Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
thu sach » tu sach, thuat sach, thu hoach
hieu van » hieu va, thien van, lieu va
ty nang » ky nang, ty xang, ty hang
nang xa » nang x, lang xa, nang ma
nam tuc » nam thuc, nam truc, nam tu
xa hanh » xa thanh, xa khanh, va hanh

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