Perhaps you should try some spelling variations:
te sach » toc sach
tang xa » trang xa, tang ma, lang xa
hieu va » lieu va
cam duc » cam xuc, cao duc, pham duc
dan tai » van tai, dan thi, han tai
sach 7 » sach y, sach 2
7 tang » 6 tang
va dan » ca dan, va dao, va dau
cua su » qua su

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 7 tang xa hoi. ((hieu va) or (hieu qua)) cam duc va dan tai ((cua vat) or (cua su))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach 7 tang xa hoi. ((hieu va) OR (hieu qua)) cam duc va dan tai ((cua vat) OR (cua su)).
• Adding a wildcard symbol may retrieve word variants: te sach 7 tang xa hoi. ((hieu va) or (hieu qua)) cam duc va dan tai ((cua vat) or (cua su))*.