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

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) OR (le cua)) 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) OR (le cua)) tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y nang ma hoi. ((hieu va) or (lieu va)) phat loc van hanh ((le cuu) OR (le cua)) tre*".