全文获取类型
收费全文 | 1158篇 |
免费 | 58篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 21篇 |
妇产科学 | 15篇 |
基础医学 | 167篇 |
口腔科学 | 48篇 |
临床医学 | 93篇 |
内科学 | 185篇 |
皮肤病学 | 10篇 |
神经病学 | 268篇 |
特种医学 | 26篇 |
外科学 | 159篇 |
综合类 | 3篇 |
预防医学 | 96篇 |
眼科学 | 29篇 |
药学 | 29篇 |
中国医学 | 1篇 |
肿瘤学 | 55篇 |
出版年
2023年 | 13篇 |
2022年 | 6篇 |
2021年 | 15篇 |
2020年 | 17篇 |
2019年 | 19篇 |
2018年 | 18篇 |
2017年 | 25篇 |
2016年 | 17篇 |
2015年 | 19篇 |
2014年 | 28篇 |
2013年 | 42篇 |
2012年 | 66篇 |
2011年 | 53篇 |
2010年 | 42篇 |
2009年 | 46篇 |
2008年 | 43篇 |
2007年 | 62篇 |
2006年 | 64篇 |
2005年 | 64篇 |
2004年 | 59篇 |
2003年 | 72篇 |
2002年 | 58篇 |
2001年 | 25篇 |
2000年 | 27篇 |
1999年 | 24篇 |
1998年 | 23篇 |
1997年 | 8篇 |
1996年 | 10篇 |
1995年 | 7篇 |
1994年 | 14篇 |
1993年 | 10篇 |
1992年 | 19篇 |
1991年 | 21篇 |
1990年 | 17篇 |
1989年 | 15篇 |
1988年 | 14篇 |
1987年 | 16篇 |
1986年 | 16篇 |
1985年 | 12篇 |
1984年 | 4篇 |
1983年 | 9篇 |
1982年 | 12篇 |
1981年 | 7篇 |
1980年 | 8篇 |
1979年 | 5篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1975年 | 3篇 |
1971年 | 4篇 |
1967年 | 4篇 |
排序方式: 共有1216条查询结果,搜索用时 10 毫秒
91.
Effect of xylitol on growth of Streptococcus pneumoniae in the presence of fructose and sorbitol 下载免费PDF全文
Tapiainen T Kontiokari T Sammalkivi L Ikäheimo I Koskela M Uhari M 《Antimicrobial agents and chemotherapy》2001,45(1):166-169
Xylitol is effective in preventing acute otitis media by inhibiting the growth of Streptococcus pneumoniae. To clarify this inhibition we used fructose, which is known to block similar growth inhibition observed in Streptococcus mutans. In addition, we evaluated the efficacy of sorbitol in inhibiting the growth of pneumococci, as sorbitol is widely used for indications similar to those for which xylitol is used. The addition of 5% xylitol to the growth medium resulted in marked growth inhibition, an effect which was totally eliminated in the presence of 1, 2.5, or 5% fructose but not in the presence of 1 or 5% glucose, 1% galactose, or 1% sucrose. This finding implies that xylitol-induced inhibition of pneumococcal growth is mediated via the fructose phosphotransferase system in a way similar to that in which mutans group streptococcal growth is inhibited. The addition of sorbitol at concentrations of 1, 2.5, or 5% to the growth medium did not affect the growth of pneumococci and neither inhibited nor enhanced the xylitol-induced growth impairment. Thus, it seems that xylitol is the only commercially used sugar substitute proven to have an antimicrobial effect on pneumococci. 相似文献
92.
The study was carried out to examine whether acupuncture treatment can reduce chronic pain in the neck and shoulders and related headache, and also to examine whether possible effects are long-lasting. Therefore, 24 female office workers (47+/-9 years old, mean+/-SD) who had had neck and shoulder pain for 12+/-9 years were randomly assigned to a test group (TG) or a control group (CG). Acupuncture was applied 10 times during 3-4 weeks either at presumed anti-pain acupoints (TG) or at placebo-points (CG). A physician measured the pain threshold (PPT) in the neck and shoulder regions with algometry before the first treatment, and after the last one and six months after the treatments. Questionnaires on muscle pain and headache were answered at the same occasions and again 3 years after the last treatment. The intensity and frequency of pain fell more for TG than for CG (Pb < or = 0.04) during the treatment period. Three years after the treatments TG still reported less pain than before the treatments (Pw < 0.001) contrary to what CG did (Pb < 0.04) The degree of headache fell during the treatment period for both groups, but more for TG than for CG (Pb=0.02) Three years after the treatments the effect still lasted for TG (Pw < 0.01) while the degree of headache for CG was back to the pre-treatment level (Pb < 0.001) PPT of some muscles rose during the treatments for TG and remained higher 6 months after the treatments (Pw < 0.05) which contrasts the situation for CG. Adequate acupuncture treatment may reduce chronic pain in the neck and shoulders and related headache. The effect lasted for 3 years. 相似文献
93.
94.
Ankelo M Westerlund A Blomberg K Knip M Ilonen J Hinkkanen AE 《Clinical chemistry》2007,53(3):472-479
BACKGROUND: Autoantibodies to glutamic acid decarboxylase (GADAs), specifically the 65-kDa isoform GAD65, and autoantibodies to the protein tyrosine phosphatase-like molecule IA-2 (IA-2As) predict development of diabetes. Our aim was to develop a time-resolved immunofluorometric (TR-IFMA) dual-label assay method for the simultaneous detection of these autoantibodies and to evaluate the diagnostic sensitivity of the method compared with single-label TR-IFMA and fluid-phase radiobinding assay (RBA) in screening children with type 1 diabetes. METHODS: We incubated combined biotinylated GAD65 and IA-2 proteins, glutathione S-transferase (GST)-IA-2, europium-labeled GAD65, terbium-labeled anti-GST antibody, and serum sample or calibrator and transferred aliquots to a streptavidin-coated 96-well microtiter plate for a second incubation. After washing, we added Delfia Enhancement solution to each well and measured the fluorescence of Eu. We developed the Tb fluorescence signal by use of the Delfia Enhancer solution and measured it. We analyzed serum samples from a cohort of 100 children with newly diagnosed type 1 diabetes. RESULTS: The correlation coefficients between the autoantibody concentrations measured by dual- and single-label TR-IFMA assays were 0.962 for GADA and 0.874 for IA-2A. Among 100 children with newly diagnosed diabetes, 65 of them were GADA positive in the dual-label assay, 64 in the single-label assay, and 66 in the RBA GADA assay. Seventy-four of the children tested positive for IA-2A in both TR-IFMA assay types, and 79 in the RBA IA-2A assay. CONCLUSIONS: The novel dual-label immunofluorometric assay performed comparably to the separate, single-label GADA and IA-2A assays in screening for beta-cell autoimmunity in children with newly diagnosed type 1 diabetes. 相似文献
95.
Altered kallikrein 7 and 10 concentrations in cerebrospinal fluid of patients with Alzheimer's disease and frontotemporal dementia 总被引:3,自引:0,他引:3
Diamandis EP Scorilas A Kishi T Blennow K Luo LY Soosaipillai A Rademaker AW Sjogren M 《Clinical biochemistry》2004,37(3):230-237
BACKGROUND: The role of various proteases in the pathogenesis of Alzheimer's disease is well documented. Recently, many members of the human tissue kallikrein family, a group of 15 secreted serine proteases, were found to be highly expressed in the central nervous system (CNS). Some of these enzymes can be measured in cerebrospinal fluid (CSF) by using ELISA-type methodologies. METHODS: We quantified various kallikreins in CSF of 20 patients with Alzheimer's disease (AD), 16 patients with frontotemporal dementia (FTD), and 15 controls. We then correlated the levels of various kallikreins with presence of AD or FTD. Among all kallikreins measured, detectable levels in CSF were identified for kallikreins hK6, hK7, and hK10. Other tested kallikreins (hK5, hK8, hK11, and hK13) were unmeasurable. The most notable differences between kallikrein levels in CSF and the three groups of subjects were seen between controls and FTD patients for hK6 (decrease in FTD; P = 0.017), controls and FTD patients for hK7 (decrease in FTD; P < 0.001), and controls and AD patients for hK7 (decrease in AD; P = 0.019). In addition, significant differences were seen between FTD patients or control subjects and patients with AD patients for hK10 (increase in AD; P < 0.02). Approximately half of the AD patients had CSF hK10 levels that were higher than all patients with FTD except one and all control subjects except two. Various kallikrein concentrations in CSF were correlated, the strongest correlation seen between hK6 and hK7 (r(s) = 0.58). We also observed a statistically significant association between decreasing hK7 concentration in CSF and possession of one or two ApoE4 alleles (P = 0.014). CONCLUSIONS: We demonstrate for the first time significant alterations of hK6, hK7, and hK10 concentration in CSF of patients with AD and FTD. Notably, all three kallikreins (hK6, hK7, and hK10) are decreased in CSF of FTD patients and hK10 is increased in CSF of AD patients, in comparison to control subjects. The possible connection between these enzymes and the pathogenesis and progression of AD and FTD needs to be further investigated. 相似文献
96.
Hampel H Wilcock G Andrieu S Aisen P Blennow K Broich K Carrillo M Fox NC Frisoni GB Isaac M Lovestone S Nordberg A Prvulovic D Sampaio C Scheltens P Weiner M Winblad B Coley N Vellas B;Oxford Task Force Group 《Progress in neurobiology》2011,95(4):579-593
The development of disease-modifying treatments for Alzheimer's disease requires innovative trials with large numbers of subjects and long observation periods. The use of blood, cerebrospinal fluid or neuroimaging biomarkers is critical for the demonstration of disease-modifying therapy effects on the brain. Suitable biomarkers are those which reflect the progression of AD related molecular mechanisms and neuropathology, including amyloidogenic processing and aggregation, hyperphosphorylation, accumulation of tau and neurofibrillary tangles, progressive functional, metabolic and structural decline, leading to neurodegeneration, loss of brain tissue and cognitive symptoms. Biomarkers should be used throughout clinical trial phases I-III of AD drug development. They can be used to enhance inclusion and exclusion criteria, or as baseline predictors to increase the statistical power of trials. Validated and qualified biomarkers may be used as outcome measures to detect treatment effects in pivotal clinical trials. Finally, biomarkers can be used to identify adverse effects. Questions regarding which biomarkers should be used in clinical trials, and how, are currently far from resolved. The Oxford Task Force continues and expands the work of our previous international expert task forces on disease-modifying trials and on endpoints for Alzheimer's disease clinical trials. The aim of this initiative was to bring together a selected number of key international opinion leaders and experts from academia, regulatory agencies and industry to condense the current knowledge and state of the art regarding the best use of biological markers in Alzheimer's disease therapy trials and to propose practical recommendations for the planning of future AD trials. 相似文献
97.
Significant inter-individual variation in the rate of animal metabolism is a widespread phenomenon that has started to accumulate general interest. Here we follow recent calls to focus on linkage between the variation in energy metabolism and animal personality. By using wild caught root voles as a study species, we examined the relationship between the behavioral patterns (assessed in open field test) and resting metabolic rate (RMR), both of which are known to show large individual differences and intra-individual consistency in voles. Our results showed only a weak relationship between personality traits and metabolism, since the most parsimonious model (according to AICc) explaining RMR included only body mass and season as factors (explaining 84.8% of variation in RMR). However, the next two alternative models (within ΔAICc = 2) also included the personality trait reflecting proactive behaviors (PC1) in addition to body mass, sex and season (85.2 and 85.8% of RMR variance explained, respectively). In all, our study does not provide compelling support for recent ideas of close linkage between behavior and metabolism. Still, our study highlights that even in the case of wild caught individuals, when behavior and metabolism often carry effects of both intrinsic and extrinsic conditions, the potential metabolic effects of varying energetically costly behaviors cannot be neglected. 相似文献
98.
Koskinen E Paavolainen P Eskelinen A Harilainen A Sandelin J Ylinen P Tallroth K Remes V 《Archives of orthopaedic and trauma surgery》2009,129(5):617-624
Aim The purpose of our study was to evaluate retrospectively the mid-term results of the Miller-Galante II (Zimmer, Warsaw, USA)
unicondylar knee arthoplasty (UKA).
Method The study included 46 patients with medial UKAs. Mean follow-up time was 7.0 years (range 2.7–13.1 years).
Results Survival rate of the prosthesis was 86.6% (95% CI 73.7–99.6) at 7 years. The mean clinical and functional Knee Society Scores
had increased from 51 and 62 points preoperatively to 76 and 93 points (P < 0.001) postoperatively. Five of the 46 knees were revised because of excessive wear of the polyethylene liner, and three
due to progression of the osteoarthritis in the lateral compartment of the knee.
Conclusion Survival of this fixed-bearing UKA was not as good as previously reported and polyethylene wear seems to be a more common
problem than previously assumed. 相似文献
99.
Eleonore Rydén Christian Johansson Kaj Blennow Mikael Landén 《Journal of neural transmission (Vienna, Austria : 1996)》2009,116(12):1667-1674
Bipolar disorder with childhood attention-deficit hyperactivity disorder (ADHD) is a subphenotype characterized by earlier
age of onset, more frequent mood episodes, more suicide attempts, and more interpersonal violence than pure bipolar patients.
The aim of this study was to test the biological validity of using childhood ADHD to subgroup bipolar disorder. The monoamine
metabolites, homovanillinic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA) and 3-methoxy-4-hydroxyphenylglycol (MHPG) were
determined in the cerebrospinal fluid (CSF) of 53 euthymic patients with bipolar disorder type 1, with (N = 17) and without (N = 36) a history of childhood ADHD. In addition to structured clinical interviews, childhood ADHD was assessed by a next of
kin using the Autism-Tics, ADHD and other comorbidities questionnaire (A-TAC), and by patients themselves using the Wender
Utah rating scale (WURS-25). Current ADHD symptoms were assessed by the Brown attention-deficit disorder scale (Brown ADD).
Bipolar patients with childhood ADHD had significantly lower CSF concentration (mean ± SD nmol/l) of HVA (89.0 ± 32.5 vs.
115.8 ± 47.1, P = 0.039) and 5-HIAA (88.7 ± 38.5 vs. 116 ± 47.9, P = 0.021) than pure bipolar patients. CSF MHPG did not differ between the groups. The WURS-25 score correlated negatively
with both HVA (r = −0.27, P = 0.048) and 5-HIAA (r = −0.30, P = 0.027). Likewise, the Brown ADD total score correlated negatively with both HVA (r = −0.34, P = 0.013) and 5-HIAA (r = −0.35, P = 0.011). These findings indicate different monoaminergic function in patients with and without childhood ADHD in bipolar
disorder type 1. This lends biological support to the notion that those with childhood ADHD represent a valid subphenotype
of bipolar disorder. 相似文献
100.
Levels of beta-secretase (BACE1) in cerebrospinal fluid as a predictor of risk in mild cognitive impairment 总被引:1,自引:0,他引:1
Zhong Z Ewers M Teipel S Bürger K Wallin A Blennow K He P McAllister C Hampel H Shen Y 《Archives of general psychiatry》2007,64(6):718-726
CONTEXT: Elevated beta-secretase (beta-site amyloid precursor protein-cleaving enzyme 1 [BACE1]) activity has been found in the brains of patients with sporadic Alzheimer disease (AD) compared with controls. Now we are particularly interested in whether BACE1 can be identified in the cerebrospinal fluid (CSF) of patients with mild cognitive impairment (MCI), a population at high risk for AD. The possible presence of BACE1 in the CSF of patients with AD and MCI has so far gone unreported. OBJECTIVE: To examine whether BACE1 can be identified in the CSF of patients with MCI. DESIGN: We evaluated CSF BACE1 levels using 2 sandwich enzyme-linked immunosorbent assays, BACE1 enzymatic activities by means of synthetic fluorescence substrate, and total amyloid-beta peptide levels using a sandwich enzyme-linked immunosorbent assay. SETTING: Two independent research centers. PARTICIPANTS: Eighty patients with sporadic AD, 59 patients with MCI, and 69 controls. MAIN OUTCOME MEASURES: BACE1 levels and enzymatic activities and amyloid-beta peptide levels. RESULTS: Increased CSF levels of BACE1 protein were associated with increased risk ratios (RRs) for patients with MCI compared with controls (RR, 2.08; 95% confidence interval [CI], 1.58-2.58) and patients with AD (RR, 1.65; 95% CI, 1.19-2.03). Similarly, patients with MCI showed increased levels of BACE1 activity compared with controls (RR, 2.17; 95% CI, 1.66-2.71) and patients with AD (RR, 3.71; 95% CI, 2.74-4.36). For total amyloid-beta peptide and tau, increased CSF levels were associated with a higher risk of MCI compared with controls. The BACE1 activity was significantly correlated with BACE1 protein level (rho = 0.23; P<.001) and amyloid-beta peptide level (rho = 0.39; P<.001), with amyloid-beta peptide correlated with BACE1 protein level (rho = 0.30; P<.001). CONCLUSION: Significant elevation of BACE1 levels and activity in CSF is an indicator of MCI, which could be an early stage of AD. 相似文献