Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
phat xuc » chat xuc, phat xuat, phap xu
su triet » su viet, su tien, ve triet
lang ha » long ha
dong ha » dong hoa, dong va, dong hoc
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
va hanh » van hanh, va thanh, va danh
va tinh » may tinh
vi su » va su, ve su, ki su

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky ((lang ha) or (dong ha)) hoi. hieu va phat xuc ((va hanh) or (va tinh)) vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky ((lang ha) OR (dong ha)) hoi. hieu va phat xuc ((va hanh) OR (va tinh)) vi su triet.
• Adding a wildcard symbol may retrieve word variants: toc sach ky ((lang ha) or (dong ha)) hoi. hieu va phat xuc ((va hanh) or (va tinh)) vi su triet*.