Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
cac phuc » cau phuc, khac phuc, cach thuc
cua tre » cuu tre, cua triet, dua tren
hanh di » hanh vi, hanh de, hang di
vu hanh » vu khanh, vu thanh, du hanh
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
nang ma » tang ma, nang cao, mang may
sang ma » tang ma, sang tao, mang may
ve cac » va cac, vien cac
cua te » cua tu

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 cac phuc vu hanh di ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ky ((nang ma) OR (sang ma)) hoi. hieu ve cac phuc vu hanh di ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ky ((nang ma) or (sang ma)) hoi. hieu ve cac phuc vu hanh di ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: thuoc sach ky ((nang ma) or (sang ma)) hoi. hieu ve cac phuc vu hanh di ((cua tre) OR (cua te))*.