全文获取类型
收费全文 | 14603篇 |
免费 | 1209篇 |
国内免费 | 369篇 |
专业分类
耳鼻咽喉 | 80篇 |
儿科学 | 245篇 |
妇产科学 | 110篇 |
基础医学 | 3316篇 |
口腔科学 | 345篇 |
临床医学 | 1213篇 |
内科学 | 2295篇 |
皮肤病学 | 231篇 |
神经病学 | 2016篇 |
特种医学 | 255篇 |
外国民族医学 | 2篇 |
外科学 | 1060篇 |
综合类 | 1307篇 |
现状与发展 | 4篇 |
预防医学 | 742篇 |
眼科学 | 277篇 |
药学 | 1580篇 |
3篇 | |
中国医学 | 657篇 |
肿瘤学 | 443篇 |
出版年
2024年 | 23篇 |
2023年 | 267篇 |
2022年 | 446篇 |
2021年 | 639篇 |
2020年 | 473篇 |
2019年 | 504篇 |
2018年 | 495篇 |
2017年 | 496篇 |
2016年 | 481篇 |
2015年 | 465篇 |
2014年 | 796篇 |
2013年 | 983篇 |
2012年 | 738篇 |
2011年 | 797篇 |
2010年 | 658篇 |
2009年 | 681篇 |
2008年 | 679篇 |
2007年 | 586篇 |
2006年 | 520篇 |
2005年 | 529篇 |
2004年 | 435篇 |
2003年 | 374篇 |
2002年 | 294篇 |
2001年 | 295篇 |
2000年 | 252篇 |
1999年 | 253篇 |
1998年 | 265篇 |
1997年 | 287篇 |
1996年 | 250篇 |
1995年 | 224篇 |
1994年 | 225篇 |
1993年 | 189篇 |
1992年 | 169篇 |
1991年 | 161篇 |
1990年 | 141篇 |
1989年 | 134篇 |
1988年 | 110篇 |
1987年 | 94篇 |
1986年 | 74篇 |
1985年 | 151篇 |
1984年 | 125篇 |
1983年 | 99篇 |
1982年 | 78篇 |
1981年 | 69篇 |
1980年 | 57篇 |
1979年 | 40篇 |
1978年 | 26篇 |
1977年 | 22篇 |
1976年 | 14篇 |
1973年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
Interdigestive small bowel motility and duodenal bacterial overgrowth in experimental acute pancreatitis 总被引:10,自引:0,他引:10
I. D. Van felius L. M. A. akkermans K. bosscha A. Verheem W. Harmsen† M. R. Visser† & H. G. Gooszen 《Neurogastroenterology and motility》2003,15(3):267-276
The objective of this study is to investigate the effects of an acute necrotizing pancreatitis (ANP), without biliary obstruction, on the migrating motor complex (MMC), small bowel bacterial overgrowth (SBBO), bacterial translocation (BT) and infection of the pancreas simultaneously. Rats were divided into four groups: mild pancreatitis, control, ANP and sham operated control. Jejunal myoelectrodes were used to measure MMCs. Blood, peritoneal fluid, bile, and abdominal organs were harvested for microbial culturing 72 h after induction of pancreatitis. The splenic portion of the pancreas was taken for histology. During ANP the MMC cycle length was significantly increased from 14.1 +/- 0.2 to 22.4 +/- 1.9 min (P < 0.05). The duodenum of ANP rats was in contrast with the other groups characterized by Enterobacteriacae (> 3 log 10 CFU g-1 in seven of 12 rats, P < 0.05). A positive correlation (r = 0.78, P < 0.01) existed between duodenal Gram-negative and anaerobic flora and the MMC cycle. Correlation between MMC cycle length and BT to the pancreas was positive as well (r = 0.70, P < 0.01). A positive correlation (r = 0.85, P < 0.01) was found between the severity of pancreatitis and duodenal bacterial overgrowth. During ANP without biliary obstruction, the jejunal MMC is disturbed and consequently SBBO occurs. The correlation between the severity of pancreatitis, the disturbance of the MMC and SBBO suggests an important pathophysiological role of the proximal small bowel in the infection of pancreatic necrosis. 相似文献
52.
Akio Tanaka Motoyoshi Okamoto Dai Yoshizawa Shigeru Ito Patricia González Alva Fumio Ide Kaoru Kusama 《Journal of oral pathology & medicine》2007,36(7):400-404
BACKGROUND: Although it has been reported that ghost cells are present in odontomas, the generation mechanism of these cells is unclear. To evaluate the presence of ghost cells and involvement of the Wnt signaling pathway, we examined the expression of hard keratins, beta-catenin and Lef-1 in odontomas. METHODS: Sixty-nine cases of odontoma were examined immunohistochemically with the use of antibodies against human hair proteins, beta-catenin and Lef-1. RESULTS: Expression of hard keratins was found only in the cytoplasm of ghost cells in 46 (66.7%) of the 69 odontomas. Compound odontomas (78.8%) showed a higher incidence of ghost cells than complex odontomas (29.4%). Histopathologically, ghost cells were found within odontogenic epithelium adjacent to immature enamel and in the centre of Liesegang-ring-like calcified materials. Expression of beta-catenin and Lef-1 was observed in the cytoplasm and nucleus of odontogenic epithelial cells adjacent to the ghost cells in immature odontomas. CONCLUSION: These findings suggest that odontoma is a hard keratin-expressing tumor-like lesion, and that the Wnt signaling pathway may be involved in the formation of ghost cells in odontomas. 相似文献
53.
Twenty-six bone marrow transplant recipients, 14 of whom had evidence of acute graft versus host disease at autopsy, were studied. The pancreas in four of these patients exhibited changes thought to be due to acute graft versus host disease. Pathognomonic findings were in exocrine ducts which showed marked epithelial cellular atypia associated with a mild lymphocytic infiltrate. This was accompanied by ulceration and intraluminal haemorrhage in severe cases. In three of these four cases ductal epithelium showed marked hyperexpression of class I and class II major histocompatibility complex molecules. By contrast islets were not inflamed, showed no evidence of endocrine cell damage and no abnormalities of major histocompatibility complex expression were seen. 相似文献
54.
Localization of bone marrow-originated cells in the central nervous system (CNS) of the rat was investigated by using bone marrow chimeras. In order to do this, Lewis rats which carry major histocompatibility complex (MHC) class I antigens haplotype 1 (RT1.Al) were reconstituted with (Lew X PVG)F1 (RT1.Al/c) bone marrow cells after lethal irradiation. Transferred bone marrow cells were detected by immunohistochemical staining using a monoclonal antibody, OX27, specific for haplotype c of rat MHC class I antigens (RT1.Ac). The spleen and thymus of chimeric rats were fully reconstituted with transferred F1 cells 4 weeks after bone marrow transplantation. At this stage, mononuclear cells in the subarachnoid space of the CNS expressed OX27 antigen indicating that they were of bone marrow origin. A few OX27-positive blood cells were scattered in the CNS parenchyma 4-12 weeks after reconstitution. Ramified microglia, however, remained OX27-negative. Bone marrow-derived microglia were not observed throughout the period of examination until 24 weeks. In addition, experimental allergic encephalomyelitis (EAE) was induced in chimeric rats in order to augment the expression of MHC class I antigens on microglia. Even under this condition, no OX27-positive microglia were observed. Taken together, ramified microglia might be of neuroectodermal origin and there is little possibility that the microglia are derived from the bone marrow. However, if the ramified microglia are derived from blood cells, the microglia may be expected to have characteristic cell kinetics from the following points: (1) the precursor cells of the microglia may enter the CNS only at the perinatal stage; and (2) even under the condition in which lymphocytes and macrophages enter the CNS as observed in EAE, the precursor cells of the microglia are not supplied from the blood. 相似文献
55.
K. Karljikovi-Raji B. Stankovi A. Granov 《Journal of pharmaceutical and biomedical analysis》1990,8(8-12):735-738
The colour reaction of 4-hydroxyiminomethyl-1-methylpyridinium chloride (PAM-4Cl) and palladium(II) chloride has been investigated. The optimum reaction conditions, spectral characteristics, conditional stability constant and composition of the yellow water-soluble complex have been established. A new spectrophotometric method is proposed for the microdetermination of PAM-4Cl. 相似文献
56.
Activated prothrombin complex concentrate (FEIBA® ) treatment during surgery in patients with inhibitors to FVIII/IX 总被引:1,自引:0,他引:1
Non-activated and activated prothrombin complex concentrates (PCC/aPCC) have been used successfully to treat bleeds in haemophilia patients with inhibitors, but most physicians do not consider these products as effective as factor VIII/IX (FVIII/IX) concentrates in non-inhibitor patients. Thus, surgical procedures in inhibitor patients have been performed reluctantly. We have performed 14 minor and five major surgical and invasive diagnostic procedures in eight patients with congenital haemophilia A and inhibitors and in two patients with acquired haemophilia. When a loading dose of 100 U kg-1 of FEIBA was given followed by 200 U kg-1 day-1 in three divided doses every 8 h for 3 days, and then, when the daily dose was tapered to 100-150 U kg-1, no severe or unexpected bleeding complications were observed. However, one adverse event was observed. A 69-year-old man who suffered a myocardial infarction the third postoperative day following sigmoidectomy was managed safely with opiate analgesia, nitrates and diuretics, and the continued use of FEIBA(R). 相似文献
57.
凋亡相关蛋白Apr-2的克隆、测序及初步表达 总被引:1,自引:0,他引:1
目的: 从HL-60细胞凋亡模型中克隆凋亡相关蛋白Apr-2编码区基因,并对其进行表达,为进一步研究Apr-2的结构功能及多克隆抗体的制备奠定基础.方法: 建立HL-60细胞凋亡模型,提取HL-60凋亡细胞总RNA,以RT-PCR方法获取Apr-2 cDNA编码区全序列,将其与PGEM-T Easy载体连接,转化E.coli DH5α,构建重组克隆载体PGEM-TEasy/apr-2,测序正确后,将目的片段亚克隆入PGEX-4T-2原核表达载体,并转化大肠杆菌, IPTG诱导重组蛋白质表达,分析蛋白质在细菌中的表达分布,进行凝胶自动扫描分析. 结果:序列分析表明,与GenBank中已登录的Apr-2 cDNA编码区序列比较,完全一致.表达的融合蛋白占菌体总蛋白质的40%以上,主要以包涵体的形式存在. 结论:成功的获得了细胞凋亡模型HL-60中Apr-2 cDNA编码区的克隆及其融合蛋白表达产物. 相似文献
58.
目的通过化学方法制成动物核性白内障模型,探讨相对能量复合指数(RECP)与角膜内皮细胞活性的关系。方法将5种化学物质注入晶状体,以透过黑白条纹的清晰程度判断晶状体混浊程度并分级。然后将实验眼球分为6组(Ⅰ组为对照组;Ⅱ-Ⅵ为实验组),行标准超声乳化白内障摘除手术。手术后立即取下角膜,作锥蓝-茜素红联合染色标本和扫描电镜标本。结果晶状体内注入甲醛、冰醋酸、无水乙醇、丙酮和苯扎溴铵均能形成晶状体混浊,其中:冰醋酸致晶状体混浊能力最弱,无水乙醇、丙酮次之,甲醛、苯扎溴铵最强。当RECP≤90时,锥蓝-茜素红双重染色和扫描电镜均表明角膜内皮细胞活性好,其形态和细胞联接均无改变。当RECP=120时,角膜内皮细胞形态尚正常,但是细胞联结和胞膜部分破坏。当RECP=150时,角膜内皮细胞严重损伤。结论用化学方法制作核性白内障模型供过渡训练使用是可行的。当RECP超过某一数值(>90)时,即与角膜内皮细胞的活性成负相关。 相似文献
59.
Ictal brain imaging in presurgical evaluation of patients with medically intractable complex partial seizures 总被引:1,自引:0,他引:1
O. N. Markand V. Salanova R. M. Worth H.-M. Park H. H. Wellman Omkar N. Markand M.D 《Acta neurologica Scandinavica》1994,89(S152):137-144
At the Indiana University Medical Center, 99 patients with medically intractable complex partial seizures (MI-CPS) had presurgical evaluation with subsequent anterior temporal lobectomy. The majority of the patients had single photon emission tomography (SPECT) performed interictally as well as during an actual epileptic seizure (ictal scan). Decreased regional cerebral perfusion (rCP) was seen in 54/94 (57%) of the interictal scans corresponding to the eventual site of the surgery. However, ictal scans provided a higher yield; increased rCP in the temporal lobe during an actual seizure was observed in 60/82 (73%) concordant to the side of surgery. SPECT is a useful, noninvasive method of localizing the epilepti-form focus in patients with MI-CPS considered for resective surgery. Both interictal and ictal SPECT need to be performed; combined interictal hypo-perfusion and ictal hyperperfusion in the same focal area are unique to epileptogenic lesions. Ictal SPECT studies can be performed in the majority of patients during the period of continuous video/EEG monitoring with only a little additional effort. Combining the results of functional brain imaging (interictal and ictal SPECT, PET) with clinical semiology of seizures, surface and sphenoidal EEG, magnetic resonance imaging and other non-invasive tests, anterior temporal lobectomy can be recommended in approximately two-thirds of the patients without resorting to potentially dangerous intracranial EEG monitoring. 相似文献
60.
本文用反复静脉注射小剂量牛血清白蛋白复制家兔慢性肾炎,用羊踯躅根治疗。同时,用该药对慢性肾炎病人进行疗效观察。阳性组兔肾小球呈现中至重度颗粒形免疫荧光,肾组织呈明显慢性硬化性肾小球肾炎改变。尿蛋白±~++。治疗组兔及病人治疗后病变及症状均明显减轻或消失。结果提示循环免疫复合物反复沉着可引起兔类似人类的慢性硬化性肾小球肾炎,羊踯躅根对病变有一定的控制和治疗作用,这可能与其抑制免疫发病机制有关。 相似文献