Perhaps you should try some spelling variations:
nam truoc » lam truoc, nam truc, nam truong
thuat tac » thuat tach, thuat tao, thuat tai
nam thuoc » nam thuc, nam thu, nha thuoc
hoc viet » hoc hien
ky lang » ky dang, ky tang, tay lang
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
hanh li » nhanh li, hanh vi, han li

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

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