Perhaps you should try some spelling variations:
thuc dan » thuc hanh, hoc dan, thuc vat
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
hai cua » thai cua, dai cua, hoi cua
hai cuu » hai chu, hai cuc, thai cua
sach ky » sac ky, sach y, sach ty
truc va » thuc va, thuc vat, trung va
van cau » van dau, van hau, van chat
nang xa » nang x, lang xa, nang ma

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 ky nang xa hoi. hieu van cau ((truc va) or (thuc dan)) thanh ((hai cuu) OR (hai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang xa hoi. hieu van cau ((truc va) OR (thuc dan)) thanh ((hai cuu) OR (hai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang xa hoi. hieu van cau ((truc va) or (thuc dan)) thanh ((hai cuu) OR (hai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. hieu van cau ((truc va) or (thuc dan)) thanh ((hai cuu) OR (hai cua)) tre*.