Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hanh vai » hanh vi, hanh va, hanh tai
van hanh » van thanh, ban hanh, van anh
sach ky » sac ky, sach y, sach ty
cuu tre » cua tre, cau treo
duc van » duc va, duc tan, duc manh
hieu va » lieu va, hieu qua
may hoi » may thoi, tay hoi, mai hoi
cac duc » cac du, cao duc, cac dac
sai ky » sac ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ky) or (sai ky)) mang may hoi. hieu va cac duc van hanh vai ((cuu tre) OR (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sai ky)) mang may hoi. hieu va cac duc van hanh vai ((cuu tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sai ky)) mang may hoi. hieu va cac duc van hanh vai ((cuu tre) OR (cau tren))".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sai ky)) mang may hoi. hieu va cac duc van hanh vai ((cuu tre) OR (cau tren))*.