Perhaps you should try some spelling variations:
thai cua » than cua, tai cuc, tri cua
sach ky » sac ky, sach ty, sach kem
hieu va » lieu va, hieu qua
cac lop » cac hop, cac loai
va dinh » van dinh, va kinh, va tinh
hai cua » dai cua, hoi cua, lai cua
lop va » lap va, hop va, nop va
x hoi » xa hoi, o hoi, x ho

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: thu ((sach ky) or (sach y)) nang x hoi. hieu va cac lop va dinh ((hai cua) OR (thai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ky) OR (sach y)) nang x hoi. hieu va cac lop va dinh ((hai cua) OR (thai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ky) or (sach y)) nang x hoi. hieu va cac lop va dinh ((hai cua) OR (thai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ky) or (sach y)) nang x hoi. hieu va cac lop va dinh ((hai cua) OR (thai cua)) tre*.