Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
vu sach » vu bach, su sach, vu khach
sach tu » sach thu, cach tu, sach ty
hieu ve » hieu va, hieu van
ve pham » vi pham, v pham, ve phan
va tinh » may tinh
tinh di » tinh doi, trinh di, tinh da
di cau » da cau, diem cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach tu ((nang x) or (nang cao)) hoi. hieu ve pham duc va tinh di cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach tu ((nang x) OR (nang cao)) hoi. hieu ve pham duc va tinh di cau tren.
• Adding a wildcard symbol may retrieve word variants: vu sach tu ((nang x) or (nang cao)) hoi. hieu ve pham duc va tinh di cau tren*.