Select checkbox using Selenium with Python

Use find_element_by_xpath with the XPath expression .//*[contains(text(), 'txt')] to find a element that contains txt as text.

browser.find_element_by_xpath(
    ".//*[contains(text(), '15 Minute Stream Flow Data: USGS (FIFE)')]"
).click()

UPDATE

Some contents are loaded after document load. I modified the code to try 10 times (1 second sleep in between).

import time

from selenium import webdriver
from selenium.webdriver.common.keys import Keys
from selenium.common.exceptions import NoSuchElementException

browser = webdriver.Firefox()
url="http://reverb.echo.nasa.gov/reverb/"
browser.get(url)

for i in range(10):
    try:
        browser.find_element_by_xpath(
            ".//*[contains(text(), '15 Minute Stream Flow Data: USGS (FIFE)')]"
        ).click()
        break
    except NoSuchElementException as e:
        print('Retry in 1 second')
        time.sleep(1)
else:
    raise e