Perhaps you should try some spelling variations:
sang than » cang thang, dang thanh, sang tao
sang tai » hang tai, sang tao, dung tai
tang tai » hang tai, dung tai, sang tao
tu sach » thu sach, su sach, te sach
cac duc » cac du, cao duc, cac dac
hieu va » lieu va, hieu qua
cao hoi » cau hoi, co hoi, cao hoc
cuu tre » cua tre, cau tren, cau treo
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach v nang cao hoi. hieu va cac duc va ((((sang tai) OR (sang than))) or (tang tai)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach v nang cao hoi. hieu va cac duc va ((((sang tai) OR (sang than))) OR (tang tai)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach v nang cao hoi. hieu va cac duc va ((((sang tai) OR (sang than))) or (tang tai)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach v nang cao hoi. hieu va cac duc va ((((sang tai) OR (sang than))) or (tang tai)) cuu tre*.