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131.
The regiochemistry of nucleophilic substitution of 4-phenylsulfonyl tetrafluoropyridine with unequal bidentate nucleophiles was investigated. The first nucleophilic substitution occurs at the 2-position of the pyridine ring by nitrogen nucleophile site (secondary or primary amine) followed by intermolecular ring closure at the geometrically accessible 3-position of the pyridine ring (by S, O and N nucleophiles). From this investigation, difluorinated tetrahydropyrido[3,4-b][1,4]oxazine, thiazine and pyrazine scaffolds were synthesized very readily by a one-pot annelation reaction of 4-phenylsulfonyl tetrafluoropyridine with appropriate unequal bidentate nucleophiles. 相似文献
132.
Essential oil of aerial parts of Tymus vulgaris L. from Babaaman montains of Iran were isolated by hydrodistillation with an average oil yield 1.9 w/w%. The components of the oil were identified by gas chromatography mass spectrometry. On a separate experiments the compositions of volatile emission of the plant were studied by headspace solid phase microextraction and gas chromatography mass spectrometry. The tempratures used during the sample preparation were 25°C and 50°C. In order to determine the effect of solvent (water) on the separation, the experiments were done in the presence and absence of distilled water in the extraction vial at the tempratures mentioned above. Ten majour components were obtained in four different experimental headspace solid phase microextraction conditions and the hydrodistillation methods from the plant. Thymol was found to be the most abundant costituent (27.2–73.09%), follwoed by p‐cymene (6.86–31.76%), γ‐terpinene (1.02–9.26%), myrcene (0.05–8.84%), α‐pinene (0.25–6.63%), caryophyllene (3.09–5.56%), thymol methyl ether (0.99–2.97%), thymolacetate (0.11–2.05%), carvacrol (0.49–1.70%) and α‐cadinol (0.38–1.10%). 相似文献
133.
H. Zavvar Mousavi Alireza Asghari Hamid Shirkhanloo 《Journal of Analytical Chemistry》2010,65(9):935-939
An online mercury preconcentration and determination system consisting of cold vapor atomic absorption spectrometry (CV-AAS) coupled to a flow injection (FI) method was studied. The method was developed involving the determination of ng/L levels of mercury retained on the silver
wool solid sorbent. Experimental conditions such as sample volume, flow rate, stability of the column and effect of foreign
ions on the determination of trace amounts of mercury were optimized. The detection limit is 3 ng/L and dynamic range 10–250
ng/L require only 50 mL of sample. The relative standard deviations (RSD) of the determinations are below 4%. The presence of common metal ions, such as K+, Na+, Cu2+, Pb2+, Fe3+, Ni2+, and Mn2+, does not interfere with the measurement of mercury by this method. The method was successfully applied to the determination
of mercury in water and wastewater samples. 相似文献
134.
M. A. Zanjanch Sh. Sohrabnezhad M. Arvand M. F. Mousavi 《Russian Journal of Electrochemistry》2007,43(7):758-763
The electrochemical properties of thionine dye adsorbed into ZSM-5 and HZSM-5 zeolites (TH/ZSM-5, TH/HZSM-5) are studied in
0.5 M KCl solution. The dye is strongly retained and not easily leached from the zeolites matrix. The samples are incorporated
into the carbon paste electrode (TH/ZSM-5/P, TH/HZSM-5/P) for cyclic voltammetric measurements. The redox reactions of thionine
incorporated into ZSM-5 zeolite contain a quasi-reversible, two-electron one proton in the pH range 1 to 10, but thionine-loaded
HZSM-5 zeolite undergoes a quasi-reversible two-electron two-protons redox reaction under acidic conditions and a one proton
two-electron redox reaction takes place under basic conditions. The separation of the anodic and cathodic potentials (E
p) is high in thionine-loaded zeolites (>100) with respect to the solution of thionine (E
p = 34 for ZSM-5/P and 36 mV for HZSM-5/P), indicating that there are strong interaction between thionine molecules and the
zeolites. The midpoint potentials (E
m) for TH/ZSM-5/P and TH/HZSM-5/P are −0.203 and −0.381 V, respectively. However, the midpoint potentials for the solution
of thionine for the electrode system of ZSM-5/P and HZSM-5/P are −0.335 and −0.407 V, respectively. Thus, thionine dye molecules
incorporated into the zeolites can be reduced more easily with respect to solution of thionine. In various electrolyte solutions,
the midpoint potentials remains constant, but the midpoint potential of the thionine-zeolite electrodes depends on the solution
pH. Influence of the pH of the solution on the midpoint potential of an immobilized dye reveals that thionine molecules are
accessible to protons. This property is ascribed to the formation of mesopores in the structure of our zeolites suffering
from a calcination step.
Published in Russian in Elektrokhimiya, 2007, Vol. 43, No. 7, pp. 794–800.
The text was submitted by the authors in English 相似文献
135.
M.H. Majles Ara S.H. Mousavi S. Salmani E. Koushki 《Journal of Molecular Liquids》2008,140(1-3):21-24
Recently the nonlinear effects of the azo-dye doped liquid crystals have attracted much interest. In this paper the nonlinear refractive indices, n2, of two dyes (Sudan Black B, Sudan III) doped nematic liquid crystal were measured at low laser powers using moiré deflectometry technique. The results show when a nonlinear sample is placed in moiré deflectometry setup, the moiré fringe patterns will rotate around the beam center because of self-focusing effect in the sample. By measuring this rotation, the magnitude and the sign of nonlinear refractive index were calculated. The n2 values for Sudan black B is larger than Sudan III, because of some differences in molecular structure and molecular polarization. 相似文献
136.
Mir Masoud Seyyed Fakhrabadi Mostafa Samadzadeh Abbas Rastgoo Mohammadreza Haeri Yazdi Mahmoud Mousavi Mashhadi 《Physica E: Low-dimensional Systems and Nanostructures》2011,44(3):565-578
This paper presents the molecular mechanics based finite element modeling of carbon nanotubes (CNTs) and their applications as mass sensors. The beam element with elastic behavior is considered as the bond between the carbon atoms and its properties are obtained using equating continuum and molecular characteristics. The first five natural frequencies of CNTs in cantilever and doubly clamped boundary conditions (BCs) and their corresponding mode shapes are studied in detail. Furthermore, a multilayer perceptron neural network is used to predict the fundamental vibration frequencies of the CNTs with different diameters and lengths. In addition, variations of the natural frequencies of the CNTs with distorted cross sections are investigated. Moreover, the effects of some attached masses with various values on the first three natural frequencies of a considered CNT are studied here. 相似文献
137.
Mahboobeh Nazari Saeideh Zamani Koukhaloo Samira Mousavi Arash Minai‐Tehrani Rahman Emamzadeh Roya Cheraghi 《Macromolecular bioscience》2019,19(11)
Despite the initial successes of gene delivery applications, they faced on several intrinsic drawbacks including toxicity and immunogenicity. Therefore, alternative gene‐delivery systems derived from recombinant peptides have emerged and is rapidly developing. Human epidermal growth factor receptor‐3 (HER3) shows high activity in tumor resistance to anti‐human epidermal growth factor receptor 2 (HER2) therapies. In this study, an affibody molecule against HER3 is conjugated to a biomimetic peptide RALA (an amphipathic and cationic peptide enriched with arginine) and the ability of the fusion vector for targeting HER3 and afterward delivering specific genes in breast cancer cells is evaluated. The results demonstrate that the biopolymeric platform, which contains an affibody‐conjugated RALA peptide, can effectively condense DNA into nanoparticles and target the overexpressed HER3 receptors in breast cancer cells and transfer specific genes. The use of such a recombinant biopolymer may pave the way for the development of sensitive and effective diagnostic and treatment tool for breast cancer. 相似文献
138.
Reyhaneh Hoseinpoor Seyed Latif Mousavi Gargari Iraj Rasooli Masoumeh Rajabibazl Bahareh Shahi 《Applied biochemistry and biotechnology》2014,172(6):3079-3091
Manipulation of clinically significant antibodies can effectively improve the processes of diagnosis and treatment. Affinity maturation process has a significant role in improvement of antibodies efficiency. Error-prone PCR technique is one of the proposed methods for improvement of the affinity of antibodies. In the present research, a method was applied to camel heavy-chain antibody (VHH, nanobody) raised against UreC subunit of urease enzyme from Helicobacter pylori. This VHH was used as a starting molecule to construct a highly diversified phage displayed VHH library. The constructed library of nanobody mutants was subjected to several rounds of panning against UreC antigen. High-affinity mutant was selected. Our VHH (HMR23) showed 1.5-fold higher binding activity than the parental VHH. In addition, the mutant VHH presented a better performance in inhibition of urease activity at low concentrations retaining its specificity and thermal stability. 相似文献
139.
Xiong Qingang Siavashi Majid Doranehgard Mohammad Hossein Mousavi Nezhad Mohaddeseh 《Journal of Thermal Analysis and Calorimetry》2020,141(5):1489-1491
Journal of Thermal Analysis and Calorimetry - 相似文献
140.
S. M. Mousavi S. Kiani M. Razavi Farmad A. Hemati B. Abbasi 《Journal of Dispersion Science and Technology》2013,34(1):123-129
In this article, the extraction of arsenic(V) from water by means of emulsion liquid membrane is investigated. The influence of operating factors such as stirring speed, concentration of sulfuric acid in the external aqueous phase, concentration of sodium sulfate in internal stripping phase, and concentration of carrier in the membrane phase on the extraction efficiency are investigated and their optimum values, which provide the maximum recovery of arsenic, are determined. Taguchi experimental design is used in order to reduce the number of experiments. The optimum amounts for the extraction of arsenic from water, based on the results, are: stirring speed, 500 rpm; concentration of sulfuric acid in the feed, 1.5 g mol/lit; concentration of reagent in internal phase, 1.5 g mol/lit; and concentration of carrier in 3 ml kerosene which is added to the membrane phase, 0.1 g mol/lit. 相似文献