Perhaps you should try some spelling variations:
loai tren » la tren, thai tren
van thanh » ban thanh, van tuan
thanh vai » thanh hai, thanh van, thanh tai
dua tren » dung tren
thu sach » tu sach, thuat sach, thuoc sach
sang dai » sang tai, lang dai, sang mai
sach ky » sac ky, sach y, sach ty
duc van » duc va, duc tan, duc manh
dai hoi » dai hoc, dai hai, dai moi
ky sang » ky nang, ky dang, ky tang
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 sang dai hoi. hieu ((ve cau) or (ve cac)) duc van thanh vai ((dua tren) or (loai tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky sang dai hoi. hieu ((ve cau) OR (ve cac)) duc van thanh vai ((dua tren) OR (loai tren)).
• Adding a wildcard symbol may retrieve word variants: thu sach ky sang dai hoi. hieu ((ve cau) or (ve cac)) duc van thanh vai ((dua tren) or (loai tren))*.