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991.
This paper reports a full evaporation (FE) headspace gas chromatographic (HS-GC) method for rapid determination of furfural in the biomass hydrolysate. The data show that a near-complete mass transfer of furfural in the sample from biomass hydrolysate to the vapor phase (headspace) was achieved within 3 min at 105°C when a very small (<40 μL) sample was added to a 20 mL headspace sample vial. The acid-catalyzed furfural decomposition under these conditions was negligible. The furfural in the vapor phase was then determined by HS-GC using a flame ionization detector. The results showed that the method has an excellent measurement precision (RSD<0.5%) and accuracy (recovery=100.2±1.7%) for furfural quantification in carbohydrate hydrolysate samples. The method requires no sample pretreatment, so it is simple, rapid and accurate, and suitable for applications in lignocellulosic biomass conversion to fuel ethanol or other high value-added products. 相似文献
992.
Li Gang Zhu Xuebin Lei Hechang Jiang Haifeng Song Wenhai Yang Zhaorong Dai Jianming Sun Yuping Pan Xu Dai Songyuan 《Journal of Sol-Gel Science and Technology》2010,53(3):641-646
CuAlO2 thin films were prepared on quartz glass and sapphire substrates by chemical solution deposition method using copper acetate
monohydrate, aluminum nitrate nonahydrate and 2-methoxyethanol as starting precursor and solvent. The effects of annealing
temperature on the structural, morphological, electrical and optical properties have been studied. Via the optimized annealing
treatment condition, CuAlO2 film annealed at 850 °C in nitrogen flow of 400sccm under atmosphere pressure exhibits the best performance with the lowest
room temperature resistivity of 3.6 × 102 Ω cm and the highest optical transmission in the visible region (>70% at around 600 nm wavelength). CuAl2O4 and CuO phases, not CuAlO2 phase are obtained when annealing temperature is lower than 850 °C. However, a further increase of annealing temperature
weakens the crystallization quality and deteriorates the surface morphology of CuAlO2 films as the annealing temperature exceeds 850 °C, leading to an increase in the resistivity and a decrease of the optical
transmission in the visible region of CuAlO2 films. 相似文献
993.
Li Peng Chunya Li Hongbo Xue Guoqing Zhan 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(5):1497-1500
ZnS-polyacrylic acid (ZnS-PAA) was prepared by an in situ polymerization method using nano-ZnS as core in the presence of acrylic acid (AA), and ZnS-PAA nanoparticles was characterized by ultraviolet spectrometry (UV) and transmission electron microscopy (TEM). Based on the significant increase of the resonance light scattering (RLS) intensity with the interaction between nanoparticles and serum albumin, RLS method was developed for the sensitive determination of serum albumin (BSA and HSA). Under optimum conditions, the change of the intensity (ΔI) of the RLS spectra at λ = 392 nm was linearly proportional to the concentration of BSA and HSA. The linear range was 1–100 ng mL?1 for HSA and 1–120 ng mL?1 for BSA, and the limit of detection (LOD) was 0.4 ng mL?1 for HSA and 0.5 ng mL?1 for BSA. This method proved to be very sensitive, rapid, simple and tolerant of most interfering substances. 相似文献
994.
995.
Cai-Hong Zhan Xiao-Juan Wang Zhan-Guo Jiang Ling-Xian Chen Yun-Long Feng 《Structural chemistry》2010,21(6):1195-1201
Abstract
p-Thioacetatebenzoic acid (H2L) and a combination of N-donor ligand of 4,4′-bipyridine (4,4′-bipy) with metal(II) ions give rise to three 3D supramolecules of general formula [M(HL)2(4,4′-bipy)2(H2O)2] · H2O, M = CoII (1), ZnII (2), NiII (3), which were characterized by crystallographic methods. The crystals are isostructural and belong to the triclinic P[`1] P\bar{1} space group. The structure can be considered to construct from 1D chains and further linked by hydrogen bonds into the final 3D supramolecular networks. The electrochemical behavior of complexes 1 and 3 were studied by cyclic voltammetry, indicating that the electron transfers in the electrode reaction are irreversible. Meanwhile, complex 2 exhibits significantly red-shifted emission in solid state at room temperature. 相似文献996.
Abstract
p-Thioacetatebenzoic acid (H2L) and a combination of N-donor ligands such as 4,4′-bipyridine (4,4′-bipy) and 1,3-bi(4-pyridyl)propane (bpp) with metal ions Mn(II) and Ni(II) give rise to two coordination polymers, namely, [Mn(HL)2(bpp)2(H2O)2] n (1), [NiL (4,4′-bipy)(H2O)3] n ·nH2O (2). 1 features an unusual “8” shaped double layer by hydrogen bonds and two different types of helical chains are arrayed alternatively in the 2D double layer framework, which further extends into a 3D supramolecular structure through C–H···O hydrogen bonds. 2 consists of 1D chains which further connect with each other via hydrogen bonds to form the final 3D framework including two different types of helical structure. Photoluminescence study reveals that 1 displays intense structure-related fluorescent emission bands (λ ex = 369 nm) at 414 nm in the solid state at room temperature. Electrochemical property of 2 reveals that the process of the redox is irreversible. 相似文献997.
XPS study of PBO fiber surface modified by incorporation of hydroxyl polar groups in main chains 总被引:1,自引:0,他引:1
Dihydroxy poly(p-phenylene benzobisoxazole) (DHPBO), a modified poly(p-phenylene benzoxazole) (PBO) polymer containing double hydroxyl groups in polymer chains, was synthesized by copolymerization of 4,6-diamino resorcinol dihydrochloride (DAR), purified terephthalic acid (TA) and 2,5-dihydroxyterephthalic acid (DHTA). DHPBO fibers were prepared by dry-jet wet-spinning method. The effects of hydroxyl polar groups on the surface elemental compositions of PBO fiber were investigated by X-ray photoelectron spectroscopy (XPS). The results show that the ratio of oxygen/carbon on the surface of DHPBO fibers is higher than that on the surface of PBO fibers, which indicates the content of polar groups on the surface of DHPBO fiber increase compared with PBO fiber. 相似文献
998.
The inter-carrier interference (ICI) of Orthogonal Frequency Division Multiplexing (OFDM) symbols, which is caused by the transducer’s dynamics, has been analysed and simulated in this paper. The small Cyclic Prefix (CP) method is proposed to overcome the ICI caused by the transducer in order to maintain the orthogonality between sub-carriers without much loss of the energy and the bandwidth efficiency. The simulation results show that the small CP whose length is longer than the transient response of the transducer can eliminate the ICI problem. 相似文献
999.
Yanyan Zhu Yan Wang Guangju Chen Chang-Guo Zhan 《Theoretical chemistry accounts》2009,122(3-4):167-178
We present the theoretical evaluation of new AMBER force field parameters for 12 copper-based nucleases with bis(2-pyridylmethyl) amine, 2,2′-dipyridylamine, imidazole, N,N-bis(2-benzimidazolylmethyl) amine and their derivative ligands based on first-principles electronic structure calculations at the B3LYP level of theory. A three-point approach was developed to accurately and efficiently evaluate the force field parameters for the copper-based nucleases with the ligands. The protocol of RESP atomic charges has been used to calculate the atomic charge distributions of the studied copper-based nucleases. The evaluated force field parameters and RESP atomic charges have been successfully applied in the testing molecular mechanics calculations and molecular dynamics simulations on the nucleases and the nuclease–DNA complexes, respectively. It has been demonstrated that the developed force field parameters and atomic charges can consistently reproduce molecular geometries and conformations in the available X-ray crystal structures and can reasonably predict the interaction properties of the nucleases with DNA. The developed force field parameters in this work provide an extension of the AMBER force field for its application to computational modeling and simulations of the copper-based artificial nucleases associated with DNA. 相似文献
1000.
A new triterpene glycoside, namely 28-O-α-L-rhamnopyranosyl (1→2)-β-D-glucopyranoside tormentic acid ester, was isolated from the leaves of Premna microphylla, together with two known triterpenes, i.e., arjunolic acid (2) and hyptatic acid A (3). Its structure was established by mass-spectrometric and spectroscopic methods, especially 2D NMR techniques. This is the
first report of the isolation of triterpenes from this plant.
Published in Khimiya Prirodnykh Soedinenii, No. 2, pp. 173–174, March–April, 2009. 相似文献