Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh hai » thanh hai, nhanh hai, hang hai
nam duoc » nam thuoc, da duoc, dat duoc
tu sach » thu sach, su sach, te sach
cao duc » dao duc, cao suc, giao duc
nang xa » nang x, lang xa, mang xa
hai cua » thai cua, dai cua, hoi cua
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
cua te » cua tu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y ((nang xa) OR (nang ma)) hoi. hieu va ((nam duoc) or (cao duc)) van hanh hai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang xa) OR (nang ma)) hoi. hieu va ((nam duoc) OR (cao duc)) van hanh hai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((nang xa) OR (nang ma)) hoi. hieu va ((nam duoc) or (cao duc)) van hanh hai cua te".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang xa) OR (nang ma)) hoi. hieu va ((nam duoc) or (cao duc)) van hanh hai cua te*.