Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
toc sach » hoc sach, doc sach, thuoc sach
hanh doi » thanh doi, hanh noi, hang doi
van hanh » van thanh, ban hanh, van anh
doi cua » dai cua, hoi cua, dong cua
van cam » van nam, van lam, van cau
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
cua tre » cua te, cuu tre, cua triet
cam o » cham o, cam lo, ca o
o van » vo van, so van, do van

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) OR (toc sach)) ky ((nang xa) or (lang xa)) hoi. hieu van cam o van hanh doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky ((nang xa) OR (lang xa)) hoi. hieu van cam o van hanh doi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) ky ((nang xa) or (lang xa)) hoi. hieu van cam o van hanh doi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) ky ((nang xa) or (lang xa)) hoi. hieu van cam o van hanh doi cua tre*.