Perhaps you should try some spelling variations:
nang cai » nang cao, nang tai, nang cap
van pham » san pham, van phan, van phat
hanh tai » thanh tai, hang tai, han tai
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
cai hoi » cau hoi, dai hoi, cai hoa
va pham » va phat, va phap, va phan
va hanh » van hanh, va thanh, va danh
tai duc » tai cuc, mai duc, tai du
duc tre » duoc tren, duc tien
duy va » duy vat, duy van, day 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 nang cai hoi. hieu ((va pham) OR (van pham)) duy va hanh tai duc tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang cai hoi. hieu ((va pham) OR (van pham)) duy va hanh tai duc tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang cai hoi. hieu ((va pham) OR (van pham)) duy va hanh tai duc tre*.