Perhaps you should try some spelling variations:
trinh vi » trinh va, trinh ve, trinh viet
ky lang » ky nang, ky dang, ky tang
hoc hoi » hoc khoi, hoc hoa, hoc noi
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
vu sac » vu sach, vu san, va sac
sac ky » cac ky, sai ky
luc va » tuc va, loc va
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sac ky lang ((hoc hoi) or (hoa hoc)). hieu va cac ((luc va) or (duc va)) trinh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sac ky lang ((hoc hoi) OR (hoa hoc)). hieu va cac ((luc va) OR (duc va)) trinh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: vu sac ky lang ((hoc hoi) or (hoa hoc)). hieu va cac ((luc va) or (duc va)) trinh vi cua tre*.