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351.
Johan Nilsson Martin Bollmark Jadwiga Jankowska Malgorzata Wenska Jacek Cieslak Adam Kraszewski 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6-7):1513-1516
New synthetic methods, based on H-phosphonate chemistry, have been developed for functionalization of oligonucleotides and for the preparation of various nucleotide analogues bearing sulfur and selenium at the phosphorus center. 相似文献
352.
Treatment of dye 3 with sodium methoxide, morpholine, or diphenylphosphine gives the respective substituted derivatives 4, 5 and 6 in high yields. The reaction of 3 with sodium acetate followed by workup affords ketone 7 which is also obtained by demethylation of a methoxy derivative 4 under non-hydrolytic conditions. 相似文献
353.
Mihaela Popovici Johan Swerts Kazuyuki Tomida Dunja Radisic Min‐Soo Kim Ben Kaczer Olivier Richard Hugo Bender Annelies Delabie Alain Moussa Christa Vrancken Karl Opsomer Alexis Franquet Malgorzata A. Pawlak Marc Schaekers Laith Altimime Sven Van Elshocht Jorge A. Kittl 《固体物理学:研究快报》2011,5(1):19-21
Crystalline rutile TiO2 films were grown by atomic layer deposition on oxidized Ru electrodes using a titanium methoxide as the metal precursor and O3 as the oxidant. A protective layer of ~0.3 nm TiO2 grown with H2O as the oxidant was first deposited in order to avoid etching of the Ru bottom electrode by the O3 used for the growth of the TiO2 (bulk) layer. Electrical evaluation of the capacitor stacks with TiO2 as dielectric, RuO2/Ru and Pt as the bottom and top electrodes respectively, resulted in superior characteristics of the rutile phase as compared to the anatase. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
354.
Malgorzata?Konopka Anna?Janaszewska Kayla?A.M.?Johnson David?Hedstrand Donald?A.?Tomalia Barbara?Klajnert-MaculewiczEmail authorView authors OrcID profile 《Journal of nanoparticle research》2018,20(8):220
A unique photoluminescent phenomenon producing inexplicable, blue emissions [λEx?=?365 nm; λEm?=?460 nm] in the absence of traditional aromatic fluorophores has been observed in a variety of surface functionalized poly(amidoamine) (PAMAM) dendrimers over the past two decades. This emission phenomenon, referred to as non-traditional intrinsic fluorescence (NTIF), originates from the intra-molecular clustering of electron-rich sub-fluorophores (i.e., tertiary amines and/or amido groups) residing in the interior of all PAMAM dendrimers. The intra-molecular clustering of these interior sub-fluorophores is hypothesized to account for the modest but reproducible, blue emissions observed for a variety of dendrimer surface moieties (i.e., –OH, –CO2H, and –NH2). Unexpectedly, a simple, one-step conversion of amine-terminated PAMAM dendrimers to 1-(4-carbomethyoxy) pyrrolidone-terminated dendrimers (4-CMP) was found to produce a 50-fold increase in blue NTIF emission compared to other surface moieties. In an effort to understand this new enhanced emission property, critical nanoscale design parameter (CNDP)-directed quenching experiments were devised to probe the increased NTIF emissions. Was it originating from the interior sub-fluorophoric tertiary amine/amido moieties or from the surface-attached, sub-fluorophoric pyrrolidone amido groups or both? Four generations of 4-CMP PAMAM dendrimers were examined. Two classical quenchers, namely, potassium iodide and acrylamide were selected to probe surface versus interior domains, respectively, as a function of predictable CNDPs associated with generation levels. With increasing dendrimer generation, quencher penetration into the dendrimer interior is impeded due to CNDP-directed generational congestion. Stern-Volmer plots for each quencher, as a function of generation, exhibited appropriate linear or non-linear correlations that corroborated behavior expected for two distinct region-specific emission sites. 相似文献
355.
Naringenin is one of the flavonoids originating from citrus fruit. This polyphenol is mainly found in grapefruit, orange and lemon. The antioxidant and antimicrobial properties of flavonoids depend on their structure, including the polymeric form. The aim of this research was to achieve enzymatic polymerization of naringenin and to study the properties of poly(naringenin). The polymerization was performed by methods using two different enzymes, i.e., laccase and horseradish peroxidase (HRP). According to the literature data, naringenin had not been polymerized previously using the enzymatic polymerization method. Therefore, obtaining polymeric naringenin by reaction with enzymes is a scientific novelty. The research methodology included analysis of the structure of poly(naringenin) by NMR, GPC, FTIR and UV-Vis and its morphology by SEM, as well as analysis of its properties, i.e., thermal stability (DSC and TGA), antioxidant activity (ABTS, DPPH, FRAP and CUPRAC) and antimicrobial properties. Naringenin oligomers were obtained as a result of polymerization with two types of enzymes. The polymeric forms of naringenin were more resistant to thermo-oxidation; the final oxidation temperature To of naringenin catalyzed by laccase (poly(naringenin)-laccase) was 28.2 °C higher, and poly(naringenin)-HRP 23.6 °C higher than that of the basic flavonoid. Additionally, due to the higher molar mass and associated increase in OH groups in the structure, naringenin catalyzed by laccase (poly(naringenin)-laccase) showed better activity for scavenging ABTS+• radicals than naringenin catalyzed by HRP (poly(naringenin)-HRP) and naringenin. In addition, poly(naringenin)-laccase at a concentration of 5 mg/mL exhibited better microbial activity against E. coli than monomeric naringenin. 相似文献