Perhaps you should try some spelling variations:
dan hanh » dang hanh, dan khanh, dan thanh
thuc dan » thuc hanh, hoc dan, thuc vat
can thuc » dan thuc, van thuc, cay thuc
tu sach » thu sach, su sach, te sach
hanh ve » hanh vi, hanh va, hanh kem
hieu va » lieu va, hieu qua
tay hoi » tay ho, tao hoi, tay thai
do dang » da dang, do danh, xo dang
cua tuc » cua duc, cua tu, cua thuoc
va can » va chan, va cac, va cao
o dang » xo dang, so dang, o dong
cua te » cua 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 ((o dang) OR (do dang)) tay hoi. hieu va can thuc dan hanh ve ((cua te) or (cua tuc))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((o dang) OR (do dang)) tay hoi. hieu va can thuc dan hanh ve ((cua te) OR (cua tuc)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((o dang) OR (do dang)) tay hoi. hieu va can thuc dan hanh ve ((cua te) or (cua tuc))".
• Adding a wildcard symbol may retrieve word variants: tu sach ((o dang) OR (do dang)) tay hoi. hieu va can thuc dan hanh ve ((cua te) or (cua tuc))*.