Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, cau treo
danh hai » dang hai, lanh hai, manh hai
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, co sach
thuc va » thuc vat, thuc dan, thuc day
ca tren » cu tren, la tren, co tren
sach ly » sach y, sach lo, sach ty
truc va » thuc vat, trung va
van lam » van nam
nang ma » tang ma, sang ma, nang cao
ly nang » ky nang, ly hang, ly vang
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ly nang ma hoi. hieu van lam ((truc va) or (thuc va)) danh hai ((cau tren) OR (ca tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ly nang ma hoi. hieu van lam ((truc va) OR (thuc va)) danh hai ((cau tren) OR (ca tren))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ly nang ma hoi. hieu van lam ((truc va) or (thuc va)) danh hai ((cau tren) OR (ca tren))*".