Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
thu sach » tu sach, thuat sach, thuoc sach
tang dai » tang tai, tang dan, tang da
lang dai » lang hai, lang mai, lang chai
vai cua » dai cua, hai cua, lai cua
va tinh » may tinh
va kinh » qua kinh
ve tham » va tham, ve cham, vi tham
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
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 dai)) hoi. hieu ve tham thuc ((va kinh) OR (va tinh)) vai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((tang dai) OR (lang dai)) hoi. hieu ve tham thuc ((va kinh) OR (va tinh)) vai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky ((tang dai) or (lang dai)) hoi. hieu ve tham thuc ((va kinh) OR (va tinh)) vai cua te".
• Adding a wildcard symbol may retrieve word variants: thu sach ky ((tang dai) or (lang dai)) hoi. hieu ve tham thuc ((va kinh) OR (va tinh)) vai cua te*.