Perhaps you should try some spelling variations:
nguoi quan » nguoi san, nguoi dan
hieu van » hieu va, thien van, lieu va
benh vi » benh va, benh ve, benh li
xuc san » xuc ban, luc sang, nuoc san
van lam » van nam
sach ty » sach y, sach tu, sach thu
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
sac ky » cac ky, sai ky
vi cua » vai cua, di 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 ty) or (sac ky)) nang ma hoi. hieu van lam ((xuc san) or (nguoi quan)) benh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (sac ky)) nang ma hoi. hieu van lam ((xuc san) OR (nguoi quan)) benh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ty) or (sac ky)) nang ma hoi. hieu van lam ((xuc san) or (nguoi quan)) benh vi cua tre*.