Perhaps you should try some spelling variations:
han thai » han tai, ban thai, van thai
cham duc » pham duc, cham soc, pham duy
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va
lang xa » lang ha, dang xay, lang van
nang ma » tang ma, sang ma, nang cao
thai va » thai van
va han » va phan, van han, va hanh
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky ((lang xa) or (nang ma)) hoi. ((hieu ve) OR (hieu van)) cham duc va han thai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((lang xa) OR (nang ma)) hoi. ((hieu ve) OR (hieu van)) cham duc va han thai va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((lang xa) or (nang ma)) hoi. ((hieu ve) OR (hieu van)) cham duc va han thai va thiet".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((lang xa) or (nang ma)) hoi. ((hieu ve) OR (hieu van)) cham duc va han thai va thiet*.