Perhaps you should try some spelling variations:
hoc nganh » hoc nhanh
hanh thai » nhanh thai, hinh thai, hanh tai
thai cua » than cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
van hoi » van hoa, van hoc, van hoe
ky dang » ky nang, ky danh
ky lang » ky nang, ky tang, tay lang
dac va » duc va, dat va, dai va
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc nganh ((ky lang) OR (ky dang)) van hoi. hieu ve cac ((dac va) or (day va)) hanh thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc nganh ((ky lang) OR (ky dang)) van hoi. hieu ve cac ((dac va) OR (day va)) hanh thai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc nganh ((ky lang) OR (ky dang)) van hoi. hieu ve cac ((dac va) or (day va)) hanh thai cua tre".
• Adding a wildcard symbol may retrieve word variants: hoc nganh ((ky lang) OR (ky dang)) van hoi. hieu ve cac ((dac va) or (day va)) hanh thai cua tre*.