Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
cac tuc » cac toc, cac tu, cac tac
cua tre » cua te, cuu tre, dua tren
xa dan » ca dan, xa dai, va dan
dan vi » doan vi, don vi, dan va

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ty ((nang ma) or (van xay)) hoi. hieu va cac tuc xa dan vi ((cua tre) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((nang ma) OR (van xay)) hoi. hieu va cac tuc xa dan vi ((cua tre) OR (cua triet)).
• Adding a wildcard symbol may retrieve word variants: su sach ty ((nang ma) or (van xay)) hoi. hieu va cac tuc xa dan vi ((cua tre) or (cua triet))*.