Perhaps you should try some spelling variations:
tan thanh » tran thanh, tang thanh, toan thanh
giai duc » giao duc, gia duc, giap duc
tan hanh » tang hanh, toan hanh, tran hanh
su sach » so sach, vu sach
sach ly » sach y, sach lo, sach ty
ly nang » ky nang, ly hang, ly vang
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
vai cua » hai cua, lai cua, bai cua
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ly nang ma hoi. hieu va giai duc ((tan hanh) OR (tan thanh)) ((vai cua) or (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ly nang ma hoi. hieu va giai duc ((tan hanh) OR (tan thanh)) ((vai cua) OR (dai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ly nang ma hoi. hieu va giai duc ((tan hanh) OR (tan thanh)) ((vai cua) or (dai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: su sach ly nang ma hoi. hieu va giai duc ((tan hanh) OR (tan thanh)) ((vai cua) or (dai cua)) tre*.