Perhaps you should try some spelling variations:
sang mai » sang ma, sang tai, hoang mai
hanh tai » thanh tai, hang tai, han tai
lang mai » lang dai, lang hai, lang man
tu sach » thu sach, su sach, te sach
tai cua » thai cua, tai cuc, tri cua
truc va » thuc va, thuc vat, trung va
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
cua tre » cua te, cuu tre, cua triet
ve cam » ve cham, ve cac, va cam

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 ky ((sang mai) OR (lang mai)) hoi. hieu ve cam ((duc va) or (truc va)) hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((sang mai) OR (lang mai)) hoi. hieu ve cam ((duc va) OR (truc va)) hanh tai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((sang mai) OR (lang mai)) hoi. hieu ve cam ((duc va) or (truc va)) hanh tai cua tre*".