Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
hieu van » hieu va, thien van, lieu va
hanh di » hanh vi, hanh de, hang di
vuc van » duc van, luc van, thuc van
cac vuc » cac nuoc, cac vung, cac cuoc
van cac » van hac, van cau, van bac
cho hoc » co hoc, khoa hoc
ly hang » ly quang
ty hang » ty xang, thi hang, thu hang
ty nang » ky nang, ty xang, ly nang
cua cau » cua cac, cua chu, cua cay
di cua » dai cua, doi cua, de 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 ((ty nang) or (((ty hang) OR (ly hang)))) cho hoc. hieu van cac vuc van hanh di cua cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ty nang) OR (((ty hang) OR (ly hang)))) cho hoc. hieu van cac vuc van hanh di cua cau*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ty nang) or (((ty hang) OR (ly hang)))) cho hoc. hieu van cac vuc van hanh di cua cau*".