Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
nam truc » nam truoc, nam thuc, nam trung
xa hanh » xa thanh, xa khanh, va hanh
truc xa » tuc xa, truc va, truoc xay
hieu va » lieu va, hieu qua
cuu tre » cua tre, cau tren, cau treo
sang ma » tang ma, nang ma, sang tao
va nam » van nam, ha nam, va nay
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: ((toc sach) OR (doc sach)) y ((mang may) or (sang ma)) hoi. hieu va nam truc xa hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) y ((mang may) OR (sang ma)) hoi. hieu va nam truc xa hanh vi cuu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (doc sach)) y ((mang may) or (sang ma)) hoi. hieu va nam truc xa hanh vi cuu tre*".