Perhaps you should try some spelling variations:
sach ky » sac ky, sach y, sach kem
cua tre » cuu tre, cua triet, dua tren
va hanh » van hanh, va thanh, va danh
cac loc » cac lop, cac toc, cac hoc
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
sach ty » sach y, sach tu, sach thu
ma hoi » mai hoi, xa hoi, ma hoa
loc va » hoc va, luc va
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: tu ((sach ky) or (sach ty)) nang ma hoi. hieu va cac loc va hanh vi ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach ty)) nang ma hoi. hieu va cac loc va hanh vi ((cua tre) OR (cua te)).
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach ty)) nang ma hoi. hieu va cac loc va hanh vi ((cua tre) or (cua te))*.