Perhaps you should try some spelling variations:
sach ky » sach y, sach ty, sach kem
hieu ve » hieu va, hieu van
ve giao » te giao, viet giao, van giao
va hanh » van hanh, va thanh, va danh
luu tre » luu tru, cuu tre
luy tre » luyen tre
sac ky » cac ky, sai ky
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: su ((sach ky) OR (sac ky)) nang x hoi. hieu ve giao duc va hanh vi ((luu tre) OR (luy tre))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) OR (sac ky)) nang x hoi. hieu ve giao duc va hanh vi ((luu tre) OR (luy tre))".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) OR (sac ky)) nang x hoi. hieu ve giao duc va hanh vi ((luu tre) OR (luy tre))*.