Perhaps you should try some spelling variations:
doan thuc » doanh thuc, dan thuc, toan thuc
hieu van » hieu va, thien van, lieu va
van doan » van doanh, van toan, van hoan
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
nang xa » nang x, lang xa, nang ma
vat dan » va dan, van dan, vat ran
vi cua » vai cua
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: ((tu sach) or (su sach)) ky nang xa hoi. hieu van doan thuc vat dan ((vi cua) or (di cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky nang xa hoi. hieu van doan thuc vat dan ((vi cua) OR (di cua)) tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ky nang xa hoi. hieu van doan thuc vat dan ((vi cua) or (di cua)) tre*.