全文获取类型
收费全文 | 15794篇 |
免费 | 1149篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 191篇 |
儿科学 | 496篇 |
妇产科学 | 327篇 |
基础医学 | 2213篇 |
口腔科学 | 200篇 |
临床医学 | 2011篇 |
内科学 | 3251篇 |
皮肤病学 | 260篇 |
神经病学 | 1711篇 |
特种医学 | 411篇 |
外国民族医学 | 2篇 |
外科学 | 1674篇 |
综合类 | 161篇 |
一般理论 | 12篇 |
预防医学 | 1765篇 |
眼科学 | 373篇 |
药学 | 998篇 |
中国医学 | 28篇 |
肿瘤学 | 882篇 |
出版年
2023年 | 104篇 |
2022年 | 168篇 |
2021年 | 415篇 |
2020年 | 214篇 |
2019年 | 358篇 |
2018年 | 380篇 |
2017年 | 317篇 |
2016年 | 339篇 |
2015年 | 364篇 |
2014年 | 552篇 |
2013年 | 755篇 |
2012年 | 1196篇 |
2011年 | 1233篇 |
2010年 | 611篇 |
2009年 | 597篇 |
2008年 | 1019篇 |
2007年 | 1030篇 |
2006年 | 1016篇 |
2005年 | 999篇 |
2004年 | 997篇 |
2003年 | 906篇 |
2002年 | 816篇 |
2001年 | 153篇 |
2000年 | 128篇 |
1999年 | 176篇 |
1998年 | 173篇 |
1997年 | 132篇 |
1996年 | 135篇 |
1995年 | 115篇 |
1994年 | 96篇 |
1993年 | 90篇 |
1992年 | 86篇 |
1991年 | 102篇 |
1990年 | 84篇 |
1989年 | 74篇 |
1988年 | 76篇 |
1987年 | 85篇 |
1986年 | 89篇 |
1985年 | 76篇 |
1984年 | 75篇 |
1983年 | 51篇 |
1982年 | 47篇 |
1981年 | 53篇 |
1980年 | 50篇 |
1979年 | 43篇 |
1978年 | 30篇 |
1977年 | 32篇 |
1976年 | 33篇 |
1975年 | 40篇 |
1974年 | 30篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Catherine E Milch David M Kent Robin Ruthazer J Hector Pope Thomas P Aufderheide Robert A McNutt Harry P Selker 《Journal of investigative medicine》2006,54(2):76-85
BACKGROUND: Many studies have shown differences in cardiac care by racial/ethnic groups without accounting for institutional factors at the location of care. OBJECTIVE: Exploratory analysis of the effect of hospital funding status (public vs private) on emergency department (ED) triage decision making for patients with symptoms suggestive of acute coronary syndromes (ACSs) and on the likelihood of ED discharge for patients with confirmed ACS. STUDY DESIGN AND SETTING: Secondary analysis of data from a randomized controlled trial of 10,659 ED patients with possible ACS in five urban academic public and five private hospitals. The main outcome measures were the sensitivity and specificity of hospital admission for the presence of ACS at public and private hospitals and the adjusted odds of a patient with ACS not being hospitalized at public versus private hospitals. RESULTS: Of 10,659 ED patients, 1,856 had confirmed ACS. For patients with suspected ACS, triage decisions at private hospitals were considerably more sensitive (99 vs 96%; p<.001) but less specific (30 vs 48%; p<.001) than at public hospitals. The difference between hospital types persisted after adjustment for multiple patient-level and hospital-level characteristics. CONCLUSION: Significant differences in triage for patients with suspected ACS exist between public and private hospital EDs, even after adjustment for multiple patient demographic, clinical, and institutional factors. Further studies are needed to clarify the causes of the differences. 相似文献
62.
Shamir Patel Geoffrey B Marshall Robin R Gray 《Journal l'Association canadienne des radiologistes》2004,55(5):288-93; quiz 293
63.
Robin Hutchinson 《Macromolecular chemistry and physics.》2006,207(15):1414-1415
Conference Reports: This section contains reports on topical conferences. Reports are usually written at the request of the editorial office, but unsolicited contributions are also welcome. Suggestions should be sent to the editorial office of the Macromolecular journals, preferably by E‐mail to macromol@wiley‐vch.de. 相似文献
64.
Laura I Sacolick Douglas L Rothman Robin A de Graaf 《Magnetic resonance in medicine》2007,57(3):548-553
Because of their excellent slice profiles and high immunity to RF inhomogeneity, adiabatic full passage (AFP) pulses are ideal for use in spatial localization. The nonlinear, position-dependent phase of a single AFP pulse generated during refocusing of transverse magnetization traditionally is eliminated by using identical pairs of AFP pulses, at the expense of increased RF power deposition and increased echo time (TE). Here it is shown that one can achieve significant phase refocusing by executing single AFP pulses along non-equivalent spatial axes. When used for volume selection in MR spectroscopic imaging (MRSI) the remaining nonlinear phase becomes inconsequential when the phase across a spectroscopic volume is small. Selection of rectangular and octagonal volumes is demonstrated with half the number of AFP pulses used in the traditional approach. It is shown that octagonal volume selection in the human brain provides excellent suppression of extracranial lipids, and thus allows multislice (1)H MRSI at 4 Tesla to be performed within the guidelines for RF power deposition. 相似文献
65.
Tamponade caused by cardiac lipomatous hypertrophy. 总被引:1,自引:0,他引:1
Saul G Myerson Robin Roberts Neil Moat Dudley J Pennell 《Journal of cardiovascular magnetic resonance》2004,6(2):565-568
Cardiac lipomatous hypertrophy is an unusual disorder that typically affects the interatrial septum. We report a case in which large subpericardial deposits of fat were initially mistaken for a pericardial effusion and the subsequent clinical picture resembled tamponade. The patient improved following a pericardiectomy. 相似文献
66.
67.
Supha K Arthurs Albert J Eid Rachel A Pedersen Ross A Dierkhising Walter K Kremers Robin Patel Raymund R Razonable 《Liver transplantation》2007,13(12):1703-1709
Clinical practice guidelines recommend antiviral prophylaxis to cytomegalovirus (CMV) donor-positive/recipient-negative (D+/R-) liver transplant recipients. We assessed the outcome of this strategy by determining the incidence, clinical features, and risk factors of CMV disease among CMV D+/R- liver transplant recipients who received antiviral prophylaxis. Sixty-seven CMV D+/R- liver transplant recipients (mean age+/-standard deviation: 49.5+/-11.4 years; 75% male) received oral ganciclovir [n=9 (13%)] or valganciclovir [n=58 (87%)] prophylaxis for a median duration of 92 days (interquartile range: 91-100). No breakthrough CMV disease was observed during antiviral prophylaxis. However, primary CMV disease was observed in 2%, 25%, 27%, 27%, and 29% of patients at 1, 3, 6, 12, and 24 months, respectively, after antiviral prophylaxis was stopped. The incidence of delayed-onset primary CMV disease was similar between those who received oral ganciclovir and valganciclovir. Nine (47%) patients had CMV syndrome, 8 (42%) had gastrointestinal CMV disease, and 2 (11%) had CMV hepatitis. Female patients (P=0.01) and younger age at transplant (P=0.03) were associated with an increased risk, whereas diabetes mellitus (P<0.001) was significantly associated with a lower risk of delayed-onset primary CMV disease. Allograft loss or mortality occurred in 8 (12%) patients during the median follow-up period of 3.31 (range: 0.8-5.9) years. No significant association was observed between CMV disease and patient and allograft survival. In conclusion, CMV disease remains a common complication in CMV D+/R- liver transplant patients during the contemporary era of antiviral prophylaxis. Female patients and younger patients are at increased risk of delayed-onset primary CMV disease. 相似文献
68.
Robin M Heidemann Mark A Griswold Nicole Seiberlich Mathias Nittka Stephan A R Kannengiesser Berthold Kiefer Peter M Jakob 《Magnetic resonance in medicine》2007,57(6):1037-1046
MRI with non-Cartesian sampling schemes can offer inherent advantages. Radial acquisitions are known to be very robust, even in the case of vast undersampling. This is also true for 1D non-Cartesian MRI, in which the center of k-space is oversampled or at least sampled at the Nyquist rate. There are two main reasons for the more relaxed foldover artifact behavior: First, due to the oversampling of the center, high-energy foldover artifacts originating from the center of k-space are avoided. Second, due to the non-equidistant sampling of k-space, the corresponding field of view (FOV) is no longer well defined. As a result, foldover artifacts are blurred over a broad range and appear less severe. The more relaxed foldover artifact behavior and the densely sampled central k-space make trajectories of this type an ideal complement to autocalibrated parallel MRI (pMRI) techniques, such as generalized autocalibrating partially parallel acquisitions (GRAPPA). Although pMRI can benefit from non-Cartesian trajectories, this combination has not yet entered routine clinical use. One of the main reasons for this is the need for long reconstruction times due to the complex calculations necessary for non-Cartesian pMRI. In this work it is shown that one can significantly reduce the complexity of the calculations by exploiting a few specific properties of k-space-based pMRI. 相似文献
69.
Stéphane Aubert Roland Henaine Olivier Raisky Nicolas Chavanis Jacques Robin René Ecochard Jean Ninet 《European journal of cardio-thoracic surgery》2005,28(2):223-228
OBJECTIVE: We consider the short- and long-term outcomes of the repair of the isolated partial atrioventricular (AV) septal defect to determine the role played by the atypical forms on the initial AV valve replacement and on the risk of reoperation. METHODS: Two hundred and eight patients underwent an operation for this malformation between 1974 and 2001. Clinical and echocardiographic examinations were performed on all patients, the AV valve regurgitation was graded from 1 to 4 and a residual interatrial shunt was sought. Median age at the intervention was 5.8 years (3 months to 67 years). RESULTS: Median follow-up time was 7.5 years (range 0-22.6 years). The cumulative 30-day, 5- and 20-year survival rates were 96.5, 95.4 and 94.6%, respectively. AV valve replacement was associated with a high mortality (P<0.001). A reoperation was performed on 12 patients (5.7%) including six patients within less than a 30-day period, especially to repair residual AV valve regurgitation. We performed four AV valve repairs by annuloplasty and six AV valve replacements. Two patients who had initially undergone an AV valve replacement underwent a reoperation for valve thrombosis. The cumulative 30-day, 5- and 20-year rates of freedom from reoperation were 96.5, 93.6 and 83%, respectively. An atypical form was present in 24 patients (11.5%) and was a risk factor for initial AV valve replacement (P<0.001) and for reoperation (P<0.001). A complete AV block occurred in 13 patients (6.2%), all of them within a 30-day period. The AV valve replacement was a high risk factor for a complete AV block (P<0.001). At the end of our study 180 patients (96%) were in NYHA I and 8 in NYHA II. CONCLUSIONS: The morbi-mortality of the isolated partial AV septal defect is primarily perioperative and is linked with the presence of an atypical form of the lesion. This atypical form was the main reason for reoperation for AV valve regurgitation. The AV valve replacement was associated with a high mortality and with the occurrence of complete AV block. Using a standardized technique, the AV septal defect can be repaired with excellent long-term clinical and echographic results. 相似文献
70.
Vinay Puri Andrew McQuillin Khalid Choudhury Susmita Datta Jonathan Pimm Srinivasa Thirumalai Robert Krasucki Jacob Lawrence Digby Quested Nicholas Bass Helen Moorey Jenny Morgan Bhaskar Punukollu Gomathinayagam Kandasami David Curtis Hugh Gurling 《Neuropsychopharmacology》2007,61(7):873-879
BACKGROUND: Linkage studies by us and others have confirmed that chromosome 1q23.3 is a susceptibility locus for schizophrenia. Based on this information, several research groups have published evidence that markers within both the RGS4 and CAPON genes, which are 700 kb apart, independently showed allelic association with schizophrenia. Tests of allelic association with both of these genes in our case control sample were negative. Therefore, we carried out further fine mapping between the RGS4 and CAPON genes. METHODS: Twenty-nine SNP and microsatellite markers in the 1q23.3 region were genotyped in the United Kingdom based sample of 450 cases and 450 supernormal control subjects. RESULTS: We detected positive allelic association after the eighth marker was genotyped and found that three microsatellite markers (p = .011, p = .014, p = .049) and two SNPs (p = .004, p = .043) localized in the 700 kb region between the RGS4 and CAPON genes, within the UHMK1 gene, were associated with schizophrenia. Tests of significance for marker rs10494370 remained significant following Bonferroni correction (alpha = .006) for multiple tests. Tests of haplotypic association were also significant for UHMK1 (p = .009) using empirical permutation tests, which make it unnecessary to further correct for both multiple alleles and multiple markers. CONCLUSIONS: These results provide preliminary evidence that the UHMK1 gene increases susceptibility to schizophrenia. Further confirmation in adequately powered samples is needed. UHMK1 is a serine threonine kinase nuclear protein and is highly expressed in regions of the brain implicated in schizophrenia. 相似文献