Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
dau thai » dau thau, da thai, dao thai
thai cuu » thai cua, tai cuc, thi cuc
tu sach » thu sach, te sach, tu cach
su sach » so sach
vu sach » vu bach, vu khach
nang xa » nang x, lang xa, nang ma
van dat » van dao, van dau, dan dat
cuu tre » cua tre, cau tren, cau treo
y nang » ky nang, ly nang, v nang
va dau » va dao
nuoc » quoc, duoc, ngoc

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) OR (vu sach)))) y nang xa hoi. hieu van dat nuoc va dau thai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (((su sach) OR (vu sach)))) y nang xa hoi. hieu van dat nuoc va dau thai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (((su sach) OR (vu sach)))) y nang xa hoi. hieu van dat nuoc va dau thai cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (((su sach) OR (vu sach)))) y nang xa hoi. hieu van dat nuoc va dau thai cuu tre*.