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391.
392.
Ganesan P Baggerman J Zhang H Sudhölter EJ Zuilhof H 《The journal of physical chemistry. A》2007,111(28):6151-6156
The photophysical properties of a tetrahedral molecule with naphthalene diimide (NDI) moieties and of two model compounds were investigated. The absorption and fluorescence spectra of dialkyl-substituted NDI are in agreement with literature. While the absorption spectra of phenyl-substituted molecules are similar to all other NDIs, their fluorescence showed a broad band between 500 and 650 nm. This band is sensitive to the polarity of the solvent and is attributed to a CT state. The absorption spectra and lifetime (10+/-2 ps) of the electronically excited singlet state of a dialkyl-substituted NDI was determined by femtosecond transient absorption spectroscopy, and the latter was confirmed by picosecond fluorescence spectroscopy. Nanosecond flash photolysis showed the subsequent formation of the triplet state. The presence of a phenyl substituent on the imide nitrogen of NDI resulted in faster deactivation of the singlet state (lifetime 0.5-1 ps). This is attributed to the formation of a short-lived CT state, which decays to the local triplet state. The faster deactivation was confirmed by fluorescence lifetime measurements in solution and in a low-temperature methyl-tetrahydrofuran glass. 相似文献
393.
Kalyanaraman S Krishnakumar V Ganesan K 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,67(3-4):750-755
Protonated form of hypoxanthinium chloride monohydrate single crystal has been grown from dilute hydrochloric acid. Single crystal X-ray analysis was carried out and the titled crystal belong to the monoclinic P2(1)/c space group. Hypoxanthine is protonated at N(1) with the hypoxanthine cations, linked to chlorine anion via weak bifurcated N-H...Cl hydrogen bonds and interconnected by hydrogen bonding contacts of the type N-H...O. Infrared, Raman and UV spectroscopic tools were applied to characterize hypoxanthinium chloride monohydrate. By applying group theoretical methods the internal and external modes of vibrations of the title crystal have been identified and discussed. 相似文献
394.
Kalyanaraman S Krishnakumar V Ganesan K 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,66(4-5):1340-1346
Single crystals of cytosine monohydrate and its copper(II) complex were grown by slow evaporation in an aqueous solution at room temperature. The solubility studies were carried out at different temperatures in deionized water. Cytosine monohydrate and the copper(II) complex of cytosine were characterized by recording IR, Raman and UV spectra. The various vibrational modes of the crystals have been classified using factor group and site group analysis. Vibrational assignments were proposed for both the systems based on the spectral investigations. 相似文献
395.
The present investigation aims to explore the active functional groups that are responsible for the antioxidant property in MFI from three cephalopods such as Sepia pharaonis (CMFI), Sepioteuthis lessioniana (SMFI) and Amphioctopus aegina (OMFI) using Fourier Transform Infrared (FTIR) spectroscopy. Highest DPPH scavenging activity of 28.29 ± 0.41% and metal chelating activity of 47.62 ± 0.48% were shown by MFI from A. aegina (OMFI) at a concentration of 0.045 mg/ml and 0.04 mg/ml, respectively. Though the invitro antioxidant values of MFI were low, when added with sardine fish mince, it retarded the lipid oxidation during the entire storage period and it was very clear with the lower TBARS values compared to the control. FTIR analysis of CMFI, SMFI and OMFI revealed the presence of characteristic strong band at 3361.92 cm?1, 3364.54 cm?1 and 3373.96 cm?1 and at 1642.20 cm?1, 1636.21 cm?1and 1635.53 cm?1,respectively. The O–H and N–H stretching vibrations and alkenyl c = c stretch corresponding to the two vibrations in all the three spectra can be accountable for its antioxidant activities leading to its wide new applications as a natural antioxidant from marine resources. 相似文献
396.
Cyclic voltammetry and electrochemical impedance studies of Fe(tmphen) 3 2+ (where tmphen?=?3,4,7,8-tetramethyl-1,10-phenanthroline)-immobilized Nafion?-modified glassy carbon electrode (GC/Nf/Fe(tmphen) 3 2+ ) are carried out in 0.1?M Na2SO4 solution. Nafion–Fe(tmphen) 3 2+ complex exhibits efficient electrocatalytic oxidation of isoniazid. The linear double reciprocal plot of current and concentration of isoniazid shows a Michaelis–Menten-type catalytic process. The catalytic oxidation currents are proportional to the concentration of isoniazid and show a wide linear calibration range for the quantitative determination of isoniazid. Detection limit and sensitivity are found to be 13?μM and 2.5?μA?mM?1, respectively. 相似文献
397.
Fakhruddin Ahmed P. K. Gutch K. Ganesan R. Vijayaraghavan 《Journal of Thermal Analysis and Calorimetry》2012,107(1):141-147
N,N′-dichloro-bis[2,4,6-trichlorophenyl]urea, known as CC2, is used as a reactive chemical decontaminant of mustard agents. The
present study was undertaken to establish the compatibility of CC2 with a number of commonly used suspending agents, using
thermoanalytical techniques viz., thermogravimetry (TG) and differential scanning calorimetry (DSC) with the support of Fourier
transform infrared spectroscopy (FTIR). The results demonstrated the applicability of TG and DSC as a fast screening tool
for analysing the compatibility of drug with excipients at the early stages of a preformulation process. Methylcellulose,
hydroxypropylcellulose, and betaine were found to be compatible with CC2. 相似文献
398.
Timo Bollermann Ganesan Prabusankar Dr. Christian Gemel Dr. Rüdiger W. Seidel Dr. Manuela Winter Roland A. Fischer Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(29):8846-8853
The synthesis and structural characterisation of low‐valent dinuclear copper(I) and copper(0) complexes supported by organogallium ligands has been accomplished for the first time by the reductive coordination reaction of [GaCp*] (Cp*=pentamethylcyclopentadienyl) and [Ga(ddp)] (ddp=HC(CMeNC6H3‐2,6‐iPr2)2 2‐diisopropylphenylamino‐4‐diisopropylphenylimino‐2‐pentene) with readily available copper(II) and copper(I) precursors. The treatment of CuBr2 and Cu(OTf)2 (OTf=CF3SO3) with [Ga(ddp)] under mild conditions resulted in elimination of [Ga(L)2(ddp)] (L=Br, OTf) and afforded the novel gallium(I)/copper(I) compounds [{(ddp)GaCu(L)}2] (L=Br ( 1 ), OTf ( 2 )). The single‐crystal X‐ray structure determinations of 1 and 2 reveal that these molecules are composed of {(ddp)GaCu(L)} dimeric units, with planar CuI? GaI four‐membered rings and short CuI???CuI distances, with 2 exhibiting the shortest CuI???CuI contact reported to date of 2.277(3) Å. The all‐gallium coordinated dinuclear [Cu2(GaCp*)(μ‐GaCp*)3Ga(OTf)3] ( 3 ) is formed when Cu(OTf)2 is combined with [GaCp*] instead of [Ga(ddp)]. Notably, in the course of this redox reaction Lewis acidic Ga(OTf)3 is formed, which coordinates to one of the electron‐rich copper(0) centres. Compound 3 is suggested as the first case of a structurally characterised complex of copper(0). By changing the copper(II) to a copper(I) source, that is, [Cu(cod)2][OTf] (cod=1,5‐cyclooctadiene), the salt [Cu2(GaCp*)3(μ‐GaCp*)2][OTf]2 ( 4 ) is formed, the cationic part of which is related to previously described isoelectronic dinuclear d10 complexes of the type [M2(GaCp*)5] (M=Pd, Pt). 相似文献
399.
400.
ABSTRACTThin films of Ge30Se70?xBix (x?=?5, 15, 20) were prepared by thermal evaporation method on glass substrates with thickness 800?nm. The films were annealed at 250°C and 320°C for 2?h to study the annealing-induced structural and optical change. The X-ray diffraction characterization revealed the amorphous to crystalline phase transformation with annealing. The indirect optical band gap decreased with annealing which is explained on the basis of phase transformation and density of localized states. The formation of surface dangling bonds around the crystallites during crystallization process reduced the band gap. The Tauc parameter and Urbach energy change show the degree of chemical disorderness in the films. The transmitivity decreased while the absorption coefficient increased with the annealing process. The microstructural study done by Field emission scanning electron microscopy shows the formation of crystallites upon annealing. Atomic force microscopy investigation on these films shows the influence of annealing on surface topography. 相似文献