\[\boxed{\mathbf{354}.}\]
\[\left( \sqrt[3]{x} + \frac{1}{\sqrt{x}} \right)^{12}\]
\[C_{12}^{k} \cdot \left( \sqrt[3]{x} \right)^{k} \cdot \left( \frac{1}{\sqrt{x}} \right)^{12 - k} =\]
\[= C_{12}^{k} \cdot x^{\frac{k}{3}} \cdot \left( \sqrt{x} \right)^{k - 12} =\]
\[= C_{12}^{k} \cdot x^{\frac{k}{3}} \cdot x^{\frac{k}{2} - 6} =\]
\[= C_{12}^{k} \cdot x^{\frac{k}{3} + \frac{k}{2} - 6} = C_{12}^{k} \cdot x^{\frac{5k}{6} - 6}\]
\[\frac{5k}{6} - 6 = - 1\]
\[5k - 36 = - 6\]
\[5k = 30\]
\[k = 6.\]
\[Ответ:T_{7} = C_{12}^{6} \cdot \frac{1}{x}.\]