Perhaps you should try some spelling variations:
va trien » va truyen, va thiet, va tuyen
hanh dai » hanh tai, hanh dao, vanh dai
nam thuc » nam thuoc, am thuc, nam thu
va hanh » van hanh, va thanh, va danh
cam tuc » cam xuc, cam tu, dam thuc
sach ky » sac ky, sach y, sach kem
hieu ve » hieu va, hieu van
nang ma » tang ma, sang ma, nang cao
sach ty » sach y, sach tu, sach thu
ma hoi » mai hoi, xa hoi, ma hoa
dai va » mai va

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 ky) or (sach ty)) nang ma hoi. hieu ve ((cam tuc) OR (nam thuc)) va hanh dai va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sach ty)) nang ma hoi. hieu ve ((cam tuc) OR (nam thuc)) va hanh dai va trien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) or (sach ty)) nang ma hoi. hieu ve ((cam tuc) OR (nam thuc)) va hanh dai va trien".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sach ty)) nang ma hoi. hieu ve ((cam tuc) OR (nam thuc)) va hanh dai va trien*.