Perhaps you should try some spelling variations:
sang mai » sang ma, sang tai, lang mai
mai khoi » mai khoa, tai khoa, cac khoi
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
truc va » thuc va, thuc vat, trung va
hieu va » lieu va, hieu qua
hieu ve » hieu van
ky sang » ky nang, ky dang, ky tang
cuu tre » cua tre, cau tren, cau treo
tuc va » thuc va, tuc xa, duc va
vi cuu » vi luu, vinh cuu

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