Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
sach van » sach han, sach va, bach van
van hanh » van thanh, ban hanh, van anh
truc van » truc va, thuc van, truc ban
cam truc » cau truc, nam truc, lam truoc
cua tre » cua te, cuu tre, dua tren
hanh de » hanh ve, hanh kem
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
dong y » dang y
dong x » dong xa, dong o, dong 1
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 van ((dong x) OR (dong y)) hoi. hieu ve cam truc van hanh de ((cua tre) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach van ((dong x) OR (dong y)) hoi. hieu ve cam truc van hanh de ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach van ((dong x) OR (dong y)) hoi. hieu ve cam truc van hanh de ((cua tre) or (cua triet))".
• Adding a wildcard symbol may retrieve word variants: su sach van ((dong x) OR (dong y)) hoi. hieu ve cam truc van hanh de ((cua tre) or (cua triet))*.