全文获取类型
收费全文 | 368041篇 |
免费 | 28136篇 |
国内免费 | 11106篇 |
专业分类
耳鼻咽喉 | 2977篇 |
儿科学 | 5049篇 |
妇产科学 | 5133篇 |
基础医学 | 53837篇 |
口腔科学 | 6544篇 |
临床医学 | 26302篇 |
内科学 | 57273篇 |
皮肤病学 | 4693篇 |
神经病学 | 26368篇 |
特种医学 | 10528篇 |
外国民族医学 | 55篇 |
外科学 | 27793篇 |
综合类 | 49341篇 |
现状与发展 | 40篇 |
一般理论 | 14篇 |
预防医学 | 24331篇 |
眼科学 | 4277篇 |
药学 | 52923篇 |
102篇 | |
中国医学 | 19767篇 |
肿瘤学 | 29936篇 |
出版年
2024年 | 925篇 |
2023年 | 6068篇 |
2022年 | 13336篇 |
2021年 | 17084篇 |
2020年 | 13292篇 |
2019年 | 12086篇 |
2018年 | 11946篇 |
2017年 | 12631篇 |
2016年 | 12768篇 |
2015年 | 13400篇 |
2014年 | 18158篇 |
2013年 | 23139篇 |
2012年 | 19633篇 |
2011年 | 23125篇 |
2010年 | 17059篇 |
2009年 | 17467篇 |
2008年 | 18638篇 |
2007年 | 18627篇 |
2006年 | 17035篇 |
2005年 | 15351篇 |
2004年 | 12973篇 |
2003年 | 11605篇 |
2002年 | 9201篇 |
2001年 | 7964篇 |
2000年 | 6711篇 |
1999年 | 5883篇 |
1998年 | 4985篇 |
1997年 | 4877篇 |
1996年 | 4479篇 |
1995年 | 3951篇 |
1994年 | 3681篇 |
1993年 | 3074篇 |
1992年 | 2718篇 |
1991年 | 2550篇 |
1990年 | 2189篇 |
1989年 | 1816篇 |
1988年 | 1735篇 |
1987年 | 1493篇 |
1986年 | 1372篇 |
1985年 | 2098篇 |
1984年 | 1802篇 |
1983年 | 1296篇 |
1982年 | 1362篇 |
1981年 | 1120篇 |
1980年 | 1028篇 |
1979年 | 811篇 |
1978年 | 525篇 |
1977年 | 448篇 |
1976年 | 429篇 |
1975年 | 301篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
中药生产过程质量控制关键技术研究进展 总被引:10,自引:8,他引:2
中医药发展已上升到国家战略层面,在医药行业贯彻实施"中国制造2025"战略的新形势下,中药生产过程质量控制是中药工业需要加快突破的关键领域之一。对中药生产过程质量控制领域在工艺设计、分析检测、过程建模、制造装备等方面的关键共性问题进行解析,综述了中药生产过程质量控制体系中工艺过程理解、生产过程实时分析方法开发、过程控制策略建立3个方面的研究进展;并结合企业研究实践,介绍了质量源于设计(quality by design,Qb D)、过程分析技术(process analytical technology,PAT)、实验设计(design of experiment,DOE)、多变量统计分析等关键技术在上述3个研究方向中的应用进展,分析了实际工业应用的难点问题并对其应用前景进行展望,旨在为中药企业应用和提升生产过程质量控制技术提供参考。 相似文献
3.
Ehsan Zarei Elmira Madarshahian Adeleh Nikkhah Soheila Khodakarim 《Journal of tissue viability》2019,28(2):70-74
Background and objective
Pressure ulcer (PU) is one of the important and frequent complications of hospitalization, associated with high treatment costs. The present study was conducted to determine the incidence of PU and its direct treatment costs for patients in intensive care unit (ICU) in Iran.Material and methods
In this retrospective study, medical records of 643 discharged patients from ICU of two selected hospitals were examined. The demographic and clinical data of all patients and data of resources and services usage for patients with PU were extracted through their records. Data analysis was done using logistic regression tests in SPSS 22 software. The cost of PU treatment was calculated for each grade of ulcer.Results
The findings showed that 8.9% of patients developed PU during their stay in ICU. Muscular paralysis (OR?=?5.1), length of stay in ICU (OR?=?4.0), diabetes (OR?=?3.5) age (OR?=?2.9), smoking (OR?=?2.1) and trauma (OR?=?1.4) were the most important risk factors of PU. The average cost of PU treatment varied from USD 12 for grade I PU to USD 66?834 for grade IV PUs. The total treatment costs for all studied patients with PU was estimated at USD 519?991.Conclusion
The cost of PU treatment is significant. Since the preventive measures are more cost-effective than therapeutic measures, therefore, effective preventive interventions are recommended. 相似文献4.
《Diagnostic and interventional imaging》2020,101(9):555-564
PurposeThe purpose of this study was to determine whether computed tomography (CT)-based machine learning of radiomics features could help distinguish autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDAC).Materials and MethodsEighty-nine patients with AIP (65 men, 24 women; mean age, 59.7 ± 13.9 [SD] years; range: 21–83 years) and 93 patients with PDAC (68 men, 25 women; mean age, 60.1 ± 12.3 [SD] years; range: 36–86 years) were retrospectively included. All patients had dedicated dual-phase pancreatic protocol CT between 2004 and 2018. Thin-slice images (0.75/0.5 mm thickness/increment) were compared with thick-slices images (3 or 5 mm thickness/increment). Pancreatic regions involved by PDAC or AIP (areas of enlargement, altered enhancement, effacement of pancreatic duct) as well as uninvolved parenchyma were segmented as three-dimensional volumes. Four hundred and thirty-one radiomics features were extracted and a random forest was used to distinguish AIP from PDAC. CT data of 60 AIP and 60 PDAC patients were used for training and those of 29 AIP and 33 PDAC independent patients were used for testing.ResultsThe pancreas was diffusely involved in 37 (37/89; 41.6%) patients with AIP and not diffusely in 52 (52/89; 58.4%) patients. Using machine learning, 95.2% (59/62; 95% confidence interval [CI]: 89.8–100%), 83.9% (52:67; 95% CI: 74.7–93.0%) and 77.4% (48/62; 95% CI: 67.0–87.8%) of the 62 test patients were correctly classified as either having PDAC or AIP with thin-slice venous phase, thin-slice arterial phase, and thick-slice venous phase CT, respectively. Three of the 29 patients with AIP (3/29; 10.3%) were incorrectly classified as having PDAC but all 33 patients with PDAC (33/33; 100%) were correctly classified with thin-slice venous phase with 89.7% sensitivity (26/29; 95% CI: 78.6–100%) and 100% specificity (33/33; 95% CI: 93–100%) for the diagnosis of AIP, 95.2% accuracy (59/62; 95% CI: 89.8–100%) and area under the curve of 0.975 (95% CI: 0.936–1.0).ConclusionsRadiomic features help differentiate AIP from PDAC with an overall accuracy of 95.2%. 相似文献
5.
6.
Alexandra Katsimardou Konstantinos Imprialos Konstantinos Stavropoulos Alexandros Sachinidis Michalis Doumas 《Expert opinion on pharmacotherapy》2020,21(10):1241-1252
ABSTRACT
Introduction
Type 1 diabetes mellitus (T1DM) is a chronic, autoimmune disease that is characterized by total absence of insulin production. Hypertension is a common comorbidity in T1DM with complex pathophysiology, while it is also a well-recognized risk factor for the development of cardiovascular disease (CVD), as well as other microvascular diabetic complications. 相似文献7.
ABSTRACTThis work collates data from the analysis of complex mixtures analysed in STRmix during routine no-suspect volume crime work. It interrogates the upload rate for these types of mixtures and which component of the profile has been able to be interpreted for upload. The number of profiles giving multiple uploads and the amount of replicate PCR analysis has been collated. 相似文献
8.
Haya Mohammed BSc MChB M. Yousuf Salmasi MRCS Massimo Caputo PhD Gianni D. Angelini PhD Hunaid A. Vohra PhD 《Journal of cardiac surgery》2020,35(6):1209-1219
Background
Limited data exists demonstrating the efficacy of minimally invasive surgery (MIS) compared to median sternotomy (MS) for multiple valvular disease (MVD). This systematic review and meta-analysis aims to compare operative and peri-operative outcomes of MIS vs MS in MVD.Methods
PubMed, Ovid, and Embase were searched from inception until August 2019 for randomized and observational studies comparing MIS and MS in patients with MVD. Clinical outcomes of intra- and postoperative times, reoperation for bleeding and surgical site infection were evaluated.Results
Five observational studies comparing 340 MIS vs 414 MS patients were eligible for qualitative and quantitative review. The quality of evidence assessed using the Newcastle-Ottawa scale was good for all included studies. Meta-analysis demonstrated increased cardiopulmonary bypass time for MIS patients (weighted mean difference [WMD], 0.487; 95% confidence interval [CI], 0.365-0.608; P < .0001). Similarly, aortic cross-clamp time was longer in patients undergoing MIS (WMD, 0.632; 95% CI, 0.509-0.755; P < .0001). No differences were found in operative mortality, reoperation for bleeding, surgical site infection, or hospital stay.Conclusions
MIS for MVD have similar short-term outcomes compared to MS. This adds value to the use of minimally invasive methods for multivalvular surgery, despite conferring longer operative times. However, the paucity in literature and learning curve associated with MIS warrants further evidence, ideally randomized control trials, to support these findings.9.
《Vaccine》2021,39(26):3498-3508
Adenovirus infections are a major cause of epidemic keratoconjunctivitis (EKC), which can lead to corneal subepithelial infiltrates and multifocal corneal opacity. In the current study, we investigated the use of an E1/E3-deleted adenovirus serotype 5 (Ad5) vector as a vaccine administered intramuscularly (IM) or intranasally (IN) against subsequent challenges with a luciferase-expressing Ad5 (Ad5-Luci) vector via eyedrop. We evaluated the adaptive immune response to Ad5 vector vaccination and confirmed a robust polyfunctional CD8 T cell response in splenic cells. Neutralizing Ad5 antibodies were also measured in the sera of vaccinated mice as well as Ad5 antibody in the eye wash solutions. Upon challenge with Ad5-Luci vector 8 weeks post the primary immunization, transduction was significantly reduced by > 70% in the vaccinated mice, which was slightly better in IM- vs. that in IN-vaccinated animals. Resistance to subsequent challenge was observed 10 months post primary IM vaccination, with sustained reduction up to 60% in the Ad5-Luci vector transduction. Passive immunization of naive mice with antisera from IM to vaccinated mice subsequently challenged with the Ad5-Luci vector resulted in approximately 40% loss in transduction efficiency. Furthermore, the mice that received IM immunization with or without CD8 T cell depletion showed > 40% and 70% reductions, respectively, in Ad8 genomic copies after Ad8 topical challenge. We conclude that Ad-vector vaccination successfully induced an adaptive immune response that prevented subsequent Ad transduction in the cornea and conjunctiva-associated tissues in a mouse model of adenovirus keratoconjunctivitis, and that both cellular and humoral immunity play an important role in preventing Ad transduction. 相似文献
10.
《Mayo Clinic proceedings. Mayo Clinic》2022,97(12):2271-2281
ObjectiveTo investigate the association between type 1 diabetes mellitus (T1D) and type 2 diabetes mellitus (T2D) with risk of sudden cardiac arrest (SCA).MethodsIn a prospective community-based study of SCA from February 1, 2002, through November 30, 2019, we ascertained 2771 cases age 18 years of age or older and matched them to 8313 controls based on geography, age, sex, and race/ethnicity. We used logistic regression to evaluate the independent association between diabetes, T1D, T2D, and SCA.ResultsPatients had a mean age of 64.5±15.9 years, were 33.3% female and 23.9% non-White race. Overall, 36.7% (n=1016) of cases and 23.8% (n=1981) of controls had diabetes. Among individuals with diabetes, the proportion of T1D was 6.5% (n=66) among cases and 2.0% among controls (n=40). Diabetes was associated with 1.5-times higher odds of SCA. Compared with those without diabetes, the odds ratio and 95% CI for SCA was 4.36 (95% CI, 2.81 to 6.75; P<.001) in T1D and 1.45 (95% CI, 1.30 to 1.63; P<.001) in T2D after multivariable adjustment. Among those with diabetes, the odds of having SCA were 2.41 times higher in T1D than in T2D (95% CI, 1.53 to 3.80; P<.001). Cases of SCA with T1D were more likely to have an unwitnessed arrest, less likely to receive resuscitation, and less likely to survive compared with those with T2D.ConclusionType 1 diabetes was more strongly associated with SCA compared with T2D and had less favorable outcomes following resuscitation. Diabetes type could influence the approach to risk stratification and prevention of SCA. 相似文献