Perhaps you should try some spelling variations:
cuu thuc » cuu tac
trinh di » trinh do, trinh dien, trinh dinh
thu sach » thuat sach, thuoc sach, thu hoach
va trinh » van trinh, va tinh, lap trinh
hieu van » thien van, lieu va, hieu ve
tu sach » su sach, te sach, tu cach
thuc va » thuc vat, thuc dan, thuc day
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
sang ma » tang ma, nang ma, sang tao
y sang » _ sang, duy sang
di cua » dai cua, doi cua, de cua

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)) y sang ma hoa. ((hieu van) or (hieu va)) cuu thuc va trinh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) y sang ma hoa. ((hieu van) OR (hieu va)) cuu thuc va trinh di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) y sang ma hoa. ((hieu van) or (hieu va)) cuu thuc va trinh di cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) y sang ma hoa. ((hieu van) or (hieu va)) cuu thuc va trinh di cua tre*.