Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
cham duc » pham duc, cham soc, pham duy
han thai » han tai, ban thai, van thai
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
thai va » thai van
va han » va phan, van han, va hanh
thiet » thieu

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

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