Perhaps you should try some spelling variations:
trinh vat » trinh van, trinh luat, sinh vat
hieu hien » bieu hien, dieu hien, chieu chien
hien cac » thien cac, vien cac, hieu cac
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
cac lao » ca lao, cac loai, cac giao
kinh va » kinh van, tinh va, sinh va
cua tre » cua te, cuu tre, cua triet
lao va » tao va, cao va, bao va

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 xa hoi. hieu hien cac lao va ((kinh va) or (trinh vat)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang xa hoi. hieu hien cac lao va ((kinh va) OR (trinh vat)) cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. hieu hien cac lao va ((kinh va) or (trinh vat)) cua tre*.