首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   13577篇
  免费   940篇
  国内免费   314篇
耳鼻咽喉   112篇
儿科学   64篇
妇产科学   158篇
基础医学   369篇
口腔科学   294篇
临床医学   1691篇
内科学   491篇
皮肤病学   58篇
神经病学   321篇
特种医学   324篇
外国民族医学   2篇
外科学   4102篇
综合类   3891篇
预防医学   658篇
眼科学   289篇
药学   1536篇
  42篇
中国医学   274篇
肿瘤学   155篇
  2024年   27篇
  2023年   211篇
  2022年   380篇
  2021年   478篇
  2020年   518篇
  2019年   415篇
  2018年   403篇
  2017年   461篇
  2016年   496篇
  2015年   505篇
  2014年   1073篇
  2013年   859篇
  2012年   984篇
  2011年   1007篇
  2010年   829篇
  2009年   747篇
  2008年   667篇
  2007年   699篇
  2006年   647篇
  2005年   605篇
  2004年   351篇
  2003年   312篇
  2002年   305篇
  2001年   246篇
  2000年   200篇
  1999年   172篇
  1998年   145篇
  1997年   143篇
  1996年   107篇
  1995年   117篇
  1994年   80篇
  1993年   82篇
  1992年   58篇
  1991年   79篇
  1990年   65篇
  1989年   53篇
  1988年   61篇
  1987年   60篇
  1986年   42篇
  1985年   34篇
  1984年   26篇
  1983年   22篇
  1982年   10篇
  1981年   11篇
  1980年   14篇
  1979年   4篇
  1978年   5篇
  1977年   7篇
  1974年   6篇
  1973年   1篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
双频谱指数在心脏瓣膜置换术中的观察   总被引:2,自引:0,他引:2  
目的应用脑电双频谱指数(BIS)监测常规经验麻醉下瓣膜置换术病人的麻醉深度(意识水平),观察BIS在伤害性刺激时的变化.方法选择30例瓣膜置换术病人,采用芬太尼、咪唑安定、哌库溴铵及心血管活性药物对病人实施麻醉;术中监测并有专人分别记录入室(基础值)、诱导后、插管后、切皮后、锯胸骨时、缝胸骨时及术毕BIS和MAP,HR各参数值,观察不同阶段各参数的变化.结果诱导后各参数均明显降低,虽然切皮后、锯胸骨及缝胸骨等强刺激后MAP和HR未见统计学意义的显著改变,但BIS却显著增高(P<0.01);全部病人锯胸骨时BIS均在60(67.28±8.97)以上,缝胸骨时63(68.46±8.70)以上,而无1例低于50者.结论该组瓣膜置换术病人麻醉偏浅,尤以锯胸骨、缝胸骨及术毕等时段为甚,表现为BIS值偏高,有知晓发生;知晓可发生在临床认为满意的麻醉中;应用BIS监测,可更加合理地评价麻醉深度.  相似文献   
52.
目的 研究全麻诱导以及手术对肥胖患者血浆抵抗素 (resistin)和肾素、血管紧张素Ⅱ及血糖的影响。方法 选择 4 0例全麻手术患者 ,根据BMI指数分为两组 :A组 (BMI>2 5 ) 2 0例为肥胖者 ;B组 (2 1 相似文献   
53.
全身麻醉插管术后院内获得性肺部感染探讨   总被引:17,自引:3,他引:14  
全身麻醉气管插管术后下呼吸道感染具有较高发生率。分析526例手术时间超过4小时普外科病例,经u检验发现全身麻醉气管插管术后患者肺部感染率明显高于持续性硬膜外麻醉术后患者,影响因素主要与全麻插管用具及麻醉机消毒情况有关,也与术前存在慢性阻塞性肺部疾患和术后保留气管插管有关。降低全麻术后肺部感染应重视无菌操作,尽可能对麻醉机管道进行常规消毒。  相似文献   
54.
对 2 45例 80岁以上老年病人髋关节手术的麻醉进行如下处理 :术前全面估计病人的全身情况和心、肺等重要脏器的功能状态 ,使病人的全身状态调整到最佳水平 ;首选连续硬膜外麻醉有其优点 ;小剂量、分次给药 ,避免麻醉阻滞平面过广 ;此手术创伤大 ,失血多 ,以及应用骨黏合剂 ,有可能出现心血管反应 ,应及时补充血容量 ,并纠正不良反应 ;肺组织退行性变 ,血氧分压降低 ,术中、术后常规吸氧 ;加强术后监测、护理 ,预防易发生的并发症  相似文献   
55.
56.
Background: Nausea and vomiting during and after spinal anaesthesia for caesarean section are distressing to the patient. This study was undertaken to evaluate the efficacy and safety of granisetron, droperidol and metoclopramide for the prevention of nausea and vomiting in parturients undergoing caesarean section under spinal anaesthesia.
Methods: In a randomized, double-blind, placebo-controlled trial, 120 patients received granisetron 3 mg, droperidol 1.25 mg, metoclopramide 10 mg or placebo (saline) ( n =30 of each) i. v. immediately after clamping of the foetal umbilical cord. Nausea, vomiting and safety assessments were performed during and after spinal anaesthesia for caesarean section.
Results: The incidence of intraoperative, post-delivery nausea and vomiting was 13%, 17%, 20% and 63% after administration of granisetron, droperidol, metoclopramide and placebo, respectively; the corresponding incidence during 0–3 h after surgery was 7%, 27%, 27% and 43%; the corresponding incidence during 3–24 h after surgery was 7%, 20%, 23% and 37% ( P <0.05; overall Fisher's exact probability test). No clinically important adverse events were observed in any of the groups.
Conclusion: Granisetron is highly effective for preventing nausea and vomiting during and after spinal anaesthesia for caesarean section. Droperidol and metoclopramide are effective for the prevention of intraoperative, post-delivery emesis, but are ineffective for the reduction of the incidence of postoperative emesis.  相似文献   
57.
Summary Magnetic resonance (MR) images of 29 consecutive patients with intraspinal neoplasms (9 intramedullary tumors, 20 extramedullary tumors) were reviewed to evaluated the utility of MR imaging in distinguishing the intraspinal compartmental localisation and signal characteristics of each lesion. Compartment and histology of all neoplasms were surgically proven. MR correctly assigned one of three compartments to all lesions, 9 intramedullary, 14 intradural extramedullary (6 schwannomas, 3 neurofibromas, 5 meningiomas), and 6 extradural (3 schwannomas, 1 meningioma, 1 cavernous hemangioma, 1 metastatic renal cell carcinoma). All intramedullary tumors showed swelling of the spinal cord itself. In all five extradural tumors a low intensity band was visualized between the spinal cord and tumor. On the other hand, a low intensity band was demonstrated in no cases with intradural tumors. Visualization of this low intensity band is important in differentiating extradural from intradural-extramedullary lesions. We call this low intensity band, the extradural sign. Signal intensity of intradural tumors varied with histology. In extramedullary tumors, signal intensity of schwannomas was similar to that of the cerebrospinal fluid (CSF) both on T1 weighted (inversion recovery) and T2 weighted spin echo (SE) images. On the other hand, meningiomas tended to be isointense to the spinal cord on both T1 and T2 weighted SE images. We found relatively reliable signal characteristics to discriminate meningioma from schwannoma.  相似文献   
58.
The effects of lung volume and respiratory airflow on airway resistance were studied in five anesthetized and paralyzed patients. Airway resistance measured during the inspiratory phase with intermittent constant airflow inflatoins decreased in inverse correlationship to increases in lung volume. Airway resistance measured during the expiratory phase with an airway interruption technique, on the other hand, increased with a linear relationship to the expiratory airflow as expressed by a function of Y = K1 + K2X. K1, calculated from the values of airway resistance corresponding to three different airflows, was unaffected by intentional expiratory resistance loading. Thus, simultaneously with the measurement of airway resistance by this method, expiratory gas sampling with a Douglas bag can be done if necessary. Since the K2 value of the endotracheal tube used in this study (Portex® I.D. 8mm, length 26cm) was quite high (5.0cmH2O·1–2·sec2), depending on the airflow, the presence of the endotracheal tube strongly affected the measurement of airway resistance during general anesthesia. K1 measured by the above method, however, may be considered as the best way to evaluate the lower airway resistance independent of either lung volume or expiratory airflow.(Sakai T, Yoshida H, Yano H et al.: Measurement of airway resistance in anesthetized and paralyzed subjects: proposal for evaluation of K1 values. J Anesth 2: 139–145, 1988)  相似文献   
59.
该研究将通过M icrosoft V isua l C 6.0和V isua l B as ic 6.0为主要的开发工具,SQL Server为数据库,采用客户端/服务器结构,设计出基于W indow s操作系统,网络环境下运行的应用程序,并将它们用于自动麻醉记录。该自动记录系统负责处理麻醉全过程中的相关病人信息,对医护现场的多种医疗设备:如监护仪、静脉输液泵、麻醉机等进行数据的实时自动采集、加工以及集成等,并在综合病人相关信息及生理参数的基础上自动输出麻醉记录单。该记录系统不仅提高了临床医师的工作效率,减低了麻醉医师的劳动强度,而且使麻醉记录更加准确和完整。  相似文献   
60.
Urethane anesthetized (< 1 .3 g/kg), Sprague-Dawley (SD) rats spontaneously cycled between a cortically desynchronized state (State I) and a cortically synchronized state (State III), which were very similar to awake and slow wave sleep (SWS) states in unanesthetized animals, based on EEG criteria. These low levels of urethane anaesthesia did not cause significant respiratory depression or reductions in sensitivity to hypoxia (10% O2 in nitrogen) or hypercapnia (5% CO2 in air) in rats in either State I or State III. Thus, breathing frequency (fR), tidal volume (VT) and total ventilation (VTOT) all increased on cortical activation in urethane-anaesthetized rats whether breathing air, the hypoxic or the hypercapnic gas mixture, in a manner that was very similar to that observed in unanaesthetized animals. The relative sensitivity to hypoxia was greater in State III than State I, the relative sensitivity to CO2, overall, was equal in both states, State III occurred less often during hypoxia and hypercapnia, and hypoxic, urethane-anaesthetized rats sighed frequently, particularly in State I. This is also similar to the situation seen in unanesthetized rats. Given the similarities seen between urethane anesthetized rats in the present study and literature values for unanesthetized rats, the data suggest that urethane-anaesthetized rats provide a good model system for studying respiratory patterns and chemoreflexes as a function of cortical activation state.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号