Perhaps you should try some spelling variations:
vat hanh » vat thanh, van hanh, va hanh
hanh vai » hanh vi, hanh va, hanh tai
tu sach » thu sach, su sach, te sach
ky lang » ky nang, ky dang, tay lang
ky tang » ky nang, ky dang, kho tang
hoa hoi » khoa hoi, hoa hoc, hoa doi
hieu ve » hieu va, hieu van
thu vat » thuc vat, thu va, thuat vat
su tien » su kien, su hien, tu tieng
ve nam » he nam, va nam, le nam
vai su » va su, van su, lai su

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 ((ky lang) or (ky tang)) hoa hoi. hieu ve nam thu vat hanh vai su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky lang) OR (ky tang)) hoa hoi. hieu ve nam thu vat hanh vai su tien.
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky lang) or (ky tang)) hoa hoi. hieu ve nam thu vat hanh vai su tien*.