Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
toc sach » hoc sach, doc sach, thuoc sach
nang tai » hang tai, tang tai, sang tai
chat cuu » chat huu, chat cua, cham cuu
dua tren » dung tren
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
ve chat » va chat, van chat
va hanh » van hanh, va thanh, va danh
cuu va » cuu van, cuu ve
kem » kiem

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 ((nang tai) or (nang ma)) hoi. hieu ve chat cuu va hanh kem ((dua tren) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky ((nang tai) OR (nang ma)) hoi. hieu ve chat cuu va hanh kem ((dua tren) OR (cua triet)).
• Adding a wildcard symbol may retrieve word variants: toc sach ky ((nang tai) or (nang ma)) hoi. hieu ve chat cuu va hanh kem ((dua tren) or (cua triet))*.