Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
hieu van » thien van, lieu va, hieu ve
dang hai » dang khai, hang hai, dung hai
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
va dang » van dang, va nang, va lang
hai cua » thai cua, dai cua, hoi cua
ma hoi » mai hoi, ma hoa, me hoi
cua te » cua tu
nuoc » quoc, duoc, ngoc

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 ky nang ((ma hoi) or (xa hoi)). ((hieu van) OR (hieu va)) dat nuoc va dang hai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach ky nang ((ma hoi) OR (xa hoi)). ((hieu van) OR (hieu va)) dat nuoc va dang hai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sach ky nang ((ma hoi) or (xa hoi)). ((hieu van) OR (hieu va)) dat nuoc va dang hai cua te".
• Adding a wildcard symbol may retrieve word variants: thuat sach ky nang ((ma hoi) or (xa hoi)). ((hieu van) OR (hieu va)) dat nuoc va dang hai cua te*.