Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
xa khanh » xa thanh, van khanh, dat khanh
tu sach » thu sach, su sach, te sach
hai cua » thai cua, dai cua, hoi cua
lai cua » dai cua, lai chau, thai cua
sach ky » sac ky, sach y, sach ty
cam tuc » cam xuc, cam tu, dam thuc
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang x hoi. hieu van ((cam tuc) OR (nam thuc)) xa khanh ((lai cua) or (hai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang x hoi. hieu van ((cam tuc) OR (nam thuc)) xa khanh ((lai cua) OR (hai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang x hoi. hieu van ((cam tuc) OR (nam thuc)) xa khanh ((lai cua) or (hai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang x hoi. hieu van ((cam tuc) OR (nam thuc)) xa khanh ((lai cua) or (hai cua)) tre*.