Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
va danh » va dinh, va hanh, dia danh
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
ve khac » vu khac, de khac, se khac
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
cu tren » tu tren, dua tren
va dan » ca dan, va dao, va dau
va cu » va cau, va chu, va su

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) or (lang xa)) hoi. hieu ve khac phuc ((va danh) or (va dan)) va cu tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ky ((nang xa) OR (lang xa)) hoi. hieu ve khac phuc ((va danh) OR (va dan)) va cu tren.
• Adding a wildcard symbol may retrieve word variants: hoc sach ky ((nang xa) or (lang xa)) hoi. hieu ve khac phuc ((va danh) or (va dan)) va cu tren*.