Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
su triet » su viet, su tien, ve triet
nang xa » nang x, lang xa, mang xa
sach tu » sach thu, sach ty, sach uu
cach tu » cach thuc
thuc va » thuc vat, thuc dan, thuc day
nang ma » tang ma, sang ma, nang cao
va dan » ca dan, va dao, va dau
dan ki » dan ky, dan ke, dan li
ki su » ky su

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 tu) OR (cach tu)) ((nang xa) or (nang ma)) hoi. hieu van nam thuc va dan ki su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach tu) OR (cach tu)) ((nang xa) OR (nang ma)) hoi. hieu van nam thuc va dan ki su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach tu) OR (cach tu)) ((nang xa) or (nang ma)) hoi. hieu van nam thuc va dan ki su triet".
• Adding a wildcard symbol may retrieve word variants: thu ((sach tu) OR (cach tu)) ((nang xa) or (nang ma)) hoi. hieu van nam thuc va dan ki su triet*.