Perhaps you should try some spelling variations:
lang dai » lang hai, lang mai, lang chai
hang hai » hoang hai, hang tai, thanh hai
so sach » so sanh, bo sach, co sach
hai cua » thai cua, dai cua, hoi cua
luu van » cuu van, luan van, luu hanh
luc van » luoc van, duc van, luc va
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
nang du » nang tu, nang luc, nang doc
ve cac » va cac, vien cac
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ky ((lang dai) or (nang du)) hoi. hieu ve cac ((luc van) OR (luu van)) hang hai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky ((lang dai) OR (nang du)) hoi. hieu ve cac ((luc van) OR (luu van)) hang hai cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky ((lang dai) or (nang du)) hoi. hieu ve cac ((luc van) OR (luu van)) hang hai cua te*".