Perhaps you should try some spelling variations:
thieu khang » chieu khong, thieu quang
nham thuc » nhan thuc, nam thuc, nham thu
toc sach » hoc sach, doc sach, thuoc sach
dieu cua » dieu tra
va danh » va dinh, va dan, va hanh
thuc va » thuc vat, thuc dan, thuc day
va nham » va cham, va tham, va nha
hieu va » lieu va, hieu qua
de cua » le cua, te cua
cu hoi » cua hoi, cuu hoi, co hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach thieu khang ((cu hoi) OR (cau hoi)). hieu va nham thuc va danh ((de cua) or (dieu cua)) tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach thieu khang ((cu hoi) OR (cau hoi)). hieu va nham thuc va danh ((de cua) OR (dieu cua)) tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach thieu khang ((cu hoi) OR (cau hoi)). hieu va nham thuc va danh ((de cua) or (dieu cua)) tu".
• Adding a wildcard symbol may retrieve word variants: toc sach thieu khang ((cu hoi) OR (cau hoi)). hieu va nham thuc va danh ((de cua) or (dieu cua)) tu*.