Perhaps you should try some spelling variations:
hach xuc » thach duc, cach xu, mach xu
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
chu tre » chu tri, cuu tre, cau tren
tinh va » tich va, trinh van, trinh vat
va tinh » may tinh
hanh xu » hanh tu, hanh sua, hanh cua
cho tre » cho thue, khoe tre
nang o » nang co, nang ho, nang ro
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. dieu khien ((hach xuc) or (hanh xu)) va tinh va ((chu tre) OR (cho tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang o hoc. dieu khien ((hach xuc) OR (hanh xu)) va tinh va ((chu tre) OR (cho tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang o hoc. dieu khien ((hach xuc) or (hanh xu)) va tinh va ((chu tre) OR (cho tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang o hoc. dieu khien ((hach xuc) or (hanh xu)) va tinh va ((chu tre) OR (cho tre))*.