Perhaps you should try some spelling variations:
nhieu viec » hieu viec, nhien viet
viec dan » viec dang, viec ban, viec dat
thuc can » thuc chan, thuc dan, thuc van
thuc cao » thuoc cao, thuc co, thuat cao
sach ty » sach y, sach tu, sach thu
te sach » toc sach
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
dan di » danh di, dan da, dan de
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: te sach ty ((nang xa) or (nang ma)) hoi. nhieu viec dan ((thuc cao) OR (thuc can)) dan di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty ((nang xa) OR (nang ma)) hoi. nhieu viec dan ((thuc cao) OR (thuc can)) dan di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty ((nang xa) or (nang ma)) hoi. nhieu viec dan ((thuc cao) OR (thuc can)) dan di cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ty ((nang xa) or (nang ma)) hoi. nhieu viec dan ((thuc cao) OR (thuc can)) dan di cua tre*.