Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
van hanh » van thanh, van anh, van ban
ban hanh » ban hang
dau tren » dau tien, dat tren, dau tieng
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cam lo » nam lo, cam ly, cam o
di dau » doi dau, bi dau, di du

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 ky nang xa hoi. hieu va ((cam lo) or (nam bo)) ((van hanh) or (ban hanh)) di dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang xa hoi. hieu va ((cam lo) OR (nam bo)) ((van hanh) OR (ban hanh)) di dau tren.
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang xa hoi. hieu va ((cam lo) or (nam bo)) ((van hanh) or (ban hanh)) di dau tren*.