. K. Parida Subhendu Rakshit Saurabh D. Rindani D. P. Roy Probir Roy Sarira Sahu N. N. Singh Sudhir K. Vempati Francesco Vissani 《Pramana》1998,51(1-2):305-311
This report summarises the activities of the working group on ‘Physics beyond the Standard Model’. The results of investigations
in incorporatingR-parity in grand unification, the possibility of a light charged Higgs boson in extension of MSSM and radiative generation
of neutral vector boson self-couplings within the MSSM are described. Also given is an account of activities in neutrino physics,
namely a proposal for a study of the atmospheric muon anomaly in deep underground mines, a field theoretic study of neutrino
oscillations and a mechanism to generate appropriate masses of three active plus one sterile neutrino species. 相似文献
59.
Dependence of film thickness on the electrical and optical properties of ZnO-Cu-ZnO multilayers 总被引:1,自引:0,他引:1
ZnO-Cu-ZnO multilayers were prepared by simultaneous RF magnetron sputtering of ZnO and DC magnetron sputtering of Cu. Cu films with different thickness were used as the intermediate metal layer. The optical and electrical properties of the multilayers studied by UV-vis spectrophotometer and four point probe method, respectively, shows that transmittance increases with decrease of copper thickness up to an optimum thickness of 5 nm and sheet resistance decreases with increase of thickness. Low resistivity and high transmission were obtained when the film structure has a thickness of ZnO/Cu/ZnO: 50/5/50 nm. The performance of the multilayers as transparent conducting material was better than the single layer ZnO of equal thickness. 相似文献
60.
Shridhar H. Thorat Sanjay Kumar Sahu Rajesh G. Gonnade 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(11):1010-1016
The synthesis of pharmaceutical cocrystals is a strategy to enhance the performance of active pharmaceutical ingredients (APIs) without affecting their therapeutic efficiency. The 1:1 pharmaceutical cocrystal of the antituberculosis drug pyrazinamide (PZA) and the cocrystal former p‐aminobenzoic acid (p‐ABA), C7H7NO2·C5H5N3O, (1), was synthesized successfully and characterized by relevant solid‐state characterization methods. The cocrystal crystallizes in the monoclinic space group P21/n containing one molecule of each component. Both molecules associate via intermolecular O—H...O and N—H...O hydrogen bonds [O...O = 2.6102 (15) Å and O—H...O = 168.3 (19)°; N...O = 2.9259 (18) Å and N—H...O = 167.7 (16)°] to generate a dimeric acid–amide synthon. Neighbouring dimers are linked centrosymmetrically through N—H...O interactions [N...O = 3.1201 (18) Å and N—H...O = 136.9 (14)°] to form a tetrameric assembly supplemented by C—H...N interactions [C...N = 3.5277 (19) Å and C—H...N = 147°]. Linking of these tetrameric assemblies through N—H...O [N...O = 3.3026 (19) Å and N—H...O = 143.1 (17)°], N—H...N [N...N = 3.221 (2) Å and N—H...N = 177.9 (17)°] and C—H...O [C...O = 3.5354 (18) Å and C—H...O = 152°] interactions creates the two‐dimensional packing. Recrystallization of the cocrystals from the molten state revealed the formation of 4‐(pyrazine‐2‐carboxamido)benzoic acid, C12H9N3O3, (2), through a transamidation reaction between PZA and p‐ABA. Carboxamide (2) crystallizes in the triclinic space group P with one molecule in the asymmetric unit. Molecules of (2) form a centrosymmetric dimeric homosynthon through an acid–acid O—H...O hydrogen bond [O...O = 2.666 (3) Å and O—H...O = 178 (4)°]. Neighbouring assemblies are connected centrosymmetrically via a C—H...N interaction [C...N = 3.365 (3) Å and C—H...N = 142°] engaging the pyrazine groups to generate a linear chain. Adjacent chains are connected loosely via C—H...O interactions [C...O = 3.212 (3) Å and C—H...O = 149°] to generate a two‐dimensional sheet structure. Closely associated two‐dimensional sheets in both compounds are stacked via aromatic π‐stacking interactions engaging the pyrazine and benzene rings to create a three‐dimensional multi‐stack structure. 相似文献