Perhaps you should try some spelling variations:
hieu thien » hieu hien, chieu chien, dieu khien
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
mach xu » cach xu, sach xu, mach cua
hanh xu » hanh tu, hanh sua, hanh cua
va tinh » may tinh
tinh va » tich va, trinh van, trinh vat
chu tre » cho tre, chu tri, cuu tre
nang o » nang co, nang ho, nang ro
va chu » va che, va cau, va chi
o hoc » co hoc, mo hoc, so hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang o hoc. hieu thien ((mach xu) or (hanh xu)) va tinh va chu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang o hoc. hieu thien ((mach xu) OR (hanh xu)) va tinh va chu tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang o hoc. hieu thien ((mach xu) or (hanh xu)) va tinh va chu tre*.