全文获取类型
收费全文 | 25595篇 |
免费 | 2438篇 |
国内免费 | 1898篇 |
专业分类
耳鼻咽喉 | 172篇 |
儿科学 | 266篇 |
妇产科学 | 240篇 |
基础医学 | 2697篇 |
口腔科学 | 431篇 |
临床医学 | 3149篇 |
内科学 | 3975篇 |
皮肤病学 | 263篇 |
神经病学 | 1283篇 |
特种医学 | 1181篇 |
外国民族医学 | 21篇 |
外科学 | 2409篇 |
综合类 | 5020篇 |
现状与发展 | 7篇 |
一般理论 | 4篇 |
预防医学 | 1883篇 |
眼科学 | 477篇 |
药学 | 2669篇 |
30篇 | |
中国医学 | 1789篇 |
肿瘤学 | 1965篇 |
出版年
2024年 | 73篇 |
2023年 | 342篇 |
2022年 | 889篇 |
2021年 | 1155篇 |
2020年 | 878篇 |
2019年 | 803篇 |
2018年 | 852篇 |
2017年 | 801篇 |
2016年 | 714篇 |
2015年 | 1101篇 |
2014年 | 1393篇 |
2013年 | 1279篇 |
2012年 | 1837篇 |
2011年 | 1972篇 |
2010年 | 1425篇 |
2009年 | 1149篇 |
2008年 | 1480篇 |
2007年 | 1445篇 |
2006年 | 1407篇 |
2005年 | 1270篇 |
2004年 | 1068篇 |
2003年 | 1283篇 |
2002年 | 1072篇 |
2001年 | 865篇 |
2000年 | 709篇 |
1999年 | 543篇 |
1998年 | 304篇 |
1997年 | 325篇 |
1996年 | 251篇 |
1995年 | 211篇 |
1994年 | 191篇 |
1993年 | 125篇 |
1992年 | 135篇 |
1991年 | 87篇 |
1990年 | 97篇 |
1989年 | 72篇 |
1988年 | 53篇 |
1987年 | 57篇 |
1986年 | 47篇 |
1985年 | 39篇 |
1984年 | 32篇 |
1983年 | 25篇 |
1982年 | 10篇 |
1981年 | 5篇 |
1978年 | 4篇 |
1976年 | 5篇 |
1975年 | 7篇 |
1973年 | 8篇 |
1972年 | 4篇 |
1968年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Zhang K Bai X Li R Xiao Z Chen J Yang F Li Z 《International journal of molecular medicine》2012,30(2):277-282
Stress-dose of glucocorticoid has been demonstrated to be beneficial for trauma patients in clinical studies. Recently, a heterogeneous population of myeloid cells with immunosuppressive activity named myeloid-derived suppressor cells (MDSCs) has been found to accumulate in the trauma host and can be induced by glucocorticoids in vitro. In order to explore the effect of endogenous glucocorticoids on MDSCs under trauma conditions, we blocked the glucocorticoid signal in a murine trauma model using the antagonist of the glucocorticoid receptor RU486 (mifepristone). We found for the first time that RU486 not only blunted MDSC expansion induced by trauma in the spleen, peripheral blood and bone marrow especially at 6 h after traumatic stress but also decreased the survival rate from 100 to 20% in traumatic mice within 7 days. Moreover, neither MDSCs producing arginase-1 nor the morphological characterization of trauma-induced MDSCs was affected by the blockage of the glucocorticoid receptor. Our results suggest that endogenous glucocorticoids may promote MDSCs expansion in a murine trauma model and MDSCs may be beneficial for the trauma host. 相似文献
992.
目的:研究B7-H1蛋白疫苗对HBV转基因小鼠免疫应答的影响,探索治疗慢性乙型肝炎的新方法。方法:用不同剂量的乙型肝炎疫苗和B7-H1蛋白疫苗联合免疫HBV转基因小鼠,应用ELISA法检测转基因小鼠在不同时间点血清抗B7-H1抗体滴度,同时在免疫后第14周末处死小鼠取脾细胞,检测不同的免疫方法对小鼠脾细胞产生HBsAg特异性Th1类细胞因子(IFN-γ及IL-2)、对HBsAg特异性分泌IFN-γT细胞数量及对小鼠淋巴细胞增殖的影响。结果:成功完成小鼠的免疫计划,5周起血清中即能测到B7-H1抗体,同一时间点各组之间的抗体滴度值并无明显差异。加B7-H1蛋白免疫各组与相同剂量单用HBsAg蛋白免疫各组相比:IL-2均明显减低(P<0.05),分泌IFN-γT的T细胞数量下降,但脾淋巴细胞分泌IFN-γ的水平各组间无明显差异;MTT法测定的淋巴细胞增殖能力各组间也无明显变化。结论:B7-H1蛋白疫苗可诱导HBV转基因小鼠产生明显的抗B7-H1抗体应答,但不能增强抗HBsAg的免疫应答。较小剂量的HBsAg即可引起HBV转基因小鼠Th1类细胞因子(IFN-γ及IL-2)的分泌以及淋巴细胞增殖。 相似文献
993.
目的:通过错配PCR技术提高1株人源化抗hIL17A单链抗体(scFv)的亲和力,为进一步开发治疗类风湿性关节炎(RA)的人源化抗体药物奠定基础。方法:本研究采用错配PCR和重叠PCR的方法,对抗体的重链、轻链可变区分别随机引入突变,并将细菌内膜展示技术和流式细胞技术(FCM)相结合进行高通量筛选,获得高亲和力突变株。由于hIL17A能刺激HeLa细胞产生白细胞介素IL-6和IL-8,因此scFv突变株经表达纯化后,利用real-time PCR技术在mRNA转录水平上检测其阻断hIL17A刺激HeLa细胞产生IL-6和IL-8的能力。结果:筛选出5株突变株,经流式细胞仪检测其中有3株亲和力与亲本相比有很大程度的提高,2株与亲本相当,而且所有突变株均保留了亲本与hIL17A的结合能力,经real-time PCR检测证明这5株突变株均有阻断hIL17A刺激HeLa细胞产生IL-6和IL-8的能力,突变株的亲和力与中和效果成正比。结论:错配PCR技术是抗体体外亲和力提高的一种可行性方法,在保证与抗原结合能力的基础上提高了其亲和力和中和活性。该实验结果为RA的靶向治疗提供了候选药物,而且也为抗体的体外亲和力的提高提供了参考方法。 相似文献
994.
Young-Chul Yoo Sun-Joon Bai Ki-Young Lee Seokyung Shin Eun Kyeong Choi Jong Wha Lee 《Yonsei medical journal》2012,53(6):1197-1202
Purpose
We investigated the effect of total intravenous anesthesia (TIVA) with propofol on postoperative nausea and vomiting (PONV) after robot-assisted laparoscopic radical prostatectomy (RLRP) in patients at low risk of developing PONV, in comparison to balanced anesthesia with desflurane.Materials and Methods
Sixty two patients were randomly assigned to the Des or TIVA group. Propofol and remifentanil were used for induction of anesthesia in both groups and for maintenance of the anesthesia in the TIVA group. In the Des group, anesthesia was maintained with desflurane and remifentanil. In both groups, postoperative pain was controlled using fentanyl-based intravenous patient controlled analgesia, and ramosetron 0.3 mg was administered at the end of surgery. The incidence of PONV, severity of nausea and pain, and requirements of rescue antiemetics and analgesics were recorded.Results
The incidence of nausea in the post-anesthetic care unit was 22.6% in the Des group and 6.5% in the TIVA (p=0.001) group. The incidence of nausea at postoperative 1-6 hours was 54.8% in the Des group and 16.1% in the TIVA group (p=0.001). At postoperative 6-48 hours, there were no significant differences in the incidence of nausea between groups.Conclusion
In order to prevent PONV after RLRP in the early postoperative period, anesthesia using TIVA with propofol is required regardless of patient-related risk factors. 相似文献995.
目的 了解甲型H1N1流感患者发病后体内流感病毒特异性血凝抑制抗体滴度变化.方法 采集28例甲型H1N1流感患者发病后不同时间的血清,采用血凝抑制试验测定其抗体滴度并分析.结果 患者距发病1、5、15、22、37、49天和58天的血凝抑制抗体滴度分别为5.36、9.39、39.02、57.99、137.92、55.19和57.99,患者的最高抗体滴度几何均数为148.55,其中96.4%( 27/28)的患者在病程中产生保护性抗体和发生抗体血清转换.结论 甲型H1N1流感患者能有效产生保护性水平的抗体,有较好的免疫反应. 相似文献
996.
This study explored the importance of hepatitis B virus infection in cholangiocarcinoma pathogenesis in northern China. The clinical data of 66 patients with cholangiocarcinoma were analyzed. The hepatitis B virus gene was amplified using nested polymerase chain reaction, and the hepatitis B virus-related antigen was detected using immunohistochemistry in formalin-fixed, paraffin-embedded tissue from patients with intrahepatic cholangiocarcinoma (n = 23) and extrahepatic cholangiocarcinoma (n = 43). Hepatitis B surface antigen seropositivity was found in 52.2% (12/23) of intrahepatic cholangiocarcinoma cases and 13.9% (6/43) of extrahepatic cholangiocarcinoma cases. Hepatitis B virus DNA (X region) was detectable in 34.8% (8/23) of intrahepatic cholangiocarcinoma cases. Hepatitis B surface antigen and/or hepatitis B core antigen was detectable in 30.4% (7/23) of intrahepatic cholangiocarcinoma cases. All cases with detected viral protein were also positive for hepatitis B virus DNA. In contrast, no hepatitis B virus antigens or hepatitis B virus gene was detected in any of the 43 extrahepatic cholangiocarcinoma cases. Our findings strongly suggest that chronic hepatitis B virus infection is a significant risk factor for intrahepatic cholangiocarcinoma, but not for extrahepatic cholangiocarcinoma, in northern China. Hepatitis B virus infection is potentially independently associated with intrahepatic cholangiocarcinoma. 相似文献
997.
Papillary thyroid carcinoma (PTC) has long been diagnosed based on its unique nuclear features (PTC-N); however, significant observer discrepancies have been reported in the diagnosis of encapsulated follicular patterned lesions (EnFPLs), because the threshold of PTC-N is subjective. An equivocal PTC-N may often occur in non-invasive EnFPLs and benign/malignant disagreements often create serious problems for patients' treatment. This review collects recent publications focusing on the so-called encapsulated follicular variant of papillary thyroid carcinoma (EnFVPTC) and tries to emphasize problems in the histopathological diagnosis of this spectrum of tumors, which covers encapsulated common-type PTC (EncPTC), EnFVPTC, well-differentiated tumor of uncertain malignant potential (WDT-UMP), follicular adenoma (FA) with equivocal PTC-N and minimally invasive follicular carcinoma (mFTC). We propose that EnFVPTC and other EnFPLs with equivocal PTC-N should be classified into a unified category of borderline malignancy, such as well-differentiated tumor of uncertain behavior (WDT-UB), based on their homogeneous excellent outcome. It is suggested that the unified nomenclature of these lesions may be helpful to reduce significant observer disagreements in diagnosis, because complete agreement in the diagnosis of an EncPTC, EnFVPTC or FA by all pathologists may be not possible for this problematic group of tumors. In conclusion, a malignant diagnosis of EnFVPTC should not be used to cover this spectrum of tumors until uncertainty about the nature of this lesion is settled, whether it is benign, precancerous or malignant. 相似文献
998.
Wang W Zhang Y Li Y Pan L Bai L Zhuang Y Huang CX Wang JP Yu HT Wei X Jiang W Nan YY Yang DQ Su WJ Wang PZ Bai XF 《Archives of virology》2012,157(6):1051-1061
Hantaviruses infect human endothelial cells (ECs) and are known to cause vascular-permeability-based diseases, including hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). The αvβ3 integrins, which are highly expressed on the surface of ECs, serve as hantavirus receptors. Specifically, the β3 integrin and vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2) form a functional complex and interact with each other. Signaling through this complex causes cytoskeletal reorganization, which is one of the most important mechanisms underlying hyperpermeability. In this study, we show that VEGF dramatically enhances Hantaan virus (HTNV)-directed permeability and increases the reorganization of the cytoskeleton and the disruption of junctional organizations in an EC monolayer at 3 days postinfection. HTNV infection reduced the effect of VEGF on adhesion, migration, and the upregulation of β3 expression, but the infection alone upregulated the expression of β3 and VEGFR2. These results indicate that in addition to its role in blocking β3 integrin activation as reported previously, HTNV blocks the function of the complex of VEGFR2 and β3 integrin, and the dysfunction of the complex may contribute to cytoskeletal reorganization in an HTNV-directed hyperpermeability response to VEGF. 相似文献
999.
1000.
Objective: Cyclooxygenase-2 (COX-2), one of the rate-limiting enzymes in the metabolism of arachidonic acid which is reported to be involved in the pathogenesis of many human tumors. As well, Vascular endothelial growth factor (VEGF) is well known to be involved in the infiltration and metastasis of many kinds of cancers. The aim of this study was to further elucidate the clinicopathologic significance of the immunohistochemical expressions of COX-2 and VEGF in thyroid carcinoma.Methods: Eighty-five patients with thyroid neoplasms were enrolled in our study from December 2003 to January 2010 from the authors'' institution retrospectively. Their tumors were examined in the Department of Pathology, the First Bethune Hospital of Jilin University. Immunohistochemistry was performed on paraffin-embedded tissues sections using monoclonal anti-human COX-2 and VEGF antibodies. The tissues were classified into four types: papillary, follicular, medullary and undifferentiated. The patients ranged in age from 23 to 71 years. Breast cancer slides acted as control slides. The immunohistochemical stains were quantified by staining intensity and by the proportion of positively stained cells which were stained brown or yellow.Results: The results were analysed by χ2 test. COX-2 and VEGF expressions were stronger in thyroid carcinoma than in thyroid adenomas and normal tissues (P<0.01). COX-2 and VEGF expressions in thyroid carcinoma correlated with the tumor type and TNM stage.Conclusion: Our results suggest that expression of COX-2 and VEGF may promote angiogenesis of thyroid carcinoma, its infiltration, and metastasis. 相似文献