Perhaps you should try some spelling variations:
nang cau » nang cao, hang cau, nang dau
cau tren » cu tren, dau tren, ca tren
tinh hai » tinh thai, tinh chat, trinh han
va tinh » may tinh
cuu tre » cua tre, cau treo
sach ty » sach y, sach tu, sach thu
hieu ve » hieu va, hieu van
cac tuc » cac toc, cac tu, cac tac
tuc va » thuc va, truc va, tuc xa
sac ky » cac ky, sai ky
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sac ky) or (sach ty)) nang cau hoi. hieu ve cac tuc va tinh hai ((cuu tre) OR (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sac ky) OR (sach ty)) nang cau hoi. hieu ve cac tuc va tinh hai ((cuu tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sac ky) or (sach ty)) nang cau hoi. hieu ve cac tuc va tinh hai ((cuu tre) OR (cau tren))".
• Adding a wildcard symbol may retrieve word variants: su ((sac ky) or (sach ty)) nang cau hoi. hieu ve cac tuc va tinh hai ((cuu tre) OR (cau tren))*.