1. A composition for dyeing keratin fibers, in particular human keratin fibers, containing at least one oxidation dye； at least one non-ionic polyoxyalkylene fatty alcohol ester of formula (i) wherein is a radical based on linear or branched, saturated or unsaturated C-hydrocarbon, R 'represents a radical based on a linear or branched, saturated or unsaturated C-hydrocarbon radical which may be substituted by a hydroxyl radical, n is an integer from 1 to 100 inclusive, Alk represents a linear or branched, preferably linear, (CC) alkylene group, such as ethylene or propylene, preferably ethylene； at least one cationic polymer； at least one fatty substance at a concentration of at least 25% based on the total weight of the composition； at least one chemical oxidizing agent. 2. A composition according to claim 1, characterized in that the non-ionic ether (s) of the polyoxyalkylene fatty alcohols are selected from compounds of formula (i), wherein R and R ', independently of one another, are a radical based on a linear or branched, preferably linear, saturated or unsaturated, preferably saturated, CC, preferably C-hydrocarbon, wherein R 'is optionally substituted with at least one hydroxyl radical and n is an integer that is greater than or equal to 20, for example from 20 to 100, preferably from 40 to 80.3. A composition according to claim 2, characterized in that the non-ionic ether (s) of the polyoxyalkylene fatty alcohols are selected from compounds of formula (i), where R is C-Salk�1. Композиция для окрашивания кератиновых волокон в частности кератиновых волокон человека, содержащаяпо меньшей мере один оксидационный краситель；по меньшей мере один неионный эфир полиоксиалкиленированного жирного спирта формулы (i)где представляет собой радикал на основе линейного или разветвленного, насыщенного или ненасыщенного С-Суглеводорода,R' представляет собой радикал на основе линейного или разветвленного, насыщенного или ненасыщенного С-Суглеводорода, который может быть заме
