Perhaps you should try some spelling variations:
dau tieng » dau tien, cau tieng, day tieng
ca tren » cau tren, cu tren, la tren
cac tuc » cac toc, cac tu, cac tac
su sach » so sach, vu sach
ty nang » ky nang, ty xang, ly nang
ty hang » ly hang, ty xang, thi hang
qua cac » cua cac
tuc va » thuc va, truc va, tuc xa
va dao » ca dao
dao vi » dao voi, dao ve, dao va

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 ((ty nang) OR (ty hang)) x ho. hieu qua cac tuc va dao vi ((ca tren) or (dau tieng))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ty nang) OR (ty hang)) x ho. hieu qua cac tuc va dao vi ((ca tren) OR (dau tieng)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ty nang) OR (ty hang)) x ho. hieu qua cac tuc va dao vi ((ca tren) or (dau tieng))".
• Adding a wildcard symbol may retrieve word variants: su sach ((ty nang) OR (ty hang)) x ho. hieu qua cac tuc va dao vi ((ca tren) or (dau tieng))*.