Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh vi » hanh vi, thanh va, thanh ve
nang ma » tang ma, sang ma, nang cao
sach ky » sach y, sach ty, sach kem
van cac » van cau, van bac, dan cac
van hac » van hoc, van ha, van hai
dat ban » bat ban, da ban, day ban
ma hoi » mai hoi, xa hoi, ma hoa
sac ky » cac ky, sai ky
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: thu ((sach ky) or (sac ky)) nang ma hoi. hieu ((van cac) OR (van hac)) dat ban thanh vi cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ky) OR (sac ky)) nang ma hoi. hieu ((van cac) OR (van hac)) dat ban thanh vi cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ky) or (sac ky)) nang ma hoi. hieu ((van cac) OR (van hac)) dat ban thanh vi cua vat".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ky) or (sac ky)) nang ma hoi. hieu ((van cac) OR (van hac)) dat ban thanh vi cua vat*.