全文获取类型
收费全文 | 278175篇 |
免费 | 22170篇 |
国内免费 | 7092篇 |
专业分类
耳鼻咽喉 | 2292篇 |
儿科学 | 5199篇 |
妇产科学 | 4916篇 |
基础医学 | 42196篇 |
口腔科学 | 5523篇 |
临床医学 | 19646篇 |
内科学 | 40500篇 |
皮肤病学 | 4274篇 |
神经病学 | 18473篇 |
特种医学 | 9209篇 |
外国民族医学 | 29篇 |
外科学 | 25864篇 |
综合类 | 34845篇 |
现状与发展 | 40篇 |
一般理论 | 8篇 |
预防医学 | 19541篇 |
眼科学 | 3314篇 |
药学 | 35586篇 |
79篇 | |
中国医学 | 14938篇 |
肿瘤学 | 20965篇 |
出版年
2023年 | 3772篇 |
2022年 | 5156篇 |
2021年 | 10692篇 |
2020年 | 9425篇 |
2019年 | 10662篇 |
2018年 | 10756篇 |
2017年 | 10561篇 |
2016年 | 9957篇 |
2015年 | 9950篇 |
2014年 | 12617篇 |
2013年 | 17096篇 |
2012年 | 13790篇 |
2011年 | 16497篇 |
2010年 | 11411篇 |
2009年 | 11685篇 |
2008年 | 12823篇 |
2007年 | 13517篇 |
2006年 | 12706篇 |
2005年 | 11420篇 |
2004年 | 9982篇 |
2003年 | 8845篇 |
2002年 | 7045篇 |
2001年 | 6250篇 |
2000年 | 5409篇 |
1999年 | 4559篇 |
1998年 | 3513篇 |
1997年 | 3511篇 |
1996年 | 3137篇 |
1995年 | 3012篇 |
1994年 | 2910篇 |
1993年 | 2435篇 |
1992年 | 2153篇 |
1991年 | 2013篇 |
1990年 | 1793篇 |
1989年 | 1437篇 |
1988年 | 1357篇 |
1987年 | 1193篇 |
1986年 | 1109篇 |
1985年 | 2550篇 |
1984年 | 3083篇 |
1983年 | 2013篇 |
1982年 | 2190篇 |
1981年 | 1989篇 |
1980年 | 1691篇 |
1979年 | 1469篇 |
1978年 | 1180篇 |
1977年 | 1031篇 |
1976年 | 1136篇 |
1975年 | 794篇 |
1973年 | 708篇 |
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
11.
12.
Species identification of unknown biological samples is crucial for forensic applications, especially in cases of explosion, disaster accidents, and body mutilation after murdering, as well as poaching, illegal trade in endangered animals, and meat food fraud. In this study, we identified 60 volatile organic compounds (VOCs) in fresh skeletal muscle tissues of seven different animal species (cattle, sheep, pigs, rabbits, rats, chickens and carp) and a human dead body by headspace-gas-chromatography ion-mobility spectrometry (HS-GC-IMS), and compared their differences by retention time, drift time and molecular weight. The results showed that these VOCs formed different gallery plot fingerprints in the skeletal muscle tissues of the human dead body and seven animal species. Principal component analysis (PCA) showed significantly different fingerprints between these species, and these fingerprints maintained good stability between the species and within the same species. Some VOCs have high species specificity, while VOCs of human fresh muscle tissues from different individual sources have little difference, demonstrating that all tested muscle tissue samples could be distinguished based on different VOCs. HS-GC-IMS has proved to be a rapid, high-throughput, highly sensitive and specific species identification method, which can be used for forensic species identification in criminal cases and disaster accidents, as well as detection in the field of food safety, such as meat fraud and adulteration. 相似文献
13.
14.
美国食品药品管理局(FDA)于2022年7月发布了"治疗等效性评价供企业用指导原则"(草案)。该指导原则阐明了FDA治疗等效性的标准以及治疗等效性编码系统,目的是准确评价仿制药与参比制剂的治疗等效性并通过治疗等效性代码,在"橙皮书"中迅速检索到治疗等效的仿制药。而中国目前尚无类似的指导原则,详细介绍FDA该指导原则主要内容,期望对中国加强仿制药的治疗等效性评价和加速完善和实施符合国情的治疗等效性编码系统有所帮助。 相似文献
15.
《Research in social & administrative pharmacy》2022,18(3):2367-2391
ObjectivesSeveral implementation strategies can reduce potentially inappropriate medication (PIM) prescribing. Although use of PIMs has declined in recent years, it remains prevalent. Various strategies exist to improve the appropriateness of medication use. However, little is known about the processes of these different implementation strategies. This scoping review aims to investigate how the process evaluation of implementation strategies for reducing PIM prescribing in the older population has been studied.MethodsWe searched for process evaluations of implementation strategies for reducing PIM prescribing in PUBMED, SCOPUS and Web of Science published between January 2000 and November 2019 in English. We applied the following inclusion criteria: patients aged ≥65 years, validated PIM criteria, and implementation process evaluated. The review focuses on decision support for health care professionals. We described the findings of the process evaluations, and compared the authors’ concepts of process evaluation of the included publications to those of Proctor et al.( 2010).ResultOf 9131 publications screened, 29 met our inclusion criteria. Different process evaluation conceptualizations were identified. Most process evaluations took place in the initial stages of the process (acceptability, adoption, appropriateness, and feasibility) and sustainability and implementation costs were seldom evaluated. None of the included publications evaluated fidelity.Multifaceted interventions were the most studied implementation strategies. Medication review was more common in acceptability evaluations, multidisciplinary interventions in adoption evaluations, and computerized systems and educational interventions in feasibility evaluations. Process evaluations were studied from the health care professionals’ viewpoint in most of the included publications, but the management viewpoint was missing.DiscussionThe conceptualization of process evaluation in the field of PIM prescribing is indeterminate. There is also a current gap in the knowledge of sustainability and implementation costs. Clarifying the conceptualization of implementation process evaluation is essential in order to effectively translate research knowledge into practice. 相似文献
16.
《Journal of Cardiovascular Computed Tomography》2022,16(1):19-26
BackgroundThe role of change in fractional flow reserve derived from CT (FFRCT) across coronary stenoses (ΔFFRCT) in guiding downstream testing in patients with stable coronary artery disease (CAD) is unknown.ObjectivesTo investigate the incremental value of ΔFFRCT in predicting early revascularization and improving efficiency of catheter laboratory utilization.MaterialsPatients with CAD on coronary CT angiography (CCTA) were enrolled in an international multicenter registry. Stenosis severity was assessed as per CAD-Reporting and Data System (CAD-RADS), and lesion-specific FFRCT was measured 2 ?cm distal to stenosis. ΔFFRCT was manually measured as the difference of FFRCT across visible stenosis.ResultsOf 4730 patients (66 ?± ?10 years; 34% female), 42.7% underwent ICA and 24.7% underwent early revascularization. ΔFFRCT remained an independent predictor for early revascularization (odds ratio per 0.05 increase [95% confidence interval], 1.31 [1.26–1.35]; p ?< ?0.001) after adjusting for risk factors, stenosis features, and lesion-specific FFRCT. Among the 3 models (model 1: risk factors ?+ ?stenosis type and location ?+ ?CAD-RADS; model 2: model 1 ?+ ?FFRCT; model 3: model 2 ?+ ?ΔFFRCT), model 3 improved discrimination compared to model 2 (area under the curve, 0.87 [0.86–0.88] vs 0.85 [0.84–0.86]; p ?< ?0.001), with the greatest incremental value for FFRCT 0.71–0.80. ΔFFRCT of 0.13 was the optimal cut-off as determined by the Youden index. In patients with CAD-RADS ≥3 and lesion-specific FFRCT ≤0.8, a diagnostic strategy incorporating ΔFFRCT >0.13, would potentially reduce ICA by 32.2% (1638–1110, p ?< ?0.001) and improve the revascularization to ICA ratio from 65.2% to 73.1%.ConclusionsΔFFRCT improves the discrimination of patients who underwent early revascularization compared to a standard diagnostic strategy of CCTA with FFRCT, particularly for those with FFRCT 0.71–0.80. ΔFFRCT has the potential to aid decision-making for ICA referral and improve efficiency of catheter laboratory utilization. 相似文献
17.
目的 围绕足三里穴(ST36)进行文献可视化分析,探索近20年来有关足三里穴的研究进程、热点以及未来发展趋势。方法 以中国知网(CNKI)为数据来源,利用citespace软件对检索出的2000年1月至2021年11月收录的基础研究和临床研究文献分别进行可视化分析,绘制关键词、作者、机构相关图谱。结果 基础研究纳入1030篇文献,得到9个关键词聚类,电针中心度最高(0.53),发文量最多的作者是胡森(22篇),发文量最大的机构是北京中医药大学针灸推拿学院(23篇)。临床研究纳入2067篇文献,得到9个关键词聚类,穴位注射和针刺中心度最高(0.27),发文量最多的作者是张波(7篇),发文量最大的机构是浙江中医药大学附属第一医院(8篇)。结论 足三里穴在基础和临床的研究重点、热点和趋势不一致。并且在基础研究和临床研究之间,针刺镇痛、电针疗法、胃肠功能这三个内容是同步的,而关于代谢组学、穴位注射、温针灸和揿针的内容则是脱节的。 相似文献
18.
19.
20.
《Transfusion Clinique et Biologique》2022,29(3):269-272
A delayed haemolytic transfusion reaction (DHTR) encompasses a positive direct antiglobulin test (DAT) developed anytime between 24 hours to 28 days after cessation of transfusion, a positive eluate or a newly identified alloantibody in the plasma or serum along with features of haemolysis in the patient. Routinely, it is expected that with the transfusion of one unit of packed red cells in a patient of average height and weight, the haemoglobin level and hematocrit increase by 1 g/dL and 3% respectively. However, in a patient with DHTR, an inadequate rise of post-transfusion haemoglobin (< 1 g/dL) or rapid fall in haemoglobin back to pre-transfusion levels is observed. Kidd antibodies are particularly known to cause DHTR, maybe alone or in unison with other antibodies. Detection of these alloantibodies is consequential in providing good transfusion support to these patients. These events may be difficult to detect as they may present as varied clinical features or immunological nuisances. In this case series, we have presented three cases of DHTR with special emphasis on their clinical presentations, immunohaematological evaluations, laboratory parameters and the role of proper transfusion support in these patients to avoid further complications. 相似文献