为制定某地区人群原发性高血压的社区综合防治方案,拟对某地区某时点原发性高血压的患病情况进行调查,这类研究是()。
A. 描述性研究
B. 分析性研究
C. 病例对照研究
D. 队列研究
E. 流行病学实验
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我国行业标准规定,切花的质量分为几级,分级指标主要有()、花形花色、花茎长度与花朵直径、叶片状态、病虫害与损伤等。
You are developing a Windows Communication Foundation (WCF) service to provide an in-memory cache for many Web applications.The service contract is defined as follows. (Line numbers are included for reference only.) 01 [ServiceContract] 02 public interface IDataCache 03 { 04 ... 05 }06 07 08 public class DataCache : IDataCache 09 { 10 ... 11 } You need to ensure that all users share the cache. Which code segment should you insert at line 07?()
A. [ServiceBehavior(TransactionIsolationLevel = IsolationLevel.RepeatableRead)]
B. [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single)]
C. [ServiceBehavior(InstanceContextMode = InstanceContextMode.PerSession)]
D. [ServiceBehavior(TransactionIsolationLevel = IsolationLevel.ReadComitted)]
口疳是由于()
A. 心火上炎
B. 肝血不足
C. 阳气虚衰
D. 肺气失宣
E. 脾气虚弱