全文获取类型
收费全文 | 87440篇 |
免费 | 9182篇 |
国内免费 | 1971篇 |
专业分类
耳鼻咽喉 | 738篇 |
儿科学 | 1276篇 |
妇产科学 | 615篇 |
基础医学 | 5408篇 |
口腔科学 | 1370篇 |
临床医学 | 16748篇 |
内科学 | 10015篇 |
皮肤病学 | 473篇 |
神经病学 | 11902篇 |
特种医学 | 22979篇 |
外国民族医学 | 18篇 |
外科学 | 6814篇 |
综合类 | 8916篇 |
现状与发展 | 1篇 |
预防医学 | 2330篇 |
眼科学 | 1334篇 |
药学 | 2912篇 |
67篇 | |
中国医学 | 1091篇 |
肿瘤学 | 3586篇 |
出版年
2024年 | 110篇 |
2023年 | 1571篇 |
2022年 | 2247篇 |
2021年 | 3984篇 |
2020年 | 3932篇 |
2019年 | 3694篇 |
2018年 | 3498篇 |
2017年 | 3863篇 |
2016年 | 4063篇 |
2015年 | 3897篇 |
2014年 | 6547篇 |
2013年 | 5983篇 |
2012年 | 5370篇 |
2011年 | 5815篇 |
2010年 | 4782篇 |
2009年 | 4865篇 |
2008年 | 4752篇 |
2007年 | 4534篇 |
2006年 | 3962篇 |
2005年 | 3407篇 |
2004年 | 2932篇 |
2003年 | 2304篇 |
2002年 | 1858篇 |
2001年 | 1717篇 |
2000年 | 1393篇 |
1999年 | 1086篇 |
1998年 | 1079篇 |
1997年 | 958篇 |
1996年 | 776篇 |
1995年 | 736篇 |
1994年 | 592篇 |
1993年 | 486篇 |
1992年 | 392篇 |
1991年 | 294篇 |
1990年 | 221篇 |
1989年 | 168篇 |
1988年 | 144篇 |
1987年 | 133篇 |
1986年 | 96篇 |
1985年 | 72篇 |
1984年 | 52篇 |
1983年 | 39篇 |
1982年 | 37篇 |
1981年 | 32篇 |
1980年 | 35篇 |
1979年 | 21篇 |
1978年 | 20篇 |
1977年 | 15篇 |
1976年 | 9篇 |
1974年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
51.
目的获得三叉苦Melicope pteleifolia转录组信息特征。方法以三叉苦幼苗根、茎、叶混合样品为对象,采用二代高通量测序平台Illumina HiSeq~(TM) 2000进行转录组测序并进行系统的生物信息学分析。结果转录组测序分析共获得47 045 040条高质量序列(clean reads),Trinity de novo组装获得67 956条unigenes,平均长度787 nt。BLAST分析显示分别有42 749(61.92%)、31 152(45.84%)、26 563(39.0 9%)、17 481(25.72%)条unigenes在NR、Swiss-port、KOG、KEGG数据库得到注释信息,参与生物过程、细胞组分和分子功能3个GO类别的47个小组,共9807条unigenes注释到130个KEGG代谢通路中,筛选到19条次生代谢通路,KOG功能分类分析获得25个不同的KOG功能类群。预测共有高等植物转录因子56个家族;借助MISA软件发现7 748个SSRs,三碱基重复SSRs数量最丰富,有4 117个,出现频率为53.1%,五碱基重复SSRs相对较少,占2.2%。结论利用高通量测序技术和生物信息分析获得三叉苦转录组信息特征,为后续三叉苦功能基因的挖掘、次生代谢途径解析及其调控机制研究奠定基础。 相似文献
52.
《European journal of surgical oncology》2019,45(11):2151-2158
IntroductionLymph node yield (LNY) in neck dissection has been identified as a prognostic factor in oral cavity cancer. The purpose of this study was to investigate the impact of additional use of optical imaging on LNY in therapeutic ND in oral cancer.MethodsConsecutive patients with oral squamous cell carcinoma with clinical neck metastasis planned for primary tumor resection were randomized to conventional neck dissection or near-infrared fluorescence (NIRF)-guided neck dissection, respectively. In the intervention group, patients were injected with ICG-Nanocoll prior to surgery. Intraoperatively, an optical hand-held camera system was used for lymph node identification. Also, NIRF imaging of the neck specimen was performed, and optical signals were pinned with needle markings to guide the pathological examination. The endpoint of the study was LNY per neck side in levels Ib-III.Results31 patients were included with 18 neck sides in the control group and 18 neck sides in the intervention group for evaluation. During NIRF-guided ND, individual lymph nodes could be identified by a bright fluorescent signal and individual tumor-related drainage patterns could be observed in the neck. The LNY in the intervention group was significantly higher compared to the control group (p = 0.032) with a mean of 24 LN (range: 12–33 LN in levels Ib-III compared to 18 LN (range: 10–36 LN) in the control group, respectively.ConclusionsNIRF-guided ND significantly improved the nodal yield compared to the control group. Intraoperative real-time optical imaging enabled direct visualization of tumor-related drainage patterns within the neck lymphatics. 相似文献
53.
近年来癌症治疗受到广泛关注,二氧化硅纳米颗粒因其独特的理化性质在肿瘤诊疗领域展现巨大潜力。基于二氧化硅纳米粒子的药物输送系统可被动或主动靶向肿瘤组织,并通过刺激响应的方式实现药物在肿瘤部位的可控释放,有效提高抗肿瘤药物在肿瘤部位的浓度,提高治疗效率。同时,二氧化硅纳米粒子通过负载造影剂可实现生物成像功能,用于肿瘤组织定位及药物追踪,实现更高效的抗肿瘤治疗。本文介绍了二氧化硅纳米粒子的制备方式,并对二氧化硅纳米粒子在药物靶向递送系统及生物成像领域中的研究进展进行综述。 相似文献
54.
《Clinical oncology (Royal College of Radiologists (Great Britain))》2020,32(3):144-148
The value of multi-parametric magnetic resonance imaging in the detection of clinically-significant prostate cancer is increasingly well-established, and has been adopted in current diagnostic pathways and clinical guidelines. Concurrently, the role of conventional ultrasound-guided systematic prostate biopsy is increasingly questioned. In this brief review, we evaluate the continued value of systematic biopsy including a review of prospective studies on targeted and systemic biopsies in the same patients. We also address current limitations of multi-parametric magnetic resonance imaging of the prostate. 相似文献
55.
Young Hyo Choi Min Yong Kang Hyun Hwan Sung Hwang Gyun Jeon Byong Chang Jeong Seong Il Seo Seong Soo Jeon Chan Kyo Kim Byung Kwan Park Hyun Moo Lee 《Clinical genitourinary cancer》2019,17(1):e19-e25
Background
The purpose of the study was to compare cancer detection rates between 12-core transrectal ultrasound-guided prostate biopsy (TRUS-Bx) and multiparametric magnetic resonance imaging (mpMRI)-guided target prostate biopsy (MRI-TBx) according to prostate-specific antigen (PSA) level in biopsy-naive patients.Patients and Methods
A retrospective study was conducted in 2009 biopsy-naive patients with suspected prostate cancer (PSA ≤20 ng/mL). Patients underwent TRUS-Bx (n = 1786) or MRI-guided target prostate biopsy (MRI-TBx; n = 223) from September 2013 to March 2017 and were stratified according to each of 4 PSA cutoffs. MRI-TBx was performed on lesions with Prostate Imaging Reporting and Data System (PI-RADS) scores of 3 to 5 on mpMRI. Clinically significant prostate cancer (csPCa) was defined as Gleason ≥7. Propensity score matching was performed using the prebiopsy variables, which included age, PSA, prostate volume, and PSA density.Results
Propensity score matching resulted in 222 patients in each group. There were significant differences between the TRUS-Bx and MRI-TBx groups in the overall detection rates of prostate cancer (41.4% vs. 55.4%; P = .003) and csPCa (30.1% vs. 42.8%; P = .005). However, across PSA cutoffs, MRI-TBx detected more prostate cancer than TRUS-Bx at PSA levels of 2.5 to <4 (29.5% vs. 56.6%; P < .001). The csPCa detection rates of TRUS-Bx and MRI-TBx did not differ significantly within the PSA cutoffs. There was a significantly higher detection rate of prostate cancer and csPCa in lesions with PI-RADS scores 4 and 5 than in those with a score of 3.Conclusion
Prebiopsy mpMRI and subsequent targeted biopsy had a higher detection rate than TRUS-Bx in patients with prostate cancer and csPCa. 相似文献56.
57.
58.
程序化死亡配体-1(PD-L1)靶向免疫治疗被广泛应用于不同类型的癌症中,患者从PD-L1靶向免疫治疗的获益主要依赖于肿瘤组织PD-L1的表达水平。目前临床主要采用穿刺活检等有创手段来评价肿瘤组织PD-L1的表达水平,严重受限于PD-L1表达的时间和空间异质性。核医学探针能够在分子水平上实现对PD-L1的在体无创检测,对于指导患者筛选、预测患者免疫治疗响应具有重要的临床意义。本文综述了靶向PD-L1的核医学分子影像探针,并讨论其在肿瘤PD-L1显像中的应用。 相似文献
59.
N. Shor R. Deschamps A. Cobo Calvo E. Maillart H. Zephir J. Ciron C. Papeix F. Durand-Dubief A. Ruet X. Ayrignac M. Cohen K. Deiva D. Laplaud B. Bourre B. Audoin N. Collongues S. Vukusic F. Cotton R. Marignier 《Revue neurologique》2021,177(1-2):39-50
Our knowledge of the radiological spectrum of myelin oligodendrocyte glycoprotein antibody associated disease (MOGAD) is growing rapidly. An update on the radiological features of the disease, and its evolution is thus necessary. Magnetic resonance imaging (MRI) has an increasingly important role in the differential diagnosis of MOGAD particularly from aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD), and multiple sclerosis (MS). Differentiating these conditions is of prime importance because the management is different between the three inflammatory diseases, and thus could prevent further attack-related disability. Therefore, identifying the MRI features suggestive of MOGAD has diagnostic and prognostic implications. We herein review optic nerve, spinal cord and the brain MRI findings from MOGAD adult patients, and compare them to AQP4-NMOSD and MS. 相似文献
60.
C. Vogrig J.-S. Louis F. Avila R. Gillet G. Hossu A. Blum-Moyse P.A. Gondim Teixeira 《Diagnostic and interventional imaging》2021,102(3):181-187
PurposeThe purpose of this study was to compare morphologic assessment and relaxometry of patellar hyaline cartilage between conventional sequences (fast spin-echo [FSE] T2-weighted fat-saturated and T2-mapping) and synthetic T2 short-TI inversion recovery (STIR) and T2 maps at 1.5 T magnetic resonance imaging (MRI).MethodThe MRI examinations of the knee obtained at 1.5 T in 49 consecutive patients were retrospectively studied. There were 21 men and 28 women with a mean age of 45 ± 17.7 (SD) years (range: 18–88 years). Conventional and synthetic acquisitions were performed, including T2-weighted fat-saturated and T2-mapping sequences. Two radiologists independently compared patellar cartilage T2-relaxation time on conventional T2-mapping and synthetic T2-mapping images. A third radiologist evaluated the patellar cartilage morphology on conventional and synthetic T2-weighted images. The presence of artifacts was also assessed. Interobserver agreement for quantitative variables was assessed using intraclass correlation coefficient (ICC).ResultsIn vitro, conventional and synthetic T2 maps yielded similar mean T2 values 58.5 ± 2.3 (SD) ms and 58.8 ± 2.6 (SD) ms, respectively (P = 0.414) and 6% lower than the expected experimental values (P = 0.038). Synthetic images allowed for a 15% reduction in examination time compared to conventional images. On conventional sequences, patellar chondropathy was identified in 35 patients (35/49; 71%) with a mean chondropathy grade of 4.8 ± 4.8 (SD). On synthetic images, 28 patients (28/49; 57%) were diagnosed with patellar chondropathy, with a significant 14% difference (P = 0.009) and lower chondropathy scores (3.7 ± 4.9 [SD]) compared to conventional images. Motion artifacts were more frequently observed on synthetic images (18%) than on conventional ones (6%). The interobserver agreement was excellent for both conventional and synthetic T2 maps (ICC > 0.83). Mean cartilage T2 values were significantly greater on synthetic images (36.2 ± 3.8 [SD] ms; range: 29-46 ms) relative to conventional T2 maps (31.8 ± 4.1 [SD] ms; range: 26-49 ms) (P < 0.0001).ConclusionDespite a decrease in examination duration, synthetic images convey lower diagnostic performance for chondropathy, greater prevalence of motion artifacts, and an overestimation of T2 values compared to conventional MRI sequences. 相似文献