请任意选择一个你熟悉的Python GUI库，实现一个科学计算器。要求至少能实现加运算、减运算、乘运算、除运算、幂运算和取余运算。

好的，我选择使用PyQt5库来实现一个科学计算器。以下是代码：

import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QWidget, QPushButton, QGridLayout, QLineEdit, QVBoxLayout

class Calculator(QWidget):
    def __init__(self):
        super().__init__()

        # 设置窗口标题和大小
        self.setWindowTitle("Scientific Calculator")
        self.resize(300, 400)

        # 设置计算器的布局
        self.layout = QVBoxLayout()

        # 添加一个文本框，用于显示输入和输出内容
        self.textbox = QLineEdit(self)
        self.textbox.setReadOnly(True)
        self.layout.addWidget(self.textbox)

        # 添加数字和运算符按钮
        grid = QGridLayout()
        self.buttons = {}
        button_labels = [
            "7", "8", "9", "+", 
            "4", "5", "6", "-", 
            "1", "2", "3", "*", 
            "0", ".", "C", "/", 
            "^", "%"
        ]
        positions = [(i, j) for i in range(4) for j in range(4)]
        for position, label in zip(positions, button_labels):
            if label == "C":
                button = QPushButton(label, self, clicked=self.clear_textbox)
            else:
                button = QPushButton(label, self, clicked=lambda label=label: self.append_textbox(label))
            grid.addWidget(button, *position)
            self.buttons[label] = button

        # 添加幂运算和取余运算按钮
        self.pow_button = QPushButton("^", self, clicked=lambda label="^": self.append_textbox(label))
        self.mod_button = QPushButton("%", self, clicked=lambda label="%": self.append_textbox(label))
        grid.addWidget(self.pow_button, 0, 3)
        grid.addWidget(self.mod_button, 1, 3)

        self.layout.addLayout(grid)
        self.setLayout(self.layout)

    def clear_textbox(self):
        self.textbox.setText("")

    def append_textbox(self, label):
        current_text = self.textbox.text()
        if label == "C":
            self.textbox.setText("")
        elif label == "=":
            try:
                result = eval(current_text)
                self.textbox.setText(str(result))
            except:
                self.textbox.setText("Error")
        else:
            self.textbox.setText(current_text + label)

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()

        # 创建一个计算器窗口
        self.calculator = Calculator()

        # 将计算器窗口添加到主窗口
        self.setCentralWidget(self.calculator)

        # 设置主窗口的标题
        self.setWindowTitle("Calculator")

if __name__ == '__main__':
    app = QApplication(sys.argv)
    win = MainWindow()
    win.show()
    sys.exit(app.exec_())

这个科学计算器有基本的加、减、乘、除、幂和取余运算能力，同时有清除按钮和等于按钮。用户可以在输入框中输入计算表达式，然后按下等于按钮进行计算，结果将显示在输出框中。如果用户输入的表达式不合法，输出框将显示"Error"。