Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
pham thuc » phap thuc, pham chuc, nham thuc
hoang dau » hoang da, hoang dai, hoang dat
thuc van » thuc vat, thuc dan, thuc va
hang dau » hang va, hang tai
hieu ve » hieu va, hieu van
ve pham » vi pham, v pham, ve phan
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, dua tren
te sach » toc sach
ma hoi » mai hoi, xa hoi, ma hoa
y nang » ky nang, ly nang, v nang

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach y nang ma hoi. hieu ve pham thuc van ((hoang dau) or (hang dau)) ((cua tre) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y nang ma hoi. hieu ve pham thuc van ((hoang dau) OR (hang dau)) ((cua tre) OR (cua triet)).
• Adding a wildcard symbol may retrieve word variants: te sach y nang ma hoi. hieu ve pham thuc van ((hoang dau) or (hang dau)) ((cua tre) or (cua triet))*.