Perhaps you should try some spelling variations:
dan hoang » dang hoang, van hoang, quan hoang
va trien » va truyen, va thiet, va tuyen
thuc dan » thuc hanh, hoc dan, thuc vat
va triet » va thiet, ve triet, cua triet
hoang di » hoang dai, hoang de, hang di
nam thuc » nam thuoc, am thuc, nam thu
thi van » thi lan, thi hanh, thi nang
nang xa » lang xa, nang ma, mang xa
tu sach » thu sach, su sach, te sach

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y ((nang xa) or (nang x)) hoi. thi van nam thuc dan hoang di ((va triet) OR (va trien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang xa) OR (nang x)) hoi. thi van nam thuc dan hoang di ((va triet) OR (va trien)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((nang xa) or (nang x)) hoi. thi van nam thuc dan hoang di ((va triet) OR (va trien))".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang xa) or (nang x)) hoi. thi van nam thuc dan hoang di ((va triet) OR (va trien))*.