Perhaps you should try some spelling variations:
vien cac » vien bach, vien dai, vien da
dinh cuu » dinh chi
sinh va » sinh vat, tinh va, dinh van
va dinh » van dinh, va kinh, va tinh
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
ve cac » va cac
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 ((ve cac) OR (vien cac)) duc va dinh ((dinh cuu) or (sinh va)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang x hoi. hieu ((ve cac) OR (vien cac)) duc va dinh ((dinh cuu) OR (sinh va)) tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang x hoi. hieu ((ve cac) OR (vien cac)) duc va dinh ((dinh cuu) or (sinh va)) tre*".