Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
bac truc » ba truc, bac trung, sach truc
tu sach » thu sach, su sach, te sach
van bac » van ban, van bao, van hac
truc va » thuc va, thuc vat, trung va
thai xu » thai cua
y nang » ky nang, ly nang, may nang
v nang » va nang, vu nang, van nang
va dan » ca dan, va dao, va dau

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 ((y nang) or (v nang)) xa hoi. hieu van bac truc va dan ((thai xu) or (tai cuc)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((y nang) OR (v nang)) xa hoi. hieu van bac truc va dan ((thai xu) OR (tai cuc)) tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ((y nang) or (v nang)) xa hoi. hieu van bac truc va dan ((thai xu) or (tai cuc)) tre*.