Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
thu sach » tu sach, thuat sach, thuoc sach
thi hang » thi hanh, thi nang, thi hong
qua giao » cua giao, qua gia, qua giai
van hanh » ban hanh, van anh, van ban
ty hang » ly hang, ty xang, thu hang
va cua » va chua, via cua, ca cua
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 sach ((ty hang) OR (thi hang)) cau hoi. hieu qua giao duc ((van hanh) or (van thanh)) va cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((ty hang) OR (thi hang)) cau hoi. hieu qua giao duc ((van hanh) OR (van thanh)) va cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((ty hang) OR (thi hang)) cau hoi. hieu qua giao duc ((van hanh) or (van thanh)) va cua te".
• Adding a wildcard symbol may retrieve word variants: thu sach ((ty hang) OR (thi hang)) cau hoi. hieu qua giao duc ((van hanh) or (van thanh)) va cua te*.