全文获取类型
收费全文 | 33651篇 |
免费 | 2105篇 |
国内免费 | 203篇 |
专业分类
耳鼻咽喉 | 318篇 |
儿科学 | 567篇 |
妇产科学 | 477篇 |
基础医学 | 4705篇 |
口腔科学 | 890篇 |
临床医学 | 3463篇 |
内科学 | 7123篇 |
皮肤病学 | 665篇 |
神经病学 | 3706篇 |
特种医学 | 1982篇 |
外科学 | 5342篇 |
综合类 | 184篇 |
一般理论 | 7篇 |
预防医学 | 1411篇 |
眼科学 | 686篇 |
药学 | 1965篇 |
中国医学 | 68篇 |
肿瘤学 | 2400篇 |
出版年
2024年 | 28篇 |
2023年 | 270篇 |
2022年 | 519篇 |
2021年 | 895篇 |
2020年 | 632篇 |
2019年 | 818篇 |
2018年 | 932篇 |
2017年 | 807篇 |
2016年 | 941篇 |
2015年 | 1147篇 |
2014年 | 1374篇 |
2013年 | 1661篇 |
2012年 | 2712篇 |
2011年 | 2810篇 |
2010年 | 1686篇 |
2009年 | 1505篇 |
2008年 | 2394篇 |
2007年 | 2385篇 |
2006年 | 2234篇 |
2005年 | 2179篇 |
2004年 | 1967篇 |
2003年 | 1792篇 |
2002年 | 1651篇 |
2001年 | 288篇 |
2000年 | 203篇 |
1999年 | 263篇 |
1998年 | 312篇 |
1997年 | 235篇 |
1996年 | 185篇 |
1995年 | 159篇 |
1994年 | 129篇 |
1993年 | 122篇 |
1992年 | 70篇 |
1991年 | 57篇 |
1990年 | 55篇 |
1989年 | 39篇 |
1988年 | 36篇 |
1987年 | 29篇 |
1986年 | 32篇 |
1985年 | 26篇 |
1984年 | 40篇 |
1983年 | 29篇 |
1982年 | 33篇 |
1981年 | 27篇 |
1980年 | 17篇 |
1978年 | 19篇 |
1977年 | 13篇 |
1974年 | 12篇 |
1971年 | 10篇 |
1970年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Martin H. Stradner Manuel Dreu Hannes Angerer Gerald Gruber Karin Wagner Daniela Peischler Verena Krischan Andreas Leithner Friedrich Anderhuber Winfried B. Graninger 《Journal of orthopaedic research》2016,34(9):1569-1575
Osteoarthritis (OA) of the hand is a common disease resulting in pain and impaired function. The pathogenesis of hand OA (HOA) is elusive and models to study it have not been described. Chondrocyte culture has been essential to understand cartilage degeneration, which is a hallmark of OA. We investigated the feasibility of human chondrocyte culture derived from proximal interphalangeal (PIP) finger joints. Hyaline cartilage of the PIP and knee joints was obtained from human cadavers. Chondrocytes harvested up to 236 h after death of the donors were viable and expressed chondrocyte‐specific genes. Gene expression comparing chondrocytes from PIP and knee joints using Affymetrix GeneChip arrays resulted in a unique PIP‐specific gene expression pattern. Genes involved in developmental processes including the WNT pathway were differentially expressed between the joints. These findings suggest that our knowledge on chondrocyte biology derived mainly from knee and hip joints may not apply to chondrocytes of the PIP joints and some of the distinctive features of HOA may be caused by the specific properties of PIP chondrocytes. Chondrocyte culture of PIP cartilage is a novel tool to study cartilage degeneration in HOA. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1569–1575, 2016. 相似文献
992.
993.
Stefano Boschi Jason T. Lee Seval Beykan Roger Slavik Liu Wei Claudio Spick Uta Eberlein Andreas K. Buck Filippo Lodi Gianfranco Cicoria Johannes Czernin Michael Lassmann Stefano Fanti Ken Herrmann 《European journal of nuclear medicine and molecular imaging》2016,43(12):2122-2130
Purpose
The aim of this study was to synthesize and preclinically evaluate an 18F-PSMA positron emission tomography (PET) tracer. Prostate-specific membrane antigen (PSMA) specificity, biodistribution, and dosimetry in healthy and tumor-bearing mice were determined.Methods
Several conditions for the labeling of 18F-PSMA-11 via 18F-AlF-complexation were screened to study the influence of reaction temperature, peptide amount, ethanol volume, and reaction time. After synthesis optimization, biodistribution and dosimetry studies were performed in C57BL6 mice. For proof of PSMA-specificity, mice were implanted with PSMA-negative (PC3) and PSMA-positive (LNCaP) tumors in contralateral flanks. Static and dynamic microPET/computed tomography (CT) imaging was performed.Results
Quantitative labeling yields could be achieved with >97 % radiochemical purity. The 18F-PSMA-11 uptake was more than 24-fold higher in PSMA-high LNCaP than in PSMA-low PC3 tumors (18.4?±?3.3 %ID/g and 0.795?±?0.260 %ID/g, respectively; p?<?4.2e-5). Results were confirmed by ex vivo gamma counter analysis of tissues after the last imaging time point. The highest absorbed dose was reported for the kidneys. The maximum effective dose for an administered activity of 200 MBq was 1.72 mSv.Conclusion
18F-PSMA-11 using direct labeling of chelate-attached peptide with aluminum-fluoride detected PSMA-expressing tumors with high tumor-to-liver ratios. The kidneys were the dose-limiting organs. Even by applying the most stringent dosimetric calculations, injected activities of up to 0.56 GBq are feasible.994.
Amir Sabet Ina Binse Hong Grafe Samer Ezziddin Rainer Görges Thorsten D. Poeppel Andreas Bockisch Sandra J. Rosenbaum-Krumme 《European journal of nuclear medicine and molecular imaging》2016,43(11):1988-1994
Purpose
Nodal involvement is an independent risk factor of recurrence in papillary thyroid cancer (PTC). Neither the international guidelines nor the recently introduced ongoing risk adaptation concept consider the extent of initial surgical clearance of radioiodine sensitive lymph node metastases in their stratification systems. We investigated the prognostic relevance of incomplete initial surgical clearance in patients with purely lymphogeneous metastatic PTC (pN1 M0) despite successful radioiodine therapy. Accurate assessment of pre-ablative nodal status was attempted using PET/CT studies with both 124I-NaI and 18F-FDG along with high-resolution cervical ultrasound.Methods
Sixty-five patients with histologically diagnosed lymph node metastases (pN1 M0) were retrospectively analyzed. Patients with iodine-negative lymph node metastases diagnosed by 18F-FDG PET/CT or distant metastases were excluded from the analysis. The association of disease recurrence with the pre-ablative nodal status, as well as other baseline characteristics, were examined applying nonparametric tests for independent samples and multiple regression analysis. Patients with persistent lymph node metastases in 124I-NaI PET/CT were further divided according to the additional presence or absence of FDG-uptake in 18F-FDG PET/CT. Survival analyses were performed using Kaplan–Meier curves and the Cox proportional hazards model for uni- and multivariate analyses to assess the influence of prognostic factors on progression free survival (PFS).Results
Incomplete metastatic lymph node resection captured by 124I-NaI PET/CT (n?=?33) was an independent risk factor for recurrence (61 % vs 25 %, p?=?0.006) and shorter PFS (46 months vs not reached, HR 4.0 [95 %-CI, 1.7–9.2], p?=?0.001). Ultrasound could detect lymph node metastases only in 19/33 patients (58 %). Among patients with positive nodal status, FDG-avidity of metastatic iodine positive lymph nodes worsened the outcome (16 vs 69 months, p?=?0.047). From all other investigated factors including age, N-stage (N1a vs N1b), and T-Stage (T4 vs T1-3), only large tumor size (pT4) had a significant impact on PFS (HR 2.9 [95 %-CI, 1.3–6.4], p?=?0.007).Conclusions
Incomplete initial surgical clearance of lymph node metastases even after successful radioiodine therapy may increase the chances of recurrence and is an independent risk factor for impaired survival of patients with PTC. Pre-ablative (dual tracer PET/CT) imaging with 124I-Na and 18F provides a prognostic tool for these patients and may considerably complement the current risk stratification systems.995.
Anncatrine Luisa Petersen Jonas Rosager Henriksen Tina Binderup Dennis Ringkjøbing Elema Palle Hedengran Rasmussen Anne Mette Hag Andreas Kjær Thomas Lars Andresen 《European journal of nuclear medicine and molecular imaging》2016,43(5):941-952
Purpose
The objective of this study was to evaluate the potential of PEGylated 64Cu-liposomes in clinical diagnostic positron emission tomography (PET) imaging and PEGylated 177Lu-liposomes in internal tumor radiotherapy through in vivo characterization and dosimetric analysis in a human xenograft mouse model.Methods
Liposomes with 5 and 10 mol% PEG were characterized with respect to size, charge, and 64Cu- and 177Lu-loading efficiency. The tumor imaging potential of 64Cu-loaded liposomes was evaluated in terms of in vivo biodistribution, tumor accumulation and tumor-to-muscle (T/M) ratios, using PET imaging. The potential of PEGylated liposomes for diagnostic and therapeutic applications was further evaluated through dosimetry analysis using OLINDA/EXM software. The 64Cu-liposomes were used as biological surrogates to estimate the organ and tumor kinetics of 177Lu-liposomes.Results
High remote loading efficiency (>95 %) was obtained for both 64Cu and 177Lu radionuclides with PEGylated liposomes, and essentially no leakage of the encapsulated radionuclide was observed upon storage and after serum incubation for 24 h at 37 °C. The 10 mol% PEG liposomes showed higher tumor accumulation (6.2?±?0.2 %ID/g) than the 5 mol% PEG liposomes, as evaluated by PET imaging. The dosimetry analysis of the 64Cu-liposomes estimated an acceptable total effective dose of 3.3·10?2 mSv/MBq for diagnostic imaging in patients. A high absorbed tumor dose (114 mGy/MBq) was estimated for the potential radiotherapeutic 177Lu-liposomes.Conclusion
The overall preclinical profile of PEGylated 64Cu-liposomes showed high potential as a new PET theranostic tracer for imaging in humans. Dosimetry results predicted that initial administered activity of 200 MBq of 64Cu-liposomes should be acceptable in patients. Work is in progress to validate the utility of PEGylated 64Cu-liposomes in a clinical research programme. The high absorbed tumor dose (114 mGy/MBq) estimated for 177Lu-liposomes and the preliminary dosimetric studies justify further therapeutic and dosimetry investigation of 177Lu-liposomes in animals before potential testing in man.996.
Anja C. Rohenkohl Monika Bullinger Andreas M. Pleil Levente Kriston Julia H. Quitmann the QoLISSY Study Group 《Child indicators research》2016,9(4):971-984
The Quality of Life in Short Stature Youth (QoLISSY) questionnaire measures health-related quality of life (HrQoL) in short statured children (8–18 years) from patient and parent perspectives. To minimize respondent burden when assessing HrQoL in clinical practice, a brief version of the currently available 22-item QoLISSY is needed. The dataset of the European QoLISSY study (N?=?268) was divided into two subdatasets at random, one to identify the items of the brief questionnaire and the other to test the operating characteristics (reliability and validity). Concept-based construction involved the selection of three items per Quality of Life (QoL)-dimension (physical, social, emotional) according to the highest corrected item-scale correlation. Psychometric properties were inspected in terms of reliability and validity supplemented by testing item fit statistics to examine item response theory (IRT) compliance. Cronbach’s alpha for the 9-item version was 0.89 for the patient- and the parent report. Pearson’s correlations with the generic KIDSCREEN questionnaire were low to moderate (children: r?=?0.17–0.58; parents: r?=?0.12–0.56). Shorter children reported significantly poorer QoL (mean difference 15.39 points; p?<?0.001) than taller children, indicating known-groups validity. Results from IRT analysis showed an acceptable fit to Masters’ Partial Credit Model. The 9-item QoLISSY brief version has satisfactory operating characteristics and is an efficient alternative for use in research and practice. 相似文献
997.
998.
999.
1000.
Miriam Michel Jana Logoteta Andreas Entenmann Jan Hinnerk Hansen Inga Voges Hans-Heiner Kramer Colin Petko 《Pediatric cardiology》2016,37(7):1250-1257
Accurate assessment of ventricular function is particularly important in children with hypoplastic left heart syndrome (HLHS) after completion of the total cavopulmonary connection (TCPC). For this purpose, two-dimensional speckle tracking (2DST) is a promising technique as it does not depend on the angle of insonation or the geometry of the ventricle. The objective of this study was to assess changes in systolic and diastolic right ventricular (RV) function within a 5-year follow-up period of HLHS patients after TCPC using conventional and 2DST echocardiography. RV fractional area change (RVFAC), tricuspid annular plane systolic excursion (TAPSE), E/A, E/e′ and 2DST parameters [global longitudinal peak systolic strain (GS) and strain rate (GSRs), global strain rate in early (GSRe) and late (GSRa) diastole] of 40 HLHS patients were compared at 1.6 and at 5.1 years after TCPC. RVFAC, E/A, E/e′ and GS did not change, whereas TAPSE (13.7 ± 3.2 vs. 10.5 ± 2.4 mm/m2, p < 0.001), GSRs (?1.56 ± 0.28 vs. ?1.35 ± 0.31 1/s, p < 0.001), GSRe (2.22 ± 0.49 vs. 1.96 ± 0.44 1/s, p = 0.004) and GSRa (1.19 ± 0.39 vs. 0.92 ± 0.39 1/s, p < 0.001) decreased significantly. Systolic and diastolic RV function parameters of HLHS patients decreased from 1.6 to 5.1 years after TCPC in our patients. Changes in global strain rate parameters may be signaling early RV dysfunction that is not detectable by traditional echocardiography. Further study is needed to verify this and to determine whether these changes are clinically relevant. 相似文献