Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
hieu van » hieu va, thien van, lieu va
dinh dai » dinh dat, sinh dai, dinh dao
tu sach » su sach, te sach, tu cach
nang xa » nang x, lang xa, nang ma
chao tu » chao xu, cao tu, chai tu
va dinh » van dinh, va kinh, va tinh
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
cho tu » choi tu, chon tu, cho du

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) or (tu sach)) y nang xa hoi. hieu van ((chao tu) OR (cho tu)) va dinh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (tu sach)) y nang xa hoi. hieu van ((chao tu) OR (cho tu)) va dinh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (tu sach)) y nang xa hoi. hieu van ((chao tu) OR (cho tu)) va dinh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (tu sach)) y nang xa hoi. hieu van ((chao tu) OR (cho tu)) va dinh dai cua tre*.