Perhaps you should try some spelling variations:
nang mau » nang ma, nang dau, dang mau
su sach » so sach, vu sach
mau hoi » cau hoi, mai hoi, mau ho
hieu va » lieu va, hieu qua
nam duc » nam duoc, nam thuc, nam buoc
tinh vi » trinh vi, tinh voi, tinh va
cuu tre » cua tre, cau tren, cau treo
vi cuu » vi luu, vinh cuu

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

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