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181.
Mangeney C Fertani M Bousalem S Zhicai M Ammar S Herbst F Beaunier P Elaissari A Chehimi MM 《Langmuir : the ACS journal of surfaces and colloids》2007,23(22):10940-10949
This paper describes the synthesis of new magnetic, reactive polystyrene/polypyrrole core/shell latex particles. The core consists of a polystyrene microsphere containing gamma-Fe2O3 superparamagnetic nanoparticles (PSmag), and the shell is made of reactive N-carboxylic acid-functionalized polypyrrole (PPyCOOH). These PSmag-PPyCOOH latex particles, average diameter 220 nm, were prepared by copolymerization of pyrrole (Py) and the active carboxyl-functionalized pyrrole (PyCOOH) in the presence of PSmag particles. PNVP was used as a steric stabilizer. The functionalized polypyrrole-coated PSmag particles were characterized in terms of their particle size, surface morphology, chemical composition, and electrochemical and magnetic properties using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry, and SQUID magnetometry. Activation of the particle surface carboxyl groups was achieved using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) and N-hydroxysuccinimide (NHS), which helps transform the carboxyl groups into activated ester groups (NSE). The activated particles, PSmag-PPyNSE, were further evaluated as bioadsorbents of biotin used as a model biomolecule. It was shown that biotin was immobilized at the surface of the PSmag-PPyNSE particles by forming interfacial amide groups. The assemblies of PSmag-PPyCOOH particles on glass plates were further investigated. When no magnetic field is applied, the particles assemble into 3D colloidal crystals. In contrast, under a magnetic field, one-particle-thick chains gathered in hedgehog-like architectures are obtained. Furthermore, PSmag-PPyCOOH coated ITO electrodes were shown to be electroactive and electrochemically stable, thus offering potentialities for creating novel high-specific-area materials for biosensing devices where the conducting polymer component would act as the transducer through its conductive properties. 相似文献
182.
Nadia Belfguira Siwar Walha Abdelhamid Ben Salah Frédéric Hatert André Mathieu Fransolet Ahlem Kabadou 《Journal of chemical crystallography》2010,40(12):1125-1128
Abstract
Single crystals of iron and manganese phosphate Fe6.36Mn0.64(PO3(OH))4(PO4)2 was synthesized by hydrothermal method. The compound crystallizes in the Fe7(PO4)6 structure type and is isotypic with the solid solution \textM7 - \textx \textM\textx¢ ( \textHPO4 )4 ( \textPO4 )2 {\text{M}}_{{7 - {\text{x}}}} {\text{M}}_{\text{x}}^{\prime} \left( {{\text{HPO}}_{4} } \right)_{4} \left( {{\text{PO}}_{4} } \right)_{2} where M is Fe, Co, Mg, Mn. The compound is triclinic, P-1, a = 6.571(5), b = 7.993(3), c = 9.547(2) Ǻ, α = 103.97(1)°, β = 109.29(2)°, γ = 101.57(3)°. The structure is based on a three-dimensional framework of distorted edge-sharing MO6 and MO5 polyhedra, forming infinite chains, which are interlinked by corner-sharing with PO4 tetrahedra. The formula unit is centrosymmetric, with all atoms in general positions except for one Fe atom, which has site symmetry −1. 相似文献183.
C‐acyl‐N‐(3‐phenyl‐5‐pyrazolyl)hydrazonoyl chlorides 1a,b react with potassium thiocyanate and potassium selenocyanate to give 5‐acyl‐2,3‐dihydro‐2‐imino‐3‐(3′‐phenyl)pyrazol‐5′‐yl)‐1,3,4‐thiadiazoles 2a,b and 5‐acetyl‐2,3‐dihydro;‐2‐imino‐3‐(3′‐phenyl)pyrazol‐5′‐yl)‐1,3,4‐selenadiazole 10a,b . Also, 2‐[mercapto‐(methylthio)methylene]indan‐1,3‐dione 16 reacts with hydrazonoyl halides 15 and 22–25 to afford 2,3‐dihydro‐1,3,4‐thiadiazoles 19 and 26–29 , respectively. Structures of the newly synthesized compounds are elucidated on the basis of spectral data, chemical transformations, and alternative synthesis methods. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:468–474, 2001 相似文献
184.
Shaila Mehwish Sanjay Varikuti Mubarak Ali Khan Tariq Khan Imdad Ullah Khan Abhay Satoskar Hamed Abdelhamid Elsayed Elserehy Nazif Ullah 《Molecules (Basel, Switzerland)》2021,26(19)
Natural products from plants contain many interesting biomolecules. Among them, quercetin (Q), gallic acid (GA), and rutin (R) all have well-reported antileishmanial activity; however, their exact mechanisms of action are still not known. The current study is a step forward towards unveil the possible modes of action of these compounds against Leishmania donovani (the causative agent of visceral leishmaniasis). The selected compounds were checked for their mechanisms of action against L. donovani using different biological assays including apoptosis and necrosis evaluation, effects on genetic material (DNA), quantitative testing of nitric oxide production, ultrastructural modification via transmission electron microscopy, and real-time PCR analysis. The results confirmed that these compounds are active against L. donovani, with IC50 values of 84.65 µg/mL, 86 µg/mL, and 98 µg/mL for Q, GA, and R, respectively. These compounds increased nitric oxide production and caused apoptosis and DNA damage, which led to changes in the treated cells’ ultrastructural behavior and finally to the death of L. donovani. These compounds also suppressed essential enzymes like trypanothione reductase and trypanothione synthetase, which are critical for leishmanial survival. The selected compounds have high antileishmanial potentials, and thus in-vivo testing and further screening are highly recommended. 相似文献
185.
Ghodbane A D'Altério S Saffon N McClenaghan ND Scarpantonio L Jolinat P Fery-Forgues S 《Langmuir : the ACS journal of surfaces and colloids》2012,28(1):855-863
2-Phenyl-benzoxazole and five derivatives bearing an alkyl or alkoxy substituent on the phenyl ring were used to prepare aqueous suspensions of particles via a solvent-exchange method. In these conditions, the methyl and methoxy derivatives spontaneously gave nanofibers, while the other compounds led to microcrystals. This shows that minor chemical changes are enough to direct the formation of a given type of particle. From a spectroscopic viewpoint, all compounds strongly emit blue light in the solid state, with spectra much broader than those registered in n-heptane and ethanol solutions. The photoluminescence quantum yields reached 38% and were slightly affected in aqueous suspension by the polarity of the environment. The molecular arrangement, deduced from X-ray analysis for the methyl and methoxy derivatives, was used to explain the fluorescence properties in the solid state. This work shows that 2-phenyl-benzoxazole derivatives are interesting candidates for applications as fluorescent nanomaterials, including in aqueous and biological media. 相似文献
186.
187.
188.
Nadia Belfguira Siwar Walha Abdelhamid Ben Salah Andr Mathieu Fransolet Ahlem Kabadou 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(3):i33-i36
Single crystals of the solid solution iron aluminium tris(dihydrogenphosphate), (Fe0.81Al0.19)(H2PO4)3, have been prepared under hydrothermal conditions. The compound is a new monoclinic variety (γ‐form) of iron aluminium phosphate (Fe,Al)(H2PO4)3. The structure is based on a two‐dimensional framework of distorted corner‐sharing MO6 (M = Fe, Al) polyhedra sharing corners with PO4 tetrahedra. Strong hydrogen bonds between the OH groups of the H2PO4 tetrahedra and the O atoms help to consolidate the crystal structure. 相似文献
189.
Monia Hamdouni Lamya Agengui Siwar Walha Ahlem Kabadou Abdelhamid Ben Salah 《Journal of chemical crystallography》2011,41(11):1742-1750
Abstract
In the present study we report the synthesis, crystal structure, spectroscopic and thermal analysis of mixed alkali A1−x (NH4) x (H2C2O4)(HC2O4)(H2O)2 with A = K, Rb. Single crystal refinements showed that the two compounds Rb0.86(NH4)0.14(H2C2O4)(HC2O4)(H2O)2 and K0.53(NH4)0.47(H2C2O4)(HC2O4)(H2O)2 adopt P − 1 space group. The nine fold coordination cationic sites are randomly occupied by Rb+/NH4 + and K+/NH4 + respectively for rubidium and potassium compounds. The structure consists of a three-dimensional network formed by the succession along (c) axis of corrugated sheets formed by alkali polyhedra layers in the packing of four-membered rings [A4(HC2O4)2(H2C2O4)2] linked and bridged by oxalate groups that behave as bi and tetradentate ligand under three different coordination modes. The stability of the crystal lattice is ensured by interesting hydrogen bonding contacts: N–H···O and O–H···O. The thermal behavior under air reveals two anomalies at 368 and 402 K attributed respectively to a structural phase transition probably due to the reorientation of ammonium tetrahedral and to the release of crystalline water. IR spectroscopy further confirms that this material loses crystallization water gradually in the temperature range 400–460 K. 相似文献190.
Two new discrete inequalities of Poincaré–Friedrichs on discontinuous spaces for Maxwell's equations
We present two new discrete inequalities of Poincaré–Friedrichs on discontinuous spaces for Maxwell's equations. The proofs of the inequalities are based on some decompositions formulas of . To cite this article: A. Zaghdani, C. Daveau, C. R. Acad. Sci. Paris, Ser. I 342 (2006). 相似文献