Perhaps you should try some spelling variations:
thuat sac » thuat sach, thuat san, thuat mach
thuat tac » thuat tach, thuat tao, thuat tai
lam truoc » lam thuoc, nam truoc, lam truong
truoc va » truc va, thuoc va, truong va
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
va lam » van lam, va lap
vi hoa » voi hoa, vi hoc, bi hoa
va hoa » van hoa, va hoc, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thuat sac) OR (thuat tac)) ky nang xa hoi. hieu va lam truoc va hanh ((vi hoa) or (va hoa)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thuat sac) OR (thuat tac)) ky nang xa hoi. hieu va lam truoc va hanh ((vi hoa) OR (va hoa)) viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thuat sac) OR (thuat tac)) ky nang xa hoi. hieu va lam truoc va hanh ((vi hoa) or (va hoa)) viet".
• Adding a wildcard symbol may retrieve word variants: ((thuat sac) OR (thuat tac)) ky nang xa hoi. hieu va lam truoc va hanh ((vi hoa) or (va hoa)) viet*.