Perhaps you should try some spelling variations:
tu cach » tu cac
hieu ve » hieu va, hieu van
la tren » loai tren, dua tren, dat tren
su sach » so sach, vu sach
xuc va » duc va, tuc va, luc va
dan vi » doan vi, don vi, gan vi
dan va » doan va, dan ca, ban va
ve cam » ve cham, ve cac, va cam
x hoi » xa hoi, o hoi, x ho

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

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