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111.
Pushpendra P. Singh Manoj Kumar Sharma Unnati Devendra P. Singh Rakesh Kumar K. S. Golda B. P. Singh R. Prasad 《The European Physical Journal A - Hadrons and Nuclei》2007,34(1):29-39
With a view to study complete- and incomplete-fusion components in 159Tb , 169Tm ( 16O , x reactions, experiments have been carried out at the Inter-University Accelerator Center, New Delhi, India using the 15UD
Pelletron accelerator facilities. The forward mean recoil ranges for some radio-nuclides; 168m
Lu , 167Lu , 167Yb , 166Tm produced in the
16O$ + $159Tb
system at ≈ 90 MeV, and 179Re , 177Re , 177W , 178Ta and 177Hf produced in the
16O$ + $169Tm
system at ≈ 87 MeV have been measured. The recoil-catcher activation technique followed by off-line γ -spectrometry has been
employed in the present work. The analysis of forward mean ranges for different radio-nuclides has been done in the framework
of the degree of linear momentum transfer from projectile to target nucleus by adopting break-up fusion model considerations.
Different complete- and incomplete-fusion components, which may be attributed to the fusion of 16O and/or 12C and 8Be transfer from the 16O projectile to the target nucleus have been observed. An attempt has also been made to separate out the relative percentage
contributions of complete- and incomplete-fusion components using experimentally measured forward recoil ranges. The complete-fusion
contributions deduced from recoil range distribution are found to be consistent with the prediction of the theoretical model
code PACE. The analysis of data indicates the complete- and incomplete-fusion competition for both the systems at the given
energies. 相似文献
112.
Fentanyl is a very potent synthetic narcotic analgesic. Because of its strong sedative properties, it has become an analogue
of illicit drugs such as heroin. Its unambiguous detection and identification in environmental samples can be regarded as
strong evidence of its illicit preparation. In this paper we report application of single-drop microextraction (SDME) for
analysis of water samples spiked with fentanyl. Experimental conditions which affect the performance of SDME, for example
the nature of the extracting solvent, sample stirring speed, extraction time, ionic strength, and solution pH, were optimized.
The method was found to be linear in the concentration range 0.10–10 ng mL−1. The limits of quantitation and detection of the method were 100 pg mL−1 and <75 pg mL−1, respectively. This technique is superior to other sample-preparation techniques because of the simple experimental set-up,
short analysis time, high sensitivity, and minimum use of organic solvent. 相似文献
113.
Pardasani D Mazumder A Gupta AK Kanaujia PK Tak V Dubey DK 《Rapid communications in mass spectrometry : RCM》2007,21(18):3109-3114
Retrospective detection and identification of markers of chemical warfare agents are important aspects of verification of the Chemical Weapons Convention. Alkyl alkylphosphonic acids (AAPAs) and alkylphosphonic acids (APAs) are important markers of nerve agents. We describe the development and optimization of a new gas chromatography/mass spectrometry (GC/MS) injection port fluorination method for the derivatization of AAPAs and APAs. The process involved the injection of acids with trifluoroacetic anhydride in GC/MS, where acids are converted into their corresponding volatile fluorides. Various reaction conditions such as fluorinating agent, injection port temperature and splitless time were optimized. The maximum reaction efficiency of the acids with trifluoroacetic anhydride was observed at 230 degrees C injection port temperature with a splitless time of 2 min. APAs showed best analytical efficiencies at 400 degrees C injection port temperature, while the other conditions were similar to those of AAPAs. The linearities of response for APAs and AAPAs were in the range of 1-25 and 5-100 microg mL(-1), respectively, with limits of detection ranging from 500 pg to 800 ng mL(-1). 相似文献
114.
Vinay Kumari Vinod Kumar B.P. Malik R.M. Mehra Devendra Mohan 《Optics Communications》2012,285(8):2182-2188
Undoped and Erbium (Er) doped zinc oxide (EZO) thin films were deposited on glass substrate by sol–gel method using spin coating technique with different doping concentration. EZO films were characterized using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), UV–VIS-NIR transmission and single beam z scan method under illumination of frequency doubled Nd:YAG laser. The deposited films were found to be well crystallized with hexagonal wurtzite structure having a preferential growth orientation along the ZnO (002) plane. A blue-shift was observed in the band gap of EZO films with increasing Er concentration. All the films exhibited a negative value of nonlinear refractive index (n2) at 532 nm which is attributed to the two photon absorption and weak free carrier absorption. Third order nonlinear optical susceptibility, χ(3) values of EZO films were observed in the remarkable range of 10? 6 esu. EZO (0.4 at.%) sample was found to be the best optical limiter with limiting threshold of 1.95 KJ/cm2. 相似文献
115.
Vaibhav Kulshrestha Garima Agarwal Kamlendra Awasthi Balram Tripathi N.K. Acharya Devendra Vyas Vibhav K. Saraswat Y.K. Vijay I.P. Jain 《Micron (Oxford, England : 1993)》2010,41(4):390-394
PES membrane of thickness 25 μm was irradiated by Cl9+ ions of energy 100 MeV at IUAC, New Delhi. Microstructure changes due to exposure to high-energy ions were investigated by Fourier transform infrared (FTIR) and ultraviolet/visible (UV/vis) absorption spectroscopies, X-ray diffraction technique and by dynamic mechanical analysis (DMA). A significant loss of crystallinity is observed by the XRD data. Particle size or grain size calculated using Scherrer formula indicates measurable change in particle size of irradiated samples. The polymer chain scissions and structure degradations are expected to occur for irradiated samples. Optical properties of the films were changed due to irradiation that could be clearly seen in the absorption spectra. FTIR does not show the remarkable change in the irradiated samples, but there is some change in the surface roughness observed by AFM. 相似文献
116.
Cloning, characterization, and expression of a new cry2Ab gene from Bacillus thuringiensis strain 14-1 总被引:2,自引:0,他引:2
Jain D Udayasuriyan V Arulselvi PI Dev SS Sangeetha P 《Applied biochemistry and biotechnology》2006,128(3):185-194
Bacillus thuringiensis is the major source for transfer of genes to impart insect resistance in transgenic plants. Cry2A proteins of B. thuringiensis are promising candidates for management of resistance development in insects owing to their difference from the currently
used Cry1A proteins, in structure and insecticidal mechanism. The cry2Ab gene was found to lack a functional promoter and, hence, is cryptic in nature. The cry2Ab7 gene was cloned from a new indigenous B. thuringiensis strain, 14-1. Nucleotide sequencing of the cry2Ab gene cloned from B. thuringiensis strain 14-1 revealed an open reading frame of 1902 bp. The deduced amino acid sequence of Cry2Ab of B. thuringiensis strain 14-1 showed a variation in three amino acid residues in comparison to the holotype sequence, Cry2Ab1. Expression of
the newly cloned cry2Ab gene was studied in an acrystalliferous strain of B. thuringiensis (4Q7) by fusing the cry2Ab gene downstream of cry2Aa promoter and orf1+orf2 sequences. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of a spore-crystal mixture obtained from transformants
of B. thuringiensis strain 4Q7 showed production of Cry2Ab protein of about 65 kDa. Alkali solubilized Cry2Ab7 protein showed toxicity against
Helicoverpa armigera neonates. 相似文献
117.
Tak V Kanaujia PK Pardasani D Gupta AK Palit M Srivastava RK Dubey DK 《Rapid communications in mass spectrometry : RCM》2006,20(16):2387-2394
Electrospray ionization tandem mass spectral (ESI-MSn) analysis of thiodiglycol, bis(2-hydroxyethylthio)alkanes (BHETAs) and their mono-, di-, tri-, and tetraoxygenated compounds was carried out to obtain their characteristic spectra for ESI-MS analysis. These compounds are important markers of chemical warfare agents, namely sulfur mustards. ESI-MSn (n > or = 3) analysis of a compound by collisionally induced dissociation in an ion trap gives rise to mass spectra that are somewhat similar to electron ionization mass spectra. These ESI-MSn spectra can be used for compound identification. Under ESI-MS and ESI-MS/MS the compounds mostly produced [M+NH4]+, [M+H]+ and [M+H--H2O]+ ions. Fragmentations of these even-electron precursors in the ion trap gave rise to characteristic product ions via neutral loss of O2, H2O, C2H4, HCHO, C2H4O, C2H4S, HSC2H4OH and C2H4SO. Fragmentation routes of these compounds are proposed that rationalize the formation of product ions in ESI-MSn analysis. 相似文献
118.
Verma D Katti K Katti D 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,64(4):1051-1057
In this work, photoacoustic Fourier transform infrared (PA-FTIR) spectroscopy has been utilized to study interfacial interactions of undisturbed nacre and nacre powder from red abalone shell. The spectra of both undisturbed nacre and nacre powder showed characteristic bands of aragonite and proteins. Although nacre powder and undisturbed nacre are chemically identical, PA-FTIR spectrum of undisturbed nacre is found to be significantly different from that of nacre powder. A broad and strong band is observed at around 1485 cm(-1) in nacre powder. The intensity of this band is notably reduced in undisturbed nacre. This result is explained on the basis of interfacial interactions between aragonite platelets and acidic proteins. It is also observed that band at around 1788 cm(-1) originates from three overlapping bands 1797, 1787 and 1778 cm(-1). The band at around 1787 cm(-1) is assigned to CO stretching of carboxylate groups of acidic proteins. The other two bands at 1797 and 1778 cm(-1), originate from aragonite and have been assigned to combination bands, nu(3)+nu(4a) and nu(3)+nu(4b), respectively. For the study of stratification in undisturbed nacre, PA-FTIR spectra have been collected in step scan mode. The variation in spectra with depth can be attributed to changes in conformation of proteins as well as interfacial interactions. 相似文献
119.
Research on Chemical Intermediates - Iron nanoparticles immobilized on reduced graphene oxide (rGO), nanocomposite Fe(0)@rGO 1, were prepared in situ by reduction of GO and FeCl3·6H2O using... 相似文献
120.