Perhaps you should try some spelling variations:
dan hanh » dang hanh, dan khanh, dan thanh
thuc dan » thuc hanh, hoc dan, thuc vat
hanh te » hanh tu, hanh ve, hanh de
van cuu » van cau, van chu, van cua
sach ty » sach y, sach tu, sach thu
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
van cu » van cau, van chu, van cua
te cua » tue cua, le cua, de cua
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 ty ((nang xa) or (nang ma)) hoi. hieu ((van cuu) OR (van cu)) thuc dan hanh te cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((nang xa) OR (nang ma)) hoi. hieu ((van cuu) OR (van cu)) thuc dan hanh te cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty ((nang xa) or (nang ma)) hoi. hieu ((van cuu) OR (van cu)) thuc dan hanh te cua te".
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((nang xa) or (nang ma)) hoi. hieu ((van cuu) OR (van cu)) thuc dan hanh te cua te*.