Perhaps you should try some spelling variations:
ki thuat » ky thuat
te sach » toc sach
tang ma » mang may, tang van
lieu ki » lieu ky, lieu li, lieu kinh
quoc va » duoc va, quoc gia, quoc oai
doi cua » hoi cua
y tang » ky tang, 6 tang, 7 tang
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 y tang ma hoi. lieu ki thuat ((quoc va) OR (nuoc va)) dinh ((doi cua) or (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y tang ma hoi. lieu ki thuat ((quoc va) OR (nuoc va)) dinh ((doi cua) OR (dai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y tang ma hoi. lieu ki thuat ((quoc va) OR (nuoc va)) dinh ((doi cua) or (dai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: te sach y tang ma hoi. lieu ki thuat ((quoc va) OR (nuoc va)) dinh ((doi cua) or (dai cua)) tre*.