Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
truc vu » truc du, truc va, truc cu
ca tren » cau tren, la tren, co tren
cu tren » tu tren, dua tren
ve cau » ke cau, va cau, ve cac
vu dau » va dau, tu dau, vu dai
dau va » dau ve, lau va

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach ky nang xa hoi. hieu ve cau truc vu dau va ((ca tren) or (cu tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ky nang xa hoi. hieu ve cau truc vu dau va ((ca tren) OR (cu tren)).
• Adding a wildcard symbol may retrieve word variants: hoc sach ky nang xa hoi. hieu ve cau truc vu dau va ((ca tren) or (cu tren))*.