全文获取类型
收费全文 | 8907篇 |
免费 | 590篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 36篇 |
儿科学 | 268篇 |
妇产科学 | 195篇 |
基础医学 | 1435篇 |
口腔科学 | 170篇 |
临床医学 | 827篇 |
内科学 | 1944篇 |
皮肤病学 | 290篇 |
神经病学 | 831篇 |
特种医学 | 228篇 |
外科学 | 1119篇 |
综合类 | 55篇 |
一般理论 | 3篇 |
预防医学 | 852篇 |
眼科学 | 69篇 |
药学 | 562篇 |
中国医学 | 26篇 |
肿瘤学 | 610篇 |
出版年
2023年 | 55篇 |
2022年 | 76篇 |
2021年 | 183篇 |
2020年 | 178篇 |
2019年 | 221篇 |
2018年 | 230篇 |
2017年 | 183篇 |
2016年 | 228篇 |
2015年 | 253篇 |
2014年 | 313篇 |
2013年 | 408篇 |
2012年 | 627篇 |
2011年 | 647篇 |
2010年 | 372篇 |
2009年 | 321篇 |
2008年 | 548篇 |
2007年 | 558篇 |
2006年 | 551篇 |
2005年 | 520篇 |
2004年 | 415篇 |
2003年 | 416篇 |
2002年 | 367篇 |
2001年 | 155篇 |
2000年 | 161篇 |
1999年 | 144篇 |
1998年 | 101篇 |
1997年 | 74篇 |
1996年 | 64篇 |
1995年 | 62篇 |
1994年 | 47篇 |
1993年 | 41篇 |
1992年 | 75篇 |
1991年 | 87篇 |
1990年 | 69篇 |
1989年 | 60篇 |
1988年 | 52篇 |
1987年 | 47篇 |
1986年 | 63篇 |
1985年 | 55篇 |
1984年 | 26篇 |
1983年 | 33篇 |
1982年 | 33篇 |
1981年 | 43篇 |
1980年 | 22篇 |
1979年 | 26篇 |
1978年 | 30篇 |
1977年 | 26篇 |
1976年 | 25篇 |
1975年 | 22篇 |
1971年 | 21篇 |
排序方式: 共有9520条查询结果,搜索用时 15 毫秒
1.
Very preterm children are at increased risk of reduced processing speed at 5 years of age,predicted by typical complications of prematurity and prenatal smoking
下载免费PDF全文
![点击此处可从《Acta paediatrica (Oslo, Norway : 1992)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
2.
Erik de Bakker Mirthe A. M. van der Putten Martijn W. Heymans Sander W. Spiekstra Taco Waaijman Liselotte Butzelaar Vera L. Negenborn Vivian K. Beekman Erman O. Akpinar Thomas Rustemeyer Frank B. Niessen Susan Gibbs 《Experimental dermatology》2021,30(1):169-178
Unpredictable hypertrophic scarring (HS) occurs after approximately 35% of all surgical procedures and causes significant physical and psychological complaints. Parallel to the need to understanding the mechanisms underlying HS formation, a prognostic tool is needed. The objective was to determine whether (systemic) immunological differences exist between patients who develop HS and those who develop normotrophic scars (NS) and to assess whether those differences can be used to identify patients prone to developing HS. A prospective cohort study with NS and HS groups in which (a) cytokine release by peripheral blood mononuclear cells (PBMC) and (b) the irritation threshold (IT) after an irritant (sodium lauryl sulphate) patch test was evaluated. Univariate regression analysis of PBMC cytokine secretion showed that low MCP‐1, IL‐8, IL‐18 and IL‐23 levels have a strong correlation with HS (P < .010‐0.004; AUC = 0.790‐0.883). Notably, combinations of two or three cytokines (TNF‐a, MCP‐1 and IL‐23; AUC: 0.942, Nagelkerke R2: 0.727) showed an improved AUC indicating a better correlation with HS than single cytokine analysis. These combination models produce good prognostic results over a broad probability range (sensitivity: 93.8%, specificity 86.7%, accuracy 90,25% between probability 0.3 and 0.7). Furthermore, the HS group had a lower IT than the NS group and an accuracy of 68%. In conclusion, very fundamental immunological differences exist between individuals who develop HS and those who do not, whereas the cytokine assay forms the basis of a predictive prognostic test for HS formation, the less invasive, easily performed irritant skin patch test is more accessible for daily practice. 相似文献
3.
4.
Ebadi Maryam Bhanji Rahima A. Mazurak Vera C. Montano-Loza Aldo J. 《Journal of gastroenterology》2019,54(10):845-859
Journal of Gastroenterology - Sarcopenia (severe muscle depletion) is a prevalent muscle abnormality in patients with cirrhosis that confers poor prognosis both pre- and post-liver transplantation.... 相似文献
5.
Effects of repetitive TMS on visually evoked potentials and EEG in the anaesthetized cat: dependence on stimulus frequency and train duration 总被引:2,自引:0,他引:2
Selcen Aydin-Abidin Vera Moliadze Ulf T. Eysel Klaus Funke 《The Journal of physiology》2006,574(2):443-455
Repetitive transcranial magnetic stimulation (rTMS) has been shown to alter cortical excitability that lasts beyond the duration of rTMS application itself. High-frequency rTMS leads primarily to facilitation, whereas low-frequency rTMS leads to inhibition of the treated cortex. However, the contribution of rTMS train duration is less clear. In this study, we investigated the effects of nine different rTMS protocols, including low and high frequencies, as well as short and long applications (1, 3 and 10 Hz applied for 1, 5 and 20 min), on visual cortex excitability in anaesthetized and paralysed cats by means of visual evoked potential (VEP) and electroencephalography (EEG) recordings. Our results show that 10 Hz rTMS applied for 1 and 5 min significantly enhanced early VEP amplitudes, while 1 and 3 Hz rTMS applied for 5 and 20 min significantly reduced them. No significant changes were found after 1 and 3 Hz rTMS applied for only 1 min, and 10 Hz rTMS applied for 20 min. EEG activity was only transiently (<20 s) affected, with increased delta activity after 1 and 3 Hz rTMS applied for 1 or 5 min. These findings indicate that the effects of rTMS on cortical excitability depend on the combination of stimulus frequency and duration (or total number of stimuli): short high-frequency trains seem to be more effective than longer trains, and low-frequency rTMS requires longer applications. Changes in the spectral composition of the EEG were not correlated to changes in VEP size. 相似文献
6.
Philippe Topart Guillaume Becouarn Patrick Ritz 《Surgery for obesity and related diseases》2007,3(5):521-525
BACKGROUND: Of patients who have undergone gastric banding, 11-25% will require a major reoperation with band removal and conversion to another bariatric procedure after they have failed to lose sufficient weight or have developed dysphagia or reflux. The aim of this study was to evaluate the respective benefits of Roux-en-Y gastric band (RYGB) or biliopancreatic diversion with duodenal switch (BPD-DS) after failed gastric banding and whether 1 of the 2 procedures might be a better procedure for such cases. METHODS: RYGB or BPD-DS was performed according to the institutional protocols with synchronous band removal, irrespective of the reason for failure. RESULTS: Of the 53 patients, 32 underwent laparoscopic RYGB for a body mass index (BMI) of 43.1 +/- 6.4 kg/m(2) (BMI 45.8 +/- 6.4 kg/m(2) before laparoscopic adjustable gastric banding) and 21 underwent BPD-DS for a BMI of 46.0 +/- 5.5 kg/m(2) (BMI 49.6 +/- 5.2 kg/m(2) before laparoscopic adjustable gastric banding). BPD-DS required significantly longer operative times (239.7 +/- 55.8 versus 135 +/- 26.7 minutes) and resulted in more complications (62% versus 12.5%; P <.002). No patients died postoperatively. The 2 groups of patients had a similar BMI at 12 and 18 months after revision (BMI 33.4 +/- 5.6 kg/m(2) and 31.4 +/- 3.5 kg/m(2)). The weight loss was greater after BPD-DS than after RYGB compared with the prerevision weight loss (66.2% versus 58.8% excess weight loss) or initial weight (73% versus 61.8%), although this was not significant. CONCLUSION: Despite an excessive rate of complications that were, in part, related to the learning curve in this series, BPD-DS resulted in greater weight loss compared with RYGB. However, both procedures were successful after failed gastric banding. A more accurate definition of failure could help to determine the respective indications for revisional surgery. 相似文献
7.
8.
Borras Merce; Valdivielso Jose M.; Egido Ramon; Vicente de Vera Pilar; Bordalba Josep Ramon; Fernandez Elvira 《Nephrology, dialysis, transplantation》2006,21(3):789-791
9.
The mitochondrial intron rI1 is a self-splicing group-II intron of algal mitochondria that can be transferred into chloroplasts
from the green alga Chlamydomonas reinhardtii for in vivo investigations (Herdenberger et al. 1994). Thus, rI1 is a suitable system to compare in vitro and in vivo RNA
processing. Interestingly, rI1 shows correct RNA splicing, although typical cis-acting exon-sequences (IBS2, δ) of group-II introns are lacking. In order to examine the effect of these exon-intron interactions on splicing, we introduced
the endogenous mitochondrial IBS2 sequence in order to produce optimal IBS2-EBS2 base pairing. In addition, the first nucleotide
of the 3′exon (δ′) was substituted to create an optimal δ-δ′ interaction. Neither of the two mutations, nor a combination of both, had any effect on the precision of the splice-site
selection. Unexpectedly, introduction of IBS2 led to a reduction in the efficiency of the second splicing step in vitro but
not in vivo. These findings lead us to conclude that trans-acting factors are present in vivo to optimize splicing efficiency. The possibility is discussed that these factors may,
for example, stabilize tertiary intron structures that are a prerequisite for correct RNA processing. Furthermore, our data
indicate that similar trans-acting factors promote correct intron splicing in chloroplasts and mitochondria.
Received: 18 October / 4 December 1997 相似文献
10.
J Bommer T Weinreich D H Lovett R Bouillon E Ritz D Gemsa 《Nephrology, dialysis, transplantation》1990,5(3):208-213
Loading of tissue macrophages with dialysis-tubing-derived particles may occur during chronic haemodialysis. Previous studies have demonstrated that these particle-laden macrophages release significant quantities of prostaglandins. In these experiments, the effects of dialysis-tubing-particle loading on the release of the central inflammatory mediator, interleukin 1 (IL 1), was examined. Rats received daily injections of silicone or polyvinylchloride (PVC) particles, and were compared to animals given saline alone. The silicone and PVC groups received a total of 3 x 10(9) particles over a 4-week period. Non-stimulated peritoneal macrophages from control animals released a median of 4.1 (range 1.2-10.3) U IL 1 per 10(6) cells. In contrast, macrophages from silicone- and PVC-loaded animals spontaneously released high levels of IL 1 (median 21.8; range 10-36.7) and 94 (range 36-336) U per 10(6) cells respectively). Following in vitro stimulation with bacterial lipopolysaccharide (LPS), peritoneal macrophages from silicone- and PVC-treated animals released large amounts of IL 1 (median 538 (range 359-2017) U and median 653 (range 326-1134) U per 10(6) cells, respectively) as compared to LPS-stimulated macrophages from control animals (median 332 (range 130-306) U per 10(6) cells]. Zymosan or LPS stimulation of splenic cells from silicone- and PVC-loaded animals also secreted increased quantities of IL 1 as compared to controls. The chronic loading of tissue macrophages in dialysis patients with tubing-derived particles may result in augmented release of IL 1, with subsequent activation of inflammatory processes. 相似文献