首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   22784篇
  免费   2661篇
  国内免费   403篇
耳鼻咽喉   392篇
儿科学   1202篇
妇产科学   1935篇
基础医学   2692篇
口腔科学   208篇
临床医学   3168篇
内科学   2817篇
皮肤病学   180篇
神经病学   1068篇
特种医学   539篇
外国民族医学   3篇
外科学   1363篇
综合类   1711篇
现状与发展   1篇
一般理论   2篇
预防医学   3078篇
眼科学   486篇
药学   2003篇
  12篇
中国医学   372篇
肿瘤学   2616篇
  2024年   14篇
  2023年   523篇
  2022年   579篇
  2021年   1011篇
  2020年   1134篇
  2019年   1151篇
  2018年   1015篇
  2017年   1038篇
  2016年   1147篇
  2015年   1070篇
  2014年   1603篇
  2013年   2265篇
  2012年   1351篇
  2011年   1375篇
  2010年   1106篇
  2009年   1063篇
  2008年   1062篇
  2007年   984篇
  2006年   858篇
  2005年   733篇
  2004年   641篇
  2003年   608篇
  2002年   441篇
  2001年   380篇
  2000年   274篇
  1999年   280篇
  1998年   209篇
  1997年   173篇
  1996年   148篇
  1995年   168篇
  1994年   159篇
  1993年   147篇
  1992年   148篇
  1991年   113篇
  1990年   107篇
  1989年   75篇
  1988年   85篇
  1987年   71篇
  1986年   64篇
  1985年   103篇
  1984年   77篇
  1983年   46篇
  1982年   44篇
  1981年   50篇
  1980年   44篇
  1979年   33篇
  1978年   25篇
  1977年   14篇
  1976年   9篇
  1975年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Serrated polyps (SPs) are precursors to one-third of colorectal cancers (CRCs), with histological subtypes: hyperplastic polyps (HPs), sessile serrated lesions (SSLs) and traditional serrated adenomas (TSAs). The incidence of early-onset CRC before the age of 50 is increasing, with limited understanding of SPs in younger cohorts. Using a large colonoscopy-based cohort, we characterized epidemiologic profiles of SP subtypes, compared to conventional adenomas, with secondary analysis on early-onset polyps. Ninety-four thousand four hundred and twenty-seven patients underwent screening colonoscopies between 2010 and 2018. Demographic, endoscopic and histopathologic characteristics of each polyp subtype were described. High-risk polyps included SSLs ≥10 mm/with dysplasia and conventional adenomas ≥10 mm/with tubulovillous/villous histology/high-grade dysplasia. We examined polyp prevalence with age and compared early- (age < 50) and late-onset polyps (age ≥ 50). Eighteen thousand one hundred and twenty-five patients had SPs (4357 SSLs, 15 415 HPs, 120 TSAs) and 26 699 had conventional adenomas. High-risk SSLs were enriched in the ascending colon (44.1% vs 2.6-35.8% for other locations; P < .003). Early- and late-onset SPs had similar subsite distribution. Early-onset conventional adenomas were more enriched in the distal colon/rectum (51.8% vs 43.4%, P < .001). Multiple conventional adenomas were more represented in late-onset groups (40.8% vs 33.8%, P < .001), with no difference in SSLs. The prevalence of conventional adenomas/high-risk conventional adenomas increased continuously with age, whereas the prevalence of SSLs/high-risk SSLs was stable from age 40 years onwards. A higher proportion of women were diagnosed with early-onset than late-onset SSLs (62.9% vs 57.6%, P = .03). Conventional adenomas, SSLs, early- and late-onset polyps have distinct epidemiology. The findings have implications for improved colonoscopy screening and surveillance and understanding the etiologic heterogeneity of CRC.  相似文献   
2.
IntroductionLung cancer (LC) is usually diagnosed at advanced stages with only a 12% 5-year survival. Trials as NLST and NELSON show a mortality decrease, which justifies implementation of lung cancer screening in risk population. Our objective was to show survival results of the largest LC screening program in Spain with low dosage computed tomography (LDCT).MethodsClinical records from International Early Lung Cancer Detection Program (IELCAP) at Valencia, Spain were analysed. This program recruited volunteers, ever-smokers aged 40-80 years, since 2008. Results are compared to those from other similar sizeable programs.ResultsA total of 8278 participants were screened with at least two-rounds until November 2020. A mean of 6 annual screening rounds were performed. We detected 239 tumours along 12-year follow-up. Adenocarcinoma was the most common histology, being 61.3% at stage I. The lung cancer prevalence and incidence proportion was 1.5% and 1.4%, respectively with an annual detection rate of 0.17. One-year survival and 10-year survival were 90% and 80.1%, respectively. Adherence was 96.84%.ConclusionLargest lung cancer screening in Spain shows that survival is improved when is performed in multidisciplinary team experienced in management of LC, and is comparable to similar screening programs.  相似文献   
3.
Obstructive sleep apnea (OSA) is a sleep disorder common among patients with type 2 diabetes (T2D). The aim of this quality improvement project was to increase identification and referral for sleep study for individuals with T2D at moderate to high risk for OSA. Pre- and post-intervention patient samples were analyzed to compare the number of referrals for sleep study. Results demonstrated that none of the patients pre-intervention were referred for sleep study compared with 77% of patients post-intervention. This project demonstrated implementing an evidence-based tool to screen patients with T2D for OSA leads to higher rates of detection and referral.  相似文献   
4.
Oral squamous cell carcinomas (OSCCs) develop in genetically altered epithelium in the mucosal lining, also coined as fields, which are mostly not visible but occasionally present as white oral leukoplakia (OL) lesions. We developed a noninvasive genetic assay using next-generation sequencing (NGS) on brushed cells to detect the presence of genetically altered fields, including those that are not macroscopically visible. The assay demonstrated high accuracy in OL patients when brush samples were compared with biopsies as gold standard. In a cohort of Fanconi anemia patients, detection of mutations in prospectively collected oral brushes predicted oral cancer also when visible abnormalities were absent. We further provide insight in the molecular landscape of OL with frequent changes of TP53, FAT1 and NOTCH1. NGS analysis of noninvasively collected samples offers a highly accurate method to detect genetically altered fields in the oral cavity, and predicts development of OSCC in high-risk individuals. Noninvasive genetic screening can be employed to screen high-risk populations for cancer and precancer, map the extension of OL lesions beyond what is visible, map the oral cavity for precancerous changes even when visible abnormalities are absent, test accuracy of promising imaging modalities, monitor interventions and determine genetic progression as well as the natural history of the disease in the human patient.  相似文献   
5.
【目的】了解上海市闵行区小学生近视状况及相关因素分析。【方法】选取2019年1月1日至12月31日期间参加屈光筛查的11 356名6~10岁小学生作为本次研究的对象,调查项目包括视力检查和电脑验光。【结果】6~10岁社区小学生近视检出率45.59%。女性高于男性,6~10岁检出率分别为22.88%、31.77%、47.62%、60.53%、69.84%,呈线性趋势(χ2=1.31,P<0.001)。多因素logistic回归分析结果显示,性别、年龄、父母近视状态是社区小学生屈光近视的影响因素;出生体重、是否早产、体重指数(BMI)对社区小学生屈光近视无影响。【结论】社区儿童青少年屈光近视的检出率较高,且不同人群特征检出情况有所差异,因此需针对不同年龄段、不同学生特征儿童青少年采取综合施策优先,重点人群重点防控的多层次防控策略。  相似文献   
6.
《Genetics in medicine》2022,24(9):1814-1820
Although still in the early stages of development, the advent of fast, high-output, and cost-effective next-generation DNA sequencing technology is moving precision medicine into public health. Before this shift toward next-generation sequencing in public health settings, individual patients met geneticists after showing symptoms and through limited family screening. In the new era of precision public health, everyone is a possible participant in genetic sequencing, simply by being born (newborn screening), by donating blood (biobanking), or through population screening. These initiatives are increasingly offered to individuals throughout their life and more individuals are encountering opportunities to use DNA sequencing. This article raises awareness of these growing areas and calls for different models of public engagement and communication about genomics, including screening asymptomatic populations, obtaining consent for unspecified and unforeseen future uses of genomic data, and managing variants of uncertain significance. Given that such communication challenges loom large, established norms of practice in genomic medicine and research should be reconsidered.  相似文献   
7.
PurposeUnderstanding the value of genetic screening and testing for monogenic disorders requires high-quality, methodologically robust economic evaluations. This systematic review sought to assess the methodological quality among such studies and examined opportunities for improvement.MethodsWe searched PubMed, Cochrane, Embase, and Web of Science for economic evaluations of genetic screening/testing (2013-2019). Methodological rigor and adherence to best practices were systematically assessed using the British Medical Journal checklist.ResultsAcross the 47 identified studies, there were substantial variations in modeling approaches, reporting detail, and sophistication. Models ranged from simple decision trees to individual-level microsimulations that compared between 2 and >20 alternative interventions. Many studies failed to report sufficient detail to enable replication or did not justify modeling assumptions, especially for costing methods and utility values. Meta-analyses, systematic reviews, or calibration were rarely used to derive parameter estimates. Nearly all studies conducted some sensitivity analysis, and more sophisticated studies implemented probabilistic sensitivity/uncertainty analysis, threshold analysis, and value of information analysis.ConclusionWe describe a heterogeneous body of work and present recommendations and exemplar studies across the methodological domains of (1) perspective, scope, and parameter selection; (2) use of uncertainty/sensitivity analyses; and (3) reporting transparency for improvement in the economic evaluation of genetic screening/testing.  相似文献   
8.
《Clinical breast cancer》2022,22(5):e718-e726
BackgroundSince 2004, an organised screening programme (OS) for breast cancer has been in place for 50-74 years women who are not at an increased risk. Despite this, 17% of cancers diagnosed within 24 months following an OS mammogram are interval cancers (IC), diagnosed even though the OS had not reported cancer. After identifying IC from the French administrative healthcare database (SNDS), our objective was to describe the care pathways of women with IC in 2016.Materials and MethodsThe IC identification algorithm is based on breast imaging tests conducted in the 24 months prior to diagnosis and on the compatibility of their timeline with ACR3 lesion follow-up (BIRADS guidelines). The care pathways of 3 groups were compared: women with IC, diagnosed through the OS, and diagnosed outside the OS programme (personalised screening or based on clinical signs, PSCS group).ResultsRespectively, 12,965 (46%), 3433 (12%), and 11,761 women (42%) were classified in the OS, IC and PSCS groups, i.e. 20.9% IC cases among the women taking part in the OS programme. The women from the IC group presented with more forms with lymph node or metastatic involvement than those of the OS group. Their pathways were more complex than in the OS group: at an equivalent stage, more total mastectomies and more adjuvant or neoadjuvant chemotherapy regimens.ConclusionThe care pathways of women with IC are intermediate with respect to those of the OS or PSCS group.Cases of IC probably include several cancer prognosis profiles.  相似文献   
9.
Genome-scale screening experiments in cancer produce long lists of candidate genes that require extensive interpretation for biological insight and prioritization for follow-up studies. Interrogation of gene lists frequently represents a significant and time-consuming undertaking, in which experimental biologists typically combine results from a variety of bioinformatics resources in an attempt to portray and understand cancer relevance. As a means to simplify and strengthen the support for this endeavor, we have developed oncoEnrichR, a flexible bioinformatics tool that allows cancer researchers to comprehensively interrogate a given gene list along multiple facets of cancer relevance. oncoEnrichR differs from general gene set analysis frameworks through the integration of an extensive set of prior knowledge specifically relevant for cancer, including ranked gene-tumor type associations, literature-supported proto-oncogene and tumor suppressor gene annotations, target druggability data, regulatory interactions, synthetic lethality predictions, as well as prognostic associations, gene aberrations and co-expression patterns across tumor types. The software produces a structured and user-friendly analysis report as its main output, where versions of all underlying data resources are explicitly logged, the latter being a critical component for reproducible science. We demonstrate the usefulness of oncoEnrichR through interrogation of two candidate lists from proteomic and CRISPR screens. oncoEnrichR is freely available as a web-based service hosted by the Galaxy platform ( https://oncotools.elixir.no ), and can also be accessed as a stand-alone R package ( https://github.com/sigven/oncoEnrichR ).  相似文献   
10.
Patient navigation is a strategy for overcoming barriers to reduce disparities and to improve access and outcomes. The aim of this umbrella review was to identify, critically appraise, synthesize, and present the best available evidence to inform policy and planning regarding patient navigation across the cancer continuum. Systematic reviews examining navigation in cancer care were identified in the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Embase, Cumulative Index of Nursing and Allied Health (CINAHL), Epistemonikos, and Prospective Register of Systematic Reviews (PROSPERO) databases and in the gray literature from January 1, 2012, to April 19, 2022. Data were screened, extracted, and appraised independently by two authors. The JBI Critical Appraisal Checklist for Systematic Review and Research Syntheses was used for quality appraisal. Emerging literature up to May 25, 2022, was also explored to capture primary research published beyond the coverage of included systematic reviews. Of the 2062 unique records identified, 61 systematic reviews were included. Fifty-four reviews were quantitative or mixed-methods reviews, reporting on the effectiveness of cancer patient navigation, including 12 reviews reporting costs or cost-effectiveness outcomes. Seven qualitative reviews explored navigation needs, barriers, and experiences. In addition, 53 primary studies published since 2021 were included. Patient navigation is effective in improving participation in cancer screening and reducing the time from screening to diagnosis and from diagnosis to treatment initiation. Emerging evidence suggests that patient navigation improves quality of life and patient satisfaction with care in the survivorship phase and reduces hospital readmission in the active treatment and survivorship care phases. Palliative care data were extremely limited. Economic evaluations from the United States suggest the potential cost-effectiveness of navigation in screening programs.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号