Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
cam truc » cau truc, nam truc, lam truoc
hanh tai » thanh tai, hang tai, han tai
nang dau » hang dau, xang dau, nang du
cua tre » cua te, cuu tre, dua tren
va hanh » van hanh, va thanh, va danh
truc va » thuc va, thuc vat, trung va
sach ky » sac ky, sach y, sach kem
dau hoi » cau hoi, dai hoi, dan hoi
sach ty » sach y, sach tu, sach thu
hieu ve » hieu va, hieu van
ve cam » ve cham, ve cac, va cam

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 ky) or (sach ty)) nang dau hoi. hieu ve cam truc va hanh tai ((cua tre) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sach ty)) nang dau hoi. hieu ve cam truc va hanh tai ((cua tre) OR (cua triet)).
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sach ty)) nang dau hoi. hieu ve cam truc va hanh tai ((cua tre) or (cua triet))*.