Perhaps you should try some spelling variations:
dieu cua » dieu tra
toc sac » toc sach, toc san, hoc sach
nang xa » nang x, lang xa, nang ma
va danh » va dinh, va dan, va hanh
sac ky » cac ky, sai ky
ve cua » de cua, te cua, ve cum
le cua » ly cua
bao va » bao ve, tao va, ban va
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: toc sac ky nang xa hoi. hieu ((ve cua) OR (le cua)) bao va danh ((di cua) OR (dieu cua)) triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sac ky nang xa hoi. hieu ((ve cua) OR (le cua)) bao va danh ((di cua) OR (dieu cua)) triet".
• Adding a wildcard symbol may retrieve word variants: toc sac ky nang xa hoi. hieu ((ve cua) OR (le cua)) bao va danh ((di cua) OR (dieu cua)) triet*.