Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
vat hanh » vat thanh, van hanh, va hanh
su triet » su viet, su tien, ve triet
ky lang » ky dang, ky tang, tay lang
hoa hoi » khoa hoi, hoa hoc, hoa doi
hieu va » hieu qua
thu vat » thuc vat, thu va, thuat vat
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: thu sach ((ky lang) OR (ky nang)) hoa hoi. ((hieu va) or (lieu va)) nam thu vat hanh vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((ky lang) OR (ky nang)) hoa hoi. ((hieu va) OR (lieu va)) nam thu vat hanh vi su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((ky lang) OR (ky nang)) hoa hoi. ((hieu va) or (lieu va)) nam thu vat hanh vi su triet".
• Adding a wildcard symbol may retrieve word variants: thu sach ((ky lang) OR (ky nang)) hoa hoi. ((hieu va) or (lieu va)) nam thu vat hanh vi su triet*.