Perhaps you should try some spelling variations:
hoc viet » hoc hien
dang mai » dang hai, dang mau, dang bai
va thanh » gia thanh, ban thanh, va tinh
va danh » va dinh, va dan, va hanh
bo sach » co sach, hoc sach
sach ky » sac ky, sach y, sach ty
mai hoi » mai khoi, dai hoi, lai hoi
ky dang » ky nang, ky danh
ve nam » he nam, le nam, te nam
vi hoc » li hoc, va hoc
va nam » van nam, ha nam, va nay

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

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