全文获取类型
收费全文 | 2231篇 |
免费 | 138篇 |
国内免费 | 42篇 |
专业分类
耳鼻咽喉 | 18篇 |
儿科学 | 78篇 |
妇产科学 | 27篇 |
基础医学 | 296篇 |
口腔科学 | 203篇 |
临床医学 | 219篇 |
内科学 | 522篇 |
皮肤病学 | 41篇 |
神经病学 | 144篇 |
特种医学 | 177篇 |
外科学 | 174篇 |
综合类 | 14篇 |
预防医学 | 238篇 |
眼科学 | 36篇 |
药学 | 134篇 |
中国医学 | 20篇 |
肿瘤学 | 70篇 |
出版年
2023年 | 14篇 |
2022年 | 23篇 |
2021年 | 56篇 |
2020年 | 43篇 |
2019年 | 55篇 |
2018年 | 56篇 |
2017年 | 50篇 |
2016年 | 35篇 |
2015年 | 72篇 |
2014年 | 73篇 |
2013年 | 108篇 |
2012年 | 140篇 |
2011年 | 155篇 |
2010年 | 109篇 |
2009年 | 95篇 |
2008年 | 115篇 |
2007年 | 148篇 |
2006年 | 84篇 |
2005年 | 88篇 |
2004年 | 77篇 |
2003年 | 58篇 |
2002年 | 52篇 |
2001年 | 46篇 |
2000年 | 38篇 |
1999年 | 29篇 |
1998年 | 63篇 |
1997年 | 54篇 |
1996年 | 56篇 |
1995年 | 44篇 |
1994年 | 45篇 |
1993年 | 30篇 |
1992年 | 14篇 |
1991年 | 20篇 |
1990年 | 15篇 |
1989年 | 31篇 |
1988年 | 31篇 |
1987年 | 20篇 |
1986年 | 18篇 |
1985年 | 11篇 |
1984年 | 9篇 |
1983年 | 9篇 |
1982年 | 13篇 |
1981年 | 9篇 |
1980年 | 16篇 |
1979年 | 8篇 |
1977年 | 10篇 |
1976年 | 7篇 |
1972年 | 8篇 |
1968年 | 8篇 |
1966年 | 6篇 |
排序方式: 共有2411条查询结果,搜索用时 15 毫秒
1.
J I?igo A Arce E Rodríguez D García de Viedma E Palenque M J Ruiz Serrano L Cabello F Chaves 《The international journal of tuberculosis and lung disease》2006,10(5):550-553
SETTING: Tuberculosis (TB) cases reported from nine districts of Madrid, where the percentage of immigrant population varied from 1.9% in 1996 to 12.2% in 2003. OBJECTIVE: To describe the trends in TB incidence from 1994 to 2003. DESIGN: Observational study. RESULTS: Between 1994-1995 and 2002-2003, the TB rate decreased from 48.5 (95% CI 45.8-51.1) to 23.3 per 100000 population (95% CI 21.5-25.1) (P < 0.001). The percentage of TB cases co-infected with HIV decreased from 55.9% in 1994 to 14.3% in 2003 (P < 0.001), whereas TB cases in foreigners increased from 2.6% in 1994 to 33.7% in 2003 (P < 0.001). CONCLUSION: Although the TB rates showed a marked decrease in the study period, the increasing impact of immigration contributed to slowing down the trend. 相似文献
2.
3.
Eros S. Chaves Robert C. Wood Archie A. Jones Dewey A. Newbold Mary A. Manwell Kenneth S. Kornman 《Journal of clinical periodontology》1993,20(2):139-143
Abstract Bleeding on probing (BOP) and the gingival index have been used to clinically characterize the degree of gingival inflammation. It is, however, unclear to what extent these parameters correlate to each other and to probing pocket depth (PD). The purpose of this clinical study was to evaluate the association between BOP and GI bleeding (scores of 2 and 3), as well as the relationship of these variables to PD, in a group of patients presenting with naturally-occurring gingivitis. Based on screening examinations of 125 subjects with at least 20 teeth, no more than 4 sites with PD over 6 mm, a BOP frequency of 30% or greater, and no systemic condition that would influence the inflammatory response, were selected. 2 weeks after screening they were examined at 6 sites per tooth for plaque index, GI, PD and BOP. A standardized pressure sensitive probe (Florida Probe) with 20 g probing force was used for BOP and PD measurements. In this population, means of 40.9% (S.E.= 1.36) BOP sites and 35.3% (S.E, = 1.81) GI bleeding sites per patient were found. A total of 20,008 sites ranging in PD up to 5.9 mm were evaluated; however, the majority of sites (19,723, 98.6%) presented with <4 mm PD. When sites were evaluated, BOP demonstrated a positive correlation with PD, whereas GI bleeding correlated with PH. For sites characterized by the absence of BOP as well as the absence of GI bleeding (scores 0 and 1), the highest % of agreement between the 2 indices (77.7%) was found in shallow sites (0.1–2 mm). In contrast, when sites presenting with both BOP and GI bleeding were analyzed, the highest % of agreement (85,4%) was found for sites with PD >4.0 mm. In this gingivitis population group, it appears that BOP and GI bleeding evaluate distinct inflammatory1 conditions of the gingival tissues, and the relationship between the 2 clinical parameters may vary according to PD at the individual site examined. 相似文献
4.
5.
6.
INVOLVEMENT OF NON-NMDA AND NMDA RECEPTORS IN GLUTAMATE-INDUCED PRESSOR OR DEPRESSOR RESPONSES OF THE PONS AND MEDULLA 总被引:1,自引:0,他引:1
SY Chen WC Wu CJ Tseng JS Kuo CY Chai 《Clinical and experimental pharmacology & physiology》1997,24(1):46-56
1. Fifty-five intact and six baroreceptor denervated and vagotomized cats of either sex were anaesthetized intraperito-neally with urethane (400 mg/kg) and a-chloralose (40 mg/kg). Responses of the systemic arterial pressure (SAP), mean SAP (MSAP) and sympathetic vertebral nerve (VNA) and renal nerve activities (RNA) were recorded. 2. In intact animals, monosodium L-glutamate (Glu, 0.1 mol/L, 50 nL) was microinjected into pressor areas of the locus coeruleus (LC), gigantocellular tegmental field (GTF), rostral ventrolateral medulla (RVLM) and dorsomedial medulla (DM), and the depressor areas of caudal ventrolateral medulla (CVLM). The induced actions were compared before and after microinjection of either glutamate antagonists, glutamate diethylester (GDEE, 0.5 mol/L, 50–100nL), a competitive AMPA receptor blocker, or 2-amino-5-phosphonovaleric acid (D-AP5, 0.025 mol/L, 50–100 nL), a competitive N-methyl-D-aspartate (NMDA) receptor blocker. GDEE completely blocked the increases of SAP and VNA elicited from all pressor areas. D-AP5 only partially blocked the pressor but slightly blocked VNA and RNA responses from LC, GTF and DM, particularly those from RVLM. Neither GDEE nor D-AP5 blocked the depressor responses of SAP and two nerve activities elicited from CVLM. 3. In baroreceptor denervated animals, NMDA (2 mmol/L, 50–100 nL) and AMPA (0.2 mmol/L, 50–100 nL) were micro-injected into the same pressor areas of GTF, RVLM and DM and the depressor area of CVLM responsive to Glu activation (0.1 mol/L, 30 nL). In RVLM, DM and CVLM, the results of either NMDA or AMPA were similar to those induced by Glu. However, in GTF, microinjection of either NMDA or AMPA did not induce similar responses to Glu. This suggests that the nature of GTF may differ from RVLM and DM. 4. The above results suggest that the Glu-induced pressor responses from LC, GTF, DM and especially RVLM, are primarily mediated through AMPA receptors. The Glu-induced depressor responses from CVLM may not be predominantly mediated by either AMPA or NMDA receptors. 5. In both baroreceptor-intact and -denervated cats stimulation of the pressor areas often produced an increase of VNA and a decrease of RNA, while in the depressor CVLM decreased both VNA and RNA. The VNA, but not RNA were positively correlated with the pressor responses, while both VNA and RNA were positively correlated with the depressor responses. This may suggest that neurons of the sympathetic vertebral and renal nerves are topographically organized in the brain. 相似文献
7.
8.
9.
M Kurian L Spinelli J Delavelle J P Willi M Velazquez V Chaves W Habre K Meagher-Villemure E Roulet J G Villeneuve M Seeck 《Epileptic Disord》2007,9(1):20-31
Multiple structural and functional imaging modalities are available to localize the epileptogenic focus. In pre-surgical evaluation of children with pharmacoresistant epilepsy, investigations with the maximum yield should be considered in order to reduce the complexity of the workup. OBJECTIVE: To determine the extent to which PET, ictal/interictal SPECT and its co-registration with the patient's MRI contributes to correct localization of the epileptogenic focus, surgical intervention and to the post surgical outcome in paediatric patients. METHODS: The study population included children and adolescents with pharmacoresistant epilepsy (n = 50) who underwent preoperative evaluation, surgery and had postoperative follow-up for at least 12 months. Outcome was measured by postoperative seizure frequency using Engel's classification. RESULTS: Thirty-nine patients (78%) became completely seizure free after surgical intervention. The likelihood to benefit from surgical treatment was significantly higher if localization with more imaging modalities (MRI, PET, SPECT) were concordant with respect to the resected brain area (p < 0.01). Preoperative PET examination provided better localizing information in patients with extratemporal epilepsy and/or dysplastic lesions, whereas SPECT was found to be superior to PET in patients with temporal lobe epilepsy and/or tumors (p < 0.05). No significant difference was noted in the surgical outcome in younger or older age group, in children with or without special education needs. CONCLUSION: In paediatric epilepsy pre-surgical evaluation, the combined use of multiple functional imaging modalities for a precise localisation of the epileptogenic focus is worthwhile for both extratemporal and temporal lobe epilepsy, also when EEG and MRI alone are non-contributive, given the potential benefit of complete postoperative seizure control. 相似文献
10.
Digital radiography of subtle pulmonary abnormalities: an ROC study of the effect of pixel size on observer performance 总被引:3,自引:0,他引:3
Forty conventional radiographs with examples of mild interstitial infiltrates and subtle pneumothoraces and 40 normal studies of the chest were selected and digitized, with pixel sizes of 1.0, 0.5, 0.2, and 0.1 mm. Observer performance tests were carried out using receiver operating characteristic analysis. Conventional radiographs and digitized images were compared. The results indicate that, in such cases, diagnostic accuracy increases significantly as the pixel size is reduced, at least to the 0.1-mm level. We conclude that, for digital systems using screen-film or similar image receptors, use of a pixel size substantially larger than 0.1 mm may result in some loss of diagnostic accuracy. 相似文献