全文获取类型
收费全文 | 23316篇 |
免费 | 1063篇 |
国内免费 | 1092篇 |
专业分类
耳鼻咽喉 | 255篇 |
儿科学 | 719篇 |
妇产科学 | 389篇 |
基础医学 | 4367篇 |
口腔科学 | 740篇 |
临床医学 | 2311篇 |
内科学 | 4028篇 |
皮肤病学 | 446篇 |
神经病学 | 1081篇 |
特种医学 | 447篇 |
外国民族医学 | 4篇 |
外科学 | 1069篇 |
综合类 | 3834篇 |
现状与发展 | 3篇 |
预防医学 | 1852篇 |
眼科学 | 384篇 |
药学 | 1809篇 |
1篇 | |
中国医学 | 325篇 |
肿瘤学 | 1407篇 |
出版年
2024年 | 21篇 |
2023年 | 201篇 |
2022年 | 398篇 |
2021年 | 580篇 |
2020年 | 497篇 |
2019年 | 500篇 |
2018年 | 446篇 |
2017年 | 446篇 |
2016年 | 447篇 |
2015年 | 455篇 |
2014年 | 1017篇 |
2013年 | 1026篇 |
2012年 | 1028篇 |
2011年 | 1316篇 |
2010年 | 1083篇 |
2009年 | 1111篇 |
2008年 | 1213篇 |
2007年 | 1402篇 |
2006年 | 1220篇 |
2005年 | 1297篇 |
2004年 | 1129篇 |
2003年 | 1084篇 |
2002年 | 955篇 |
2001年 | 838篇 |
2000年 | 821篇 |
1999年 | 787篇 |
1998年 | 725篇 |
1997年 | 581篇 |
1996年 | 506篇 |
1995年 | 545篇 |
1994年 | 448篇 |
1993年 | 317篇 |
1992年 | 241篇 |
1991年 | 158篇 |
1990年 | 100篇 |
1989年 | 61篇 |
1988年 | 53篇 |
1987年 | 32篇 |
1986年 | 17篇 |
1985年 | 58篇 |
1984年 | 50篇 |
1983年 | 31篇 |
1982年 | 42篇 |
1981年 | 36篇 |
1980年 | 36篇 |
1979年 | 18篇 |
1978年 | 22篇 |
1977年 | 12篇 |
1976年 | 13篇 |
1973年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
Hideaki Iwaki Kazuyoshi Johnin Susumu Kageyama Chul Jang Kim Takahiro Isono Tatsuhiro Yoshiki 《International journal of urology》2007,14(10):918-923
OBJECTIVES: Vesicoureteral reflux (VUR) is the most common congenital urinary tract anomaly. This disease can pose a major threat to the kidneys as twenty percent of patients with endstage renal disease are reported to have VUR. Although genetic studies for uroplakin III (UPIII) have been reported recently, no study has focused on UPIII gene expression in VUR patients. We describe here the up-regulation of UPIII mRNA in exfoliated urinary cells from primary VUR patients. METHODS: A real-time RT-PCR for UPIII mRNA was performed on exfoliated urothelial cells from 18 primary VUR and 38 control samples. UPIII mRNA copies were calculated for each sample. The statistical differences were assessed by the Mann-Whitney U test. Receiver operator characteristic curves were constructed for analysis of the diagnostic values. RESULTS: UPIII mRNA was found to be up-regulated to a greater extent in VUR than in control exfoliated urinary cells (mean +/- SE: 497.0 +/- 178.5 copies vs. 69.0 +/- 10.0 copies, respectively, P < 0.001). In evaluating the measurement of urinary UPIII mRNA as a screening test for VUR, the sensitivity was 77.8% and the specificity was 76.3% by the best diagnostic cutoff point. CONCLUSIONS: This is the first report demonstrating up-regulation of UPIII in mRNA levels in VUR patients. We submit that the quantitative measurement of urinary UPIII mRNA has a potential of developing into the first non-invasive screening test for VUR. 相似文献
13.
14.
ltiswellknownthattheskinofextensivelyburnedcasesthemselvesisinsufficienttoprovidecoverageforwounds.Thoughallogeneicskincancoverthewoundstemporari1y,itwillberejectedwithin2-3weeks.Thiscanthreatenthepatient'slifeifthereisnoenoughautogenousskintoreplacetherejectedoneontime.GreenetalL1]reportedthattheburnwoundsofpatientswithextensiveburnscouldbetreatedbytransplantingepidermalautograftsafterautologousepidermalcellsmulti-plyforthousandsoftimesinvltrowithinashortperiodoftime-Butittakesatleast2-3weeks… 相似文献
15.
16.
P. Andersson K. LeBlanc B-. Eriksson J. Samuelsson 《European journal of haematology》1997,59(5):310-317
Abstract: Polycythaemia vera (PV) is a myeloproliferative disorder characterized by haematopoietic progenitor cells being hypersensitive to cytokines such as erythropoietin, interleukin-3, stem cell factor and insulin-like growth factor 1, which results in an increased production of mature blood cells. The pathogenetic cellular mechanism(s) behind this hypersensitivity to cytokines is unknown, but the number of cytokine receptors and the interaction between ligand and receptor are normal in PV. Interest has therefore focused on post-receptor mechanism(s). Haematopoietic cell phosphatase (HCP) is an intracellular tyrosine phosphatase that has been demonstrated to regulate proliferative signals negatively induced by the cytokines mentioned above. Moreover, motheaten mice that genetically lack HCP have an increased amount of erythroid progenitors that are hypersensitive to Epo, and patients with familial polycythaemia have been shown to exhibit a mutation of the Epo receptor gene that includes the docking site for HCP. We therefore studied mRNA expression of HCP in pure populations of CD34+ cells, granulocytes, platelets and lymphocytes from patients with PV, chronic myeloid leukaemia (CML) or essential thrombocythemia (ET), as well as healthy controls. Using a polymerase chain reaction analysis employing specific primers for HCP, we failed to detect any abnormalities of HCP expression in PV in any of the cell populations that were examined. Moreover, HCP mRNA expression was similar in ET and CML compared to controls. Finally, Western blot analysis revealed a normal HCP protein content in PV granulocytes and platelets. We therefore conclude that neither an impaired expression of the HCP gene nor a defect in HCP protein synthesis is present in PV, and does not seem to play a role in the aetiology of this disorder. 相似文献
17.
C. V. Dalchow A. L. Weber S. Bien N. Yanagihara J. A. Werner 《European archives of oto-rhino-laryngology》2006,263(2):92-99
Digital volume tomography (DVT) is an extension of panoramic tomography. With this diagnostic technique, characterized by high resolution, a narrow section width (0.125 mm) and three-dimensional display, small pathological processes can be well visualized. Twenty-five patients with the history of a progressive hearing loss were examined with DVT (Accu-I-tomo, Morita, Japan). The results were compared with pre- and intraoperative findings to evaluate the diagnostic value of DVT in cases of erosion of the ossicular chain. With high resolution and artifact-free demonstration of the middle ear and the ossicular chain, it was possible to define its continuity preoperatively by DVT in all 25 cases. An intact ossicular chain was found by DVT in 13 cases and was later confirmed by surgery. The predicted erosion of the ossicles was verified in 12 patients, and a tympanoplasty type III was performed. Digital volume tomography is an excellent technique to examine the middle ear cleft and inner ear, and expands the application of diagnostic possibilities in the lateral skull base. Therefore, improvement in preoperative diagnosis is achieved along with more accurate planning of the surgical procedure. Digital volume tomography delivers a small radiation dose with a high resolution and a low purchase price for the equipment. 相似文献
18.
INTRODUCTION Under physiological conditions, interferon-α (IFN-α) is a key cytokine produced by virtually all cells in the mammalian organism in response to a variety of bacterial and viral stimuli. In response to viral infection, IFN-α produced by the infected target cells induces a number of cellular genes involved in inhibition of viral replication. In addition, IFN-α is secreted by stimulated NK-cells and T-cells and exerts a multitude of immune stimulatory effects of innate a… 相似文献
19.
目的比较聚合酶链反应-序列特异性引物(PCR-SSP)进行HLA-Ⅰ类A、B抗原位点分型的准确性,并探讨血清学分型错误发生的原因。方法用PCR-SSP以及单克隆抗体血清学分型技术对HLA-A、B分型并比较。结果34例样本PCR-SSP基因分型无假阳性和假阴性出现。PCR-SSP法与血清学比较,血清学检出错误或漏检率分别为HLA-A位点23.5%,B位点26.5%。血清学发生错误或易混淆的抗原有:A2和A68、A32和A33,B5、B60和61。结论PCR-SSP法进行HLA-A、B抗原等位基因分型具有分辨率高、特异性强、重复性好、实验过程简捷快速、分型结果较血清学更加准确可靠的优点。 相似文献
20.
目的 :探讨宫颈癌细胞中凋亡相关蛋白激酶 1(DAPK1 )基因CpG岛甲基化及其表达与宫颈癌的相关性 .方法 :应用甲基化特异性PCR和SABC免疫组化方法 ,检测 32(鳞癌 1 8,腺癌 1 4 )例宫颈癌组织DAPK1基因CpG岛甲基化修饰及蛋白表达 .结果 :宫颈癌中DAPK1基因甲基化扩增阳性率明显增高 5 6 .3% ,与正常宫颈比较有显著性差异 (P <0 .0 5 ) ,鳞癌与腺癌甲基化扩增阳性率无显著差异 (P >0 .0 5 ) ;宫颈癌中DAPK1蛋白表达阳性率降低 1 5 .6 3% ,与正常宫颈比较有显著性差异 (P <0 .0 5 ) ,鳞癌和 7例与腺癌无显著性差异 (P >0 .0 5 ) .结论 :DAPK1基因CpG岛异常甲基化修饰能抑制DAPK1的转录 ,使DAPK1蛋白不表达 ,丧失抑癌作用 ,是促进正常宫颈上皮细胞癌变的一个重要因素 相似文献