Perhaps you should try some spelling variations:
truoc van » truc van, truong van, truoc bang
lam truoc » lam thuoc, nam truoc, lam truong
van hanh » van thanh, ban hanh, van anh
sach ty » sach y, sach tu, sach thu
qua lam » cua lam, qua la, qua lao
tu sach » thu sach, su sach, te sach
lang ra » lang ha, lang xa, lang va
nang co » nang cao, nang doc, nang noi
cua tu » cua tuc, cua su, cua te
cua cu » cua chu, cua cau, cua su

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 ty ((nang co) or (lang ra)) hoi. hieu qua lam truoc van hanh vi ((cua tu) or (cua cu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((nang co) OR (lang ra)) hoi. hieu qua lam truoc van hanh vi ((cua tu) OR (cua cu)).
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((nang co) or (lang ra)) hoi. hieu qua lam truoc van hanh vi ((cua tu) or (cua cu))*.