Python 为什么刮痧反复刮一次结果就只有一次？

请帮助我解决这个问题：下面的spider代码将返回start\u url中列出的所有作业。但是，它只返回第一个作业的多个副本。Xpath代码在“Xpath检查器”中进行了正确测试。怎么了？谢谢你的意见

from scrapy.spiders import Spider
from scrapy.selector import Selector
from Testjobs.items import TestjobsItem, TestjobsItemLoader

class TestjobSpider(Spider):
    name = "test"
    allowed_domains = ['http://careers.pathologyjobstoday.org/']
    start_urls = [
        'http://careers.pathologyjobstoday.org/jobseeker/search/results'
    ]

    def parse(self, response):
        hxs = Selector(response)  
        sites = hxs.xpath('//tr[contains(@id, "jt_jobrow_")]') 

        for site in sites:
            il = TestjobsItemLoader(response=response, selector=site)
            il.add_xpath('title', 'normalize-space(//div[@class="jt_jobs_title"]/text())') 
            yield il.load_item()

您需要通过在“内部”XPath上下文前加一个点，使其特定：

normalize-space(.//div[@class="jt_jobs_title"]/text())
            HERE^