Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
cau tren » cu tren, dau tren, ca tren
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
di cau » da cau, diem cau
ve cam » ve cham, ve cac, va cam

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 y ((nang ma) or (tang ma)) hoi. hieu ((ve cam) or (va cac)) thuc va hanh di cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y ((nang ma) OR (tang ma)) hoi. hieu ((ve cam) OR (va cac)) thuc va hanh di cau tren.
• Adding a wildcard symbol may retrieve word variants: thu sach y ((nang ma) or (tang ma)) hoi. hieu ((ve cam) or (va cac)) thuc va hanh di cau tren*.