Perhaps you should try some spelling variations:
manh hanh » xanh hanh, danh thanh, minh thanh
sach van » sach han, sach va, bach van
van nang » van quang, van ban, van dong
duc manh » suc manh, duc anh, duc minh
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
ve cham » va cham, ve chat, vu cham
su viet » so viet
ma hoi » mai hoi, xa hoi, ma hoa
ve cam » ve cac, va cam, ve cai
vi su » va su, ve su, ki su

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach van nang ma hoi. hieu ((ve cam) or (ve cham)) duc manh hanh vi su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach van nang ma hoi. hieu ((ve cam) OR (ve cham)) duc manh hanh vi su viet*.