In[]:=
data=Dataset[{<|"year"->1971,"country"->"China"|>,<|"year"->1969,"country"->"Canada"|>,<|"year"->1972,"country"->"Germany"|>}]
Out[]=
year
country
1971
China
1969
Canada
1972
Germany
In[]:=
searchCountries={"Ethiopia","Venezuela","Canada","Finland","Brazil","China","Greece","Italy","Netherlands","Norway","Kenya","Sweden"}
Out[]=
{Ethiopia,Venezuela,Canada,Finland,Brazil,China,Greece,Italy,Netherlands,Norway,Kenya,Sweden}
In[]:=
Query[Select[#year>=1970&&MemberQ[searchCountries,#country]&]]@data
Out[]=
year
country
1971
China