Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
thuc xay » thuc day, tuc xay, thuat xay
lanh hai » thanh hai, lang chai, lanh dao
manh hai » minh hai, thanh hai, van hai
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
ky dang » ky danh
cua tre » cua te, cuu tre, cua triet
ve nam » he nam, va nam, le nam

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 ((ky dang) or (ky nang)) xa hoi. hieu ve nam thuc xay ((manh hai) OR (lanh hai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky dang) OR (ky nang)) xa hoi. hieu ve nam thuc xay ((manh hai) OR (lanh hai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky dang) or (ky nang)) xa hoi. hieu ve nam thuc xay ((manh hai) OR (lanh hai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky dang) or (ky nang)) xa hoi. hieu ve nam thuc xay ((manh hai) OR (lanh hai)) cua tre*.