全文获取类型
收费全文 | 16922篇 |
免费 | 925篇 |
国内免费 | 164篇 |
专业分类
耳鼻咽喉 | 213篇 |
儿科学 | 323篇 |
妇产科学 | 374篇 |
基础医学 | 1948篇 |
口腔科学 | 628篇 |
临床医学 | 1309篇 |
内科学 | 4381篇 |
皮肤病学 | 214篇 |
神经病学 | 1954篇 |
特种医学 | 626篇 |
外科学 | 2800篇 |
综合类 | 39篇 |
一般理论 | 2篇 |
预防医学 | 643篇 |
眼科学 | 273篇 |
药学 | 903篇 |
中国医学 | 17篇 |
肿瘤学 | 1364篇 |
出版年
2024年 | 10篇 |
2023年 | 179篇 |
2022年 | 436篇 |
2021年 | 700篇 |
2020年 | 415篇 |
2019年 | 574篇 |
2018年 | 613篇 |
2017年 | 469篇 |
2016年 | 518篇 |
2015年 | 570篇 |
2014年 | 747篇 |
2013年 | 998篇 |
2012年 | 1430篇 |
2011年 | 1493篇 |
2010年 | 785篇 |
2009年 | 752篇 |
2008年 | 1085篇 |
2007年 | 1080篇 |
2006年 | 933篇 |
2005年 | 918篇 |
2004年 | 893篇 |
2003年 | 695篇 |
2002年 | 639篇 |
2001年 | 86篇 |
2000年 | 46篇 |
1999年 | 77篇 |
1998年 | 130篇 |
1997年 | 116篇 |
1996年 | 85篇 |
1995年 | 72篇 |
1994年 | 70篇 |
1993年 | 51篇 |
1992年 | 31篇 |
1991年 | 27篇 |
1990年 | 37篇 |
1989年 | 32篇 |
1988年 | 22篇 |
1987年 | 18篇 |
1986年 | 25篇 |
1985年 | 14篇 |
1984年 | 19篇 |
1983年 | 19篇 |
1982年 | 24篇 |
1981年 | 15篇 |
1980年 | 18篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1976年 | 4篇 |
1973年 | 3篇 |
1892年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
32.
Lynn R. Sorbara Zhichun Tang Alessandro Cama Jinru Xia Esther Schenker Ronald A. Kohanski Leonid Poretsky Elizabeth Koller Simeon I. Taylor Andrea Dunaif 《Metabolism: clinical and experimental》1994,43(12)
Women with polycystic ovary syndrome (PCOS) are markedly insulin-resistant, but the molecular mechanisms of these changes and their relationship to the hyperandrogenic state remain to be clarified. Mutations have recently been identified in the insulin receptor gene of patients with extreme forms of insulin resistance associated with hyperandrogenism (eg, type A insulin resistance), and these mutations account for the insulin resistance in such patients. We performed this study to determine whether mutations in the coding portion of the insulin receptor gene were responsible for insulin resistance in PCOS. Insulin binding studies using cultured skin fibroblasts of three obese (body mass index > 27 kg/m2) women with PCOS (ie, mild hyperandrogenemia and chronic anovulation of unknown etiology) and documented insulin resistance showed no apprarent abnormalities in either the number or affinity of insulin binding sites. Direct sequencing of all 22 exons of the insulin receptor gene from two of the women with PCOS did not reveal any mutations. Furthermore, both alleles of the gene were expressed at equal levels. In a third insulin-resistant PCOS woman, there was no evidence for a mutation in the coding portion of the insulin receptor gene as determined by denaturing gradient gel electrophoresis (DGGE). We conclude that the insulin resistance in these PCOS women was caused by a defect extrinsic to the insulin receptor. 相似文献
33.
Gonzalo Varela Alessandro Brunelli Gaetano Rocco Rita Marasco Marcelo F Jiménez Valeria Sciarra José Luis Aranda Tindaro Gatani 《European journal of cardio-thoracic surgery》2006,30(4):644-648
OBJECTIVE: Scanty information can be found regarding ppoFEV1% correlation with true FEV1% in the immediate days after surgery, when most cardio-respiratory complications are developed. This prospective multicentric investigation aims to describe the evolution of FEV1 in a series of uneventful lobectomy cases before hospital discharge, and to identify factors associated with the variation of postoperative residual FEV1, with the ratio between the actual and the predicted postoperative FEV1 measured during the first 6 postoperative days. METHODS: One hundred and sixty-one patients submitted to lobectomy were prospectively enrolled in the study. Patients with chest wall resections and postoperative complications were excluded. Data from a total of 125 patients were thus used for the analysis. The following clinical variables were recorded: age, preoperative FEV1, ppoFEV1, presence of chronic obstructive pulmonary disease (COPD), surgical approach (VATS or muscle-sparing thoracotomy), side (right or left) and site (upper or lower) of resection, type of analgesia (epidural or intravenous), and daily visual analogue pain score (VAS). FEV1 was measured in every patient at hospital admission and daily until discharge or up to postoperative day 6. Random effects time-series cross-sectional regression analyses were performed to identify factors associated with variation of postoperative residual function (100-(preoperative FEV1-postoperative FEV1/preoperative FEV1 x 100)), and of FEV1 ratio ((actual postoperative FEV1 x 100)/ppoFEV1). For these analyses, the dependent variables (postoperative residual function and FEV1 ratio) and the pain score were analysed as panel longitudinal data. The regression analyses were subsequently validated by bootstrap procedure. RESULTS: FEV1% was lower at first postoperative day and increased gradually up to day 6 but mean values never reached ppoFEV1%. Pain scores decreased from day 1 to day 6. Preoperative FEV1 (p<0.0001) and postoperative pain score (p<0.0001) resulted independently and reliably inversely associated with postoperative residual FEV1 (model R2, 0.16). Preoperative FEV1 (p=0.001), postoperative pain score (p<0.0001), and epidural analgesia (p=0.04) resulted independently and reliably associated with postoperative FEV1 ratio (model R2, 0.13). CONCLUSION: Current methods of prediction of postoperative FEV1 greatly underestimated the real functional loss in the immediate postoperative period. Therefore, for the purpose of a more accurate risk stratification we need to correct the traditional prediction of postoperative FEV1. 相似文献
34.
Imad Sheiban M. D. Dino Casarotto Giampaolo Trevi Paolo Benussi Alberto Marini Roberto Accardi Antonio Motta Massimo Brunelli Claudio Muneretto Alessandro Tenuti Ludovico Antonio Scuro 《Cardiovascular and interventional radiology》1987,10(3):157-161
The accuracy of two-dimensional echocardiography in the detection of intracardiac masses was verified in 334 patients who
underwent cardiac catheterization in our laboratory over 21 consecutive months. A complete two-dimensional echocardiographic
(2DE) examination was performed a day before catheterization. The presence or absence of a mass was verified at surgery in
77 patients who successively underwent mitral or aortic valve replacement (51), left ventricular aneurysmectomy with or without
myocardial revascularization (25), and resection of atrial myxoma (2). In 32 patients 2DE revealed the presence of a mass-left
or right atrial thrombi in 12, left atrial myxoma in 2, left ventricular thrombi in 16, and endocardial vegetations in 2.
The other 45 patients were free of intracardiac masses on 2DE. Anatomic verification at surgery revealed the presence of an
intracardiac mass in 34 patients. In 30 (true positives) of these, 2DE revealed the mass as well, and in 4 (false negatives)
the presence of a mass had not been identified by 2DE. In 2 patients (false positives) the predicted mass was not found at
surgery. Absence of a mass was correctly predicted by 2DE in 41 patients (true negatives). Thus 2DE detected intracardiac
masses with sensitivity of 88.2% and a specificity of 95.3%. We recommend that 2DE be performed in all patients prior to hemodynamic
study and/or cardiac surgery to enable safer management of patients with intracardiac masses during cardiac catheterization
and/or cardiac surgery. 相似文献
35.
Carlo Aprile Raffaella Saponaro Giuseppe Villa Mauro Carena Fabio Lunghi Sebastiano B. Solerte Alessandro Salvadeo 《European journal of nuclear medicine and molecular imaging》1986,12(1):37-40
The aim of this work is to correlate the net kidney uptake of99mTc-aprotinin (TcA) in 103 subjects with separate effective renal plasma flow (ERPF) and some blood chemistry parameters at 90, 180, and 360 min postinjection both in the normal and diseased kidney. Correlations found with separate ERPFs are highly significant at any time (P < 0.001). However, although the slope of the regression line is steeper at 180 min,r tends to deteriorate slightly with time postinjection and a higher intercept on they axis: this pattern is more pronounced if diseased kidneys are considered separately. The following are probably related to the renal handling of TcA: (1) Early scans better reflect blood flow to the kidney, while later scans are more related to the metabolism/excretion tubular mechanisms; (2) correlations found with urea, creatinine, urea clearance, and creatinine clearance are highly significant at any time; (3) in 20 additional patients with diseased kidneys, renal uptake measurements done 360 min postinjection first with TcA and then with DMSA showed better correlations with ERPF employing TcA. Our results indicate that TcA is a feasible indicator of split renal function even at 90 min postinjection when a scan is easily carried out on an outpatient basis.This paper was in part presented at the European Nuclear Medicine Congress, August 14–17, 1984, Helsinki, Finland 相似文献
36.
Ennio Toscano Alessandro Simonati Yasuhiro Indo Generoso Andria 《Annals of neurology》2003,53(3):418-419
37.
38.
Andrea Gallamini Alberto Biggi Adriana Fruttero Francesco Pugno Giobatta Cavallero Patrizia Pregno Mariella Grasso Chiara Farinelli Alessandro Leone Eugenio Gallo 《European journal of nuclear medicine and molecular imaging》1997,24(12):1499-1506
The purpose of this study was threefold: to evaluate the role of gallium-67 scintigraphy in the staging of low-grade non-Hodgkin’s
lymphomas (LGNHL), to assess the relationship between the expression of CD71 on the surface of the neoplastic cells and the
67Ga uptake by the tumour, and to establish the contribution of 67Ga scan in defining the prognosis of LGNHL. Forty-eight patients with untreated LGNHL diagnosed in a single institution over
a decade were reviewed. The end point of the study was survival of the patients according to the scintigraphic 67Ga score at diagnosis. In addition to 67Ga scan, other prognostic variables were studied, relating to the neoplastic burden, the biology of the tumour and the host.
Univariate and multivariate analyses were used. 67Ga scan identified only 116/286 (41%) nodes involved by lymphoma that were detected by clinical examination or computed tomography
scan. A scintigraphic scoring system with an arbitrary cut-off value of 3 (high scan score) was able to predict patients with
a dismal prognosis: with a mean follow-up of 47 months (range: 1–146 months) the median survival time was 28 months in patients
with a high scan score and 74 months in patients with a low scan score (P=0.002). CD71 values were 27.4%±14.9% (mean ±SD) in the former and 8.9%±7.2% in the latter (P=0.0001). Only performance status and extranodal sites were significant variables for prognosis in multivariate analysis.
It is concluded that 67Ga scan is inaccurate in staging but might be very important in defining the prognosis in LGNHL, in association with other
prognostic variables.
Received 1 May and in revised form 6 August 1997 相似文献
39.
40.
Prof. Alessandro Bianco MD Marco Cagossi MD Daniela Scrimieri MD Virgilio Greco MD 《Digestive diseases and sciences》1986,31(1):40-48
The authors studied 22 patients with severe dysphagia, and follow-up studies showed the appearance of some esophageal peristalsis for the first time in three of these patients after Heller myotomy. Comparison of pre- and postoperative clinical, radiological, and manometric data of these three subjects and the data of the other 19 patients showed no statistically significant differences between the two groups of patients either before or after cardiomyotomy except for the unusual appearance of esophageal peristalsis after surgery. According to these results it is not possible to predict which patients will develop peristalsis after cardiomyotomy. The different motor pattern observed after surgery might suggest the existence of a different pathogenesis underlying the esophageal motor disorders in these two groups of patients. 相似文献