Perhaps you should try some spelling variations:
manh hanh » xanh hanh, danh thanh, minh thanh
vien cac » vien bach, vien dai, gian cac
cau tren » cu tren, dau tren, ca tren
tu tong » tu tuong, tu trong, tu dong
vien da » vien dai, hien dai
tu nong » tu dong, tu cong, tu tuong
tu sach » thu sach, su sach, te sach
vi cau » va cau, ve cau, di cau

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 ((tu nong) or (tu tong)) xa hoi. hieu ((vien cac) OR (vien da)) suc manh hanh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((tu nong) OR (tu tong)) xa hoi. hieu ((vien cac) OR (vien da)) suc manh hanh vi cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((tu nong) or (tu tong)) xa hoi. hieu ((vien cac) OR (vien da)) suc manh hanh vi cau tren".
• Adding a wildcard symbol may retrieve word variants: tu sach ((tu nong) or (tu tong)) xa hoi. hieu ((vien cac) OR (vien da)) suc manh hanh vi cau tren*.