Perhaps you should try some spelling variations:
nang mai » nang ma, nang tai, lang mai
hieu van » thien van, lieu va, hieu ve
lanh hai » manh hai, thanh hai, lang chai
bao truc » bao thuc, ba truc, vao truc
tu cach » tu cac
truc va » thuc va, thuc vat, trung va
hai cua » thai cua, dai cua, hoi cua
so sach » so sanh, bo sach, co sach
mai hoi » mai khoi, dai hoi, lai hoi
hieu va » lieu va, hieu qua
va lanh » va lang, va danh, va hanh
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu cach) or (so sach)) ky nang mai hoi. ((hieu van) OR (hieu va)) bao truc va lanh hai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu cach) OR (so sach)) ky nang mai hoi. ((hieu van) OR (hieu va)) bao truc va lanh hai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu cach) or (so sach)) ky nang mai hoi. ((hieu van) OR (hieu va)) bao truc va lanh hai cua te".
• Adding a wildcard symbol may retrieve word variants: ((tu cach) or (so sach)) ky nang mai hoi. ((hieu van) OR (hieu va)) bao truc va lanh hai cua te*.