Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
van hanh » van thanh, ban hanh, van anh
luc van » luoc van, luu van, duc van
lua tre » cua tre, luy tre, dua tren
ty nang » ky nang, ty hang, ly nang
ve cac » va cac, vien cac
vi lua » vi luu
ve cau » ke cau, va cau, le cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach ((ty nang) OR (ty xang)) ma hoa. hieu ((ve cau) or (ve cac)) luc van hanh vi lua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ((ty nang) OR (ty xang)) ma hoa. hieu ((ve cau) OR (ve cac)) luc van hanh vi lua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ((ty nang) OR (ty xang)) ma hoa. hieu ((ve cau) or (ve cac)) luc van hanh vi lua tre*".