Perhaps you should try some spelling variations:
nam thuong » nam phuong, tam thuong, nam thong
thuong va » truong va, thong va, thuong mai
doc sach » hoc sach, toc sach, nuoc sach
cau tren » cu tren, dau tren, ca tren
ky tang » ky nang, ky dang, kho tang
hieu va » hieu qua
ky lang » ky nang, ky dang, tay lang
dan vai » dan va, dan tai, dan vat
vai cau » va cau, van cau, vai cac
va dan » ca dan, va dao, va dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ((ky lang) OR (ky tang)) xa hoi. ((hieu va) or (lieu va)) nam thuong va dan vai cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ((ky lang) OR (ky tang)) xa hoi. ((hieu va) OR (lieu va)) nam thuong va dan vai cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ((ky lang) OR (ky tang)) xa hoi. ((hieu va) or (lieu va)) nam thuong va dan vai cau tren".
• Adding a wildcard symbol may retrieve word variants: doc sach ((ky lang) OR (ky tang)) xa hoi. ((hieu va) or (lieu va)) nam thuong va dan vai cau tren*.