Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hanh via » hanh vi, hanh va, anh va
van hanh » van thanh, ban hanh, van anh
nang doc » nang luc
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach kem
hieu va » lieu va, hieu qua
doc hoi » duoc hoi, hoc hoi, doc hai
sach ty » sach y, sach tu, sach thu
bao bo » bac bo, ban bo, nao bo
bo van » vo van, so van, do van
va bao » va bai

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 doc hoi. hieu va bao bo van hanh via ((cua tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sach ty)) nang doc hoi. hieu va bao bo van hanh via ((cua tre) OR (cau tren)).
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sach ty)) nang doc hoi. hieu va bao bo van hanh via ((cua tre) or (cau tren))*.