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   10591篇
  免费   318篇
  国内免费   223篇
耳鼻咽喉   183篇
儿科学   281篇
妇产科学   1007篇
基础医学   1230篇
口腔科学   171篇
临床医学   789篇
内科学   2020篇
皮肤病学   422篇
神经病学   626篇
特种医学   228篇
外科学   2231篇
综合类   111篇
一般理论   2篇
预防医学   643篇
眼科学   192篇
药学   588篇
中国医学   55篇
肿瘤学   353篇
  2018年   93篇
  2017年   91篇
  2016年   135篇
  2015年   145篇
  2014年   141篇
  2013年   257篇
  2012年   255篇
  2011年   270篇
  2010年   231篇
  2009年   176篇
  2008年   289篇
  2007年   337篇
  2006年   412篇
  2005年   437篇
  2004年   422篇
  2003年   416篇
  2002年   462篇
  2001年   308篇
  2000年   267篇
  1999年   208篇
  1998年   118篇
  1997年   121篇
  1996年   129篇
  1995年   166篇
  1994年   139篇
  1993年   141篇
  1992年   185篇
  1991年   172篇
  1990年   161篇
  1989年   210篇
  1988年   178篇
  1987年   212篇
  1986年   145篇
  1985年   206篇
  1984年   145篇
  1983年   142篇
  1982年   180篇
  1981年   160篇
  1980年   137篇
  1979年   145篇
  1978年   131篇
  1977年   140篇
  1976年   129篇
  1975年   146篇
  1974年   117篇
  1973年   108篇
  1971年   82篇
  1968年   128篇
  1967年   102篇
  1966年   87篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
A 20-yr-old black male was admitted with a 5-month history of profound weight loss and diarrhea. Appetite and dietary intake had been remarkably well preserved up until the week before admission. The severity of his depletion was evidenced by a body weight of only 38% of standard, multiple electrolyte deficiencies, and reduced metabolic expenditure, protein turnover, protein synthesis, and pancreatic function. Immunological defects included diminished lymphocyte numbers, lymphocyte transformation, gamma-globulin concentration, and cell-mediated immunity. A diagnosis of alpha-heavy chain disease (alpha-HCD) was made on endoscopic duodenal biopsy and serology--lymphoma being excluded by scanning and laparotomy. Treatment consisted initially of intravenous nutrition (because of the extreme malnutrition, severe diarrhea, and malabsorption of fluid, electrolytes, carbohydrates, and fat) and oral tetracycline. Response was dramatic, with a doubling of body weight within 6 wk, and resolution of malabsorption. He was discharged on a normal diet and long-term oral tetracycline (250 mg/day), and at 1-yr follow-up, nutritional status and gut function were normal despite persistence of duodenal mucosal abnormalities and markers of alpha-HCD and bacterial overgrowth. These results suggest that the malabsorption initially identified in this patient was not due simply to the mucosal abnormalities that characterize alpha-HCD, but was more a consequence of the superimposition of nutrient maldigestion and absorption resulting from the extreme state of protein deficiency and its effects on gut and pancreatic function.  相似文献   
42.
Aim The aim of this study is to correlate the β-endorphin levels at the early and more chronic stages of the disease in an attempt to find or confirm an etiological factor of vitiligo. Background The exact pathogenesis of vitiligo is still unclear. The most important theories are the self destruction, the autoimmune and the neural theories. Methods Patients with vitiligo (n= 28) were divided into two groups according to the duration of their disease. A group of 15 members of medical staff was the control group. β-endorphin levels were determined with a radioimmunoassay (125I-β-endorphin IncstarCo). Results The mean β-endorphin levels (11.88 ± 2.25 pmol/l) in patients at the early years of the disease (Group A) were statistically elevated compared to those of patients with ‘chronic’ vitiligo (9.27 ± 2.73 pmol/l) and to those of controls (8.53 ± 2.53) pmol/l). Conclusion We suggest that high β-endorphin levels play a role in the pathogenesis of vitiligo as well as in the prognosis of the disease.  相似文献   
43.
44.
45.
46.
The 2006, annual meeting of the senior physicians and emergency medical technicians of the German Air Rescue Service (Deutschen Rettungsflugwacht, DRF) was titled “From Concept to Practice”. The themes of security in the air rescue services and the current practice of cardiopulmonary respiration were discussed. In addition, different concepts and networks for treating patients with acute coronary syndrome or severe trauma were presented. The training of emergency technicians and quality assessment using the database of the whole TeamDRF was explained. New helicopter stations as well as long-range transport using normal aviation by the TeamDRF were presented.  相似文献   
47.
In a prospective study we compared duplex-ultrasound characteristics of symptomatic internal carotid artery (ICA) stenoses with cranial computerized tomographic (CCT) findings in 82 patients suffering from completed or transient middle cerebral artery symptoms. The aim was to assess the pathogenic role of ICA plaque morphology and the potential embolic risk of ICA plaques. The degree of carotid stenosis was estimated by spectral analysis of the pulsed Doppler signal. The CCT findings were classified as being either normal, lacunar lesions, hemodynamically induced low-perfusion infarctions, or territorial embolic infarctions. According to their ultrasonic features we characterized the ICA plaque surface as smooth or irregular and their structure as homogeneous or heterogeneous. Plaques with an irregular surface and heterogeneous echogenicity dominated significantly in CCT-territorial infarctions (p < 0.01), whereas hemodynamically induced low-perfusion infarctions showed no relationship with any plaque characteristic. High degree ICA stenoses (> 50>%) dominated in both territorial infarctions and low-perfusion infarctions, as compared to ipsilateral normal CCT or lacunes (p < 0.05). Normal CCT and lacunar infarctions were associated with homogeneous and smooth plaques (both p < 0.05). We conclude that > 50% ICA stenoses can cause both hemodynamically induced low-perfusion infarctions as well as thromboembolic territorial infarctions, whereas ulcerated and heterogeneous plaques constitute a high risk factor for arterio-arterial embolic stroke. Furthermore, carotid ultrasound may help to estimate the clinical significance of carotid lesions.  相似文献   
48.
Mechanical femoral artery compression devices have several limitations. We compared a novel disposable beltheld pneumatic compression device to manual compression alone in 213 patients randomized into two equal groups. Both were comparable for age, gender, current therapy with aspirin (ASA) and warfarin, diameter of the arterial sheath, previous procedures via the same artery, procedure duration, and blood pressure. Manual compression time was 12 ± 3 minutes. Pneumatic compression was reduced during 60 minutes. Patient discomfort was assessed as none (82% vs 88%), mild (13% vs 8%), moderate (3% vs 4%), or severe (2% vs 0%) for the manual versus pneumatic group, respectively. Bleeding and hematoma occurred in 7.5% of patients with no difference between the treatment groups. However, manual compression was significantly more effective in the higher range of systolic blood pressure, and pneumatic in the lower range, with a cut point of approximately 170 mmHg. Predictors for bleeding were systolic blood pressure and dose of ASA. Among 113 patients with systolic blood pressure < 160 mmHg and low dose (75 mg) or no ASA, only / patient (0.9%) experienced bleeding while 31% of 16 patients with both elevated systolic blood pressure and high dose ASA (150–330 mg) bled. We conclude that pneumatic femoral artery compression does not reduce bleeding and hematoma compared with manual compression. The use of low dose (75 mg) or no ASA, as well as giving special attention to patients with elevated systolic blood pressure, may reduce the risk of bleeding after cardiac catheterization .  相似文献   
49.
50.
Summary A neurological complication occurs in 40–60% of HIV infected patients during the course of the disease. In 10–20% the neurological complication is the first manifestation of the HIV infection. A reliable neuropathological diagnosis is a prerequisite for a specifically selected treatment. While modern computer-assisted imaging techniques, such as computed tomography or magnetic resonance imaging, do possess a high sensitivity, they do not as a rule permit an unambiguous diagnosis.Between October 1989 and July 1994 we biopsied 38 HIV infected patients stereotactically. The indication for the biopsy was determined by having radiologically detectable lesions with no regression tendency in patients under antitoxoplasmosis therapy. In 89% an unambiguous diagnosis wa made based on the biopsy; 11 % of the biopsies were not diagnostic. For the most part, toxoplasmosis (31%) and progressive multifocal leucoencephalopathy (29%) were involved. 18% of the patients suffered from a non-Hodgkin lymphoma. The foci were primarily frontal (47%), parietal (21%) or localised in the basal ganglia area (11%). The result of the biopsy led to a change in treatment for 52% of the patients. Morbidity and mortality of the operation were 0%.The results or our research series are similar to other groups. It was shown that stereotactic brain biopsy is a safe and effective method for establishing a sound basis for treating the frequently life-threatening cerebral complications of AIDS.  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