全文获取类型
收费全文 | 13177篇 |
免费 | 715篇 |
国内免费 | 381篇 |
专业分类
耳鼻咽喉 | 37篇 |
儿科学 | 453篇 |
妇产科学 | 397篇 |
基础医学 | 4228篇 |
口腔科学 | 117篇 |
临床医学 | 628篇 |
内科学 | 2004篇 |
皮肤病学 | 85篇 |
神经病学 | 1288篇 |
特种医学 | 376篇 |
外科学 | 729篇 |
综合类 | 1323篇 |
现状与发展 | 1篇 |
预防医学 | 511篇 |
眼科学 | 89篇 |
药学 | 879篇 |
1篇 | |
中国医学 | 349篇 |
肿瘤学 | 778篇 |
出版年
2022年 | 165篇 |
2021年 | 225篇 |
2020年 | 214篇 |
2019年 | 293篇 |
2018年 | 304篇 |
2017年 | 251篇 |
2016年 | 264篇 |
2015年 | 304篇 |
2014年 | 412篇 |
2013年 | 564篇 |
2012年 | 445篇 |
2011年 | 550篇 |
2010年 | 452篇 |
2009年 | 480篇 |
2008年 | 513篇 |
2007年 | 499篇 |
2006年 | 527篇 |
2005年 | 440篇 |
2004年 | 468篇 |
2003年 | 422篇 |
2002年 | 416篇 |
2001年 | 417篇 |
2000年 | 364篇 |
1999年 | 363篇 |
1998年 | 330篇 |
1997年 | 369篇 |
1996年 | 334篇 |
1995年 | 343篇 |
1994年 | 249篇 |
1993年 | 254篇 |
1992年 | 194篇 |
1991年 | 171篇 |
1990年 | 166篇 |
1989年 | 123篇 |
1988年 | 126篇 |
1987年 | 101篇 |
1986年 | 110篇 |
1985年 | 142篇 |
1984年 | 119篇 |
1983年 | 109篇 |
1982年 | 142篇 |
1981年 | 154篇 |
1980年 | 181篇 |
1979年 | 159篇 |
1978年 | 148篇 |
1977年 | 118篇 |
1976年 | 175篇 |
1975年 | 172篇 |
1974年 | 176篇 |
1973年 | 168篇 |
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
1.
《Research in social & administrative pharmacy》2022,18(9):3694-3698
In this paper, we argue that understanding and addressing the problem of poor-quality medical products requires a more interdisciplinary approach than has been evident to date. While prospective studies based on rigorous standardized methodologies are the gold standard for measuring the prevalence of poor-quality medical products and understanding their distribution nationally and internationally, they should be complemented by social science research to unpack the complex set of social, economic, and governance factors that underlie these patterns. In the following sections, we discuss specific examples of prospective quality surveys and of social science studies, highlighting the value of cross-sector partnerships in driving high-quality, policy-relevant research in this area. 相似文献
2.
《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
3.
Cadmium is a toxic metal that can damage the brain and other organs. This study aimed to explore the protective effects of Potentilla anserine L. polysaccharide (PAP) against CdCl2-induced neurotoxicity in N2a and SH-SY5Y cells and in the cerebral cortex of BALB/c mice. In addition, we aimed to identify the potential mechanisms underlying these protective effects. Relative to CdCl2 treatment alone, pretreatment with PAP prevented the reduction in cell viability evoked by CdCl2, decreased rates of apoptosis, promoted calcium homeostasis, decreased ROS accumulation, increased mitochondrial membrane potential, inhibited cytochrome C and AIF release, and prevented the cleavage of caspase-3 and PARP. In addition, PAP significantly decreased the CdCl2-induced phosphorylation of CaMKII, Akt, and mTOR. In conclusion, PAP represents a potential therapeutic agent for the treatment of Cd-induced neurotoxicity, functioning in part via attenuating the activation of the mitochondrial apoptosis pathway and the Ca2+-CaMKII-dependent Akt/mTOR pathway. 相似文献
4.
Marta López-Fauqued Laura Campora Frédérique Delannois Mohamed El Idrissi Lidia Oostvogels Ferdinandus J. De Looze Javier Diez-Domingo Thomas C. Heineman Himal Lal Janet E. McElhaney Shelly A. McNeil Wilfred Yeo Fernanda Tavares-Da-Silva 《Vaccine》2019,37(18):2482-2493
Background
The ZOE-50 (NCT01165177) and ZOE-70 (NCT01165229) phase 3 clinical trials showed that the adjuvanted recombinant zoster vaccine (RZV) was ≥90% efficacious in preventing herpes zoster in adults. Here we present a comprehensive overview of the safety data from these studies.Methods
Adults aged ≥50 (ZOE-50) and ≥70 (ZOE-70) years were randomly vaccinated with RZV or placebo. Safety analyses were performed on the pooled total vaccinated cohort, consisting of participants receiving at least one dose of RZV or placebo. Solicited and unsolicited adverse events (AEs) were collected for 7 and 30?days after each vaccination, respectively. Serious AEs (SAEs) were collected from the first vaccination until 12?months post-last dose. Fatal AEs, vaccination-related SAEs, and potential immune-mediated diseases (pIMDs) were collected during the entire study period.Results
Safety was evaluated in 14,645 RZV and 14,660 placebo recipients. More RZV than placebo recipients reported unsolicited AEs (50.5% versus 32.0%); the difference was driven by transient injection site and solicited systemic reactions that were generally seen in the first week post-vaccination. The occurrence of overall SAEs (RZV: 10.1%; Placebo: 10.4%), fatal AEs (RZV: 4.3%; Placebo: 4.6%), and pIMDs (RZV: 1.2%; Placebo: 1.4%) was balanced between groups. The occurrence of possible exacerbations of pIMDs was rare and similar between groups. Overall, except for the expected local and systemic symptoms, the safety results were comparable between the RZV and Placebo groups irrespective of participant age, gender, or race.Conclusions
No safety concerns arose, supporting the favorable benefit-risk profile of RZV. 相似文献5.
Sex chromosome trisomies (SCT) are among the most common chromosomal duplications in humans. Due to recent technological advances in non-invasive screening, SCT can already be detected during pregnancy. This calls for more knowledge about the development of (young) children with SCT. This review focused on neurocognitive functioning of children with SCT between 0 and 18 years, on domains of global intellectual functioning, language, executive functioning, and social cognition, in order to identify targets that could benefit from early treatment. Online databases were used to identify peer-reviewed scientific articles using specific search terms. In total 18 studies were included. When applicable, effect sizes were calculated to indicate clinical significance. Results of the reviewed studies show that although traditionally, the focus has been on language and intelligence (IQ) in this population, recent studies suggest that executive functioning and social cognition may also be significantly affected already in childhood. These findings suggest that neuropsychological screening of children diagnosed with SCT should be extended, to also include executive functioning and social cognition. Knowledge about these neurocognitive risks is important to improve clinical care and help identify targets for early support and intervention programs to accommodate for the needs of individuals with SCT. 相似文献
6.
《Cancer cell》2020,37(1):123-134.e5
7.
8.
T.‐F. WANG S. W. HORSLEY K.‐F. LEE S.‐C. CHU C.‐C. LI R.‐H. KAO 《International journal of laboratory hematology》2006,28(3):160-163
Cytogenetic abnormalities are observed in approximately two‐thirds of patients with acute myeloid leukemia (AML). Chromosome rearrangements are associated with specific subtypes of AML and associated prognosis. We report a patient with AML, M2, who was primarily refractory to standard induction chemotherapy with idarubicin and cytarabine. Flow cytometry of a bone marrow aspirate showed aberrant expression of B‐cell markers including CD19. Cytogenetic studies disclosed a translocation between 5q35 and 11q13. Fluorescence in situ hybridization analyses demonstrated that neither the NSD1 nor MLL genes were involved in this case. Further study is required to define conclusively the genes involved and their contribution to pathogenesis in this case. 相似文献
9.
10.
补肾排毒合剂治疗慢性肾衰竭营养不良60例临床观察 总被引:1,自引:0,他引:1
目的:观察补肾排毒合剂治疗慢性肾衰竭营养不良的疗效.方法:90例慢性肾衰竭营养不良患者随机分为治疗组60例和对照组30例,并设健康对照组30例.治疗组和对照组在综合治疗的基础上,治疗组加用补肾排毒合剂,对照组加用爱西特和百令胶囊.比较两组肾功能、营养状态和血浆瘦素、神经肽Y的变化.结果:治疗组治疗后BUN、Scr明显降低,与治疗前及对照组相比均有统计学差异(P<0.05).治疗组营养状态好转,与治疗前及对照组相比均有统计学差异(P<0.05).两组慢性肾衰竭营养不良患者治疗前Leptin、NPY水平均高于健康组(P<0.05),治疗后治疗组Leptin、NPY较治疗前下降,有统计学意义(P<0.05),但与对照组相比无统计学差异(P>0.05).结论:补肾排毒合剂治疗慢性肾衰竭营养不良疗效明显,可降低BUN、Scr,改善营养不良状态. 相似文献