Perhaps you should try some spelling variations:
nhan thuc » nhan luc, dan thuc, toan thuc
van hanh » van thanh, ban hanh, van anh
vat hanh » vat thanh, va hanh, nhat hanh
nang mai » nang ma, nang tai, lang mai
ve nhan » ve nha, de nhan, va nhan
hieu ve » hieu va, hieu van
sach ky » sach y, sach ty, sach kem
mai hoi » mai khoi, dai hoi, lai hoi
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach ky) or (sac ky)) nang mai hoi. hieu ve nhan thuc ((vat hanh) OR (van hanh)) di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sac ky)) nang mai hoi. hieu ve nhan thuc ((vat hanh) OR (van hanh)) di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) or (sac ky)) nang mai hoi. hieu ve nhan thuc ((vat hanh) OR (van hanh)) di cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sac ky)) nang mai hoi. hieu ve nhan thuc ((vat hanh) OR (van hanh)) di cua tre*.