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61.
Morpholine adducts of nickel(II), cobalt(II), and manganese(II) benzoylacetonates, as well as a morpholine solvate of manganese(II)
benzoylacetonate, were prepared and characterized by X-ray diffraction and thermal analysis. All four compounds crystallize
in the P21/c space group with two complex molecules per unit cell. The morpholine solvate, along with the two adduct molecules, also contains
four solvent morpholine molecules in the unit cell. The non-solvate compounds are isostructural, with crystal structures comprising
2D networks formed by C–H···O hydrogen bonding between phenyl rings and morpholine oxygen atoms. The topology of these networks
can be described as intersecting C22(24) chains forming R44(48) rings. Networks with the same topology are also present in the solvate, but they are heavily distorted due to the presence
of solvent morpholine molecules. Thermogravimetric analysis shows similar behavior of the non-solvate compounds upon thermal
decomposition, with three degradation steps which can be related to gradual loss of morpholine molecules and subsequent overall
decomposition. Decomposition of the solvate also proceeds in several steps, the first of which can be related to loss of solvent
morpholine molecules and the further steps are analogous to those in the non-solvate compounds. 相似文献
62.
Poly(ether amide)s containing naphthalene unit were prepared either by the polyaddition reaction of aromatic bis(2‐oxazoline)s with the different dihydroxynaphthalenes or by the homopolyaddition of a monomer containing an oxazoline, a hydroxy, and naphthalene moieties. First, polymerization method represents AA + BB mode where 1,4‐phenylene‐2,2′‐bis(2‐oxazoline) (A) and 1,3‐phenylene‐2,2′‐bis(2‐oxazoline) (B) were used as AA monomers and four different dihydroxynaphthalenes 1–4 were used as BB monomers. In the second case, 2‐(6‐hydroxynaphthalene‐2‐yl)‐2‐oxazoline (5) was used as AB‐type monomer in thermally induced polymerizations. The time dependences of polyadditions in bulk as well as in the solution were examined. The reduction of molar mass was observed after the initial fast increase of molar mass. This can be explained by the presence of side and degradation reactions. In both cases, polyadditions resulted in the linear poly(ether amide)s, which were characterized by 1H and 13C NMR spectroscopy. Thermal properties of the prepared polymers were studied by differential scanning calorimetry (DSC) measurements. Comparison of the temperatures of glass transition for polymers prepared in AA + BB mode shows the strong dependence of thermal properties on the structure of the polymers. The values were in the range of 136–171°C. The glass‐transition temperature (Tg) of poly[2‐(6‐hydroxynaphthalene‐2‐yl)‐2‐oxazoline] prepared by AB‐type polyaddition is 183°C, which corresponds to the higher contents of hard aromatic segments in the latter type of polymers compared to the polymers prepared in the AA + BB‐type polyadditions. The described polymers represent novel naphthalene unit‐containing poly(ether amide)s for different applications in material science. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
63.
Rubelj I Stepanić V Jelić D Vidaček NŠ Kalajžić AĆ Ivanković M Nujić K Matijašić M Verbanac D 《Molecules (Basel, Switzerland)》2012,17(7):7864-7886
In vitro high-throughput screening was carried out in order to detect new activities for old drugs and to select compounds for the drug development process comprising new indications. Tebrophen, a known antiviral drug, was found to inhibit activities on inflammation and cancer related targets. In primary screening this semisynthetic halogenated polyphenol was identified to inhibit the activities of kinases ZAP-70 and Lck (IC?? 0.34 μM and 16 μM, respectively), as well as hydrolase DPPIV (at 80 μM 41% inhibition). Next, it showed no cytotoxic effects on standard cell lines within 24 h. However, tebrophen slowed propagation of breast cancer (MDA-MB-231), osteosarcoma (U2OS) and cervical carcinoma (HeLa), through at least 35 population doublings in a dose-dependent manner. It completely stopped the division of the prostate cancer (PC3) cell line at 50 μM concentration and the cells entered massive cell death in less than 20 days. On the other hand, tebrophen did not influence the growth of normal fibroblasts. According to the measured oxidative burst and estimated in silico parameters its direct antioxidative ability is limited. The obtained results indicate that tebrophen can be considered a promising lead molecule for generating more soluble derivatives with specific anticancer efficacy. 相似文献
64.
We present a new criterion for indecomposability of polynomialsover . Using the criterion, we obtain general finiteness resulton the polynomial Diophantine equation f(x) = g(y). 相似文献
65.
Miodrag Zivkovic 《Semigroup Forum》2006,73(3):404-426
Let
be the set of all
Boolean matrices. Let R(A) denote the row space of
, let
, and let
. By extensive computation we found that
and therefore
. Furthermore,
for
. We proved that if
, then the set
contains at least
elements. 相似文献
66.
67.
Ivica Kopriva Ivanka Jeri Marko Filipovi Lidija Brklja
i 《Journal of Chemometrics》2014,28(9):704-715
Nonlinear underdetermined blind separation of nonnegative dependent sources consists in decomposing a set of observed nonlinearly mixed signals into a greater number of original nonnegative and dependent component (source) signals. This hard problem is practically relevant for contemporary metabolic profiling of biological samples, where sources (a.k.a. pure components or analytes) are aimed to be extracted from mass spectra of nonlinear multicomponent mixtures. This paper presents a method for nonlinear underdetermined blind separation of nonnegative dependent sources that comply with a sparse probabilistic model, that is, sources are constrained to be sparse in support and amplitude. This model is validated on experimental pure component mass spectra. Under a sparse prior, a nonlinear problem is converted into an equivalent linear one comprised of original sources and their higher‐order, mostly second‐order, monomials. The influence of these monomials, which stand for error terms, is reduced by preprocessing a matrix of mixtures by means of robust principal component analysis and hard, soft and trimmed thresholding. Preprocessed data matrices are mapped in high‐dimensional reproducible kernel Hilbert space (RKHS) of functions by means of an empirical kernel map. Sparseness‐constrained nonnegative matrix factorizations in RKHS yield sets of separated components. They are assigned to pure components from the library using a maximal correlation criterion. The methodology is exemplified on demanding numerical and experimental examples related respectively to extraction of eight dependent components from three nonlinear mixtures and to extraction of 25 dependent analytes from nine nonlinear mixture mass spectra recorded in nonlinear chemical reaction of peptide synthesis. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
68.
Ivica Gusi? 《Journal of Number Theory》2005,115(2):343-347
We give a characterization of linear polynomials over a number field k as the only non-constant polynomials f for which the equation f(x)=g(y) has a k-rational solution for each polynomial g over k. 相似文献
69.
Ivica Cepanec Mladen Litvi? Mirela Filipan-Litvi? Ivana Grüngold 《Tetrahedron》2007,63(48):11822-11827
Antimony(III) chloride (20 mol %) in refluxing acetonitrile efficiently catalyses the synthesis of dihydropyrimidinones (50-90% yields) by the Biginelli reaction of aromatic aldehydes, acetoacetate esters and urea. This reaction proceeds through 3-ureido-crotonates followed by cyclisation with an aromatic aldehyde to the dihydropyrimidinone. 相似文献
70.
An efficient method for the Biginelli reaction of aldehydes, acetoacetate esters and urea employing tetraethyl orthosilicate in the presence of ferric chloride is described. These improved reaction conditions allow the preparation of a wide variety of substituted dihydropyrimidinones (including sterically encumbered ones) in high yields and purity under mild reaction conditions. 相似文献