Perhaps you should try some spelling variations:
va thuat » ky thuat, ki thuat, va thuc
te sach » toc sach
danh du » danh dau, danh tu, dinh du
danh di » xanh di, danh dien, danh gia
cua tre » cua te, cuu tre, cua triet
tang ma » mang may, tang van
duoc va » duc va, duoc ma, duong va
sach 6 » sach y, sach 2
ma hoi » mai hoi, xa hoi, ma hoa

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 6 tang ma hoi. lieu va thuat ((duoc va) or (nuoc va)) ((danh di) OR (danh du)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach 6 tang ma hoi. lieu va thuat ((duoc va) OR (nuoc va)) ((danh di) OR (danh du)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach 6 tang ma hoi. lieu va thuat ((duoc va) or (nuoc va)) ((danh di) OR (danh du)) cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach 6 tang ma hoi. lieu va thuat ((duoc va) or (nuoc va)) ((danh di) OR (danh du)) cua tre*.