全文获取类型
收费全文 | 9046篇 |
免费 | 710篇 |
国内免费 | 44篇 |
专业分类
耳鼻咽喉 | 73篇 |
儿科学 | 249篇 |
妇产科学 | 55篇 |
基础医学 | 1173篇 |
口腔科学 | 176篇 |
临床医学 | 943篇 |
内科学 | 1866篇 |
皮肤病学 | 147篇 |
神经病学 | 1193篇 |
特种医学 | 683篇 |
外科学 | 1602篇 |
综合类 | 47篇 |
一般理论 | 4篇 |
预防医学 | 436篇 |
眼科学 | 157篇 |
药学 | 419篇 |
中国医学 | 6篇 |
肿瘤学 | 571篇 |
出版年
2024年 | 17篇 |
2023年 | 116篇 |
2022年 | 174篇 |
2021年 | 387篇 |
2020年 | 245篇 |
2019年 | 288篇 |
2018年 | 331篇 |
2017年 | 290篇 |
2016年 | 360篇 |
2015年 | 351篇 |
2014年 | 469篇 |
2013年 | 554篇 |
2012年 | 841篇 |
2011年 | 830篇 |
2010年 | 467篇 |
2009年 | 392篇 |
2008年 | 592篇 |
2007年 | 586篇 |
2006年 | 488篇 |
2005年 | 368篇 |
2004年 | 337篇 |
2003年 | 290篇 |
2002年 | 283篇 |
2001年 | 88篇 |
2000年 | 59篇 |
1999年 | 67篇 |
1998年 | 46篇 |
1997年 | 21篇 |
1996年 | 23篇 |
1995年 | 19篇 |
1994年 | 16篇 |
1993年 | 18篇 |
1992年 | 39篇 |
1991年 | 28篇 |
1990年 | 32篇 |
1989年 | 27篇 |
1988年 | 26篇 |
1987年 | 26篇 |
1986年 | 15篇 |
1985年 | 20篇 |
1984年 | 8篇 |
1983年 | 12篇 |
1982年 | 11篇 |
1981年 | 8篇 |
1979年 | 11篇 |
1978年 | 14篇 |
1976年 | 11篇 |
1973年 | 10篇 |
1972年 | 12篇 |
1922年 | 14篇 |
排序方式: 共有9800条查询结果,搜索用时 15 毫秒
51.
Comparison of a shiga toxin enzyme-linked immunosorbent assay and two types of PCR for detection of shiga toxin-producing Escherichia coli in human stool specimens
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Pulz M Matussek A Monazahian M Tittel A Nikolic E Hartmann M Bellin T Buer J Gunzer F 《Journal of clinical microbiology》2003,41(10):4671-4675
Shiga toxin (Stx)-producing Escherichia coli (STEC) is a major cause of sporadic cases of disease as well as serious outbreaks worldwide. The spectrum of illnesses includes mild nonbloody diarrhea, hemorrhagic colitis, and hemolytic-uremic syndrome. STEC produces one or more Stxs, which are subdivided into two major classes, Stx1 and Stx2. The ingestion of contaminated food or water, person-to-person spread, and contact with animals are the major transmission modes. The infective dose of STEC may be less than 100 organisms. Effective prevention of infection is dependent on rapid detection of the causative bacterial pathogen. In the present study, we examined 295 stool specimens for the presence of Stx-producing E. coli by three different methods: an Stx enzyme-linked immunosorbent assay, a conventional PCR assay, and a LightCycler PCR (LC-PCR) assay protocol recently developed by our laboratory at the Institute of Medical Microbiology at Hannover Medical School. Our intent was to compare these three methods and to examine the utility of the STEC LC-PCR protocol in a clinical laboratory. The addition of a control DNA to each sample to clearly discriminate inhibited specimens from negative ones enhanced the accuracy of the LC-PCR protocol. From our results, it can be concluded that LC-PCR is a very useful tool for the rapid and safe detection of STEC in clinical samples. 相似文献
52.
Marius Schwabenland Henrike Salié Jovan Tanevski Saskia Killmer Marilyn Salvat Lago Alexandra Emilia Schlaak Lena Mayer Jakob Matschke Klaus Püschel Antonia Fitzek Benjamin Ondruschka Henrik E. Mei Tobias Boettler Christoph Neumann-Haefelin Maike Hofmann Angele Breithaupt Nafiye Genc Christine Stadelmann Bertram Bengsch 《Immunity》2021,54(7):1594-1610.e11
- Download : Download high-res image (276KB)
- Download : Download full-size image
53.
Video-rate nonlinear microscopy of neuronal membrane dynamics with genetically encoded probes 总被引:4,自引:0,他引:4
Biological membranes decorated with suitable contrast agents give rise to nonlinear optical signals such as two-photon fluorescence and harmonic up-conversion when illuminated with ultra-short, high-intensity pulses of infrared laser light. Microscopic images based on these nonlinear contrasts were acquired at video or higher frame rates by scanning a focused illuminating spot rapidly across neural tissues. The scan engine relied on an acousto-optic deflector (AOD) to produce a fast horizontal raster and on corrective prisms to offset the AOD-induced dispersion of the ultra-short excitation light pulses in space and time. Two membrane-bound derivatives of the green fluorescent protein (GFP) were tested as nonlinear contrast agents. Synapto-pHluorin, a pH-sensitive GFP variant fused to a synaptic vesicle membrane protein, provided a time-resolved fluorescent read-out of neurotransmitter release at genetically specified synaptic terminals in the intact brain. Arrays of dually lipidated GFP molecules at the plasma membrane generated intense two-photon fluorescence but no detectable second-harmonic power. Comparison with second-harmonic generation by membranes stained with a synthetic styryl dye suggested that the genetically encoded chromophore arrangement lacked the orientational anisotropy and/or dipole density required for efficient coherent scattering of the incident optical field. 相似文献
54.
Vitamin D food fortification in European countries: the underused potential to prevent cancer deaths
Niedermaier Tobias Gredner Thomas Kuznia Sabine Schöttker Ben Mons Ute Lakerveld Jeroen Ahrens Wolfgang Brenner Hermann 《European journal of epidemiology》2022,37(4):309-320
European Journal of Epidemiology - Background: Meta-analyses of randomized controlled trials have shown that vitamin D supplementation reduces cancer mortality by 13%. Vitamin D fortification of... 相似文献
55.
Suraj Suresh Mohammad Siddiqui Mouhanna Abu Ghanimeh Jessica Jou Stephen Simmer Vivek Mendiratta Sarah Russell Mustafa Al-Shammari Abigail Chatfield Eva Alsheik Duyen Dang Jeffrey Genaw Tobias Zuchelli 《Obesity research & clinical practice》2021,15(2):172-176
BackgroundAlthough recent studies have shown an association between obesity and adverse coronavirus disease 2019 (COVID-19) patient outcomes, there is a paucity in large studies focusing on hospitalized patients. We aimed to analyze outcomes associated with obesity in a large cohort of hospitalized COVID-19 patients.MethodsWe performed a retrospective study at a tertiary care health system of adult patients with COVID-19 who were admitted between March 1 and April 30, 2020. Patients were stratified by body mass index (BMI) into obese (BMI ≥ 30 kg/m 2) and non-obese (BMI < 30 kg/m 2) cohorts. Primary outcomes were mortality, intensive care unit (ICU) admission, intubation, and 30-day readmission.ResultsA total of 1983 patients were included of whom 1031 (51.9%) had obesity and 952 (48.9%) did not have obesity. Patients with obesity were younger (P < 0.001), more likely to be female (P < 0.001) and African American (P < 0.001) compared to patients without obesity. Multivariable logistic models adjusting for differences in age, sex, race, medical comorbidities, and treatment modalities revealed no difference in 60-day mortality and 30-day readmission between obese and non-obese groups. In these models, patients with obesity had increased odds of ICU admission (adjusted OR, 1.37; 95% CI, 1.07?1.76; P = 0.012) and intubation (adjusted OR, 1.37; 95% CI, 1.04?1.80; P = 0.026).ConclusionsObesity in patients with COVID-19 is independently associated with increased risk for ICU admission and intubation. Recognizing that obesity impacts morbidity in this manner is crucial for appropriate management of COVID-19 patients. 相似文献
56.
Welmoed van Loon Heike Rssig Susen Burock Jrg Hofmann Julian Bernhard Elisabeth Linzbach Domenika Pettenkofer Christian Schnfeld Maximilian Gertler Joachim Seybold Tobias Kurth Frank P. Mockenhaupt 《Emerging infectious diseases》2021,27(7):1931
Within 5 weeks in 2021, B.1.1.7 became the dominant severe acute respiratory syndrome coronavirus 2 lineage at an outpatient testing site in Berlin, Germany. Compared with outpatients with wild-type virus infection, patients with B.1.1.7 had similar cycle threshold values, more frequent sore throat and travel history, and less frequent anosmia/ageusia. 相似文献
57.
Paolo Dell’Oglio Philippa Meershoek Tobias Maurer Esther M.K. Wit Pim J. van Leeuwen Henk G. van der Poel Fijs W.B. van Leeuwen Matthias N. van Oosterom 《European urology》2021,79(1):124-132
BackgroundThe DROP-IN gamma probe was introduced to overcome the restricted manoeuvrability of traditional laparoscopic gamma probes. Through enhanced manoeuvrability and surgical autonomy, the DROP-IN promotes the implementation of radioguided surgery in the robotic setting.ObjectiveTo confirm the utility and safety profile of the DROP-IN gamma probe and to perform a comparison with the traditional laparoscopic gamma probe and fluorescence guidance.Design, setting, and participantsTwenty-five prostate cancer patients were scheduled for a robot-assisted sentinel lymph node (SN) procedure, extended pelvic lymph node dissection, and prostatectomy at a single European centre.Surgical procedureAfter intraprostatic injection of indocyanine green (ICG)-99mTc-nanocolloid (n = 12) or 99mTc-nanocolloid + ICG (n = 13), SN locations were defined using preoperative imaging. Surgical excision of SNs was performed under image guidance using the DROP-IN gamma probe, the traditional laparoscopic gamma probe, and fluorescence imaging.MeasurementsIntraoperative SN detection was assessed for the different modalities and related to anatomical locations. Patient follow-up was included (a median of 18 mo).Results and limitationsOverall, 47 SNs were pursued in vivo by the DROP-IN gamma probe, of which 100% were identified. No adverse events related to its use were observed. In vivo fluorescence imaging identified 91% of these SNs. The laparoscopic gamma probe identified only 76% of these SNs, where the detection inaccuracies appeared to be related to specific anatomical regions.ConclusionsOwing to improved manoeuvrability, the DROP-IN probe yielded improved SN detection rates compared with the traditional gamma probe and fluorescence imaging. These findings underline that the DROP-IN technology provides a valuable tool for radioguided surgery in the robotic setting.Patient summaryRadioguided robot-assisted surgery with the novel DROP-IN gamma probe is feasible and safe. It enables more efficient intraoperative identification of sentinel lymph nodes than can be achieved with a traditional laparoscopic gamma probe. The use of the DROP-IN probe in combination with fluorescence imaging allows for a complementary optical confirmation of node localisations. 相似文献
58.
Matthias Meyer Lukas Parik Felix Greimel Tobias Renkawitz Joachim Grifka Markus Weber 《The Journal of arthroplasty》2021,36(5):1533-1542
BackgroundModels for risk stratification and prediction of outcome, such as the Charlson Comorbidity Index (CCI), the Elixhauser Comorbidity Method (ECM), the 5-factor modified Frailty Index (mFI-5), and the Hospital Frailty Risk Score (HFRS) have been validated in orthopedic surgery. The aim of this study is to compare the predictive power of these models in total hip and knee replacement.MethodsIn a retrospective analysis of 8250 patients who had undergone total joint replacement between 2011 and 2019, CCI, ECM, mFI-5, and HFRS were calculated for each patient. Receiver operating characteristic curve plots were generated and the area under the curve (AUC) was compared between each score with regard to adverse events such as transfusion, surgical, medical, and other complications. Multivariate logistic regression models were used to assess the relationship among risk stratification models, demographic factors, and postoperative adverse events.ResultsIn prediction of surgical complications, HFRS performed best (AUC: 0.719, P < .001), followed by ECM (AUC: 0.578, P < .001), mFI-5 (AUC: 0.564, P = .003), and CCI (AUC: 0.555, P = .012). With regard to medical complications, other complications, and transfusion, HFRS also was superior to ECM, mFI-5, and CCI. Multivariate logistic regression analyses revealed HFRS as an independent risk stratification model associated with all captured adverse events (P ≤ .001).ConclusionThe HFRS is superior to current risk stratification models in the context of total joint replacement. As the HRFS derives from routinely collected administrative data, healthcare providers can identify at-risk patients without additional effort or expense. 相似文献
59.
Die Anaesthesiologie - 相似文献