Perhaps you should try some spelling variations:
hieu van » thien van, lieu va
cham duc » pham duc, cham soc, pham duy
cau tren » cu tren, dau tren, ca tren
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
va anh » van anh, va danh, va hanh
anh ve » hanh ve, anh va, anh viet
ve cau » ke cau, va cau, ve cac
x hoi » xa hoi, o hoi, x ho

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

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