Perhaps you should try some spelling variations:
sach thue » sach thu, sach thieu, sach tham
thue mang » thuat mang, thu hang, thu bang
thien van » thi van
thuc dan » thuc hanh, hoc dan
cau tren » cu tren, dau tren, ca tren
tu sach » thu sach, su sach, te sach
may hoi » may thoi, tay hoi, mai hoi
van cau » van dau, van hau, van chat
vi cau » va cau, ve cau, di cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach thue mang may hoi. thien van cau ((thuc vat) or (thuc dan)) hanh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thue mang may hoi. thien van cau ((thuc vat) OR (thuc dan)) hanh vi cau tren.
• Adding a wildcard symbol may retrieve word variants: tu sach thue mang may hoi. thien van cau ((thuc vat) or (thuc dan)) hanh vi cau tren*.