Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
phat loc » hau loc, nhat loi, phap lo
van hanh » van thanh, ban hanh, van anh
nang ma » tang ma, sang ma, nang cao
hieu va » hieu qua
loc van » luoc van, hoc van, lo van
hanh le » thanh le, hanh ve, hanh de
cuu tre » cua tre, cau tren, cau treo
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa
le cuu » le cua, le huu, le cau

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 y nang ma hoi. ((hieu va) or (lieu va)) phat loc van hanh le cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang ma hoi. ((hieu va) OR (lieu va)) phat loc van hanh le cuu tre*.