Perhaps you should try some spelling variations:
hien cac » thien cac, hieu cac, dien cac
danh vai » danh sai, danh va, doanh van
vien cac » vien bach, vien dai, vien da
vai cua » dai cua, hai cua, lai cua
va danh » va dinh, va dan, va hanh
sach ty » sach y, sach tu, sach thu
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
lo va » lo van, lao va, ly va

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 ty ((nang xa) OR (nang ma)) hoi. hieu ((hien cac) or (vien cac)) lo va danh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((nang xa) OR (nang ma)) hoi. hieu ((hien cac) OR (vien cac)) lo va danh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty ((nang xa) OR (nang ma)) hoi. hieu ((hien cac) or (vien cac)) lo va danh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((nang xa) OR (nang ma)) hoi. hieu ((hien cac) or (vien cac)) lo va danh vai cua tre*.