Is it permissible for heirs to sell their share of an inherited land while leaving the share of some partners who refuse to sell?

If your share of the land is distinct from the share of your paternal uncles, then there is no harm in selling it, and you are not obliged to obtain their approval. Rather, you are required to offer it to them first. If they wish to buy it, then that is excellent. Otherwise, sell it to whomever you wish, based on the agreed-upon Hadith narrated by Jabir: "Whoever has a partner in a dwelling or a date palm, he may not sell it until he informs his partner. If his partner agrees, he takes it; and if he disapproves, he leaves it."