Perhaps you should try some spelling variations:
tao nganh » tao nhan, da nganh, nam nganh
cac nganh » hoc nganh
van hanh » van thanh, ban hanh, van anh
hanh va » hang va, hanh vi
duc van » duc va, duc tan, duc manh
cam duc » cam xuc, cao duc, pham duc
hieu va » lieu va, hieu qua
so sach » so sanh, bo sach, co sach
bac hoi » bac ho, bac hoc, sach hoi
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao
va cua » va chua, via cua, ca cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ((((tao nganh) OR (cac nganh))) or (bao cao)) bac hoi. hieu va cam duc van hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ((((tao nganh) OR (cac nganh))) OR (bao cao)) bac hoi. hieu va cam duc van hanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ((((tao nganh) OR (cac nganh))) or (bao cao)) bac hoi. hieu va cam duc van hanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach ((((tao nganh) OR (cac nganh))) or (bao cao)) bac hoi. hieu va cam duc van hanh va cua tre*.