Perhaps you should try some spelling variations:
sach thi » sach thu, sach tai, sach thieu
thi nang » thi cong, ki nang, thi hanh
su sach » so sach, vu sach
va hanh » van hanh, va thanh, va danh
ve chat » va chat, van chat
va tham » van tham, va cham, va thanh
cao hoi » cau hoi, co hoi, cao hoc
va cuu » va cau, va chu
va huu » vu huu

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach thi nang cao hoi. hieu ((va tham) or (ve chat)) hoc va hanh ((va cuu) OR (va huu)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach thi nang cao hoi. hieu ((va tham) OR (ve chat)) hoc va hanh ((va cuu) OR (va huu)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach thi nang cao hoi. hieu ((va tham) or (ve chat)) hoc va hanh ((va cuu) OR (va huu)) tre".
• Adding a wildcard symbol may retrieve word variants: su sach thi nang cao hoi. hieu ((va tham) or (ve chat)) hoc va hanh ((va cuu) OR (va huu)) tre*.