\[ y''(x)-\frac {h\left (\frac {y(x)}{\sqrt {x}}\right )}{x^{3/2}}=0 \] ✓ Mathematica : cpu = 3.43107 (sec), leaf count = 754
DSolve[-(h[y[x]/Sqrt[x]]/x^(3/2)) + Derivative[2][y][x] == 0,y[x],x]
\[\left \{\text {Solve}\left [\int _1^{y(x)}\frac {2}{\sqrt {x} \sqrt {\frac {K[3]^2+4 x c_1+8 x \int _1^{\frac {K[3]}{\sqrt {x}}}h(K[2])dK[2]}{x}}}dK[3]-\int _1^x\left (\frac {2 \left (\frac {y(x)}{2 \sqrt {K[4]}}-\frac {\sqrt {\frac {y(x)^2}{2 K[4]}+2 c_1+4 \int _1^{\frac {y(x)}{\sqrt {K[4]}}}h(K[2])dK[2]}}{\sqrt {2}}\right )}{K[4] \sqrt {\frac {y(x)^2+4 c_1 K[4]+8 K[4] \int _1^{\frac {y(x)}{\sqrt {K[4]}}}h(K[2])dK[2]}{K[4]}}}+\int _1^{y(x)}\left (-\frac {\frac {4 c_1+8 \int _1^{\frac {K[3]}{\sqrt {K[4]}}}h(K[2])dK[2]-\frac {4 h\left (\frac {K[3]}{\sqrt {K[4]}}\right ) K[3]}{\sqrt {K[4]}}}{K[4]}-\frac {K[3]^2+4 c_1 K[4]+8 K[4] \int _1^{\frac {K[3]}{\sqrt {K[4]}}}h(K[2])dK[2]}{K[4]^2}}{\sqrt {K[4]} \left (\frac {K[3]^2+4 c_1 K[4]+8 K[4] \int _1^{\frac {K[3]}{\sqrt {K[4]}}}h(K[2])dK[2]}{K[4]}\right ){}^{3/2}}-\frac {1}{K[4]^{3/2} \sqrt {\frac {K[3]^2+4 c_1 K[4]+8 K[4] \int _1^{\frac {K[3]}{\sqrt {K[4]}}}h(K[2])dK[2]}{K[4]}}}\right )dK[3]\right )dK[4]=c_2,y(x)\right ],\text {Solve}\left [\int _1^{y(x)}-\frac {2}{\sqrt {x} \sqrt {\frac {K[5]^2+4 x c_1+8 x \int _1^{\frac {K[5]}{\sqrt {x}}}h(K[2])dK[2]}{x}}}dK[5]-\int _1^x\left (\int _1^{y(x)}\left (\frac {\frac {4 c_1+8 \int _1^{\frac {K[5]}{\sqrt {K[6]}}}h(K[2])dK[2]-\frac {4 h\left (\frac {K[5]}{\sqrt {K[6]}}\right ) K[5]}{\sqrt {K[6]}}}{K[6]}-\frac {K[5]^2+4 c_1 K[6]+8 K[6] \int _1^{\frac {K[5]}{\sqrt {K[6]}}}h(K[2])dK[2]}{K[6]^2}}{\sqrt {K[6]} \left (\frac {K[5]^2+4 c_1 K[6]+8 K[6] \int _1^{\frac {K[5]}{\sqrt {K[6]}}}h(K[2])dK[2]}{K[6]}\right ){}^{3/2}}+\frac {1}{K[6]^{3/2} \sqrt {\frac {K[5]^2+4 c_1 K[6]+8 K[6] \int _1^{\frac {K[5]}{\sqrt {K[6]}}}h(K[2])dK[2]}{K[6]}}}\right )dK[5]-\frac {2 \left (\frac {y(x)}{2 \sqrt {K[6]}}+\frac {\sqrt {\frac {y(x)^2}{2 K[6]}+2 c_1+4 \int _1^{\frac {y(x)}{\sqrt {K[6]}}}h(K[2])dK[2]}}{\sqrt {2}}\right )}{K[6] \sqrt {\frac {y(x)^2+4 c_1 K[6]+8 K[6] \int _1^{\frac {y(x)}{\sqrt {K[6]}}}h(K[2])dK[2]}{K[6]}}}\right )dK[6]=c_2,y(x)\right ]\right \}\] ✓ Maple : cpu = 0.224 (sec), leaf count = 92
dsolve(diff(diff(y(x),x),x)-1/x^(3/2)*h(y(x)/x^(1/2))=0,y(x))
\[y \left (x \right ) = \RootOf \left (\textit {\_Z} \,x^{\frac {3}{2}}+4 h \left (\frac {\textit {\_Z}}{\sqrt {x}}\right ) x^{2}\right )\]