Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
vat danh » va danh, van danh, luat danh
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
danh va » doanh va, hanh va, anh va
lang ha » long ha
lang xa » dang xay, lang van
cua tre » cua te, cuu tre, cua triet
va cua » va chua, via cua, ca cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc ((sach y) or (sach thu)) ((lang xa) OR (lang ha)) hoi. hieu van nam thuc vat danh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc ((sach y) OR (sach thu)) ((lang xa) OR (lang ha)) hoi. hieu van nam thuc vat danh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc ((sach y) or (sach thu)) ((lang xa) OR (lang ha)) hoi. hieu van nam thuc vat danh va cua tre".
• Adding a wildcard symbol may retrieve word variants: toc ((sach y) or (sach thu)) ((lang xa) OR (lang ha)) hoi. hieu van nam thuc vat danh va cua tre*.