Perhaps you should try some spelling variations:
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
cam duc » cam xuc, cao duc, pham duc
la tren » loai tren, dua tren, dat tren
ve cam » ve cham, ve cac, va cam
x hoi » xa hoi, o hoi, x ho
do vi » doc vi, do voi, do va

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) or (su sach)) ky nang x hoi. hieu ve cam duc va ((do vi) OR (don vi)) la tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky nang x hoi. hieu ve cam duc va ((do vi) OR (don vi)) la tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) ky nang x hoi. hieu ve cam duc va ((do vi) OR (don vi)) la tren".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ky nang x hoi. hieu ve cam duc va ((do vi) OR (don vi)) la tren*.