Find all poltnomials $ P(x)$ with real coefficients satisfying: For all $ a>1995$, the number of real roots of $ P(x)\equal{}a$ (incuding multiplicity of each root) is greater than 1995, and every roots are greater than 1995.
1. Let \( P(x) \) be a polynomial of degree \( n \) with real coefficients. We need to find \( P(x) \) such that for every \( a > 1995 \), the equation \( P(x) = a \) has exactly \( n \) real roots, all of which are greater than 1995.

2. Consider the polynomial \( Q(x) = P(x) - a \). For \( a > 1995 \), \( Q(x) = 0 \) must have exactly \( n \) real roots, all greater than 1995. This implies that \( P(x) \) must be strictly increasing for \( x > 1995 \) because if \( P(x) \) were not strictly increasing, it could not have exactly \( n \) real roots for every \( a > 1995 \).

3. Since \( P(x) \) is strictly increasing for \( x > 1995 \), its derivative \( P'(x) \) must be positive for \( x > 1995 \). This implies that \( P(x) \) is a polynomial of odd degree because only polynomials of odd degree can be strictly increasing or strictly decreasing over the entire real line.

4. Let us assume \( P(x) \) is a polynomial of degree \( n \). Since \( P(x) \) is strictly increasing for \( x > 1995 \), it must have the form:
   \[
   P(x) = a_n x^n + a_{n-1} x^{n-1} + \cdots + a_1 x + a_0
   \]
   where \( a_n > 0 \).

5. To ensure that \( P(x) = a \) has all roots greater than 1995 for every \( a > 1995 \), we need to shift the polynomial such that its behavior is consistent with the given conditions. Consider the polynomial \( P(x) = (x - 1995)^n \). This polynomial is strictly increasing for \( x > 1995 \) and has the required properties.

6. For \( P(x) = (x - 1995)^n \), the equation \( P(x) = a \) becomes:
   \[
   (x - 1995)^n = a
   \]
   Taking the \( n \)-th root on both sides, we get:
   \[
   x - 1995 = a^{1/n}
   \]
   \[
   x = 1995 + a^{1/n}
   \]
   Since \( a > 1995 \), \( a^{1/n} > 1 \), and thus \( x > 1995 \). This ensures that all roots of \( P(x) = a \) are greater than 1995.

7. Therefore, the polynomial \( P(x) = (x - 1995)^n \) satisfies the given conditions.

The final answer is \( \boxed{ P(x) = (x - 1995)^n } \) for any positive integer \( n \).