Perhaps you should try some spelling variations:
khien hach » thien hach, khien thich, hien hanh
trinh vat » trinh van, trinh luat, sinh vat
phuc may » hoc may, chua may, truc may
xuc may » xuc hay, truc may
vat cuu » vat cua
sach ky » sac ky, sach ty, sach kem
cuu tre » cua tre, cau tren, cau treo
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 ky) OR (sach y)) nang x hoi. dieu khien hach ((xuc may) or (phuc may)) trinh vat cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach y)) nang x hoi. dieu khien hach ((xuc may) OR (phuc may)) trinh vat cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) OR (sach y)) nang x hoi. dieu khien hach ((xuc may) or (phuc may)) trinh vat cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) OR (sach y)) nang x hoi. dieu khien hach ((xuc may) or (phuc may)) trinh vat cuu tre*.