Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
hieu van » hieu va, thien van, lieu va
van pham » san pham, van phan, van phat
thanh do » thanh de, thanh pho, thanh hoa
ve triet » va trien, su triet
tu sach » thu sach, su sach, te sach
thuc va » thuc dan, thuc day
y nang » ky nang, ly nang, v nang
do ve » dao ve, do ke, de ve

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 (thuoc sach)) y nang x ho. hieu van pham ((thuc va) OR (thuc vat)) thanh do ve triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thuoc sach)) y nang x ho. hieu van pham ((thuc va) OR (thuc vat)) thanh do ve triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thuoc sach)) y nang x ho. hieu van pham ((thuc va) OR (thuc vat)) thanh do ve triet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thuoc sach)) y nang x ho. hieu van pham ((thuc va) OR (thuc vat)) thanh do ve triet*.