Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
thuc dan » thuc hanh, thuc vat
nang xa » nang x, lang xa, nang ma
van cuu » van cau, van chu, van cu
hanh de » hanh ve, hanh kem
sac ky » sai ky
de cua » le cua, te cua, dieu cua
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sac ky) OR (cac ky)) nang xa hoi. hieu van cuu ((thuc dan) or (hoc dan)) hanh de cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sac ky) OR (cac ky)) nang xa hoi. hieu van cuu ((thuc dan) OR (hoc dan)) hanh de cua tu*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sac ky) OR (cac ky)) nang xa hoi. hieu van cuu ((thuc dan) or (hoc dan)) hanh de cua tu*".