全文获取类型
收费全文 | 493篇 |
免费 | 30篇 |
专业分类
耳鼻咽喉 | 13篇 |
儿科学 | 3篇 |
妇产科学 | 7篇 |
基础医学 | 68篇 |
口腔科学 | 13篇 |
临床医学 | 17篇 |
内科学 | 65篇 |
皮肤病学 | 101篇 |
神经病学 | 60篇 |
特种医学 | 5篇 |
外科学 | 73篇 |
综合类 | 5篇 |
一般理论 | 1篇 |
预防医学 | 17篇 |
眼科学 | 20篇 |
药学 | 46篇 |
中国医学 | 1篇 |
肿瘤学 | 8篇 |
出版年
2023年 | 3篇 |
2022年 | 1篇 |
2021年 | 9篇 |
2020年 | 6篇 |
2019年 | 10篇 |
2018年 | 16篇 |
2017年 | 11篇 |
2016年 | 9篇 |
2015年 | 8篇 |
2014年 | 22篇 |
2013年 | 24篇 |
2012年 | 46篇 |
2011年 | 35篇 |
2010年 | 25篇 |
2009年 | 21篇 |
2008年 | 36篇 |
2007年 | 50篇 |
2006年 | 37篇 |
2005年 | 20篇 |
2004年 | 18篇 |
2003年 | 12篇 |
2002年 | 13篇 |
2001年 | 17篇 |
2000年 | 11篇 |
1999年 | 4篇 |
1998年 | 1篇 |
1997年 | 4篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有523条查询结果,搜索用时 15 毫秒
31.
A rare case of angiokeratoma Fordyce localized on the margin of the glans penis in a 52-year-old Caucasian patient is reported. Combined treatment with Erbium: YAG and 532 nm KTP (frequency doubled Neodynium: YAG) laser led to excellent cosmetic results. 相似文献
32.
Martin EM Pitrak DL Rains N Grbesic S Pursell K Nunnally G Bechara A 《Neuropsychology》2003,17(2):283-288
Working memory (WM) deficits are common in HIV-seropositive (HIV+) individuals and can be amplified by manipulating a variety of task parameters, such as increasing memory load or information complexity. The authors investigated the role of timing in HIV-associated WM defects by varying the amount of time required to maintain information online while holding memory load and information complexity constant. The authors studied 50 HIV+ and 35 HIV-seronegative (HIV-) polydrug abusers abstinent at testing and well-matched on demographic variables. The HIV- group outperformed the HIV+ group across all stimulus-response time delays. HIV-associated WM defects are not critically dependent on the amount of time stimulus representations must be maintained and might be attributed to impaired encoding or retrieval of stimulus representations. 相似文献
33.
Barnett SD Halpin LS Speir AM Albus RA Akl BF Massimiano PS Burton NA Collazo LR Lefrak EA 《The Annals of thoracic surgery》2003,76(3):726-731
BACKGROUND: The octogenarian patient is often perceived as too fragile to undergo cardiothoracic surgery. Our study aimed to compare postoperative complications in patients aged less than 80 versus elderly patients (80 years or more) after surgical cardiac intervention (coronary artery bypass or valve replacement). METHODS: Subjects were all patients (n = 8,361) who had an open-heart procedure, either coronary artery bypass or valve implantation or replacement, at two medical centers located in northern Virginia using the same surgical group. A computerized medical record database was reviewed to determine preoperative risk factors and postoperative outcomes. Predictors of complications were identified by univariate and multivariate logistic regression. RESULTS: A total of 3,214 complications were recorded. The most prevalent complications were prolonged ventilation time in the intensive care unit, reoperation for bleeding, and pneumonia. The overall mortality rate was 2.4% (204 of 8,361). Persons aged over 80 years had nearly double the mortality rate compared with younger patients (4.1% [18 of 444] to 2.3% [186 of 7,917]). Age greater than 80 years (odds ratio = 2.65, 95% confidence interval = 2.18 to 3.22) and male gender (odds ratio = 0.62, 95% confidence interval = 0.56 to 0.69) were the best univariate predictors of a single postoperative complication. CONCLUSIONS: Octogenarian patients manifested twice the risk of death from a cardiac intervention with an average 2-day longer hospital stay compared with their younger counterparts. Furthermore, octogenarians were at markedly higher risk of nonfatal postoperative complications. 相似文献
34.
Aminoacetone (AA) is a threonine and glycine catabolite long known to accumulate in cri-du-chat and threoninemia syndromes and, more recently, implicated as a contributing source of methylglyoxal (MG) in diabetes mellitus. Oxidation of AA to MG, NH(4)(+), and H(2)O(2) has been reported to be catalyzed by a copper-dependent semicarbazide sensitive amine oxidase (SSAO) as well as by Cu(II) ions. We here study the mechanism of AA aerobic oxidation, in the presence and absence of iron ions, and coupled to iron release from ferritin. Aminoacetone (1-7 mM) autoxidizes in Chelex-treated phosphate buffer (pH 7.4) to yield stoichiometric amounts of MG and NH(4)(+). Superoxide radical was shown to propagate this reaction as indicated by strong inhibition of oxygen uptake by superoxide dismutase (SOD) (1-50 units/mL; up to 90%) or semicarbazide (0.5-5 mM; up to 80%) and by EPR spin trapping studies with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), which detected the formation of the DMPO-(*)OH adduct as a decomposition product from the DMPO-O(2)(*)(-) adduct. Accordingly, oxygen uptake by AA is accelerated upon addition of xanthine/xanthine oxidase, a well-known enzymatic source of O(2)(*)(-) radicals. Under Fe(II)EDTA catalysis, SOD (<50 units/mL) had little effect on the oxygen uptake curve or on the EPR spectrum of AA/DMPO, which shows intense signals of the DMPO-(*)OH adduct and of a secondary carbon-centered DMPO adduct, attributable to the AA(*) enoyl radical. In the presence of iron, simultaneous (two) electron transfer from both Fe(II) and AA to O(2), leading directly to H(2)O(2) generation followed by the Fenton reaction is thought to take place. Aminoacetone was also found to induce dose-dependent Fe(II) release from horse spleen ferritin, putatively mediated by both O(2)(*)(-) and AA(*) enoyl radicals, and the co-oxidation of added hemoglobin and myoglobin, which may be viewed as the initial step for potential further iron release. It is thus tempting to propose that AA, accumulated in the blood and other tissues of diabetics, besides being metabolized by SSAO, may release iron and undergo spontaneous and iron-catalyzed oxidation with production of reactive H(2)O(2) and O(2)(*)(-), triggering pathological responses. It is noteworthy that noninsulin-dependent diabetes has been frequently associated with iron overload and oxidative stress. 相似文献
35.
36.
Peripheral receptors mediate the aversive conditioning effects of morphine in the rat 总被引:2,自引:1,他引:1
Previous evidence has shown that morphine produces positive reinforcing effects (as measured in the place conditioning paradigm) through an action in the central nervous system (CNS). The aversive conditioning effects of morphine (as measured in the place and taste conditioning paradigms) were produced when drug action was restricted to peripheral sites, particularly in the gut region. We now demonstrate that most of the aversive conditioning effects of morphine (using place and taste conditioning paradigms) are receptor mediated effects exerted through an action on peripheral opiate receptors. The conditioned taste aversions induced by intraperitoneal (IP) morphine (15 mg/kg) but not amphetamine (1 mg/kg) were attenuated by low IP doses of opiate antagonists (0.1 mg/kg of naltrexone or 1 mg/kg of the peripherally acting antagonist methynaltrexone (MN]. Morphine-, but not amphetamine-induced conditioned taste aversions were also attenuated in animals whose small sensory neurons, bearing the majority of primary afferent opiate receptors, were destroyed by neonatal treatments with capsaicin. In the place conditioning paradigm, the aversive conditioning effects produced by low IP administrations of morphine were blocked by opiate antagonists. Intraperitoneal pretreatments with 1 mg/kg of the quaternary opiate antagonist MN (which does not cross the blood-brain barrier effectively) were shown to block the conditioned place aversions produced by low IP doses of morphine (0.05 mg/kg), but not the place aversions produced by lithium chloride (75 mg/kg IP), or by high doses of naloxone (10 mg/kg SC). These results demonstrate that the aversive conditioning effects of morphine are primarily mediated through an action on peripheral opiate receptors.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
37.
38.
39.
40.
Panagiotis Kougias Aaron Chen Catherine Cagiannos M.D. Carlos F. Bechara M.D. Tam T. Huynh M.D. Peter H. Lin M.D. 《American journal of surgery》2009,198(5):645-649