Perhaps you should try some spelling variations:
dau tren » dau tien, dat tren, dau tieng
thuc dan » thuc hanh, hoc dan, thuc vat
cau tren » cu tren, ca tren, cau treo
danh hai » dang hai, lanh hai, manh hai
hieu van » hieu va, thien van, lieu va
vu sach » vu bach, su sach, vu khach
sach ly » sach y, sach lo, sach ty
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: vu sach ly nang ma hoi. hieu van lam ((tuc xa) or (thuc dan)) danh hai ((cau tren) OR (dau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ly nang ma hoi. hieu van lam ((tuc xa) OR (thuc dan)) danh hai ((cau tren) OR (dau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ly nang ma hoi. hieu van lam ((tuc xa) or (thuc dan)) danh hai ((cau tren) OR (dau tren))".
• Adding a wildcard symbol may retrieve word variants: vu sach ly nang ma hoi. hieu van lam ((tuc xa) or (thuc dan)) danh hai ((cau tren) OR (dau tren))*.