Perhaps you should try some spelling variations:
thanh phan » thanh pho, thanh san, thanh toan
van thanh » ban thanh, van tuan
thu sach » tu sach, thuat sach, thuoc sach
dua tren » dung tren
lang mai » lang dai, lang hai, lang man
mai hoi » mai khoi, dai hoi, lai hoi
sach ky » sac ky, sach y, sach ty
luc van » luoc van, luu van, duc van
ky lang » ky nang, ky dang, ky tang
la tren » loai tren, dat tren, dau tren
ve cau » ke cau, va cau, le cau
ve cac » va cac, vien cac

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 lang mai hoi. hieu ((ve cau) or (ve cac)) luc van thanh phan ((la tren) OR (dua tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky lang mai hoi. hieu ((ve cau) OR (ve cac)) luc van thanh phan ((la tren) OR (dua tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky lang mai hoi. hieu ((ve cau) or (ve cac)) luc van thanh phan ((la tren) OR (dua tren))".
• Adding a wildcard symbol may retrieve word variants: thu sach ky lang mai hoi. hieu ((ve cau) or (ve cac)) luc van thanh phan ((la tren) OR (dua tren))*.