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   1967篇
  免费   111篇
  国内免费   10篇
耳鼻咽喉   6篇
儿科学   52篇
妇产科学   56篇
基础医学   319篇
口腔科学   38篇
临床医学   150篇
内科学   437篇
皮肤病学   105篇
神经病学   197篇
特种医学   65篇
外科学   162篇
综合类   16篇
预防医学   199篇
眼科学   38篇
药学   113篇
中国医学   7篇
肿瘤学   128篇
  2023年   20篇
  2022年   47篇
  2021年   86篇
  2020年   41篇
  2019年   60篇
  2018年   70篇
  2017年   46篇
  2016年   52篇
  2015年   43篇
  2014年   91篇
  2013年   105篇
  2012年   135篇
  2011年   161篇
  2010年   80篇
  2009年   98篇
  2008年   120篇
  2007年   130篇
  2006年   120篇
  2005年   112篇
  2004年   86篇
  2003年   96篇
  2002年   90篇
  2001年   16篇
  2000年   17篇
  1999年   19篇
  1998年   19篇
  1997年   19篇
  1996年   16篇
  1995年   16篇
  1994年   2篇
  1993年   3篇
  1992年   10篇
  1991年   4篇
  1990年   6篇
  1989年   7篇
  1988年   4篇
  1987年   3篇
  1986年   4篇
  1985年   3篇
  1984年   3篇
  1983年   3篇
  1980年   4篇
  1978年   3篇
  1977年   2篇
  1948年   1篇
  1947年   1篇
  1943年   1篇
  1934年   1篇
  1913年   2篇
  1912年   3篇
排序方式: 共有2088条查询结果,搜索用时 0 毫秒
91.
We evaluated blood pressure in a sample of patients with neurofibromatosis type 1 (NF1), using ambulatory blood pressure monitoring (ABPM), to determine whether ABPM, when compared with casual BP recordings, allowed the detection of a higher risk for hypertension. We also evaluated the correlation between BP and vascular abnormalities. We studied 69 NF1 patients (36 males and 33 females) with a mean age of 11±4 years, divided into group A, with 24-h mean systolic blood pressure (SBP) or diastolic blood pressure (DBP) <95th percentile, and group B, with mean SBP or DBP >95th percentile. Standard electrocardiography and M-mode, two-dimensional echocardiography were performed and all patients were in sinus rhythm. ABPM identified 11 hypertensive patients (16%); 5 had a mean SBP >95th percentile, 3 mean SBP–DBP >95th percentile, and 3 a mean DBP >95th percentile. Laboratory and other investigations to exclude secondary hypertension were normal. Cardiac abnormalities were found in 13 of the 69 patients (18.8%) with NF1. There were no significant clinical and cardiac differences between the normotensive and hypertensive group. Our data emphasize the importance of periodic ABPM in NF1 patients to diagnose hypertension early and avoid target organ damage and increased mortality.  相似文献   
92.
Accidental trauma and heavy endurance exercise, both induce a kind of systemic inflammatory response, also called systemic inflammatory response syndrome (SIRS). Exercise-related SIRS is conditioned by hyperthermia and concomitant heat shock responses, whereas trauma-induced SIRS manifests concomitantly with tissue necrosis and immune activation, secondarily followed by fever. Inflammatory cytokines are common denominators in both trauma and exercise, although there are marked quantitative differences. Different anti-inflammatory cytokines may be involved in the control of inflammation in trauma- and exercise-induced stress. Exercise leads to a balanced equilibrium between inflammatory and anti-inflammatory responses. Intermittent states of rest, as well as anti-oxidant capacity, are lacking or minor in trauma but are high in exercising individuals. Regular training may enhance immune competence, whereas trauma-induced SIRS often paves the way for infectious complications, such as sepsis.  相似文献   
93.
BACKGROUND: Impairment in attention is prominent in schizophrenia and may be a valuable genetic indicator for vulnerability to this disease. AIMS: We set out to characterize the attention deficits that may be associated with genetic liability to schizophrenia. METHODS: We compared attention performance in 55 people with schizophrenia, 95 of their first-degree relatives, and 61 unrelated controls. We also segregated presumed obligate carriers of genetic risk (POCs, N=12) and compared their performance with that of controls. RESULTS: Although the relatives of people with schizophrenia did not significantly differ from the normal controls on the tasks of attention, their scores were significantly ordered such that patients>relatives>normal controls during tasks of sustained and selective attention as measured by the Jonckheere-Terpstra Test (p<.05). Additionally, POCs were significantly worse than normal controls during selective attention tasks such as the Stroop (p=.03) and Letter Cancellation Task (p=.04). CONCLUSIONS: Heterogeneity in the first-degree relatives may have diluted the attention deficits present in those who are at genetic risk for schizophrenia. On the other hand, our findings in the more homogeneous group of POCs suggest that selective attention may be an indicator of genetic liability for schizophrenia.  相似文献   
94.
BACKGROUND: Atrial fibrillation (AF) is considered a predictive factor of poor clinical outcome in patients with an ischemic stroke (IS). This study addressed whether the impact of AF on the in-hospital mortality after first ever IS is different according to the patient's gender. METHODS: We prospectively studied 1678 patients with first ever IS consecutively admitted to two University Hospitals. We recorded demographic data, vascular risk factors, and the stroke severity (NIHSS) at admission analyzing their impact on the in-hospital mortality and on the combined mortality-dependency at discharge using a Cox proportional hazards model. Two variable interactions between those factors independently related to in-hospital mortality and combined mortality-dependency at discharge were tested. RESULTS: Overall in-hospital mortality was 11.3%. Cox proportional hazards model showed that NIHSS at admission (HR: 1.178 [95% CI 1.149-1.207]), age (HR: 1.044 [95% CI 1.026-1.061]), AF (HR: 1.416 [95% CI 1.048-1.913]), male gender (HR: 1.853 [95% CI 1.323-2.192) and ischemic heart disease (HR: 1.527 [95% CI 1.063-2.192]) were independent predictors of in-hospital mortality. A significant interaction between gender and AF was found (p = 0.017). Data were stratified by gender, showing that AF was an independent predictor of poor outcome just for woman (HR: 2.183 [95% CI 1.403-3.396]; p < 0.001). The independent predictors of combined mortality-disability at discharge were NIHSS at admission (HR: 1.052 [95% CI 1.041-1.063]), age (HR: 1.011 [95% CI 1.004-1.018]), AF (HR: 1.197 [95% CI 1.031-1.390]), ischemic heart disease (HR: 1.222 [95% CI 1.004-1.488]), and smoking (HR: 1.262 [95% CI 1.033-1.541]). CONCLUSIONS: The impact of AF is different in the two genders and appears as a specific ischemic stroke predictor of in-hospital mortality just for women.  相似文献   
95.
Cosmetic outcome is an important quality of life‐related end point following breast‐conserving therapy (BCT). To advise on a gold standard, we compare cosmetic outcome evaluated by panel and an objective evaluation (BCCT.core software). Second, patient‐reported outcome measures (PROMs) are compared to cosmetic outcome evaluation by panel and BCCT.core. Sixty‐eight breast cancer patients were included following BCT between 2007 and 2012. Two independent 6‐member panels and two observers using the BCCT.core evaluated cosmetic outcome. First, reproducibility, repeatability, and relatedness of panel and BCCT.core were analyzed using the interclass correlation coefficient (ICC). Second, the association between panel/BCCT.core with PROMs (EORTC‐QLQ‐C30/BR23, EQ‐5D‐5L, and BREAST‐Q) was analyzed with a linear regression and the goodness of fit by the R2. Both panel and BCCT.core evaluations showed “excellent” intraobserver agreement (ICC 0.93 [95% CI: 0.83; 0.97] and 0.93 [95% CI: 0.84; 0.97]) for respectively panel 1 and BCCT.core 1 and “excellent” interobserver agreement (ICC 0.94 [95% CI: 0.90; 0.96] and 0.85 [95% CI: 0.77; 0.91]) respectively for panel and BCCT.core. Association between panel and BCCT.core varied, ICC 0.59‐0.69. Only the PROM BREAST‐Q showed a significant association with both panel evaluations and BCCT.core observers (panel 1 and BCCT.core 1; R2 of .157 [P = .002] and .178 [P = .001]). Both panel and BCCT.core showed comparable “excellent” intraobserver and interobserver agreement. For future trials evaluating cosmetic outcome following BCT, one of those can be chosen. Solely, the PROM BREAST‐Q showed a significant association with panel and/or BCCT.core evaluation. To enable standardized cosmetic outcome evaluation and corresponding patient satisfaction in future trials, at least the BREAST‐Q should be combined with a panel or BCCT.core evaluation.  相似文献   
96.
Aim:  To study if infant crying is associated with maternal postnatal depression.
Methods:  Data from 1015 mothers and their children participating in a prospective European multicentre study were analysed. Infantile colic and prolonged crying were defined as excessive crying as reported by the mothers 2 and 6 months after delivery, and at the same time the mothers completed the Edinburgh Postnatal Depression Scale (EPDS).
Results:  In cross-sectional analyses, infant crying was associated with high EPDS scores both 2 (OR: 4.4; 95% CI: 2.4–8.2) and 6 months postpartum (OR: 10.8; 95% CI: 4.3–26.9). More than one-third of the others of infants with prolonged crying had high EPDS scores 6 months postpartum. Longitudinal analyses showed that mothers of infants with colic had increased odds of having high EPDS scores 6 months after delivery even if crying had resolved (OR: 3.7; 95% CI: 1.4–10.1).
Conclusion: Both infantile colic and prolonged crying were associated with high maternal depression scores. Most noteworthy, infantile colic at 2 months of age was associated with high maternal depression scores
4 months later.  相似文献   
97.
98.
Salivaricin CRL 1328 is a heat-stable bacteriocin produced by Lactobacillus salivarius CRL 1328, a strain isolated from healthy human vagina, with potential applications for preventing urogenital infections. The objective of this study was to characterize the locus responsible for salivaricin CRL 1328 production and its mechanism of action against Enterococcus faecalis MP97 as the sensitive strain. Oligonucleotides were designed based on sequences of antimicrobial peptides previously described in the literature. The salivaricin CRL 1328 cluster was identified, sequenced and analyzed. This cluster was similar to the previously described ABP118 which codified for a two-peptide bacteriocin. The putative mature peptides of salivaricin CRL 1328, Salα and Salβ were chemically synthesized. These peptides did not show bacteriocin activity when assayed individually. Both peptides exhibited optimal antimicrobial activity at an equimolar ratio. Spectroscopic fluorescence assays were carried out using the synthetic peptides to study the effect of salivaricin on proton motive force. This bacteriocin was shown to dissipate membrane potential and the transmembrane proton gradient, both components of proton motive force. E. faecalis MP97 cells treated with salivaricin CRL 1328 peptides were observed in transmission electron microscopy which revealed ultrastructural modifications of the cell wall.  相似文献   
99.
100.
Abstract:  Free radicals are involved in pathophysiology of ischemia/reperfusion injury (IRI). Melatonin is a potent scavenger of reactive oxygen and nitrogen species. Thus, this study was designed to elucidate its effects in a model of rat kidney transplantation. Twenty Lewis rats were randomly divided into 2 groups (n = 10 animals each). Melatonin (50 mg/kg BW) dissolved in 5 mL milk was given to one group via gavage 2 hr before left donor nephrectomy. Controls were given the same volume of milk only. Kidney grafts were then transplanted into bilaterally nephrectomized syngeneic recipients after 24 hr of cold storage in Histidine–Tryptophan–Ketoglutarate solution. Both graft function and injury were assessed after transplantation through serum levels of blood urea nitrogen (BUN), creatinine, transaminases, and lactate dehydrogenase (LDH). Biopsies were taken to evaluate tubular damage, the enzymatic activity of superoxide dismutase (SOD) and lipid hydroperoxide (LPO), and the expression of NF-kBp65, inducible nitric oxide synthase (iNOS), caspase-3 as indices of oxidative stress, necrosis, and apoptosis, respectively. Melatonin improved survival ( P  < 0.01) while decreasing BUN, creatinine, transaminases, and LDH values up to 39–71% ( P  < 0.05). Melatonin significantly reduced the histological index for tubular damage, induced tissue enzymatic activity of SOD while reducing LPO. At the same time, melatonin down-regulated the expression of NF-kBp65, iNOS, and caspase-3. In conclusion, donor preconditioning with melatonin protected kidney donor grafts from IRI-induced renal dysfunction and tubular injury most likely through its anti-oxidative, anti-apoptotic and NF-kB inhibitory capacity.  相似文献   
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