Perhaps you should try some spelling variations:
thien van » thi van
cau tren » cu tren, dau tren, ca tren
cam thuc » am thuc, nam thuc, cam thu
hai cau » hai chau, hai chu, hai hau
sach ly » sach lo, sach ty, sach hay
nang ma » tang ma, sang ma, nang cao
van cam » van nam, van lam, van cau
ma hoi » mai hoi, xa hoi, ma hoa
va dan » va dao, va dau, va dap
ca dan » cac dan, ca dao

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach ly) or (sach y)) nang ma hoi. thien van cam thuc ((va dan) or (ca dan)) hai cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ly) OR (sach y)) nang ma hoi. thien van cam thuc ((va dan) OR (ca dan)) hai cau tren.
• Adding a wildcard symbol may retrieve word variants: su ((sach ly) or (sach y)) nang ma hoi. thien van cam thuc ((va dan) or (ca dan)) hai cau tren*.