全文获取类型
收费全文 | 140301篇 |
免费 | 12410篇 |
国内免费 | 5646篇 |
专业分类
耳鼻咽喉 | 906篇 |
儿科学 | 2548篇 |
妇产科学 | 1644篇 |
基础医学 | 26224篇 |
口腔科学 | 1881篇 |
临床医学 | 9712篇 |
内科学 | 27176篇 |
皮肤病学 | 2653篇 |
神经病学 | 7644篇 |
特种医学 | 2638篇 |
外国民族医学 | 27篇 |
外科学 | 9809篇 |
综合类 | 18612篇 |
现状与发展 | 29篇 |
预防医学 | 8917篇 |
眼科学 | 1266篇 |
药学 | 20077篇 |
22篇 | |
中国医学 | 6251篇 |
肿瘤学 | 10321篇 |
出版年
2024年 | 218篇 |
2023年 | 2026篇 |
2022年 | 3266篇 |
2021年 | 5366篇 |
2020年 | 4648篇 |
2019年 | 5381篇 |
2018年 | 5240篇 |
2017年 | 5053篇 |
2016年 | 5035篇 |
2015年 | 5809篇 |
2014年 | 8844篇 |
2013年 | 9622篇 |
2012年 | 8777篇 |
2011年 | 9881篇 |
2010年 | 7915篇 |
2009年 | 7686篇 |
2008年 | 7387篇 |
2007年 | 6968篇 |
2006年 | 6281篇 |
2005年 | 5401篇 |
2004年 | 4732篇 |
2003年 | 3981篇 |
2002年 | 3074篇 |
2001年 | 2607篇 |
2000年 | 2208篇 |
1999年 | 1883篇 |
1998年 | 1767篇 |
1997年 | 1597篇 |
1996年 | 1323篇 |
1995年 | 1383篇 |
1994年 | 1148篇 |
1993年 | 957篇 |
1992年 | 843篇 |
1991年 | 735篇 |
1990年 | 648篇 |
1989年 | 578篇 |
1988年 | 469篇 |
1987年 | 440篇 |
1986年 | 407篇 |
1985年 | 884篇 |
1984年 | 1012篇 |
1983年 | 699篇 |
1982年 | 751篇 |
1981年 | 652篇 |
1980年 | 563篇 |
1979年 | 483篇 |
1978年 | 369篇 |
1977年 | 301篇 |
1976年 | 337篇 |
1975年 | 269篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Micro‐evolution of the hepatitis B virus genome in hepatitis B e‐antigen‐positive carriers: Comparison of genotypes B and C at various immune stages 下载免费PDF全文
72.
This study aimed to observe the therapeutic effects of magnesium lithospermate B on acute and chronic colitis induced by dextran sodiumsulfate (DSS) and the role of inflammasome complex (NOD-like receptor protein, NLRP; apoptosis-associated speck-like protein containing, ASC; caspase-1). Establishment of acute and chronic colitis models were by using 5% DSS oral administration in BALB/C male mice. Magnesium lithospermate B (240 mg/kg body weight) was given by subcutaneous injection. Samples were collected for biomarker assay, histological examination, immunohistochemical evaluation and western blot. There was obvious increase in TNF-α level and NLPR3, ASC, and caspase-1 expressions in acute and chronic colitis groups compared with the normal control. Significant decrease of the tumor necrosis factor-α level and the expressions of NLPR3, ASC, and caspase-1 were observed after treatment with magnesium lithospermate B. This study showed that magnesium lithospermate B could be used to treat acute and chronic colitis by inhibiting the activation of the NLRP3/ASC/Caspase-1 pathway. 相似文献
73.
Flavia Temperilli Aldona Rina Isabella Massimi Anna Lisa Montemari Maria Luisa Guarino Alessandra Zicari 《Platelets》2015,26(8):783-787
Serum thromboxane-B2 (TxB2), together with arachidonic acid (AA)-induced platelet aggregation, are, at the moment, the most used tests to identify patients displaying high on-aspirin treatment platelet reactivity (HAPR). Both tests are specific for aspirin action on cyclooxygenase-1. While the correlation between serum TxB2 assay and clinical outcome is established, data are conflicting with regard to aspirin treatment and a possible association with AA-stimulated platelet markers and clinical outcome. To understand such discrepancy, we performed a retrospective study to compare both assays. We collected data from 132 patients receiving a daily dose of aspirin (100?mg/day) and data from 48 patients receiving aspirin on alternate days. All Patients who received a daily dose of aspirin were studied for AA-induced platelet aggregation together with serum TxB2 levels and AA-induced TxB2 formation was also studied in 71 patients out of entire population. Consistent with recommendations in the literature, we defined HAPR by setting a cut-off point at 3.1?ng/ml for serum levels of thromboxane B2 and 20% for AA-induced platelet aggregation. According to this cut-off point, we divided our overall population into two groups: (1) TxB2?<?3.1?ng/ml and (2) TxB2?>?3.1?ng/ml. We found low agreement between such tests to identify patients displaying HAPR. Our results show that AA-induced platelet aggregation >20% identify a smaller number of HAPR patients in comparison with TxB2. A good correlation between serum TxB2 and arachidonic acid-induced TxB2 production was found (r?=?0.76619). 相似文献
74.
75.
白细胞介素4(IL-4)是T辅助2(Th2)介导的免疫反应的基本免疫调节细胞因子,IL-4具有复杂的信号系统和多效的功能,但在脑组织中,诸多研究发现IL-4可在炎症中保护认知功能。该文总结了关于IL-4保护认知功能的证据及机制,以及在阿尔茨海默病、缺血性脑血管病以及手术后认知功能障碍中IL-4保护认知功能的途径及证据。 相似文献
76.
《Journal of vascular and interventional radiology : JVIR》2020,31(5):760-768.e1
PurposeTo investigate dynamic variables obtained from retrospective computed tomography angiography for ability to predict thoracic endovascular aortic repair (TEVAR) outcomes in patients with complicated type B aortic dissection (cTBAD).Materials and MethodsSeventy-nine patients with cTBAD who received TEVAR from March 2009 to June 2018 were retrospectively enrolled. Relative true lumen area (r-TLA) was computed at the level of tracheal bifurcation every 5% of all R-R intervals. Parameters that reflect the state of intimal motion were evaluated, including difference between maximum and minimum r-TLA (D-TLA) and true lumen collapse. The endpoints comprised early (≤ 30 days) and late (> 30 days) outcomes after intervention.ResultsOverall early mortality rate was 13.9% (11/79), and early adverse events rate was 24.1% (19/79). Patients who received TEVAR within 2 days of symptom onset demonstrated the worst outcomes. A longer time of r-TLA < 25% in 1 cardiac cycle (P = .049) and larger D-TLA (P < .001) were correlated to an increased early death. In addition, D-TLA was an independent predictor of early mortality. Area under the curve of D-TLA was 0.849 (95% confidence interval 0.730–0.967) for predicting early mortality and 0.742 (95% CI 0.611–0.873) for predicting early adverse events. Survival and event-free survival rates during follow-up were decreased in the D-TLA > 21.5% group compared with the D-TLA ≤ 21.5% group (all P < .001).ConclusionsLarger D-TLA is correlated with worse postoperative outcomes and might be a crucial parameter for future risk stratification in patients with cTBAD. 相似文献
77.
78.
《Clinical therapeutics》2019,41(5):836-847
PurposeA role for the immune system in causing myalgic encephalopathy/chronic fatigue syndrome (ME/CFS) is long suspected, but few studies have looked for specific autoantibodies that might contribute to the symptoms. Our aim was to look for evidence of antibodies to neuronal proteins in patients with ME/CSF.MethodsSera samples from 50 patients and 50 healthy individuals were sent coded to the Neuroimmunology Laboratory in Oxford. Screening for antibody binding to neuronal tissue was performed on brain tissue and neuronal cultures. Specific serum antibodies were assessed by antigen-specific cell-based assays and radioimmunoassays. After antibody testing, the associations between seropositive status and clinical data were investigated.FindingsOverall, 8 patients and 11 participants were found to have some serum immunoreactivity toward neuronal or neuromuscular junction proteins, but only 1 patient and 2 participants had specific serum antibodies. Nevertheless, seropositive status in patients with ME was associated with shorter duration since onset and a more severe disease.ImplicationsThe results indicate no overall increased frequency of antibodies to neuronal proteins in ME/CSF and no evidence of a specific antibody that might be causative or contribute to clinical features in patients. However, the association of seropositive status with shorter duration of disease and more severe symptoms suggests a possible role of antibodies at onset in some patients and should be the focus of future studies. 相似文献
79.
目的 分析CSTB、A-FABP在膀胱癌诊断和预后的意义。方法 选取2014年1月至2016年7月在本院进行手术、病理证实的膀胱癌患者45例、良性膀胱病变患者88例,检测膀胱癌样本癌组织、癌旁组织、良性膀胱病变组织中CSTB、A-FABP表达水平。评价CSTB、A-FABP在鉴别诊断膀胱癌的效用。对比膀胱癌进展对象(2年内转移、复发、肿瘤死亡)以及未进展对象组织中CSTB、A-FABP表达水平。结果 癌组织、癌旁组织、良性病变对象组织中CSTB、A-FABP表达水平差异有统计学意义(P<0.05)。CSTB、A-FABP作为诊断标准(任意一项为阳性),鉴别诊断膀胱癌与良性病变的灵敏度为84.4%、特异度为90.9%、阳性预测值82.6%、阴性预测值92.0%、符合率88.7%。2年内转移、复发、肿瘤死亡的患者共30例,无转移、复发、死亡的患者共15例,膀胱癌进展对象CSTB、A FABP表达量高于未进展对象,差异有统计学意义(P<0.05)。结论 CSTB、A-FABP在膀胱癌诊断、预后预测中均有一定的临床价值。 相似文献
80.