Perhaps you should try some spelling variations:
thuc dan » thuc hanh, hoc dan, thuc vat
danh sai » dung sai, danh bat, danh dau
hieu van » hieu va, thien van, lieu va
van chat » cao chat
thuc day » thuc vat
danh dai » danh dau, danh di, vanh dai
tu sach » thu sach, su sach, te sach
cua tre » cua te, cuu tre, cua triet
sach ty » sach y, sach tu, sach thu
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang

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 hoi. hieu van chat ((thuc day) or (thuc dan)) ((danh dai) OR (danh sai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang xa hoi. hieu van chat ((thuc day) OR (thuc dan)) ((danh dai) OR (danh sai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang xa hoi. hieu van chat ((thuc day) or (thuc dan)) ((danh dai) OR (danh sai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang xa hoi. hieu van chat ((thuc day) or (thuc dan)) ((danh dai) OR (danh sai)) cua tre*.