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
tay hoi » tay ho, tao hoi, tay thai
sach ty » sach y, sach tu, sach thu
hac duc » hoc duc, thach duc, pham duc
xay hoi » xa hoi, cay phoi, gay thoi
ty dang » ty xang, ky dang, ty hang
ha duc » ho duc, ha dac, xa duc

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