Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
ky sang » ky nang, ky dang, ky tang
sang ma » tang ma, nang ma, sang tao
hieu he » hieu ve, hiem he, hieu le
cua tre » cua te, cuu tre, cua triet
he nam » ha nam, nghe nam

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 sang ma hoa. hieu he nam ((thuat xay) or (thu ha)) lanh dao ((cua tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky sang ma hoa. hieu he nam ((thuat xay) OR (thu ha)) lanh dao ((cua tre) OR (cau tren)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky sang ma hoa. hieu he nam ((thuat xay) or (thu ha)) lanh dao ((cua tre) or (cau tren))*.