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   68907篇
  免费   4526篇
  国内免费   1759篇
耳鼻咽喉   449篇
儿科学   967篇
妇产科学   598篇
基础医学   7918篇
口腔科学   1132篇
临床医学   6481篇
内科学   7006篇
皮肤病学   391篇
神经病学   9023篇
特种医学   2172篇
外国民族医学   2篇
外科学   4735篇
综合类   10971篇
现状与发展   6篇
预防医学   10190篇
眼科学   708篇
药学   7581篇
  108篇
中国医学   2561篇
肿瘤学   2193篇
  2024年   783篇
  2023年   1323篇
  2022年   2073篇
  2021年   2789篇
  2020年   2694篇
  2019年   2073篇
  2018年   1957篇
  2017年   1968篇
  2016年   2171篇
  2015年   2120篇
  2014年   4285篇
  2013年   4638篇
  2012年   4123篇
  2011年   4476篇
  2010年   3511篇
  2009年   3378篇
  2008年   3467篇
  2007年   3272篇
  2006年   2967篇
  2005年   2507篇
  2004年   2085篇
  2003年   1854篇
  2002年   1452篇
  2001年   1259篇
  2000年   1057篇
  1999年   897篇
  1998年   897篇
  1997年   862篇
  1996年   726篇
  1995年   682篇
  1994年   673篇
  1993年   573篇
  1992年   543篇
  1991年   530篇
  1990年   437篇
  1989年   388篇
  1988年   400篇
  1987年   377篇
  1986年   348篇
  1985年   474篇
  1984年   411篇
  1983年   248篇
  1982年   267篇
  1981年   243篇
  1980年   228篇
  1979年   147篇
  1978年   139篇
  1977年   124篇
  1976年   89篇
  1974年   46篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
目的探讨经单一切E1腹腔镜手术系统(SILS—Port系统)胸、腹腔镜联合在食管癌根治术中的应用。方法2011年8月~2013年5月我科经SILS—Port系统施行胸、腹镜联合食管癌根治术5例。肩胛听诊三角区第6肋间为观察孔,胸腔镜下两操作孔游离胸段食管及清扫淋巴结,通过SILS系统,腹腔镜下两孔游离胃及清扫淋巴结,胃上提至颈部与食管吻合。结果手术过程顺利,围手术期无死亡。腔镜手术时间(296.0±24.1)min,术中出血量(114±40)ml,术后胸、腹腔引流时间均是(1.2±0.4)d。术后第3天疼痛评分(2.2±0.8)分。5例分别清扫淋巴结9、8、6、5、7枚,其中2枚阳性。5例分别随访10、22、8、16、3个月,1例术后16个月肿瘤复发转移,无死亡。结论经SILS-Port系统胸、腹腔镜联合根治性切除早期、无明显外侵的中下段食管癌,创伤小,出血少,安全可靠。  相似文献   
52.
“中气不足,溲便为之变”这一理论在治疗肾系疾病中具有很大的指导意义,本文通过医案举例、分析,强调“中气不足,溲便为之变”这一理论在实际指导临床中的重大意义,强调该理论在病因分析、疾病治疗方面取得的良好效果,理论指导临床,为治疗疾病,研究病因,开阔了思路。  相似文献   
53.
PURPOSE: To describe and compare clients who were readmitted to the hospital during an episode of home health care, before and after the inception of the prospective payment system (PPS). DESIGN: A longitudinal mixed design was used to replicate a study conducted 9 years previously (pre-PPS) in the same home care agency in the central part of the United States. METHODS: Seventy-six closed-case medical records from a not-for-profit hospital-affiliated home care agency were retrospectively reviewed and compared to pre-PPS data. The same data collection tool, the Hospital Readmission Inventory, was used for both pre- and post-PPS studies. Nurse administrators at the data collection agency were interviewed concerning comparative results. FINDINGS: Currently readmitted clients were sicker than were those in the previous research report, they were readmitted sooner for a different diagnosis, and they had less continuity of services. CONCLUSIONS: The home health care industry has undergone a dramatic change in payment for services, from fee-for-service to PPS. Of particular concern is the adverse patient outcome of an unplanned hospital readmission. Prior studies have characterized such patients in home health care, but no comparative reports were found in a literature search since the inception of PPS. Findings from this study indicated that an increased emphasis on cost containment and higher-risk clients appear to have changed patterns of care delivery.  相似文献   
54.
In humans, intermittent and continuous theta‐burst stimulation (iTBS and cTBS) elicit long‐term changes in motor‐evoked potentials (MEPs) reflecting long‐term potentiation (LTP)‐ and depression (LTD)‐like plasticity in the primary motor cortex (M1). In this study, we used TBS to investigate M1 plasticity in patients with MSA. We also assessed whether responses to TBS reflect M1 excitability as tested by short‐interval intracortical inhibition (SICI), intracortical facilitation (ICF), short‐interval intracortical facilitation (SICF), and the input/output curves. We studied 20 patients with MSA and 20 healthy subjects (HS). Patients were clinically evaluated with the Unified Multiple System Atrophy Rating Scale. The left M1 was conditioned with TBS. Twenty MEPs were recorded from the right first dorsal interosseous muscle before TBS and 5, 15, and 30 minutes thereafter. In a subgroup of 10 patients, we also tested MEPs elicited by SICI, ICF, SICF, and input/output curves, before TBS. Between‐group analysis of variance showed that at all time points after iTBS MEPs increased, whereas after cTBS they decreased only in HS. In both subgroups tested, patients with predominant parkinsonian and cerebellar features, iTBS and cTBS left MEPs unchanged. MSA patients had reduced SICI, but normal ICF, SICF, and input/output curves. No correlation was found between patients' clinical features and responses to TBS and M1 excitability variables. These findings suggest impaired M1 plasticity in MSA. © 2013 International Parkinson and Movement Disorder Society  相似文献   
55.
Strong epidemiologic evidence suggests that smokers and coffee drinkers have a lower risk of Parkinson's disease (PD). The explanation for this finding is still unknown, and the discussion has focused on two main hypotheses. The first suggests that PD patients have premorbid personality traits associated with dislike for coffee‐drinking and smoking. The second posits that caffeine and nicotine are neuroprotective. We propose an alternative third hypothesis, in which both cigarette and coffee consumption change the composition of the microbiota in the gut in a way that mitigates intestinal inflammation. This, in turn, would lead to less misfolding of the protein alpha‐synuclein in enteric nerves, reducing the risk of PD by minimizing propagation of the protein aggregates to the central nervous system, where they otherwise can induce neurodegeneration. © 2014 International Parkinson and Movement Disorder Society  相似文献   
56.
《Pediatric neurology》2014,50(3):265-268
BackgroundMurine typhus is a systemic febrile illness caused by Rickettsia typhi, a gram-negative, obligate intracellular bacterium. It is found worldwide, including in the United States, where cases are concentrated in suburban areas of Texas and California. The disease manifests with fever, headache, and rash. Central nervous system involvement is rare in both adults and children. Aseptic meningitis and meningoencephalitis are the most common neurological presentations, occurring in 2% to 5% of cases. Neurological dysfunction, including memory impairment and behavioral alterations, can occur and usually are reversible. Long-term deficits are considered rare even in untreated cases and have not been described in the pediatric population.MethodsSingle case report.ResultsWe describe a previously healthy 17-year-old girl infected with R. typhi who developed meningoencephalitis that resulted in chronic cognitive impairment despite treatment.ConclusionMurine typhus should be considered in the differential diagnosis of aseptic meningitis and meningoencephalitis. Early diagnosis and treatment can prevent death and long-term morbidity.  相似文献   
57.
58.
Although olfaction in birds is known to be involved in a variety of behaviors, there is comparatively little detailed information on the olfactory brain. In the pigeon brain, the olfactory bulb (OB) is known to project to the prepiriform cortex (CPP), piriform cortex (CPi), and dorsolateral corticoid area (CDL), which together are called the olfactory pallium, but centrifugal pathways to the OB have not been fully explored. Fiber connections of CPi and CDL have been reported, but those of other olfactory pallial nuclei remain unknown. The present study examines the fiber connections of OB and CPP in pigeons to provide a more detailed picture of their connections using tract‐tracing methods. When anterograde and retrograde tracers were injected in OB, projections to a more extensive olfactory pallium were revealed, including the anterior olfactory nucleus, CPP, densocellular part of the hyperpallium, tenia tecta, hippocampal continuation, CPi, and CDL. OB projected commissural fibers to the contralateral OB but did not receive afferents from the contralateral olfactory pallium. When tracers were injected in CPP, reciprocal ipsilateral connections with OB and nuclei of the olfactory pallium were observed, and CPP projected to the caudolateral nidopallium and the limbic system, including the hippocampal formation, septum, lateral hypothalamic nucleus, and lateral mammillary nucleus. These results show that the connections of OB have a wider distribution throughout the olfactory pallium than previously thought and that CPP provides a centrifugal projection to the OB and acts as a relay station to the limbic system. J. Comp. Neurol. 522:1728–1752, 2014. © 2013 Wiley Periodicals, Inc.  相似文献   
59.

Background

Gouty arthritis (GA) is a chronic inflammatory arthritis in which both clinical and subclinical atherosclerosis are more frequent. The dynamic equilibrium between coagulation and fibrinolysis is impaired in inflammatory diseases. We determined TFPI and TAFI antigen levels in GA patients and evaluated their association with subclinical atherosclerosis.

Methods

We included 45 GA patients (41 males, 4 females; mean age: 51.6 years) and 25 asymptomatic hyperuricemic (AHU) subjects (19 males, 6 females; mean age: 48.1 years). Cardiovascular risk factors were determined. TAFI and TFPI levels were determined by ELISA. B-mode ultrasonography was used to detect subclinical atherosclerosis.

Results

Cardiovascular risk factors were similar in both groups. The carotid IMT was significantly higher in GA group than in AHU group (0.74 ± 0.23 mm vs. 0.61 ± 0.13 mm, p = 0.009). TFPI level was significantly higher in GA group than in AHU group (86.2 ± 48.9 ng/mL vs. 25.8 ± 21.4 ng/mL, p < 0.001); TAFI antigen was significantly higher in AHU group (22.6 ± 3.6 ng/mL vs. 25.7 ± 5.3 ng/mL, p = 0.006) than in GA patients. Atherosclerotic plaque formation was more frequent in GA group (p = 0.041). When GA patients with and without plaques were compared, the first group had significantly higher mean age (p = 0.01) and TFPI level (p = 0.028). TFPI level correlated with carotid IMT (r = 0.302; p = 0.028). Logistic regression analysis showed that age (OR: 1.236, 95%CI: 1.059-1.443, p = 0.007) and TFPI (OR: 1.031, 95%CI: 1.008-1.054, p = 0.008) were independent risk factors for the presence of plaques.

Conclusions

GA patients had more frequent subclinical atherosclerosis than subjects with AHU. Higher TFPI levels in GA patients –probably associated with enhanced endothelial damage- were related to subclinical atherosclerosis. Lower TAFI levels in GA pointed to impaired fibrinolysis.  相似文献   
60.
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