Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
manh khai » minh khai, manh hai, dang khai
thuc dan » thuc hanh, hoc dan
sach ky » sac ky, sach y, sach ty
khai va » thai va, hai va, khi va
va viet » hoa viet, san viet, mai viet
ve nam » va nam, le nam, te nam
he nam » ha nam, nghe nam
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuat sach ky nang x hoi. hieu ((ve nam) OR (he nam)) ((thuc dan) or (thuc vat)) manh khai va viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach ky nang x hoi. hieu ((ve nam) OR (he nam)) ((thuc dan) OR (thuc vat)) manh khai va viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sach ky nang x hoi. hieu ((ve nam) OR (he nam)) ((thuc dan) or (thuc vat)) manh khai va viet".
• Adding a wildcard symbol may retrieve word variants: thuat sach ky nang x hoi. hieu ((ve nam) OR (he nam)) ((thuc dan) or (thuc vat)) manh khai va viet*.