Perhaps you should try some spelling variations:
te sach » toc sach
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
y tang » ky tang, 6 tang, 5 tang
7 tang » 6 tang
ma hoi » mai hoi, xa hoi, ma hoa
cac tu » cac thu, cach tu, cac du
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va
vi cua » vai cua, di cua

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) OR (7 tang)) ma hoi. hieu va cac tu va dan vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((y tang) OR (7 tang)) ma hoi. hieu va cac tu va dan vi cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ((y tang) OR (7 tang)) ma hoi. hieu va cac tu va dan vi cua tre*.