Perhaps you should try some spelling variations:
toan hanh » toan thanh, toan anh, tran hanh
thu sach » thuat sach, thuoc sach, thu hoach
duc toan » duc tan, duc ton, duc hoan
hieu ve » hieu va, hieu van
ve pham » vi pham, v pham, ve phan
tu sach » su sach, te sach, tu cach
sang ma » tang ma, nang ma, sang tao
ky sang » ky nang, ky dang, ky tang
ma hoi » mai hoi, xa hoi, ma hoa
vi cua » vai cua
di cua » dai cua, doi cua, de cua

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 (thu sach)) ky sang ma hoi. hieu ve pham duc toan hanh ((vi cua) or (di cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky sang ma hoi. hieu ve pham duc toan hanh ((vi cua) OR (di cua)) tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ky sang ma hoi. hieu ve pham duc toan hanh ((vi cua) or (di cua)) tre*.