Perhaps you should try some spelling variations:
thien van » thi van
nam thuc » nam thuoc, am thuc, nam thu
hanh de » hanh ve, hanh kem
hanh di » hanh vi, hang di, danh di
thuc va » thuc vat, thuc dan, thuc day
tu sach » thu sach, su sach, te sach
sach lo » sach dao, sach doi, sach hoi
mai hoi » mai khoi, dai hoi, lai hoi
lo nang » ho nang, ly nang, loai nang

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 lo nang ((xa hoi) or (mai hoi)). thien van nam thuc va ((hanh di) OR (hanh de)) cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach lo nang ((xa hoi) OR (mai hoi)). thien van nam thuc va ((hanh di) OR (hanh de)) cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach lo nang ((xa hoi) or (mai hoi)). thien van nam thuc va ((hanh di) OR (hanh de)) cua vat".
• Adding a wildcard symbol may retrieve word variants: tu sach lo nang ((xa hoi) or (mai hoi)). thien van nam thuc va ((hanh di) OR (hanh de)) cua vat*.