Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
thu sach » thuat sach, thuoc sach, thu hoach
tu sach » su sach, te sach, tu cach
danh va » doanh va, hanh va, anh va
truc va » thuc va, trung va
van cam » van nam, van lam, van cau
nang co » nang cao, nang doc, nang noi
co hoi » co hoc, co loi
va chu » va che, va cau, va chi
chu te » chu de, chu tu

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) or (thu sach)) ky nang co hoi. hieu van cam ((truc va) OR (thuc vat)) danh va chu te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang co hoi. hieu van cam ((truc va) OR (thuc vat)) danh va chu te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ky nang co hoi. hieu van cam ((truc va) OR (thuc vat)) danh va chu te".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ky nang co hoi. hieu van cam ((truc va) OR (thuc vat)) danh va chu te*.