以下是一个简单的示例代码，包含3个单行文本框、一个计算按钮和一个保存按钮。计算按钮将计算文本框中的数值并在结果文本框中显示，保存按钮将保存所有文本框中的数值和结果到一个文本文件中。

import tkinter as tk

class DataEntryGUI:
    def __init__(self, master):
        self.master = master
        master.title("实验数据录入")

        # 创建文本框
        self.entry1 = tk.Entry(master)
        self.entry2 = tk.Entry(master)
        self.entry3 = tk.Entry(master)
        self.result = tk.Entry(master, state='readonly')

        # 创建标签
        tk.Label(master, text="数据1").grid(row=0)
        tk.Label(master, text="数据2").grid(row=1)
        tk.Label(master, text="数据3").grid(row=2)
        tk.Label(master, text="结果").grid(row=3)

        # 放置文本框
        self.entry1.grid(row=0, column=1)
        self.entry2.grid(row=1, column=1)
        self.entry3.grid(row=2, column=1)
        self.result.grid(row=3, column=1)

        # 创建按钮
        self.calculate_button = tk.Button(master, text="计算", command=self.calculate)
        self.calculate_button.grid(row=4, column=0, pady=10)
        self.save_button = tk.Button(master, text="保存", command=self.save)
        self.save_button.grid(row=4, column=1, pady=10)

    def calculate(self):
        # 计算结果并显示
        try:
            data1 = float(self.entry1.get())
            data2 = float(self.entry2.get())
            data3 = float(self.entry3.get())
            result = data1 + data2 + data3
            self.result.config(state='normal')
            self.result.delete(0, tk.END)
            self.result.insert(0, result)
            self.result.config(state='readonly')
        except ValueError:
            self.result.config(state='normal')
            self.result.delete(0, tk.END)
            self.result.insert(0, "输入错误")
            self.result.config(state='readonly')

    def save(self):
        # 保存数据到文件
        try:
            data1 = float(self.entry1.get())
            data2 = float(self.entry2.get())
            data3 = float(self.entry3.get())
            result = float(self.result.get())
            with open("data.txt", "w") as f:
                f.write("数据1: {}
".format(data1))
                f.write("数据2: {}
".format(data2))
                f.write("数据3: {}
".format(data3))
                f.write("结果: {}
".format(result))
        except ValueError:
            pass

root = tk.Tk()
gui = DataEntryGUI(root)
root.mainloop()