Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
hieu van » hieu va, thien van, lieu va
cac thuc » cach thuc, cac thu, can thuc
vat dan » va dan, van dan, vat ran
ky lang » ky nang, ky dang, ky tang
hoa hoi » khoa hoi, hoa doi, hoc hoi
van cac » van hac, van cau, van bac
di cua » dai cua, doi cua, de cua
cua te » cua tu
dan di » danh di, dan da, dan de

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu hoach) or (thuoc sach)) ky lang ((hoa hoi) OR (hoa hoc)). hieu van cac thuc vat dan di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu hoach) OR (thuoc sach)) ky lang ((hoa hoi) OR (hoa hoc)). hieu van cac thuc vat dan di cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu hoach) or (thuoc sach)) ky lang ((hoa hoi) OR (hoa hoc)). hieu van cac thuc vat dan di cua te".
• Adding a wildcard symbol may retrieve word variants: ((thu hoach) or (thuoc sach)) ky lang ((hoa hoi) OR (hoa hoc)). hieu van cac thuc vat dan di cua te*.