Perhaps you should try some spelling variations:
lieu viet » sieu viet, lieu vien, tieu viet
sach nuoc » sach duoc, bach tuoc, dich nuoc
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
xanh doi » thanh doi, tinh doi, anh doc
cau tren » cu tren, dau tren, ca tren
nang xa » nang x, lang xa, nang ma
xanh di » danh di, vanh dai, xanh tai
su cao » cu cao, vu cao, su co

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

• Performing a fuzzy search may retrieve terms with similar spellings: su cao ky nang xa hoi. lieu viet ((sach nuoc) or (cac nuoc)) va ((xanh doi) OR (xanh di)) cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su cao ky nang xa hoi. lieu viet ((sach nuoc) OR (cac nuoc)) va ((xanh doi) OR (xanh di)) cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su cao ky nang xa hoi. lieu viet ((sach nuoc) or (cac nuoc)) va ((xanh doi) OR (xanh di)) cau tren".
• Adding a wildcard symbol may retrieve word variants: su cao ky nang xa hoi. lieu viet ((sach nuoc) or (cac nuoc)) va ((xanh doi) OR (xanh di)) cau tren*.