Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
van hanh » van thanh, ban hanh, van anh
dua tren » dung tren
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang ma » tang ma, sang ma, nang cao
luc van » luoc van, luu van, duc van
ve cau » ke cau, va cau, le cau
ve cac » va cac, vien cac
vi dua » vi du, vi dum, vi lua

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 ma hoa. hieu ((ve cau) or (ve cac)) luc van hanh vi dua tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ty nang ma hoa. hieu ((ve cau) OR (ve cac)) luc van hanh vi dua tren*.