Perhaps you should try some spelling variations:
van tuan » van quan, van ban, anh tuan
thu sach » thuat sach, thuoc sach, thu hoach
hang hoi » hang hoa, hang hai, hang doi
hieu van » hieu va, thien van, lieu va
hoi cua » hoi chuc
thuc va » thuc vat, thuc dan, thuc day
tu sach » su sach, te sach, tu cach
cua tre » cua te, cuu tre, cua triet
nang ma » tang ma, sang ma, nang cao
luc va » duc va, tuc va, loc va
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) OR (thu sach)) v nang ma hoa. hieu van tuan ((luc va) or (thuc va)) hang hoi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) v nang ma hoa. hieu van tuan ((luc va) OR (thuc va)) hang hoi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) v nang ma hoa. hieu van tuan ((luc va) or (thuc va)) hang hoi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) v nang ma hoa. hieu van tuan ((luc va) or (thuc va)) hang hoi cua tre*.