Perhaps you should try some spelling variations:
dap truoc » phap truoc, lam truoc, nam truoc
truoc va » truc va, thuoc va, truong va
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
sac ky » sai ky
va dap » va dao, va dau
dan di » danh di, dan de, dan li
dan da » dan dat, dan ca, dan va

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) or (cac ky)) nang xa hoi. hieu va dap truoc va ((dan di) OR (dan da)) hoa viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat ((sac ky) OR (cac ky)) nang xa hoi. hieu va dap truoc va ((dan di) OR (dan da)) hoa viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat ((sac ky) or (cac ky)) nang xa hoi. hieu va dap truoc va ((dan di) OR (dan da)) hoa viet".
• Adding a wildcard symbol may retrieve word variants: thuat ((sac ky) or (cac ky)) nang xa hoi. hieu va dap truoc va ((dan di) OR (dan da)) hoa viet*.