Perhaps you should try some spelling variations:
danh tai » doanh tai, dinh tai, hanh tai
tu sach » thu sach, su sach, te sach
thuc va » thuc vat, thuc dan, thuc day
cuc tre » duc tre, cua tre, cuu tre
hieu ve » hieu va, hieu van
sang xa » song xa, lang xa, sang ma
ky sang » ky nang, ky dang, ky tang
tuc va » truc va, tuc xa, duc va
ve cam » ve cham, ve cac, va cam

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 hoach)) ky sang xa hoi. hieu ve cam ((tuc va) OR (thuc va)) danh tai cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu hoach)) ky sang xa hoi. hieu ve cam ((tuc va) OR (thuc va)) danh tai cuc tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu hoach)) ky sang xa hoi. hieu ve cam ((tuc va) OR (thuc va)) danh tai cuc tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu hoach)) ky sang xa hoi. hieu ve cam ((tuc va) OR (thuc va)) danh tai cuc tre*.