已知数列\(\{a_{n}\}\)中，\(a_{1}=1\)，\(a_{n+1}= \begin{cases} \dfrac {1}{3}a_{n}+n,n{为奇数} \\ a_{n}-3n,n{为偶数}\end{cases}\)
\((1)\)求证：数列\(\{a_{2n}- \dfrac {3}{2}\}\)是等比数列；
\((2)\)求数列\(\{a_{n}\}\)的前\(2n\)项和\(S_{2n}\)，并求满足\(S_{n} > 0\)的所有正整数\(n\)．