Perhaps you should try some spelling variations:
hanh hai » thanh hai, nhanh hai, hang hai
lan hanh » ban hanh, van hanh, lan anh
quoc lan » quoc ban, nuoc luan, quoc quan
cau quoc » cac quoc, cao quoc, han quoc
hieu van » thien van, lieu va, hieu ve
hieu va » lieu va, hieu qua
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
sach ky » sach y, sach ty, sach kem
lang xa » lang ha, dang xay, lang van
sac ky » cac ky, sai ky

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) or (sac ky)) lang xa hoi. ((hieu van) or (hieu va)) cau quoc lan hanh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) lang xa hoi. ((hieu van) OR (hieu va)) cau quoc lan hanh hai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sac ky)) lang xa hoi. ((hieu van) or (hieu va)) cau quoc lan hanh hai cua tre*.