Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
hanh tai » thanh tai, hang tai, han tai
van hanh » van thanh, ban hanh, van anh
lang hai » lang chai, lang thai, lang ha
tu sach » su sach, te sach, tu cach
tai cuu » tai cuc, tai buu, tai cua
luc van » luoc van, luu van, duc van
cuu tre » cua tre, cau tren, cau treo
hai hoi » dai hoi, hai moi, hai hai
ky lang » ky nang, ky dang, ky tang
va cam » va cham, va cac, va cao
ve cam » ve cham, ve cac, ve cai

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 (thu sach)) ky lang hai hoi. hieu ((ve cam) or (va cam)) luc van hanh tai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky lang hai hoi. hieu ((ve cam) OR (va cam)) luc van hanh tai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) ky lang hai hoi. hieu ((ve cam) or (va cam)) luc van hanh tai cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) ky lang hai hoi. hieu ((ve cam) or (va cam)) luc van hanh tai cuu tre*.