Perhaps you should try some spelling variations:
dua tren » dung tren
nhan hoc » nha hoc, nhan hoa, than hoc
te sach » toc sach
sach ky » sac ky, sach y, sach ty
hieu vu » hieu va, hieu ve, hieu su
vu nhan » cu nhan, vu ngan, tu nhan
va danh » va dinh, va hanh, dia danh
va dan » ca dan, va dao, va dau
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky nang x ho. hieu vu nhan hoc ((va danh) OR (va dan)) dai ((dua tren) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang x ho. hieu vu nhan hoc ((va danh) OR (va dan)) dai ((dua tren) OR (cua te))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang x ho. hieu vu nhan hoc ((va danh) OR (va dan)) dai ((dua tren) or (cua te))*".