Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
hieu van » hieu va, thien van, lieu va
khai cua » thai cua, hai cua, khi cua
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
va nang » van nang, da nang, cam nang
va dang » van dang, va lang, da dang
van cac » van hac, van cau, van bac
nang ma » tang ma, sang ma, nang cao
mang xa » lang xa, mang may, dang xay
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: thuat sach y ((mang xa) or (nang ma)) hoi. hieu van cac nuoc ((va dang) OR (va nang)) khai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach y ((mang xa) OR (nang ma)) hoi. hieu van cac nuoc ((va dang) OR (va nang)) khai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sach y ((mang xa) or (nang ma)) hoi. hieu van cac nuoc ((va dang) OR (va nang)) khai cua te".
• Adding a wildcard symbol may retrieve word variants: thuat sach y ((mang xa) or (nang ma)) hoi. hieu van cac nuoc ((va dang) OR (va nang)) khai cua te*.