Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
sach ky » sac ky, sach y, sach ty
cua tre » cua te, cuu tre, cua triet
nang ma » tang ma, sang ma, nang cao
ve cac » va cac, vien cac
ve cau » ke cau, va cau, le cau
ma hoi » mai hoi, xa hoi, ma hoa
de cua » le cua, te cua, dieu cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky nang ma hoi. hieu ((ve cau) OR (ve cac)) luc ((van hanh) or (van minh)) de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang ma hoi. hieu ((ve cau) OR (ve cac)) luc ((van hanh) OR (van minh)) de cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang ma hoi. hieu ((ve cau) OR (ve cac)) luc ((van hanh) or (van minh)) de cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ky nang ma hoi. hieu ((ve cau) OR (ve cac)) luc ((van hanh) or (van minh)) de cua tre*.