Perhaps you should try some spelling variations:
danh hai » dang hai, lanh hai, manh hai
xach tay » canh tay
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
va danh » va dinh, va dan, va hanh
thuc va » thuc vat, thuc dan, thuc day
su viet » so viet
sang ma » tang ma, sang tao, mang may
nang ma » tang ma, nang cao, mang may
hai su » hai vu, lai su, hai so

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach y) or (xach tay)) ((nang ma) or (sang ma)) hoi. hieu van nam thuc va danh hai su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach y) OR (xach tay)) ((nang ma) OR (sang ma)) hoi. hieu van nam thuc va danh hai su viet.
• Adding a wildcard symbol may retrieve word variants: su ((sach y) or (xach tay)) ((nang ma) or (sang ma)) hoi. hieu van nam thuc va danh hai su viet*.