首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   29826篇
  免费   3492篇
  国内免费   1043篇
耳鼻咽喉   18篇
儿科学   1141篇
妇产科学   138篇
基础医学   2118篇
口腔科学   94篇
临床医学   2865篇
内科学   4028篇
皮肤病学   186篇
神经病学   195篇
特种医学   676篇
外国民族医学   1篇
外科学   11659篇
综合类   4476篇
现状与发展   2篇
一般理论   1篇
预防医学   997篇
眼科学   26篇
药学   2390篇
  16篇
中国医学   2765篇
肿瘤学   569篇
  2024年   132篇
  2023年   810篇
  2022年   1251篇
  2021年   2146篇
  2020年   1550篇
  2019年   1638篇
  2018年   1483篇
  2017年   1456篇
  2016年   1458篇
  2015年   1450篇
  2014年   2267篇
  2013年   2308篇
  2012年   1569篇
  2011年   1763篇
  2010年   1470篇
  2009年   1308篇
  2008年   1315篇
  2007年   1196篇
  2006年   1102篇
  2005年   934篇
  2004年   805篇
  2003年   682篇
  2002年   580篇
  2001年   544篇
  2000年   362篇
  1999年   303篇
  1998年   265篇
  1997年   213篇
  1996年   231篇
  1995年   201篇
  1994年   188篇
  1993年   150篇
  1992年   149篇
  1991年   143篇
  1990年   106篇
  1989年   114篇
  1988年   79篇
  1987年   81篇
  1986年   65篇
  1985年   65篇
  1984年   71篇
  1983年   39篇
  1982年   52篇
  1981年   49篇
  1980年   33篇
  1979年   45篇
  1978年   33篇
  1977年   29篇
  1976年   26篇
  1975年   18篇
排序方式: 共有10000条查询结果,搜索用时 54 毫秒
41.
大鼠肾移植模型技术的改进   总被引:6,自引:0,他引:6  
目的 为开展器官移植的实验研究,建立了大鼠异体肾移植模型。方法使用Wistar大鼠分别作为供者和受者,采用原位低温灌洗,肾动脉带一小段主动脉,肾静脉带一小段下腔静脉、输尿管末端带一直径约为0.5cm的膀胱瓣的供者手术方式;受者主动脉与供者主动脉、受者下腔静脉与供者下腔静脉进行端侧吻合,在受者膀胱上剪去一膀胱瓣与供者相同大小的圆瓣,然后进行一层膀胱吻合。结果 第一阶段为实验探索阶段,经过半年近150次的实验摸索,克服了移植物灌洗、血管吻合、膀胱吻合等技术难关,终于建立了比较稳定的大鼠同种异体肾移植模型。第二阶段为模型成熟阶段,冷热缺血时间、血管吻合的速度以及手术时间都比第一阶段有所缩短。手术成功率为85%左右,动物死亡的原因主要为血管吻合口出血、灌洗不良、休克、血栓形成以及膀胱漏尿致弥漫性腹膜炎等。结论 此模型容易掌握,可以在条件比较简单的实验室开展,除常规显微外科器械外不需要特殊的器械或设备。  相似文献   
42.
Abstract. A total of 81 rat kidney grafts, flushed out and cold stored in either Sacks' or University of Wisconsin (UW) solution, were transplanted into hemodiluted (Hct = 30%± 4%) or untreated (Hct = 43%± 3%) recipients. The cold ischemia times (CIT) used were 24 and 36 h. One week after transplantation, the surviving recipients ( n = 67) were contralaterally nephrectomized. The experiment was terminated after a total period of 4 weeks, and the percentage of surviving animals was determined for each treatment. Data was pooled and the results show that grafts cold stored in UW solution were viable to a significantly greater extent and after longer CIT than grafts cold stored in Sacks' solution (47% vs 23%; P < 0. 05). Recipient hemodilution did not improve graft viability (39% vs 32%; NS). Kidneys cold stored for 24 h were viable to a greater extent than kidneys with a CIT of 36 h (50% vs 15%; P < 0. 01).  相似文献   
43.
Transplant patients are at the risk for posttransplant lymphoproliferative disease (PTLD), a virally-driven malignancy. Induction with the depleting antibody preparations Thymoglobulin and OKT3 is associated with PTLD suggesting that the T-cell depletion increases PTLD risk. We therefore studied 59 560 kidney recipients from the Organ Procurement and Transplantation Network/United Network for Organ Sharing (OPTN/UNOS) database for a relationship between induction agent use and PTLD. Two agents with comparable T-cell depletional effects, alemtuzumab and Thymoglobulin, were compared to nondepletional induction agents or no induction. The overall incidence of PTLD was 0.46% and differed significantly by induction strategy (p < 0.01): without induction (0.43%), basiliximab (0.38%), daclizumab (0.33%), Thymoglobulin (0.67%) and alemtuzumab (0.37%). Thymoglobulin was associated with significantly increased PTLD risk (p = 0.0025), but alemtuzumab (p = 0.74), basiliximab (p = 0.33) and daclizumab, which trended toward a protective effect (p = 0.06), were not. Alemtuzumab and Thymoglobulin treated patients did not differ in any established parameter affecting PTLD risk although alemtuzumab is known to have a more pronounced B-cell depleting effect. Interestingly, maintenance therapy with an mTOR inhibitor was strongly associated with PTLD (0.71%, p < 0.0001). Thus, depletional induction is not an independent risk factor for PTLD. Rather, maintenance drug selection or perhaps the balance between B- and T-cell depletion may be more relevant determinants of PTLD risk.  相似文献   
44.
AIMS: To investigate the association between estimated glomerular filtration rate (eGFR) and total and cardiovascular mortality in a population-based cohort of diabetic subjects. METHODS: A longitudinal study using a population-based district diabetes register comprising 3288 subjects in South Tees, UK. The eGFR was calculated using the Modification of Diet in Renal Disease (MDRD) study equation. Patients were stratified by baseline eGFR into five stages as per the National Kidney Foundation guidelines: Stage 1, eGFR > 90; Stage 2, eGFR 60-89; Stage 3, eGFR 30-59; Stage 4, eGFR 15-29; and Stage 5, eGFR < 15 ml/min per 1.73 m(2). Main outcome was all-cause and cardiovascular mortality between 1 January 1994 and 31 July 2004. RESULTS: At baseline, mean age (58.4 years) differed between groups. Persons with lower eGFR were older (P < 0.001). Thirty-six percent (n = 1193, males 56%) had died by 10 years (cardiovascular cause in 60%). Median follow-up was 10.5 years amounting to 28 342 person years. Stages 4 and 5 (eGFR 相似文献   
45.
Despite reports demonstrating the safety of laparoscopic donor nephrectomy (LDN) for pediatric recipients of renal transplants, recent evidence has challenged using LDN for recipients 5 years of age or younger. We retrospectively reviewed the records of all pediatric recipients of living donor renal transplants from September 2000 through August 2004. We compared those who received allografts recovered by LDN (n = 34) with those recovered by open donor nephrectomy (ODN, n = 26). Outcomes of interest included operative complications, postoperative renal function, the incidence of delayed graft function or episodes of acute rejection and long-term graft function. Donor and recipient demographic data were similar for the LDN and ODN groups. Serum creatinine and calculated creatinine clearance were not significantly different between groups both in the early postoperative period and at long-term follow-up (p > 0.142). Rates of delayed graft function and acute rejection did not differ between groups. Among recipients aged 5 years old or younger stratified by donor technique (9 LDN, 5 ODN recipients), no difference was noted in graft outcomes both early and long-term (p > 0.079). At our center, pediatric LDN recipients have graft outcomes comparable to those of ODN recipients. At experienced centers, we recommend continued use of LDN for pediatric recipients of all ages.  相似文献   
46.
Bacterial infections are frequent in cadaveric organ donors and can be transmitted to the transplantation recipient, which could have devastating consequences for the recipients if adequate preventive measures are not adopted.
From the 355 consecutive brain dead cadaveric organ donors procured at our center in the last four years, 2000–2003, four of them (1.1%) had bacterial endocarditis as cause of death. The bacteria responsible for the endocarditis were Staphylococcus epidermidis, coagulase-negative Staphylococcus , Staphylococcus hominis and Streptococcus viridans , respectively. We performed five kidney and two liver transplantations on seven recipients. All donors and recipients received antibiotic treatment against the germ causing the respective endocarditis.
Infection by the bacteria responsible for the endocarditis in the respective donors was not transmitted to any of the recipients. Six of the seven recipients were alive with normal-functioning grafts after between 13 and 24 months' follow-up. Transplantectomy was performed on one kidney recipient due to thrombosis of the renal vein of the graft not related to the endocarditis.
Liver and kidney transplantation from donors dying from bacterial endocarditis can be performed without causing the transmission of infection to the recipient or the dysfunction of the graft.  相似文献   
47.
目的 研究脑钠素(BNP)与慢性肾脏病(CKD)非透析患者动脉粥样硬化及心功能不全的关系。 方法 采用双抗夹心免疫荧光法检测203例CKD非透析患者与16例高血压患者对照组全血BNP水平,分析其与颈动脉超声结果、心脏彩超结果及既往心血管疾病史的关系。 结果 CKD非透析患者BNP水平与对照组相比显著升高[M(范围):54.40(15.10~ 173.00) ng/L比9.35(7.35~15.00) ng/L,P < 0.01]。Spearman相关分析显示CKD患者BNP与颈动脉内膜中层厚度(IMT)、左室心肌重量指数(LVMI)等呈正相关。存在颈动脉斑块、左室肥厚或既往发生过心血管事件的患者血BNP水平显著增高。多元回归分析显示LVMI、既往心血管事件均是影响BNP水平的独立因素。 结论 CKD非透析患者BNP水平和动脉粥样硬化性疾病、左室肥厚及心功能不全相关,提示BNP水平可作为一项评价CKD非透析患者心功能及动脉粥样硬化的敏感生物学指标。  相似文献   
48.
With the introduction of more potent immunosuppressive agents, rejection has decreased in simultaneous pancreas/kidney transplant (SPK) recipients. However, as a consequence, opportunistic infections have increased. The purpose of this report is to outline the course of SPK patients who developed polyomavirus-associated nephropathy (PVAN). A retrospective review of 146 consecutive SPK recipients from January 1, 1996 to December 31, 2002 was performed. Immunosuppression, rejection and development of PVAN were reviewed. Nine patients were identified. All received induction with either OKT3 or thymoglobulin. Immunosuppression included tacrolimus/cyclosporine, MMF/azathioprine and sirolimus/prednisone. Two patients were treated for kidney rejection prior to the diagnosis of PVAN. Time to diagnosis was an average of 359.3 days post-transplantation. Immunosuppression was decreased but five ultimately lost function. However, none developed pancreatic abnormalities as demonstrated by normal glucose and amylase. Two underwent renal retransplantation after PVAN diagnosis and both have normal kidney function. PVAN was the leading cause of renal loss in SPK patients in the first 2 years after transplantation and is a serious concern for SPK recipients. The pancreas, however, is spared from evidence of infection, and no pancreatic rejection occurred when immunosuppression was decreased.  相似文献   
49.
AIMS: Laparoscopic nephrectomy has become a standardized procedure for removal of benign non-functioning kidneys. We present our experience of retroperitoneoscopic pre-transplant native kidneys nephrectomy. METHODS: Comparison of 40 patients who underwent retroperitoneoscopy with 40 open simple pre-transplant nephrectomy patients was done. RESULTS: Forty retroperitoneoscopic nephrectomies were done between June 2003 and April 2005. The mean operative time was similar in the two groups; however, the mean blood loss, postoperative analgesic requirement, complication rate, hospital stay and convalescence period were significantly less in the retroperitoneoscopic group. CONCLUSION: Retroperitoneoscopic nephrectomy should be offered as the primary treatment modality to patients requiring pre-transplant native kidney nephrectomy, except in patients where it is contraindicated.  相似文献   
50.
Interleukin-18 is predominantly a macrophage-derived cytokine with a key role in inflammation and cell-mediated immunity. Having previously demonstrated IL-18 upregulation in a rat model of kidney rejection, here we examined IL-18 in a fully MHC-mismatched murine model of acute kidney rejection using IL-18-deficient recipients (IL-18-/-) and animals administered neutralizing IL-18 binding protein (IL-18BP). Gene expression of IL-18 and its receptor were significantly upregulated in allografts compared to isografts, as was the cellular infiltrate (T cells and macrophages) (p < 0.001). Allografts developed kidney dysfunction (p < 0.05) and tubulitis (p < 0.01) not observed in controls. There was a significant reduction in gene expression of IL-18 downstream pro-inflammatory molecules (iNOS, TNFalpha and IFNgamma) in IL-18-/- recipients (p < 0.01), and IL-18BP-treated animals. The CD4+ infiltrate and IL-4 mRNA expression was greater in the IL-18-/- recipients than wild-type (WT) allografts and IL-18BP-treated animals (p < 0.05), suggesting a Th2-bias which was supported by IFNgamma and IL-4 ELISPOT data and an increased eosinophil accumulation (p < 0.001). Neither IL-18 deficiency nor neutralization prevented renal dysfunction or tubulitis. This study demonstrates increased production of IL-18 in murine kidney allograft rejection and provides evidence that IL-18-induced pathways of inflammation are active. However, neither IL-18 deficiency nor neutralization was protective against the development of allograft rejection.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号