Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
dan hanh » dang hanh, dan khanh, dan thanh
thuc dan » thuc hanh, hoc dan, thuc vat
hanh di » hanh vi, hanh de, hang di
sach ky » sac ky, sach y, sach ty
cua tre » cua te, cuu tre, cua triet
sang ma » tang ma, sang tao, mang may
nang ma » tang ma, nang cao, mang may
va cau » van cau, va cac, va dau
di cua » dai cua, doi cua, de cua
ve cau » ke cau, ve cac, 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: thuoc sach ky ((nang ma) or (sang ma)) hoi. hieu ((ve cau) OR (va cau)) thuc dan hanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ky ((nang ma) OR (sang ma)) hoi. hieu ((ve cau) OR (va cau)) thuc dan hanh di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ky ((nang ma) or (sang ma)) hoi. hieu ((ve cau) OR (va cau)) thuc dan hanh di cua tre".
• Adding a wildcard symbol may retrieve word variants: thuoc sach ky ((nang ma) or (sang ma)) hoi. hieu ((ve cau) OR (va cau)) thuc dan hanh di cua tre*.