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931.
Şahin Samet Kaya Şevval Üstündağ Zafer Caglayan Mustafa Oguzhan 《Journal of Solid State Electrochemistry》2022,26(4):907-915
Journal of Solid State Electrochemistry - Insulin hormone is of great importance for many diseases, especially for diabetes management. Therefore, different detection strategies have been used for... 相似文献
932.
Spectral features and antibacterial properties of Cu-doped ZnO nanoparticles prepared by sol-gel method 下载免费PDF全文
Zn_(1-x)Cu_x O(x=0.00, 0.01, 0.03, and 0.05) nanoparticles are synthesized via the sol-gel technique using gelatin and nitrate precursors. The impact of copper concentration on the structural, optical, and antibacterial properties of these nanoparticles is demonstrated. Powder x-ray diffraction investigations have illustrated the organized Cu doping into ZnO nanoparticles up to Cu concentration of 5%(x = 0.05). However, the peak corresponding to CuO for x= 0.01 is not distinguishable. The images of field emission scanning electron microscopy demonstrate the existence of a nearly spherical shape with a size in the range of 30–52 nm. Doping Cu creates the Cu–O–Zn on the surface and results in a decrease in the crystallite size. Photoluminescence and absorption spectra display that doping Cu causes an increment in the energy band gap. The antibacterial activities of the nanoparticles are examined against Escherichia coli(Gram negative bacteria)cultures using optical density at 600 nm and a comparison of the size of inhibition zone diameter. It is found that both pure and doped ZnO nanoparticles indicate appropriate antibacterial activity which rises with Cu doping. 相似文献
933.
In this study, a mathematical model was developed for falling film evaporation in vacuum using heat transfer relations. An experimental device was designed. experimental set-up which was used was equipped with a triangular weir distribution device and it had the ability to record data up to 3?m. Experiments were performed in a single-effect process with sucrose–water solution varying from 3 to 20% concentration rate of sucrose and we used a vertical tube evaporator with the dimensions of laboratory scale. The model that was developed considers convection, shear stress, viscosity and conjugate heat transfer while most of the previous works ignored these factors. The main factors influencing the heat transfer mechanism performance of the unit were investigated and analyzed. We concluded that the experimental studies are verified by the developed model. Furthermore, it was also concluded that, the heat transfer is affected by the mass flow rate, sucrose concentration rate in solution, film thickness and pressure. 相似文献
934.
Glass-ceramic materials, obtained by sinter-crystallization of melted alkaline-olivine basaltic tuffs, were investigated. The kinetics of bulk crystallization was evaluated by differential thermal analysis (DTA) at different heating rates. The phase formation and the sintering behavior of glass powders (<75 μm) were studied in air and in nitrogen atmospheres by DTA and dilatometry, respectively. The crystalline phases formed were identified by X-ray diffraction. The DTA traces showed an unusual phase formation behavior with a higher crystallization trend for the bulk samples. The crystallization activation energy was evaluated as 590 ± 20 kJ/mol in the range 1080–1110 K. A value of about 3 of the Avrami constant, corresponding to three-dimensional growth on a fixed number of nuclei, was evaluated by Ozawa and Augis–Bennet methods. The densification at low-temperatures is reduced by the intensive crystallization process in both air and nitrogen atmospheres. The sintering starts again at 1150–1250 K. In air atmospheres, due to the FeO oxidation, the sintering temperature increases and the percentage of formed crystal phase decreases by 15–20%. 相似文献
935.
Hande Petek Çiğdem Albayrak Mustafa Odabaşoğlu İsmet Şenel Orhan Büyükgüngör 《Journal of chemical crystallography》2008,38(12):901-905
Abstract The single crystal X-ray diffraction analysis of the title compound, C15H15NO3, shows that the structure is adopted to its NH tautomeric form and crystallizes in the orthorhombic space group P bcn with a = 21.2424(15) ?, b = 12.7696(9) ?, c = 9.3605(10) ?, Z = 8, V = 2539.1(4) ?3, D
c
= 1.346 g/cm3. The molecular conformation in the crystal is stabilized by an intramolecular H-bond and the crystal structure is stabilized
by the bifurcated O–H···O type intermolecular H-bonds. In order to understand the effects on conformational flexibility of
the title molecule, molecular energy profile was calculated as a function of the selected torsion angle by means of AM1 semi-empirical
method.
Index Abstract Molecular and crystal structure of [(Z)-2-ethoxy-6-[(2-hydroxyphenylamino)methylene]cyclohexa-2,4-dienone], C15H15NO3, have been determined by single crystal X-ray diffraction study, and conformational analysis of the title molecule with respect
to the selected torsion angle has been achieved by AM1 semi-empirical calculations. 相似文献
936.
Ayla Balaban Naki Çolak Hüseyin Ünver Birgül Erk Tahsin Nuri Durlu D. Mehmet Zengin 《Journal of chemical crystallography》2008,38(5):369-372
Abstract A new multidentate ligand N,N′-bis((thiophene-2-carboxamide)propyl)piperazine has been synthesized from the reaction of thiophene-2-carbonylchloride and
1,4-bis(3-aminopropyl)piperazine. The title compound has been characterized by elemental analysis, FT-IR, 1H-NMR and 13C-NMR spectroscopic techniques. The crystal structure of the title compound (C20H30N4O2S2Cl2) has also been determined by X-ray analysis. The title compound crystallize in the monoclinic space group P21/c with a = 9.768(1), b = 12.895(1), c = 10.083(1) ?, β = 115.12(1)°, V = 1149.9(2) ?3, D
x
= 1.425 g cm−3 and Z = 2. The crystal structure was solved by direct methods and refined by full-matrix least squares to a find R = 0.039 [I > 2σ (I)] for 2,786 observed reflections.
Graphical Abstract The (N,N’–bis((thiophene-2- carboxamido)propyl)piperazine) molecule has been synthesized and its molecule structure has been
investigated by using , FT-IR, 13C NMR and 1H-NMR spectroscopic and crystallographic techniques.
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Hüseyin ünverEmail: |
937.
Mustafa S. Yavuz Weiyang Li Younan Xia 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(47):13181-13187
Herein we describe a protocol that generates Au icosahedra in high yields by simply mixing aqueous solutions of HAuCl4 and N‐vinyl pyrrolidone. Our mechanistic study reveals that water plays an important role in this synthesis: as a nucleophile, it attacks the gold–vinyl complex, leading to the production of an alcohol‐based AuI intermediate. This intermediate then undergoes a redox reaction in which AuI is reduced to Au0, leading to the formation of Au atoms and then Au icosahedra of about 18 nm in size at a yield of 94 %, together with a carboxylic acid in the final product. This new protocol has also been employed to prepare multiply twinned nanoparticles of Ag (15–20 nm in size), spherical aggregates (25–30 nm in size) of Pd nanoparticles, and very small nanoparticles of Pt (2 nm in size). Since no organic solvent, surfactant, or polymer stabilizer is needed for all these syntheses, this protocol may provide a simple, versatile, and environmentally benign route to noble‐metal nanoparticles having various compositions and morphologies. 相似文献
938.
Ying Lin Mohamed E. El‐Khouly Dr. Yu Chen Prof. Dr. Mustafa Supur Lingling Gu Yongxi Li Shunichi Fukuzumi Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(41):10818-10824
A new π‐conjugated copolymer, namely, poly{cyanofluore‐alt‐[5‐(N,N′‐diphenylamino)phenylenevinylene]} ((CNF–TPA)n), was synthesized by condensation polymerization of 2,2′‐(9,9‐dioctyl‐9H‐fluorene‐2,7‐diyl)diacetonitrile and 5‐(N,N′‐diphenylamino)benzene‐1,3‐dicarbaldehyde by using the Knoevenagel reaction. By design, diphenylamine, alkylfluorene and poly(p‐phenylenevinylene) linkages were combined to form a (CNF–TPA)n copolymer which exhibits high thermal stability and glass‐transition temperature. Photodynamic measurements in polar benzonitrile indicate fast and efficient photoinduced electron transfer (≈1011 s?1) from triphenylamine (TPA) to cyanofluorene (CNF) to produce the long‐lived charge‐separated state (90 μs). The finding that the charge‐recombination process of (CNF.?–TPA.+)n is much slower than the charge separation in polar benzonitrile suggests a potential application in molecular‐level electronic and optoelectronic devices. 相似文献
939.
α-Bromo chalcones containing 2-thiene ring were prepared in good yields by the condensation of 1-(thien-3-yl)ethanone with aromatic aldehydes, followed by bromination with bromine and selective dehydrobromination with triethyl amine at room temperature. 相似文献
940.
Maram R. Al-Dweik Jalal A. Zahra Monther A. Khanfar Mustafa M. El-Abadelah Klaus-Peter Zeller Wolfgang Voelter 《Monatshefte für Chemie / Chemical Monthly》2009,140(2):221-228
Abstract A series of ethyl 2-(substituted)-9-cyclopropyl-4-fluoro-6-oxo-1H-imidazo[4,5-h]quinoline-7-carboxylates has been prepared from ethyl 7,8-diamino-1,4-dihydroquinoline-3-carboxylate via thermally induced
reactions with model alkanoic acids or via microwave-assisted cyclocondensation with some arene carboxaldehydes. Acid-catalysed
hydrolysis of the resulting ester derivatives furnished the corresponding imidazoquinoline-7-carboxylic acids. The structures
of these new acid and ester derivatives are based on microanalytical and spectral (IR, MS, and NMR) data.
Graphical abstract
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