全文获取类型
收费全文 | 17143篇 |
免费 | 1043篇 |
国内免费 | 41篇 |
专业分类
耳鼻咽喉 | 149篇 |
儿科学 | 435篇 |
妇产科学 | 322篇 |
基础医学 | 2562篇 |
口腔科学 | 412篇 |
临床医学 | 2225篇 |
内科学 | 3662篇 |
皮肤病学 | 151篇 |
神经病学 | 1295篇 |
特种医学 | 761篇 |
外科学 | 2022篇 |
综合类 | 69篇 |
一般理论 | 4篇 |
预防医学 | 1428篇 |
眼科学 | 234篇 |
药学 | 1291篇 |
中国医学 | 21篇 |
肿瘤学 | 1184篇 |
出版年
2023年 | 105篇 |
2022年 | 155篇 |
2021年 | 265篇 |
2020年 | 219篇 |
2019年 | 344篇 |
2018年 | 403篇 |
2017年 | 307篇 |
2016年 | 361篇 |
2015年 | 393篇 |
2014年 | 531篇 |
2013年 | 818篇 |
2012年 | 1224篇 |
2011年 | 1211篇 |
2010年 | 685篇 |
2009年 | 626篇 |
2008年 | 970篇 |
2007年 | 1115篇 |
2006年 | 986篇 |
2005年 | 1036篇 |
2004年 | 901篇 |
2003年 | 788篇 |
2002年 | 825篇 |
2001年 | 262篇 |
2000年 | 254篇 |
1999年 | 251篇 |
1998年 | 185篇 |
1997年 | 144篇 |
1996年 | 136篇 |
1995年 | 116篇 |
1994年 | 104篇 |
1993年 | 89篇 |
1992年 | 171篇 |
1991年 | 172篇 |
1990年 | 159篇 |
1989年 | 159篇 |
1988年 | 144篇 |
1987年 | 120篇 |
1986年 | 121篇 |
1985年 | 159篇 |
1984年 | 111篇 |
1983年 | 109篇 |
1982年 | 62篇 |
1980年 | 48篇 |
1979年 | 63篇 |
1978年 | 56篇 |
1977年 | 55篇 |
1975年 | 60篇 |
1974年 | 68篇 |
1973年 | 52篇 |
1972年 | 57篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
The difficulty of diagnosing NCSE in clinical practice; external validation of the Salzburg criteria
Rianne J. M. Goselink Jeroen J. van Dillen Marjolein Aerts Johan Arends Charlotte van Asch Inge van der Linden Jaco Pasman Christiaan G. J. Saris Machiel Zwarts Nens van Alfen 《Epilepsia》2019,60(8):e88-e92
To improve the diagnostic accuracy of electroencephalography (EEG) criteria for nonconvulsive status epilepticus (NCSE), external validation of the recently proposed Salzburg criteria is paramount. We performed an external, retrospective, diagnostic accuracy study of the Salzburg criteria, using EEG recordings from patients with and without a clinical suspicion of having NCSE. Of the 191 EEG recordings, 12 (12%) was classified as an NCSE according to the reference standard. In the validation cohort, sensitivity was 67% and specificity was 89%. The positive predictive value was 47% and the negative predictive value was 95%. Ten patients in the control group (n = 93) were false positive, resulting in a specificity of 89.2%. The interrater agreement between the reference standards and between the scorers of the Salzburg criteria was moderate; disagreement occurred mainly in patients with an epileptic encephalopathy. The Salzburg criteria showed a lower diagnostic accuracy in our external validation study than in the original design, suggesting that they cannot replace the current practice of careful weighing of both clinical and EEG information on an individual basis. 相似文献
3.
Marie Warrer Petersen Tine Sylvest Meyhoff Marie Helleberg Maj-Brit Nørregaard Kjær Anders Granholm Carl Johan Steensen Hjortsø Thomas Steen Jensen Morten Hylander Møller Peter Buhl Hjortrup Mik Wetterslev Gitte Kingo Vesterlund Lene Russell Vibeke Lind Jørgensen Klaus Tjelle Thomas Benfield Charlotte Suppli Ulrik Anne Sofie Andreasen Thomas Mohr Morten H. Bestle Lone Musaeus Poulsen Mette Friberg Hitz Thomas Hildebrandt Lene Surland Knudsen Anders Møller Christoffer Grant Sølling Anne Craveiro Brøchner Bodil Steen Rasmussen Henrik Nielsen Steffen Christensen Thomas Strøm Maria Cronhjort Rebecka Rubenson Wahlin Stephan Jakob Luca Cioccari Balasubramanian Venkatesh Naomi Hammond Vivekanand Jha Sheila Nainan Myatra Christian Gluud Theis Lange Anders Perner 《Acta anaesthesiologica Scandinavica》2020,64(9):1365-1375
Introduction
Severe acute respiratory syndrome coronavirus-2 has caused a pandemic of coronavirus disease (COVID-19) with many patients developing hypoxic respiratory failure. Corticosteroids reduce the time on mechanical ventilation, length of stay in the intensive care unit and potentially also mortality in similar patient populations. However, corticosteroids have undesirable effects, including longer time to viral clearance. Clinical equipoise on the use of corticosteroids for COVID-19 exists.Methods
The COVID STEROID trial is an international, randomised, stratified, blinded clinical trial. We will allocate 1000 adult patients with COVID-19 receiving ≥10 L/min of oxygen or on mechanical ventilation to intravenous hydrocortisone 200 mg daily vs placebo (0.9% saline) for 7 days. The primary outcome is days alive without life support (ie mechanical ventilation, circulatory support, and renal replacement therapy) at day 28. Secondary outcomes are serious adverse reactions at day 14; days alive without life support at day 90; days alive and out of hospital at day 90; all-cause mortality at day 28, day 90, and 1 year; and health-related quality of life at 1 year. We will conduct the statistical analyses according to this protocol, including interim analyses for every 250 patients followed for 28 days. The primary outcome will be compared using the Kryger Jensen and Lange test in the intention to treat population and reported as differences in means and medians with 95% confidence intervals.Discussion
The COVID STEROID trial will provide important evidence to guide the use of corticosteroids in COVID-19 and severe hypoxia.4.
Olle Zetterström Christer Andersson Leif Eriksson ers Fredriksson Johan Friskopp Gunnar Heden Bernt Jansson Tord Lundgren Rolf Nilveus ers Olsson Stefan Renvert Lars Salonen Lars Sjöström ers Winell ers Östgren Stina Gestrelius 《Journal of clinical periodontology》1997,24(9):697-704
Abstract The aim of the present clinical trial was to test tolerability during 2 treatments with EMDOGAIN® in a large number of patients. An open, controlled study design in 10 Swedish specialist clinics was chosen, with a test group of 107 patients treated with EMDOGAIN® in connection with periodontal surgery at 2 surgical test sites per patient. The procedures were performed 2 to 6 weeks apart on one-rooted teeth with at least 4 mm deep intraosseous lesions. A control group of 33 patients underwent flap surgery without EMDOGAIN® at I comparable site. In total 214 test and 33 control surgeries were performed. Serum samples were obtained from test patients for analysis of total and specific antibody levels. 10 of the patients had samples taken before and after the first surgery. 56 other samples were taken after one treatment with EMDOGAIN®, and 63 after 2 treatments. None of the samples, not even from allergy-prone patients after 2 treatments, indicated deviations from established baseline ranges. This indicates that the immunogenic potential of EMDOGAIN® is extremely low when applied in conjunction with periodontal surgery. Comparison between the test and control groups demonstrated the same type and frequency of post-surgical experiences, i.e., reactions caused by the surgical procedure itself. Clinical probing and radiographic evaluation was performed at baseline and 8 months postsurgery. About half of the patients (44 test and 21 control) were also evaluated after 3 years. There was a significant difference between the test and control results at 8 months post surgery. and this difference had increased further at the 3 year follow-up. The 2.5–3 mm increase in attachment and bone level after treatment with EMDOGAIN® was of the same magnitude as seen in the studies with split-mouth design aiming for lest of effectiveness of EMDOGAIN®. 相似文献
5.
A Moberg Wing K Wing K Tholin R Sj?str?m B Sandstr?m G Hallmans 《European journal of clinical nutrition》1992,46(8):585-595
Exposure to cadmium via the diet is known to depend to a large extent on the intake of cereal grains, particularly the high-fibre fractions of wheat. Subjects with low iron status absorb more cadmium than those with better iron status. The purpose of the present study was to determine to what extent cadmium accumulation in human placenta is affected by the intake of grain fibre and maternal iron status during pregnancy. Thirty-nine pregnant women participated in the study. In each trimester the women were requested to complete a dietary history and to allow blood samples to be taken for haemoglobin, serum ferritin and serum thiocyanate determinations, the latter as a marker for smoking. At delivery the whole placenta was taken for the determination of the cadmium concentration. The 32 women who had serum thiocyanate levels less than 70 mumol/l, who had completed at least one dietary history and from whom a blood sample was obtained in the third trimester, were included in the final statistical analyses. In the group of women who consumed less than the median intake of grain fibre and had more than 15 micrograms ferritin/l serum in the third trimester, the placenta cadmium concentration was nearly half that in the placentae of women who had consumed more grain fibre or had lower iron status in late pregnancy. 相似文献
6.
The annual conferences of the European Public Health Associationare a good opportunity to look around in the old continent.I vividly remember the Dresden conference in 2002, which broughtthe European public health community to a city reflecting thegreat and tragic history of Germany. Some of that history, andits effects on German public health, can be experienced firsthand 相似文献
7.
The galanin peptide family and its three receptors have with compelling evidence been implicated in several high-order physiological disorders. The co-localization with other neuromodulators and the distinct up-regulation during and after pathological disturbances has drawn attention to this neuropeptide family. In the current study we present data on receptor binding and functional response for a novel galanin receptor type 2 (GalR2) selective chimeric peptide, M1145 [(RG)2-N-galanin(2-13)-VL-(P)3-(AL)2-A-amide]. The M1145 peptide shows more than 90-fold higher affinity for GalR2 over GalR1 and a 76-fold higher affinity over GalR3. Furthermore, the peptide yields an agonistic effect in vitro, seen as an increase in inositol phosphate (IP) accumulation, both in the absence or the presence of galanin. The peptide design with a N-terminal extension of galanin(2-13), prevails new insights in the assembly of novel subtype specific ligands for the galanin receptor family and opens new possibilities to apply the galanin system as a putative drug target. 相似文献
8.
9.
10.
Changes in latencies of the visual evoked response (VER) during early post-natal development were examined in protein-deprived (PD) rats. The evoked response to light-flash stimulation was recorded in the dorsal lateral geniculate nucleus (dLGN) and on the surface of the visual cortex. In control rats, latencies of the cortical VER decreased rapidly up to 20 days and slowly thereafter. In PD rats, the latencies of the cortical VER were increased by 10-15 ms at 17 days; the developmental decrease was delayed by approximately 3 days. After 20 days, PD rats also went into a phase with slow decrease of the latencies, and the onset latency of the cortical VER was still increased by some 10 ms at 26/27 days. At this age, PD rats showed an increase in the latencies of the VER in the dLGN which was of similar magnitude to that in the cortical VER, indicating that alterations were more marked in the peripheral parts of the visual system at this stage of development. The findings are in agreement with previous studies indicating that there is a delay of visual system development in PD rats before 20 days. A maturational event which turns rapid into slow development at approximately 20 days in both C and PD rats turns this delay into a distortion of development. The delays and distortions of visual system development may be one causative factor for the functional deficit present in the visual cortex of adult PD rats. 相似文献