Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
hieu van » hieu va, thien van, lieu va
sach ky » sac ky, sach y, sach ty
van dat » van dao, van dau, dan dat
va dang » van dang, va nang, va lang
hai cua » thai cua, dai cua, lai cua
hoi cua » hoi chuc
ma hoi » mai hoi, ma hoa, me hoi
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 dat nuoc va dang ((hai cua) OR (hoi 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 dat nuoc va dang ((hai cua) OR (hoi 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 dat nuoc va dang ((hai cua) OR (hoi cua)) te".
• Adding a wildcard symbol may retrieve word variants: thuat sach ky nang ((ma hoi) or (xa hoi)). hieu van dat nuoc va dang ((hai cua) OR (hoi cua)) te*.