Perhaps you should try some spelling variations:
cham thuc » pham thuc, tham thuc, pham thuoc
nham thuc » nhan thuc, nam thuc, nham thu
thu sach » tu sach, thuat sach, thuoc sach
tang dai » tang tai, tang dan, lang dai
kinh vai » kinh hai, kinh va, kinh van
lang hai » lang chai, lang thai, lang ha
vai cua » dai cua, hai cua, lai cua
va kinh » va tinh, qua kinh
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 dai) or (lang hai)) hoi. hieu ve ((cham thuc) or (nham thuc)) va kinh vai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((tang dai) OR (lang hai)) hoi. hieu ve ((cham thuc) OR (nham thuc)) va kinh vai cua te.
• Adding a wildcard symbol may retrieve word variants: thu sach ky ((tang dai) or (lang hai)) hoi. hieu ve ((cham thuc) or (nham thuc)) va kinh vai cua te*.