Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
van thanh » ban thanh, van tuan
thu sach » tu sach, thuat sach, thuoc sach
dua tren » dung tren
sach ky » sac ky, sach y, sach ty
luu van » cuu van, luan van, luu hanh
sang ma » tang ma, nang ma, sang tao
ky sang » ky nang, ky dang, ky tang
vai dua » dai dua, vai cua
ma hoi » mai hoi, xa hoi, ma hoa
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 ma hoi. hieu ((ve cau) or (ve cac)) luu van thanh vai dua tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky sang ma hoi. hieu ((ve cau) OR (ve cac)) luu van thanh vai dua tren.
• Adding a wildcard symbol may retrieve word variants: thu sach ky sang ma hoi. hieu ((ve cau) or (ve cac)) luu van thanh vai dua tren*.