Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
hanh via » hanh vi, hanh va, anh va
van hanh » van thanh, ban hanh, van anh
phan duc » pham duc, phan tu, phan dau
te sach » toc sach
via cuu » via cua, vinh cuu
duc van » duc va, duc tan, duc manh
va phan » van phan, va phat, va phap
hieu va » lieu va, hieu qua
cuu tre » cua tre, cau tren, cau treo
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (doc sach)) ky ((nang xa) OR (nang ma)) hoi. hieu va phan duc van hanh via cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (doc sach)) ky ((nang xa) OR (nang ma)) hoi. hieu va phan duc van hanh via cuu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (doc sach)) ky ((nang xa) OR (nang ma)) hoi. hieu va phan duc van hanh via cuu tre*".