Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nam thu, nha thuoc
hieu van » hieu va, thien van, lieu va
nam duoc » da duoc, dat duoc, nam moc
ma hanh » va hanh, da hanh, na hanh
sach ly » sach lo, sach ty, sach hay
hanh va » hang va, hanh vi
cua tre » cua te, cuu tre, cua triet
vang x » nang x
va cua » va chua, via cua, ca cua
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: thu ((sach ly) or (sach y)) vang x hoi. hieu van ((nam duoc) OR (nam thuoc)) ma hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ly) OR (sach y)) vang x hoi. hieu van ((nam duoc) OR (nam thuoc)) ma hanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ly) or (sach y)) vang x hoi. hieu van ((nam duoc) OR (nam thuoc)) ma hanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ly) or (sach y)) vang x hoi. hieu van ((nam duoc) OR (nam thuoc)) ma hanh va cua tre*.