Perhaps you should try some spelling variations:
thi nang » thi cong, ki nang, thi hanh
su sach » so sach, vu sach
cuu tre » cau tren, cau treo
cac toc » cac toi, cac nuoc, cac thoi
sach ty » sach y, sach tu, sach thu
cac tuc » cac tu, cac tac, cac nuoc
cua tre » cua te, cua triet, dua tren
nang ma » tang ma, sang ma, nang cao
ty nang » ky nang, ty xang, ty hang
ma hoi » mai hoi, xa hoi, ma hoa
ca dan » cac dan, ca dao
dan vi » doan vi, don vi, dan va

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ty nang ma hoi. thi nang ((cac tuc) OR (cac toc)) ca dan vi ((cuu tre) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang ma hoi. thi nang ((cac tuc) OR (cac toc)) ca dan vi ((cuu tre) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty nang ma hoi. thi nang ((cac tuc) OR (cac toc)) ca dan vi ((cuu tre) or (cua tre))".
• Adding a wildcard symbol may retrieve word variants: su sach ty nang ma hoi. thi nang ((cac tuc) OR (cac toc)) ca dan vi ((cuu tre) or (cua tre))*.