Perhaps you should try some spelling variations:
hieu van » hieu va, thien van
cau tren » cu tren, dau tren, ca tren
te sach » toc sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
cao hoi » cau hoi, co hoi, cao hoc
hieu ve » hieu va
cac tuc » cac toc, cac tu, cac tac
dan cua » dan ca, ban cua, dai cua
cua cau » cua cac, cua chu, cua cay
xa dan » ca dan, xa dai, va dan

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

• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty nang cao hoi. ((hieu ve) OR (((hieu van) OR (lieu va)))) cac tuc xa dan cua cau tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty nang cao hoi. ((hieu ve) or (((hieu van) OR (lieu va)))) cac tuc xa dan cua cau tren~".
• Adding a wildcard symbol may retrieve word variants: te sach ty nang cao hoi. ((hieu ve) or (((hieu van) OR (lieu va)))) cac tuc xa dan cua cau tren*.