Perhaps you should try some spelling variations:
thuat sac » thuat sach, thuat san, thuat tac
lang van » dang van, tang van, hoang van
lam truc » lam truoc, nam truc, lam thuoc
lang xa » dang xay
lang ha » long ha
hieu va » lieu va, hieu qua
truc va » thuc va, thuc vat, trung va
va hanh » van hanh, va thanh, va danh
sac ky » cac ky, sai ky
va lam » van lam, va lap
vi hoa » voi hoa, vi hoc, va 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 ky ((((lang xa) OR (lang van))) or (lang ha)) hoi. hieu va lam truc va hanh vi hoa viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sac ky ((((lang xa) OR (lang van))) OR (lang ha)) hoi. hieu va lam truc va hanh vi hoa viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sac ky ((((lang xa) OR (lang van))) or (lang ha)) hoi. hieu va lam truc va hanh vi hoa viet".
• Adding a wildcard symbol may retrieve word variants: thuat sac ky ((((lang xa) OR (lang van))) or (lang ha)) hoi. hieu va lam truc va hanh vi hoa viet*.