Perhaps you should try some spelling variations:
nham thuc » nhan thuc, nham thu, pham thuc
thu sach » tu sach, thuat sach, thuoc sach
tang mai » tang ma, lang mai, sang mai
dinh vai » dinh van, dinh vi, dinh va
van dinh » van minh, van dich, va dinh
tang tai » hang tai, dung tai, sang tao
nam thuc » nam thuoc, am thuc, nam thu
vai cua » dai cua, hai cua, lai cua
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
cua te » cua tu

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 ((tang mai) or (tang tai)) hoi. hieu ve ((nham thuc) OR (nam thuc)) van dinh vai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((tang mai) OR (tang tai)) hoi. hieu ve ((nham thuc) OR (nam thuc)) van dinh vai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky ((tang mai) or (tang tai)) hoi. hieu ve ((nham thuc) OR (nam thuc)) van dinh vai cua te".
• Adding a wildcard symbol may retrieve word variants: thu sach ky ((tang mai) or (tang tai)) hoi. hieu ve ((nham thuc) OR (nam thuc)) van dinh vai cua te*.