Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh dai » hanh dao, vanh dai, thanh dat
hanh tai » thanh tai, hang tai, han tai
va triet » va thiet, va trien, ve triet
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
ve cac » va cac, vien cac
dao va » dao van, tao va, do va
ve ca » ve cai, ve cau, ve cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky nang xa hoi. hieu ((ve ca) or (ve cac)) dao va ((hanh dai) OR (hanh tai)) va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang xa hoi. hieu ((ve ca) OR (ve cac)) dao va ((hanh dai) OR (hanh tai)) va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky nang xa hoi. hieu ((ve ca) or (ve cac)) dao va ((hanh dai) OR (hanh tai)) va triet".
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang xa hoi. hieu ((ve ca) or (ve cac)) dao va ((hanh dai) OR (hanh tai)) va triet*.