Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
than kiem » toan kiem, phan kiem, tran kiem
hieu van » hieu va, thien van, lieu va
tu nano » truc nano
van cac » van hac, van cau, van bac
duc ban » duc van, dua ban, duc man
tu nang » tru nang, tu nong, tu lang
tra te » tra tu
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc sach ((tu nang) OR (tu nano)) x hoi. hieu van cac ((duc ban) or (duc tan)) than kiem tra te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ((tu nang) OR (tu nano)) x hoi. hieu van cac ((duc ban) OR (duc tan)) than kiem tra te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ((tu nang) OR (tu nano)) x hoi. hieu van cac ((duc ban) or (duc tan)) than kiem tra te".
• Adding a wildcard symbol may retrieve word variants: thuoc sach ((tu nang) OR (tu nano)) x hoi. hieu van cac ((duc ban) or (duc tan)) than kiem tra te*.