Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
hanh san » thanh san, khach san, thanh son
thuc dan » thuc hanh, hoc dan, thuc vat
su triet » su viet, su tien, ve triet
hieu vi » hieu voi, hieu va, hieu ve
thuc va » thuc vat, thuc day
sach ty » sach y, sach tu, sach thu
nang ma » tang ma, sang ma, nang cao
ty nang » ky nang, ty xang, ty hang
hanh va » hang va, hanh vi
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ty nang ma hoi. hieu vi pham ((thuc va) OR (thuc dan)) ((hanh san) or (hanh va)) su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ty nang ma hoi. hieu vi pham ((thuc va) OR (thuc dan)) ((hanh san) OR (hanh va)) su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ty nang ma hoi. hieu vi pham ((thuc va) OR (thuc dan)) ((hanh san) or (hanh va)) su triet".
• Adding a wildcard symbol may retrieve word variants: doc sach ty nang ma hoi. hieu vi pham ((thuc va) OR (thuc dan)) ((hanh san) or (hanh va)) su triet*.