Perhaps you should try some spelling variations:
nang mai » nang ma, nang tai, lang mai
van hanh » van thanh, ban hanh, van anh
su triet » su viet, su tien, ve triet
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
mai hoi » mai khoi, dai hoi, lai hoi
hieu va » lieu va, hieu qua
va danh » va dinh, va dan, va hanh
va cam » va cham, va cac, va cao
cam tu » cam thu, nam tu, dam tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky nang mai hoi. hieu va cam tu ((van hanh) or (va danh)) va su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang mai hoi. hieu va cam tu ((van hanh) OR (va danh)) va su triet.
• Adding a wildcard symbol may retrieve word variants: su sach ky nang mai hoi. hieu va cam tu ((van hanh) or (va danh)) va su triet*.