Perhaps you should try some spelling variations:
thuat san » thuat toan, thuat song, thuat lanh
hanh dai » hanh tai, hanh dao, vanh dai
tang mai » tang ma, tang tai, lang mai
tu sach » thu sach, su sach, te sach
va hanh » van hanh, va thanh, va danh
mai hoi » mai khoi, dai hoi, lai hoi
ky tang » ky nang, ky dang, kho tang
ve cac » vien cac
luc va » duc va, tuc va, loc va
cua tu » cua tuc, cua su, cua cu

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 (thuat san)) ky tang mai hoi. hieu ((ve cac) OR (va cac)) luc va hanh dai cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thuat san)) ky tang mai hoi. hieu ((ve cac) OR (va cac)) luc va hanh dai cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thuat san)) ky tang mai hoi. hieu ((ve cac) OR (va cac)) luc va hanh dai cua tu".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thuat san)) ky tang mai hoi. hieu ((ve cac) OR (va cac)) luc va hanh dai cua tu*.