Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
van thanh » ban thanh, van tuan
dua tren » dung tren
sang ma » tang ma, nang ma, sang tao
sach ky » sach y, sach ty, sach kem
luu van » cuu van, luan van, luu hanh
vai dua » dai dua, vai cua
ma hoi » mai hoi, xa hoi, ma hoa
sac ky » cac ky, sai ky
ve cac » va cac, vien cac
ve cau » ke cau, va cau, le cau

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) OR (sac 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) OR (sac ky)) sang ma hoi. hieu ((ve cau) OR (ve cac)) luu van thanh vai dua tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ky) OR (sac 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) OR (sac ky)) sang ma hoi. hieu ((ve cau) or (ve cac)) luu van thanh vai dua tren*.