Perhaps you should try some spelling variations:
dang xay » dang van, van xay
nam duoc » nam thuoc, da duoc, dat duoc
chu tren » cu tren, cau tren, chu trang
xay hoi » xa hoi, tay hoi, cay phoi
sach ky » sach y, sach ty, sach kem
nam duc » pham duc, nam thuc, nam buoc
va danh » va dinh, va dan, va hanh
danh ve » dinh ve, hanh ve, anh ve
sac ky » cac ky, sai ky
ve chu » ve cau, va chu, ve che

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((sach ky) OR (sac ky)) dang xay hoi. hieu qua ((nam duc) or (nam duoc)) va danh ve chu tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((sach ky) OR (sac ky)) dang xay hoi. hieu qua ((nam duc) OR (nam duoc)) va danh ve chu tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((sach ky) OR (sac ky)) dang xay hoi. hieu qua ((nam duc) or (nam duoc)) va danh ve chu tren".
• Adding a wildcard symbol may retrieve word variants: hoc ((sach ky) OR (sac ky)) dang xay hoi. hieu qua ((nam duc) or (nam duoc)) va danh ve chu tren*.