Perhaps you should try some spelling variations:
trinh vat » trinh van, trinh luat, sinh vat
ban trinh » ban tinh, dan trinh, van trinh
cau tren » cu tren, dau tren, ca tren
dang xay » dang van, van xay
ve cach » ve cac, ve canh
vat cau » dat cau, va cau, van cau
va cach » va cac
tu sach » thu sach, su sach, tu cach
xay hoi » xa hoi, tay hoi, cay phoi
ky dang » ky nang, ky danh
te sach » toc sach

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) or (te sach)) ky dang xay hoi. hieu ((ve cach) OR (va cach)) cua ban trinh vat cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) ky dang xay hoi. hieu ((ve cach) OR (va cach)) cua ban trinh vat cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (te sach)) ky dang xay hoi. hieu ((ve cach) OR (va cach)) cua ban trinh vat cau tren".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (te sach)) ky dang xay hoi. hieu ((ve cach) OR (va cach)) cua ban trinh vat cau tren*.