Perhaps you should try some spelling variations:
khien hach » thien hach, khien thich, hien hanh
trinh vat » trinh luat, sinh vat, trinh han
trinh van » trinh han, trinh quan, trinh toan
hach xuc » thach duc, hanh xu, cach xu
tu sach » thu sach, su sach, te sach
xuc may » xuc hay, truc may, phuc may
cuu tre » cau tren, cau treo
cua tre » cua te, cua triet, dua tren
y nang » ky nang, ly nang, v nang
x hoi » xa hoi, o hoi, x ho

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 y nang x hoi. dieu khien hach xuc may ((trinh vat) OR (trinh van)) ((cuu tre) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang x hoi. dieu khien hach xuc may ((trinh vat) OR (trinh van)) ((cuu tre) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang x hoi. dieu khien hach xuc may ((trinh vat) OR (trinh van)) ((cuu tre) or (cua tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang x hoi. dieu khien hach xuc may ((trinh vat) OR (trinh van)) ((cuu tre) or (cua tre))*.