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   1143篇
  免费   89篇
  国内免费   7篇
耳鼻咽喉   11篇
儿科学   55篇
妇产科学   21篇
基础医学   130篇
口腔科学   13篇
临床医学   171篇
内科学   182篇
皮肤病学   12篇
神经病学   81篇
特种医学   62篇
外国民族医学   1篇
外科学   202篇
综合类   15篇
预防医学   136篇
眼科学   9篇
药学   93篇
肿瘤学   45篇
  2021年   15篇
  2020年   11篇
  2019年   12篇
  2018年   17篇
  2016年   11篇
  2015年   12篇
  2014年   30篇
  2013年   33篇
  2012年   43篇
  2011年   48篇
  2010年   24篇
  2009年   28篇
  2008年   47篇
  2007年   46篇
  2006年   31篇
  2005年   39篇
  2004年   44篇
  2003年   42篇
  2002年   24篇
  2001年   30篇
  2000年   28篇
  1999年   22篇
  1998年   26篇
  1997年   18篇
  1996年   26篇
  1995年   26篇
  1994年   17篇
  1993年   19篇
  1992年   33篇
  1991年   20篇
  1990年   28篇
  1989年   28篇
  1988年   32篇
  1987年   18篇
  1986年   31篇
  1985年   34篇
  1984年   16篇
  1983年   16篇
  1982年   16篇
  1981年   12篇
  1980年   10篇
  1979年   27篇
  1978年   14篇
  1977年   13篇
  1976年   12篇
  1975年   16篇
  1973年   8篇
  1972年   8篇
  1970年   9篇
  1969年   9篇
排序方式: 共有1239条查询结果,搜索用时 781 毫秒
1.
BackgroundRural populations face many health disadvantages compared to urban areas. There is a critical need to better understand the current lung cancer screening landscape in these communities to identify targeted areas to improve the impact of this proven tool.MethodsData from the County Health Rankings of New Hampshire and Vermont was reviewed for population density, distribution of adult smokers, and level of education compared to the distribution of Lung Cancer Screening Facilities throughout these two states.ResultsScreening programs in southern counties of Vermont with lower levels of education have decreased access. In New Hampshire, there are no programs within 30 miles of the areas with the largest distribution of smokers, and decreased access in some areas with the lowest levels of education.ConclusionsImproving equitable access to high-quality screening services in rural regions and the creation of targeted interventions to address decreased access in areas of high tobacco use and low education is vital to decreasing the incidence of latestage presentations of lung cancer within these populations.  相似文献   
2.
3.
Femoropopliteal artery stent placement: evaluation of long-term success   总被引:4,自引:0,他引:4  
Strecker  EP; Boos  IB; Gottmann  D 《Radiology》1997,205(2):375
  相似文献   
4.
5.
A variant left hepatic artery occurs at a rate of approximately 10%. In standard esophagogastrectomy and some proximal gastric operations this variant artery is sacrificed, which has led to reported fatalities secondary to hepatic necrosis. We report our method of esophagogastrectomy in the presence of an aberrant left hepatic artery.  相似文献   
6.
We have devised assays to detect both circulating alloantibodies to platelets (indirect assay) and platelet-association IgG and IgM (direct assay) using a flow cytometric technique. A variety of patients with immune thrombocytopenia were studied. Employment of a confocal lens in the flow cytometer increased the discrimination power of the instrument. Patients with autoimmune thrombocytopenia (idiopathic thrombocytic purpura [ITP], systemic lupus erythematosus (SLE), lymphoma, leukemia, and drug-induced thrombocytopenia showed a significant increase in platelet-associated antibody. Circulating antibodies to platelets (alloantibodies) were demonstrated in cases of platelet refractoriness and neonatal isoimmune purpura. Day-today precision of the assays ranged from 3% to 6% (coefficient of variation). No interference was shown in the presence of hemoglobin (5 g/L), triglycerides (10 g/L), or polyclonal and monoclonal immunoglobulinemia (50 g/L: IgG, IgA, IgM). The sensitivity of the direct assay was 500 attograms of IgG or IgM platelet.  相似文献   
7.
BACKGROUND & AIMS: Nutrients and properties of lipases affect survival of lipolytic activity during aboral gastrointestinal transit. Whether different doses and formulations of bacterial lipase and diets affect steatorrhea was tested in pancreatic-insufficient dogs. METHODS: A dose of 0-600,000 IU of powdered and 135,000 and 300,000 IU of liquid bacterial lipase was given with a standard meal to 5 dogs with ligated pancreatic ducts. In 4 dogs, 0 or 300,000 IU (normal 6-hour postprandial amount) of powder bacterial lipase was also given with five meals containing 850 kcal with different nutrient caloric densities (mixture design). Coefficients of fat absorption during 72- hour fecal balance studies were used to assess treatments. RESULTS: With the standard meal, powder bacterial lipase reduced steatorrhea in a dose-dependent manner (P = 0.03), and 135,000 and 300,000 IU of the liquid form decreased steatorrhea more than powder bacterial lipase (P = 0.017 and 0.057, respectively). Coefficients of fat absorption with 300,000 IU of powder bacterial lipase correlated (r2 = 0.79; P < 0.001) with increasing proportions of fat calories in diets. CONCLUSIONS: Liquid bacterial lipase decreases steatorrhea more than powder, and 300,000 IU of powder bacterial lipase ingested with high-fat meals corrects canine pancreatic steatorrhea. The combination of adequate mixing of small amounts (milligrams) of bacterial lipase and high-fat meals abolishes canine steatorrhea and may abolish human pancreatic steatorrhea. (Gastroenterology 1997 Jun;112(6):2048-55)  相似文献   
8.
OBJECTIVE: The aim was to establish the potential efficacy, tolerabilityand side-effect profile of electromagnetic therapy as an adjunctto conventional dressings in the treatment of venous leg ulcers. METHOD: A prospective, randomized, double blind controlled clinicaltrial was carried out in a dedicated leg ulcer clinic basedin one urban general practice. Nineteen patients with leg ulcersof confirmed venous aetiology were assessed. The main outcomemeasures were rate and scale of venous leg ulcer healing, changesin patient-reported pain levels, quality of life, degree ofmobility, side effect profile and acceptability to patientsand staff. RESULTS: Sixty-eight per cent of patients attending this dedicated clinicachieved improvements in the size of their ulcer (4, 21%, healedfully) and in reduced pain levels (P < 0.05) during the trial,despite the chronicity of ulcer histories. Patients treatedwith electromagnetic therapy at 800 Hz were found at day 50to have significantly greater healing (P < 0.05) and paincontrol (P < 0.05) than placebo therapy or treatment with600 Hz. All patients reported improved mobility at the end ofthe study. The electromagnetic therapy was well tolerated bypatients, with no differences between groups in reporting adverseevents, and proved acceptable to staff. CONCLUSION: Despite the small numbers in this pilot study, electromagnetictherapy provided significant gains in the healing of venousleg ulcers and reduction in pain. Keywords. Electromagnetic therapy, RCT, leg ulcers, primary care.  相似文献   
9.
Morphologic studies were undertaken in a sheep model of pulmonary permeability edema (PPE) induced by cecal ligation and perforation. Biopsies taken every 24 hours through 96 hours following induction of sepsis showed, at 24 hours, interstitial edema accompanied by widespread aggregation of polymorphonuclear leukocytes. This was confirmed by electron microscopy, which also demonstrated endothelial cell swelling, platelet aggregation, and fibrin deposition. By 48 hours, a "thromboangiitis" had developed that persisted through 96 hours. In vitro pulmonary angiograms done at 60 and 96 hours showed multiple filling defects; it was possible to demonstrate that these defects corresponded to the "thromboangiitis." These thrombotic lesions, which were not the result of embolization from indwelling lines, closely resembled vascular changes described in the adult respiratory distress syndrome. It is believed that this is the first time that such lesions have been described in a model of PPE resulting from nonpulmonary sepsis.  相似文献   
10.
Two cases of unusual benign tumors of the neck are described, both of which were initially misdiagnosed on cytology as carcinomas. Fine-needle aspiration findings in each case demonstrated a pleomorphic population of cells including bizarre multi-nucleated giant cells, the latter raising the false impression of malignancy. However, on review the cytological appearances of the tumors, a pleomorphic lipoma and a carotid body tumor, were characteristic. the correct diagnosis in each case would have been made or suggested if the pathologist had been familiar with the cytologic features characteristic of the lesion and the differential diagnosis of the head and neck tumors. in addition, the point is made that adequate clinical information is essential for the pathologist if all relevant conditions are not to be missed in the differential diagnosis.  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