Perhaps you should try some spelling variations:
sach ky » sac ky, sach y, sach ty
thi van » thi lan, thi hanh, thi nang
va hanh » van hanh, va thanh, va danh
ca tren » cau tren, la tren, co tren
cu tren » tu tren, dua tren
sai ky » sac ky
nam tu » nam thu, nam thuc
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ky) or (sai ky)) nang x hoi. thi van nam tu va hanh vi ((ca tren) OR (cu tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sai ky)) nang x hoi. thi van nam tu va hanh vi ((ca tren) OR (cu tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sai ky)) nang x hoi. thi van nam tu va hanh vi ((ca tren) OR (cu tren))".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sai ky)) nang x hoi. thi van nam tu va hanh vi ((ca tren) OR (cu tren))*.