Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
quoc tran » quoc toan, quoc tuan, quoc trung
cac quoc » cac nuoc, cac cuoc, cao quoc
tran anh » tran manh, tuan anh, tran thanh
ty lang » tay lang, ty xang, ty hang
lang xa » lang ha, dang xay, lang van
anh hai » lanh hai, manh hai, anh thai
cua tre » cuu tre, cua triet, dua tren
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu hoach) or (thuat sach)) ty lang xa hoi. lieu va cac quoc tran anh hai ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu hoach) OR (thuat sach)) ty lang xa hoi. lieu va cac quoc tran anh hai ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu hoach) or (thuat sach)) ty lang xa hoi. lieu va cac quoc tran anh hai ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: ((thu hoach) or (thuat sach)) ty lang xa hoi. lieu va cac quoc tran anh hai ((cua tre) OR (cua te))*.