Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hanh hai » thanh hai, nhanh hai, hang hai
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
va cham » va chat, va tham
xuc van » luc van, vuc van, thuc van
duc van » duc va, duc tan, duc manh
xuc ban » duc ban, cuc ban, quoc ban
ma hoi » mai hoi, xa hoi, ma hoa
hai va » hai van, thai va, hoi va
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky nang ma hoi. hieu va cham ((((xuc van) OR (duc van))) or (xuc ban)) hanh hai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang ma hoi. hieu va cham ((((xuc van) OR (duc van))) OR (xuc ban)) hanh hai va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang ma hoi. hieu va cham ((((xuc van) OR (duc van))) or (xuc ban)) hanh hai va thiet".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang ma hoi. hieu va cham ((((xuc van) OR (duc van))) or (xuc ban)) hanh hai va thiet*.