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   1158篇
  免费   91篇
  国内免费   64篇
耳鼻咽喉   4篇
儿科学   49篇
妇产科学   4篇
基础医学   116篇
口腔科学   25篇
临床医学   108篇
内科学   213篇
皮肤病学   27篇
神经病学   34篇
特种医学   267篇
外科学   206篇
综合类   62篇
预防医学   30篇
眼科学   6篇
药学   102篇
肿瘤学   60篇
  2022年   16篇
  2021年   14篇
  2020年   5篇
  2019年   8篇
  2018年   17篇
  2017年   7篇
  2016年   10篇
  2015年   16篇
  2014年   28篇
  2013年   29篇
  2012年   22篇
  2011年   23篇
  2010年   28篇
  2009年   39篇
  2008年   26篇
  2007年   51篇
  2006年   28篇
  2005年   42篇
  2004年   26篇
  2003年   27篇
  2002年   21篇
  2001年   32篇
  2000年   25篇
  1999年   33篇
  1998年   62篇
  1997年   66篇
  1996年   57篇
  1995年   60篇
  1994年   34篇
  1993年   44篇
  1992年   27篇
  1991年   24篇
  1990年   25篇
  1989年   54篇
  1988年   43篇
  1987年   39篇
  1986年   21篇
  1985年   25篇
  1984年   16篇
  1983年   11篇
  1982年   21篇
  1981年   19篇
  1980年   20篇
  1979年   14篇
  1978年   8篇
  1977年   14篇
  1976年   15篇
  1975年   9篇
  1973年   4篇
  1969年   3篇
排序方式: 共有1313条查询结果,搜索用时 250 毫秒
81.
Parenteral iron therapy exacerbates experimental sepsis   总被引:3,自引:0,他引:3  
BACKGROUND: Catalytic iron can potentiate systemic inflammation via its pro-oxidant effects. This raises the possibility that parenteral iron administration might exacerbate a concomitant septic state. This study sought to experimentally test this hypothesis. METHODS: Male CD-1 mice were subjected to experimental sepsis via intraperitoneal injection of heat-killed Escherichia coli +/- concomitant intravenous iron sucrose (Venofer; 2 mg). Nonseptic mice +/- iron therapy served as controls. Plasma tumor necrosis factor-alpha (TNF-alpha) levels were assessed 2 hours postinjections (serving as an inflammatory marker). Oxidative stress was gauged in heart or kidney tissue (at either 4 or 24 hours) by heme oxygenase-1 (HO-1) mRNA or protein levels. Overall sepsis severity was assessed by morbidity/mortality rates (at 24 hours). RESULTS: Iron alone or sepsis alone each induced oxidant stress in heart and kidney (HO-1 mRNA/protein increases). When iron and E. coli were coadministered, additive or synergistic HO-1 mRNA/protein increments resulted. Iron injection alone only slightly raised TNF-alpha levels (from 0 to 2.3 pg/mL; P= 0.01). However, iron approximately doubled the TNF-alpha increments which arose from the septic state (1400 --> 2600 pg/mL). Neither sepsis alone, nor iron alone, induced any mortality and no mice became moribund (0/24 mice). However, when iron + sepsis were combined, approximately 60% of mice either died (5/12) or developed a moribund (2/12) state (P= 0.005). CONCLUSION: Parenteral iron administration can induce systemic oxidative stress and modest TNF-alpha release. However, when iron is given during experimental sepsis, profound increases in both processes, and approximately 60% mortality, result. Given that renal failure patients have decreased antioxidant defenses and intermittently develop bacteremia, the potential for parenteral iron therapy to exacerbate clinical sepsis needs to be addressed.  相似文献   
82.
This article gives a presentation of a variety of surgical cases of peripheral nerve tumors for illustration and discussion. The first three cases include a schwannoma, a neurofibroma, and a desmoid tumor of the brachial plexus region. Case 4 is that of a patient with a common peroneal ganglion cyst, and case 5 is that of a patient with an angiolipoma of the forearm. Cases 6 through 8 illustrate a plexiform neurofibroma, a malignant peripheral nerve sheath tumor, and a metastatic carcinoma to the brachial plexus region. In case 9, a patient with schwannomatosis was treated for multiple spinal schwannomas.  相似文献   
83.
This pilot study was conducted to identify the metals used by home-based Native American jewelry makers, to quantify the metals in dust samples taken from jewelers' homes, and to compare these concentrations with background levels from control homes in which jewelry was not made. Participants were recruited from Zuni Pueblo, New Mexico. Surface dust samples were collected from the work and living areas of 20 jewelers' homes, and from the living areas of 20 control homes. Silver, copper, tin, boron, nickel, zinc, lead, and cadmium were significantly higher in work areas than in living areas of jewelry-making homes (p < or = 0.02). Silver, copper, nickel, and antimony were significantly higher in living areas of jewelers' homes compared with control homes (p < or = 0.04). Ventilation measures did not effectively reduce metal concentrations in jewelers' homes; concentrations in nonwork areas remained elevated.  相似文献   
84.
BACKGROUND: The aim of the study was to determine whether hepatic regeneration stimulates growth of tumour residing within the liver, and whether a difference in the rate of DNA synthesis in liver and tumour may be used to target cancer using the radiolabelled thymidine analogue 5-iodo-2'-deoxyuridine (IUdR). METHODS: Partial hepatectomy was performed on Buffalo rats bearing solitary nodules of syngeneic Morris hepatoma. Liver and tumour DNA synthesis was measured by incorporation of radioactive IUdR. [(125)I]IUdR was tested as an adjuvant therapy after hepatectomy in Buffalo rats bearing diffuse microscopic Morris hepatomas to simulate the clinical situation. RESULTS: Liver regeneration enhanced liver and tumour DNA synthesis as measured by incorporation of radioactive IUdR. Liver DNA synthesis returned to baseline by 7 days, whereas tumour DNA synthesis remained above baseline level. Hepatectomy enhanced the growth of microscopic liver tumours. [(125)I]IUdR (250 micro Ci or 1 mCi/kg) administered 4 days after hepatectomy significantly reduced tumour growth without signs of systemic toxicity or liver dysfunction. CONCLUSION: The local environment of the regenerating liver stimulates tumour growth. The thymidine analogue [(125)I]IUdR may be used preferentially to target tumour DNA synthesis in the regenerating liver, and may prove useful as an adjuvant therapy for hepatic tumours after surgical resection.  相似文献   
85.
86.
BACKGROUND/AIMS: Inflammatory fibrous polyps (IFPs), also known as inflammatory pseudotumors, occur rarely in the gastrointestinal tract. IFPs have variable presentations, often presenting as small bowel obstruction due to intussusception or, less commonly, as an incidental finding on radiological examinations or screening colonoscopies. The diagnosis and management of IFPs will be discussed through a review of the literature and a series of cases from our own institution. METHODS: A retrospective analysis of the diagnosis, management and complications of IFPs was performed by a literature review. This was accompanied by a series of 3 cases of IFPs, 2 of which causing intussusception, diagnosed and treated in our own institution. CONCLUSIONS: IFP is a rare disease and has a variable presentation, from asymptomatic to small bowel obstruction due to intussusception. IFPs cannot be differentiated from malignancy without histological examination. Therefore, whether diagnosed incidentally or in the setting of intussusception, the treatment of IFPs is surgical resection of the involved bowel.  相似文献   
87.
The clinicopathological associations of 33 singleton infants who died with intraventricular haemorrhage (IVH) without hyaline membrane disease (HMD) ('IVH only') were compared with those of 39 infants who died with IVH+HMD over the same gestation range in order to determine what factors other than those related to HMD may contribute to the pathogenesis of IVH. The incidence of 'IVH only' was inversely related to gestational age in the Hammersmith birth population, whereas the incidence of IVH+HMD rose to a peak at 28-29 weeks' gestation. Infants with 'IVH only' lived longer on average than those with IVH+HMD despite a lower birthweight and shorter gestation. Infants who died in the first 12 hours from 'IVH only' had suffered severe birth asphyxia but in those who died later the main symptom was recurrent apnoea. Fewer infants with asphyxia but in those who died later the main symptom was.recurrent apnoea. Fewer infants with 'IVH only' were given alkali therapy or were connected to the ventilator as compared to those with IVH+HMD, but there were no differences in alkali therapy in those who lived for 12 hours or more. In the 'IVH only' group there was a high incidence of haemorrhage from other sites and of bacterial infections. It is suggested that, in the absence of HMD, extreme immaturity is the main factor determining the occurrence of IVH. Birth asphyxia, apnoeic attacks, haemorrhage, and infections may play subsidiary roles, possibly through development of metabolic acidosis.  相似文献   
88.
89.
Original Gianturco expandable stents and their modifications were used to create an experimental intrahepatic portacaval anastomosis (EIPCA) in 30 young domestic swine without portal hypertension. The study focused on the design of a suitable stent, the technique of its application, and the evaluation of short-term patency of the EIPCA. A stent with a 2.5-cm-long body and wire skirts on both ends was most suitable for EIPCA creation. Well-positioned stents shunted most of the portal blood in the inferior vena cava circulation and remained patent for 4-6 weeks. Ingrowth of liver parenchyma and abundant proliferation of the intima and connective tissue inside the stent lumen in these rapidly growing animals gradually decreased EIPCA patency, and thrombus formation with diminished blood flow closed them completely.  相似文献   
90.
据文献记载和作者的调查,我国产麻黄属(Ephedra)植物共有13种3变种1变型。本文报道我国北方生产的7种麻黄生药形态组织学比较研究结果。7种麻黄是:草麻黄Ephedra sinica Stapf、木贼麻黄E.equisetina Bunge、中麻黄E.intermedia Schrenk ex Mey.、膜果麻黄E.przewalskii Stapf,单子麻黄E.monosperma Gmel.ex Mey.、雌雄麻黄E.fedtschenkoae Pauls和细子麻黄E.reaeliana Florin。文中附有生药性状与组织构造特征比较表及生药组织图  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