Perhaps you should try some spelling variations:
des developpement » des developpements, de developpement, le developpement
variation series » education series, action series, edition series
des variation » does variation, de variation, der variation
series nejm » series new
des afrique » en afrique, de l'afrique
nejm risk » term risk
a des » a der, a das
typologie » typologies, typology

You may be able to get more results by adjusting your search query.

• Adding a wildcard symbol may retrieve word variants: typologie des variation series nejm risk communication a des developpement des afrique.*.