Perhaps you should try some spelling variations:
viet tech » viet sach
hieu viet » sieu viet, hieu viec, lieu viet
tech nuoc » dich nuoc, sach nuoc
su sach » so sach, vu sach
sach ly » sach y, sach lo, sach ty
ly nang » ky nang, ly hang, ly vang
mai hoi » mai khoi, lai hoi, mai doi
dai hoi » dai hoc, dai hai, dai moi
va xanh » va danh, va hanh, va anh
xanh di » danh di, vanh dai, xanh tai
cua tre » cua te, cuu tre, cua triet
di cua » dai cua, doi cua, de cua

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 ly nang ((mai hoi) OR (dai hoi)). hieu viet tech nuoc va xanh di cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ly nang ((mai hoi) OR (dai hoi)). hieu viet tech nuoc va xanh di cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ly nang ((mai hoi) OR (dai hoi)). hieu viet tech nuoc va xanh di cua tre*.