\[ \boxed { x \left ( {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) \right ) ^{2}+y \left ( x \right ) {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) - \left ( y \left ( x \right ) \right ) ^{4}=0} \]
Mathematica: cpu = 0.210027 (sec), leaf count = 133 \[ \left \{\left \{y(x)\to -\frac {\sqrt {\tanh ^2\left (\frac {1}{2} \left (c_1-\log (x)\right )\right )-1}}{2 \sqrt {x}}\right \},\left \{y(x)\to \frac {\sqrt {\tanh ^2\left (\frac {1}{2} \left (c_1-\log (x)\right )\right )-1}}{2 \sqrt {x}}\right \},\left \{y(x)\to -\frac {\sqrt {\tanh ^2\left (\frac {1}{2} \left (\log (x)-c_1\right )\right )-1}}{2 \sqrt {x}}\right \},\left \{y(x)\to \frac {\sqrt {\tanh ^2\left (\frac {1}{2} \left (\log (x)-c_1\right )\right )-1}}{2 \sqrt {x}}\right \}\right \} \]
Maple: cpu = 0.655 (sec), leaf count = 95 \[ \left \{ y \left ( x \right ) =-{\frac {1}{2}{\frac {1}{\sqrt {-x}}}},y \left ( x \right ) ={\frac {1}{2}{\frac {1}{\sqrt {-x}}}},y \left ( x \right ) =-{\frac {1}{2\,x}\sqrt {- \left ( \tanh \left ( -{\frac {\ln \left ( x \right ) }{2}}+{\frac {{\it \_C1}}{2}} \right ) \right ) ^{2}x +x} \left ( \tanh \left ( -{\frac {\ln \left ( x \right ) }{2}}+{\frac {{ \it \_C1}}{2}} \right ) \right ) ^{-1}},y \left ( x \right ) ={\frac {1}{ 2\,x}\sqrt {- \left ( \tanh \left ( -{\frac {\ln \left ( x \right ) }{2}} +{\frac {{\it \_C1}}{2}} \right ) \right ) ^{2}x+x} \left ( \tanh \left ( -{\frac {\ln \left ( x \right ) }{2}}+{\frac {{\it \_C1}}{2}} \right ) \right ) ^{-1}} \right \} \]