Perhaps you should try some spelling variations:
danh dinh » dang dinh, anh dinh, danh vinh
cau tren » cu tren, dau tren, ca tren
hieu van » hieu va, thien van, lieu va
dinh cau » dinh chau, dinh cuu, dinh cu
sach ty » sach y, sach tu, sach thu
te sach » toc sach
ty nang » ky nang, ty xang, ty hang
van cam » van nam, van lam, van cau
xuc va » duc va, luc va, xac va
tuc va » thuc va, truc va, tuc xa
o hoc » co hoc, mo hoc, so hoc

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 ty nang ((o hoc) or (x ho)). hieu van cam ((xuc va) OR (tuc va)) danh dinh cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty nang ((o hoc) OR (x ho)). hieu van cam ((xuc va) OR (tuc va)) danh dinh cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty nang ((o hoc) or (x ho)). hieu van cam ((xuc va) OR (tuc va)) danh dinh cau tren".
• Adding a wildcard symbol may retrieve word variants: te sach ty nang ((o hoc) or (x ho)). hieu van cam ((xuc va) OR (tuc va)) danh dinh cau tren*.