全文获取类型
收费全文 | 32896篇 |
免费 | 2089篇 |
国内免费 | 853篇 |
专业分类
耳鼻咽喉 | 286篇 |
儿科学 | 525篇 |
妇产科学 | 859篇 |
基础医学 | 3086篇 |
口腔科学 | 572篇 |
临床医学 | 3778篇 |
内科学 | 6347篇 |
皮肤病学 | 393篇 |
神经病学 | 2565篇 |
特种医学 | 2101篇 |
外国民族医学 | 8篇 |
外科学 | 4910篇 |
综合类 | 2555篇 |
一般理论 | 1篇 |
预防医学 | 1626篇 |
眼科学 | 448篇 |
药学 | 1837篇 |
25篇 | |
中国医学 | 438篇 |
肿瘤学 | 3478篇 |
出版年
2024年 | 34篇 |
2023年 | 2345篇 |
2022年 | 3354篇 |
2021年 | 3303篇 |
2020年 | 3675篇 |
2019年 | 1801篇 |
2018年 | 1224篇 |
2017年 | 1394篇 |
2016年 | 1300篇 |
2015年 | 1399篇 |
2014年 | 2756篇 |
2013年 | 1900篇 |
2012年 | 1558篇 |
2011年 | 1227篇 |
2010年 | 1541篇 |
2009年 | 1384篇 |
2008年 | 631篇 |
2007年 | 817篇 |
2006年 | 595篇 |
2005年 | 441篇 |
2004年 | 397篇 |
2003年 | 417篇 |
2002年 | 380篇 |
2001年 | 366篇 |
2000年 | 256篇 |
1999年 | 200篇 |
1998年 | 99篇 |
1997年 | 79篇 |
1996年 | 80篇 |
1995年 | 72篇 |
1994年 | 78篇 |
1993年 | 73篇 |
1992年 | 47篇 |
1991年 | 36篇 |
1990年 | 39篇 |
1989年 | 37篇 |
1988年 | 35篇 |
1987年 | 33篇 |
1986年 | 28篇 |
1985年 | 46篇 |
1984年 | 42篇 |
1983年 | 32篇 |
1982年 | 45篇 |
1981年 | 42篇 |
1980年 | 41篇 |
1979年 | 28篇 |
1978年 | 24篇 |
1977年 | 21篇 |
1976年 | 16篇 |
1972年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 734 毫秒
1.
《HPB : the official journal of the International Hepato Pancreato Biliary Association》2022,24(10):1720-1728
BackgroundTo determine whether the short-term benefits associated with an enhanced recovery after surgery programme (ERAS) following pancreaticoduodenectomy (PD) vary with age.Methods830 consecutive patients who underwent PD between January 2009 and March 2019 were divided according to age: elderly (≥75 years) vs. non-elderly patients (<75 years). Within each age group, cohort characteristics and outcomes were compared between patients treated pre- and post-ERAS (ERAS was systematically introduced in December 2012). Univariable and multivariable analysis were then performed, to assess whether ERAS was independently associated with length of hospital stay (LOS).ResultsOf the entire cohort, 577 of 830 patients (69.5%) were managed according to an ERAS protocol, and 170 patients (20.5%) were aged ≥75 years old. Patients treated post-ERAS were significantly more comorbid than those pre-ERAS, with a mean Charlson Comorbidity Index of 4.6 vs. 4.1 (p < 0.001) and 6.0 vs. 5.7 (p = 0.039) for the non-elderly and elderly subgroups, respectively. There were significantly fewer medical complications in non-elderly patients treated post-ERAS compared to pre-ERAS (12.4% vs. 22.4%; p = 0.002), but not in elderly patients (23.6% vs. 14.0%; p = 0.203). On multivariable analysis, ERAS was independently associated with reduced LOS in both elderly (14.8% reduction, 95% CI: 0.7–27.0%, p = 0.041) and non-elderly patients (15.6% reduction, 95% CI: 9.2–21.6%, p < 0.001), with the effect size being similar in each group.ConclusionERAS protocols can be safely applied to patients undergoing pancreaticoduodenectomy irrespective of age. Implementation of an ERAS protocol was associated with a significant reduction in postoperative LOS in both elderly and non-elderly patients, despite higher comorbidity in the post-ERAS period. 相似文献
2.
Although methadone is effective in the management of acute pain, the complexity of its absorption-distribution-metabolism-excretion profile limits its use as an opioid of choice for perioperative analgesia. Because deuteration is known to improve the pharmacokinetic, pharmacodynamic and toxicological properties of some drugs, here we characterized the single dose pharmacokinetic properties and post-operative analgesic efficacy of d9-methadone.The pharmacokinetic profiles of d9-methadone and methadone administered intravenously to CD-1 male mice revealed that deuteration leads to a 5.7- and 4.4-fold increase in the area under the time-concentration curve and maximum concentration in plasma, respectively, as well as reduction in clearance (0.9 ± 0.3 L/h/kg vs 4.7 ± 0.8 L/h/kg). The lower brain-to-plasma ratio of d9-methadone compared to that of methadone (0.35 ± 0.12 vs 2.05 ± 0.62) suggested that deuteration decreases the transfer of the drug across the blood-brain barrier. The estimated LD50 value for a single intravenous dose of d9-methadone was 2.1-fold higher than that for methadone. Moreover, d9-methadone outperformed methadone in the efficacy against postoperative pain by primarily activating peripheral opioid receptors. Collectively, these data suggest that the replacement of three hydrogen atoms in three methyl groups of methadone altered its pharmacokinetic properties, improved safety, and enhanced its analgesic efficacy. 相似文献
3.
《HPB : the official journal of the International Hepato Pancreato Biliary Association》2022,24(5):681-690
BackgroundThe American Joint Committee on Cancer (AJCC) made improvements for staging pancreatic neuroendocrine tumors (pNETs) in its 8th Edition; however, multicenter studies were not included.MethodsWe collected multicenter datasets (n = 1,086, between 2004 and 2018) to validate the value of AJCC 8 and other coexisting staging systems through univariate and multivariate analysis for well-differentiated (G1/G2) pNETs.ResultsCompared to other coexisting staging systems, AJCC 7 only included 12 (1.1%) patients with stage III tumors. Patients with European Neuroendocrine Tumor Society (ENETS) stage IIB disease had a higher risk of death than patients with stage IIIA (hazard ratio [HR]: 4.376 vs. 4.322). For the modified ENETS staging system, patients with stage IIB disease had a higher risk of death than patients with stage III (HR: 6.078 vs. 5.341). According to AJCC 8, the proportions of patients with stage I, II, III, and IV were 25.7%, 40.3%, 23.6%, and 10.4%, respectively. As the stage advanced, the median survival time decreased (NA, 144.7, 100.8, 72.0 months, respectively), and the risk of death increased (HR: II = 3.145, III = 5.925, and IV = 8.762).ConclusionThese findings suggest that AJCC 8 had a more reasonable proportional distribution and the risk of death was better correlated with disease stage. 相似文献
4.
《Pancreatology》2022,22(8):1175-1180
BackgroundHepatic steatosis has been described as a common finding in adults following total pancreatectomy with islet autotransplantation (TPIAT) but it is unknown if this occurs in children and adolescents.ObjectivesTo define the frequency of post-TPIAT hepatic steatosis in a sample of children and adolescents and to identify clinical predictors of incident steatosis post-TPIAT.MethodsIn this prospective study, consecutive participants at least 1-month post-TPIAT underwent a liver MRI with proton density fat fraction (PDFF) and blood draw at our pediatric academic medical center between April 2021 and January 2022. Comparison clinical pre-TPIAT liver MRI or ultrasound and insulin use and graft function data were extracted from the medical record. T-tests were used for the comparison of means across continuous variables between participants with and without post-TPIAT steatosis.ResultsA total of 20 participants (mean: 13 ± 4 years; 12 female) were evaluated. Mean liver PDFF at research MRI was 7.4 ± 6.2% (range: 2–25%). Seven participants (35%) had categorical hepatic steatosis (PDFF>5%) post-TPIAT, five of whom had pre-TPIAT steatosis, reflecting a 13% (2/15; 95% CI: 2–40%) incidence of post-TPIAT steatosis. Participant characteristics were not significantly different between subgroups with and without post-TPIAT steatosis. Mean PDFF at research MRI was not different between graft function subgroups (7.5% optimal/good vs. 7.3% marginal/failure; p = .96).ConclusionOur study shows a moderate prevalence but low incidence of hepatic steatosis in a small sample of children and adolescents post-TPIAT. This study raises questions about a causal relationship between TPIAT and hepatic steatosis. 相似文献
5.
Diabetic retinopathy (DR) is one of the most important complications of diabetes. Accurate segmentation of DR lesions is of great importance for the early diagnosis of DR. However, simultaneous segmentation of multi-type DR lesions is technically challenging because of 1) the lack of pixel-level annotations and 2) the large diversity between different types of DR lesions. In this study, first, we propose a novel Poisson-blending data augmentation (PBDA) algorithm to generate synthetic images, which can be easily utilized to expand the existing training data for lesion segmentation. We perform extensive experiments to recognize the important attributes in the PBDA algorithm. We show that position constraints are of great importance and that the synthesis density of one type of lesion has a joint influence on the segmentation of other types of lesions. Second, we propose a convolutional neural network architecture, named DSR-U-Net++ (i.e., DC-SC residual U-Net++), for the simultaneous segmentation of multi-type DR lesions. Ablation studies showed that the mean area under precision recall curve (AUPR) for all four types of lesions increased by >5% with PBDA. The proposed DSR-U-Net++ with PBDA outperformed the state-of-the-art methods by 1.7%-9.9% on the Indian Diabetic Retinopathy Image Dataset (IDRiD) and 67.3% on the e-ophtha dataset with respect to mean AUPR. The developed method would be an efficient tool to generate large-scale task-specific training data for other medical anomaly segmentation tasks. 相似文献
6.
Desmoid-type fibromatosis (DF) is a distinctly rare condition, mostly of younger adults, characterized by the development of locally aggressive tumors of mesenchymal origin. Desmoid tumors (DT) arise either sporadically or in association with FAP (familial adenomatous polyposis), although certain risk factors have also been identified, including pregnancy and antecedent surgical trauma. They can emerge from any connective tissue including muscle, fascia and aponeurosis and are therefore classified, according to location, as intra-abdominal, of the abdominal wall and extra-abdominal. Despite the lack of metastasizing potential, the course can be unpredictable. Various mutations of APC and β-catenin genes, among others, play a catalytic role in the pathogenesis of this neoplastic entity. Surgery has lost its traditional role as first line treatment of the disease and several other treatment methods are being considered. Cytotoxic chemotherapy, non-cytotoxic systemic therapy and targeted therapy have been revealed as part of different treatment regimens. Recent progress regarding DT biology and molecular pathways has led to the development of promising novel biological agents. In any case, a multidisciplinary approach is required and is gradually employed, espe-cially in intra-abdominal DTs. In this review, we aim to present current knowledge on DF and summarize current treatment regimens as well as their effectiveness, with emphasis on the intraperitoneal type of DT. 相似文献
7.
8.
9.
10.
《Trends in Cardiovascular Medicine》2022,32(4):221-225
Correctly diagnosing the cause of wide QRS tachycardias remain an area of difficulty for many clinicians. The authors provide a concise update to the different ECG algorithms that have been developed as well as caveats in their application. 相似文献