Perhaps you should try some spelling variations:
nang mai » nang tai, lang mai, nang cai
hieu va » lieu va, hieu qua
danh di » danh du, xanh di, danh dien
va danh » va dinh, va dan, va hanh
cao luc » bao luc, cao duc, cao suc
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
va cao » va cac, va co, va dao
luc va » duc va, tuc va, loc va
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 (thu hoach)) ky ((nang mai) OR (nang ma)) hoi. hieu va cao luc va danh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu hoach)) ky ((nang mai) OR (nang ma)) hoi. hieu va cao luc va danh di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu hoach)) ky ((nang mai) OR (nang ma)) hoi. hieu va cao luc va danh di cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu hoach)) ky ((nang mai) OR (nang ma)) hoi. hieu va cao luc va danh di cua tre*.