Perhaps you should try some spelling variations:
hanh tinh » hanh trinh, nhanh tinh, thanh tinh
toc sach » hoc sach, doc sach, thuoc sach
tinh cau » trinh cau, tinh cao, sinh cau
tan hanh » tan thanh, tang hanh, toan hanh
hieu van » hieu va, thien van, lieu va
cau tren » cu tren, dau tren, ca tren
sach ky » sac ky, sach y, sach ty
van hac » van hoc, van ha, van hai
hac duc » hoc duc, ha duc, thach duc
xay hoi » cay phoi, gay thoi, may thoi
ky dang » ky nang, ky danh
tay hoi » tay ho, tao hoi, tay thai

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 dang ((((xay hoi) OR (xa hoi))) or (tay hoi)). hieu van hac duc tan hanh tinh cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky dang ((((xay hoi) OR (xa hoi))) OR (tay hoi)). hieu van hac duc tan hanh tinh cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky dang ((((xay hoi) OR (xa hoi))) or (tay hoi)). hieu van hac duc tan hanh tinh cau tren".
• Adding a wildcard symbol may retrieve word variants: toc sach ky dang ((((xay hoi) OR (xa hoi))) or (tay hoi)). hieu van hac duc tan hanh tinh cau tren*.