Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cac nuoc » cap nuoc, dat nuoc, cua nuoc
tinh vi » trinh vi, tinh voi, tinh va
va tinh » may tinh
sach ty » sach y, sach tu, sach thu
tu sach » thu sach, su sach, te sach
nang xa » lang xa, nang ma, mang xa
vi cua » vai cua, di cua
cua tu » cua tuc, cua su, cua cu

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