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161.
Complexes of formula [(H2N2O2)TiCl2] and [(H2N2O2)Ti(OiPr)2] (H2N2O2H2 = HOPh’CH2NH(CH2)2NHCH2Ph’OH, where Ph’ = 2,4-(CMe2Ph)C6H2) were synthesized by the reaction of the salan ligand precursor H2N2O2H2 with TiCl4 and Ti(OiPr)4, respectively, in high yields. The dichlorido complex [(H2N2O2)TiCl2] revealed to be an efficient catalyst for the reduction of benzaldehyde in toluene. Full conversion was observed after 24 h at 55 °C in THF. The same catalyst also converted phenylacetaldehyde and hydrocinnamaldehyde into the corresponding alkanes quantitatively. 相似文献
162.
Dan Chen Weiben Chen Dr. Guolong Xing Dr. Ting Zhang Prof. Long Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(38):8377-8381
A highly crystalline bicarbazole-based covalent organic framework (BCzP-COF) was synthesized via an upgraded “two-in-one” strategy by the self-polycondensation of A2B2 monomer with two neopentyl acetal and two amine groups. Such a strategy is propitious to afford higher crystallinity, larger special surface areas and better morphology than that of using unprotected monomer with free aldehydes and amines. Additionally, the off-white powder of BCzP-COF could serve as acidichromism sensor with a significant color change. Intriguingly, the conductivity of the protonated BCzP-COF can improve by six orders of magnitude compared to that of the pristine samples. This work has the potential to lead to bicarbazole-functional materials for chemosensors and electronic devices. 相似文献
163.
J.S Yadav V GeethaA Krishnam Raju D GnaneshwarS Chandrasekhar 《Tetrahedron letters》2003,44(14):2983-2985
Ceramides containing the 6-hydroxy-4E-sphingenines, previously unknown long-chain bases, have recently been found in human skin. A total synthesis of 6-hydroxy-4E-sphingenines has been achieved. 相似文献
164.
Marco Lombardo 《Tetrahedron》2004,60(51):11725-11732
The reaction of 3-bromo-propenyl acetate with the Garner aldehyde promoted by zinc or indium metal is studied in different solvents; besides the stereoselectivity, attention is focused on a comparative environmental assessment of different experiments carried out in NH4Cl, THF or DMF, using green chemistry metrics and a qualitative analysis of environmental risks. 相似文献
165.
Some central intermediates useful for the synthesis of aza-analogues of the anti-cancer drug podophyllotoxin have been prepared starting from l-DOPA and (R)-Garner aldehyde. 相似文献
166.
Substituted-benzene-1,2-dicarbaldehydes were synthesized by the reaction of substituted-1,2-bis(dibromomethyl) benzenes with fuming sulfuric acid,followed by hydrolysis. The yields were signifi-cantly improved by introducing solid sodium bicarbonate into the reaction mixture before hydrolysis and workup. 相似文献
167.
An intermolecular Stetter reaction of aromatic aldehydes with maleimides has been developed using thiazolylidene salt derived Isa?NHC as an efficient organocatalyst. The synthesized Stetter products “3?aroylsuccinimides” are important building blocks for the synthesis of natural products and bioactive compounds. The reaction conditions are mild, and various substituents on aromatic aldehyde and maleimide nitrogen were tolerated. 相似文献
168.
《Macromolecular bioscience》2018,18(4)
Quercetin, a naturally occurring potent antioxidant, is limited in therapeutic use, owing to its poor water solubility and stability. Herein, a method of conjugating quercetin to an aldehyde functionalized dextran via an HCl catalyzed condensation reaction to yield a water soluble quercetin functionalized polymer is reported. The prepared conjugate is characterized by 1H and 1H‐13C heteronuclear single quantum correlation (HSQC) NMR, which demonstrate that conjugation occurs via both the A‐ and B‐rings of quercetin. The degree of quercetin functionalization can be tuned by varying the reaction temperature and/or the concentration of the HCl catalyst. However, as temperatures and HCl concentrations are increased above 40 °C and 2 m , respectively, the increase in functionalization is accompanied by an increase in the oxidation of the conjugated quercetin and a decrease in polymer yield. The prepared conjugate is shown to have improved stability compared with native quercetin while maintaining substantial free‐radical scavenging activity. Anticancer activity is evaluated in vitro in a neuroblastoma cell line. The dextran–aldehyde–quercetin conjugate prepared at 40 °C and 2 m HCl is shown to be cytotoxic to neuroblastoma cells (SH‐SY5Y–IC50 = 123 µg mL−1 and BE(2)‐C–IC50 = 380 µg mL−1) but shows no activity against nonmalignant MRC‐5 cells at concentrations up to 400 µg mL−1. 相似文献
169.
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