Perhaps you should try some spelling variations:
qua cham » qua hai, va cham, qua cua
cua viet » ca viet, hoa viet, cua vat
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
nang xa » nang x, lang xa, nang ma
qua cac » cua cac
va doan » va doanh, van doan, va dan
y nang » ky nang, ly nang, v nang
luc va » duc va, tuc va, loc va
va cua » va chua, via cua, ca cua

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) or (su sach)) y nang xa hoi. hieu ((qua cham) OR (qua cac)) luc va doan va cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) y nang xa hoi. hieu ((qua cham) OR (qua cac)) luc va doan va cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) y nang xa hoi. hieu ((qua cham) OR (qua cac)) luc va doan va cua viet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) y nang xa hoi. hieu ((qua cham) OR (qua cac)) luc va doan va cua viet*.