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   11034篇
  免费   616篇
  国内免费   52篇
耳鼻咽喉   145篇
儿科学   383篇
妇产科学   112篇
基础医学   1793篇
口腔科学   221篇
临床医学   786篇
内科学   2506篇
皮肤病学   234篇
神经病学   943篇
特种医学   354篇
外科学   1398篇
综合类   64篇
一般理论   1篇
预防医学   489篇
眼科学   186篇
药学   797篇
中国医学   12篇
肿瘤学   1278篇
  2023年   87篇
  2022年   137篇
  2021年   228篇
  2020年   122篇
  2019年   186篇
  2018年   241篇
  2017年   197篇
  2016年   204篇
  2015年   197篇
  2014年   305篇
  2013年   414篇
  2012年   634篇
  2011年   671篇
  2010年   354篇
  2009年   402篇
  2008年   612篇
  2007年   741篇
  2006年   693篇
  2005年   701篇
  2004年   690篇
  2003年   630篇
  2002年   632篇
  2001年   207篇
  2000年   198篇
  1999年   207篇
  1998年   139篇
  1997年   116篇
  1996年   100篇
  1995年   85篇
  1994年   62篇
  1993年   86篇
  1992年   171篇
  1991年   144篇
  1990年   98篇
  1989年   102篇
  1988年   107篇
  1987年   114篇
  1986年   92篇
  1985年   84篇
  1984年   61篇
  1983年   50篇
  1982年   28篇
  1981年   23篇
  1980年   30篇
  1979年   45篇
  1975年   24篇
  1974年   32篇
  1973年   33篇
  1971年   23篇
  1968年   25篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
This study was designed with two purposes: first, to elucidate immunologic mechanisms in different cutaneous reactions, particularly in hypersensitivity to mosquito bites, and, second, to develop a more reliable and safer method of identifying the causative species of mosquito in severe cases. The amounts of IgG, IgG4 and IgE specific to the mosquito salivary gland extract of Aedes albopictus were determined in the sera of 116 volunteers with normal reactions, either immediate or delayed, and 4 patients with severe systemic symptoms caused by mosquito bites. Titers of IgG and IgE in the severe cases were considerably higher than in volunteers with normal reactions, but there were no differences in IgG, titers between the two groups. These results indicate that high titers of IgG and IgE may be involved in development of systemic symptoms in severe cases and verify the possibility of in vitro tests to identify causative species of the mosquito.  相似文献   
42.
The present study examined the relationship between number of steps and body mass index (BMI) among male workers in the metropolitan area. The number of subjects were 310 (aged 30-59) and they were studied for seven consecutive days. The number of steps was measured by a pedometer. Energy expenditure was assessed by the activity record method. Energy intake was assessed by a food frequency questionnaire. Height and body weight were examined by a self-administered questionnaire. BMI of 81 subjects (26.1%) was greater than 25 kg/m2. The number of steps was 10,682 +/- 4,365 on working days, and 7,135 +/- 4,536 on holidays. Average energy expenditure in seven days was 2,259 +/- 378 kcal/d. The physical activity level (PAL) was 1.5 +/- 0.1. There was a significant correlation between BMI and the number of steps in a working day (r=-0.188, p<0.01). In addition, there were significant correlations between PAL and daily steps on working days (r=0.301, p<0.001), and on holidays (r=0.296, p<0.001). Subjects were divided into four groups according to the median number of steps on working days and energy intake (I; > or =9,894 steps, <1,901 kcal, II; > or =9,894 steps, > or =1,901 kcal, III; <9,894 steps, <1,901 kcal, IV; <9,894 steps, > or =1,901 kcal). BMI of Group IV (24.7 kg/m2) was significantly higher than that of the other Groups. Group III had the highest proportion of subjects (15.7%) with lifestyle related diseases.  相似文献   
43.
The purpose of this study was to determine whether the late component of somatosensory evoked potentials (SEP) induced by electrical tooth stimulation and pain intensity are inhibited by heterotopic ischemic stimulation. The tourniquet pressure with 50 mmHg greater than the individual's systolic pressure was applied to the left upper arm for 10 min as ischemic conditioning stimulation. The late component of SEP and visual analogue scale (VAS) were recorded at 4 times and both were significantly decreased when ischemic conditioning stimulation was applied. The maximum reductions in SEP amplitude and the VAS value were 26.1% and 21.2%, respectively, during ischemic conditioning stimulation. After-effect was observed 5 min after removal of the conditioning stimulation. The present study revealed that heterotopic ischemic stimulation attenuated the late component of SEP induced by electrical tooth stimulation, triggering diffuse noxious inhibitory controls (DNIC) and after-effects in the trigeminal nerve territory. It was also suggested that the DNIC effect differs, depending on the intensity, kind, and quality of the test and conditioning stimuli.  相似文献   
44.
Tracer experiments were carried out to compare the plant uptake behavior of Tc and Re from nutrient solutions. Radish plants, transplanted to nutrient solution including various tracers, showed the same uptake and distribution of 95mTc and 183Re. The trend was the same when the 99Tc and stable-Re concentrations were increased in nutrient solution. The behavior of other elements was different from that of Tc and Re. These findings suggest the possible use of Re as the chemical analogue of Tc in soil solution to plant uptake experiments.  相似文献   
45.
46.
47.
A 57-year-old man with a history of renal cell carcinoma presented with presyncope. He underwent nephrectomy years earlier followed by HLA-matched allogeneic peripheral-blood stem-cell transplantation. Echocardiographic investigation revealed a solitary right ventricle mass without contiguous vena caval or right atrial involvement. The mass was pathologically confirmed to be metastatic carcinoma in the right ventricular cavity. This case highlights the need to consider an underlying neoplastic syndrome in patients presenting isolated right ventricle mass by echocardiography.  相似文献   
48.
We report a patient manifesting seizures with bilateral symmetric tonic posturing, which were markedly reduced after resection of the left precuneus. A 16-year-old man had sudden onset, complex partial seizures with bilateral symmetric tonic posturing since the age of eight years. Magnetic resonance fluid-attenuated inversion-recovery imaging revealed a hyperintense lesion in left precuneus. In almost all focal seizures recorded during an invasive EEG evaluation, ictal onset was detected from the inferomesial aspect of the lesion, but fast paroxysmal discharges from the ipsilateral supplementary motor area (SMA) were observed just before the clinical onset. After surgical excision of the EEG onset zone, including the lesion, seizure frequency was markedly (> 95%) reduced. By the 20th month after surgery, there were only brief nocturnal seizures involving slight elevation of both shoulders and slight abduction of both arms, with preservation of consciousness occurring once every few days. Invasive EEG findings and surgical outcome suggested that the epileptic activity originating from the epileptogenic zone may have propagated to the symptomatogenic zone including mainly the ipsilateral SMA. In summary, we report an interesting case of bilateral symmetric tonic posturing suggesting propagation to the SMA. MRI and invasive EEG confirmed the epileptogenic focus as a precuneate cortical dysplasia lesion.[Published with video sequences].  相似文献   
49.
A 61-year-old man had been treated for malignant fibrous histiocytoma with the pulmonary and the lymph node metastasis in the department of orthopedics in our hospital. He was admitted to our department because of an acute onset of conscious disturbance and non-fluent aphasia. Diffusion-weighted imaging (DWI) showed high signal intensity areas in the bilateral cerebella, thalami and posterior lobes. T2WI did not show any mass effects. Enhanced CT did not reveal any enhanced lesion. He was diagnosed as having cerebral embolism, and his conscious disturbance was improved after medication. Eight weeks later, he presented dysphagia, dysarthria, and ataxia in his extremities. DWI showed multiple lesions of low signal intensity located at the identical place where had showed high signal intensity in the initial DWI. T2WI showed high signal intensity area with mass effect. It was indicated that cerebral metastasis might grow after tumorgenic embolism. This is a rare case that tumor emboluses were developed to the metastatic brain tumors.  相似文献   
50.
The first acute case of methylmercury (MeHg) poisoning by the consumption of fish arose in Minamata, Japan, in 1953. It was officially recognized and called Minamata disease (MD) in 1956. There are still arguments about the definition of MD in terms of its associated clinical symptoms and lesions even 50 years after the initial recognition of MD. Studies on this MD epidemic are reviewed along with its historical background. Since MeHg dispersed from Minamata to the Shiranui Sea, residents living around the sea had been exposed to low-dose MeHg through fish consumption for about 20 years (at least from 1950 to 1968). These chronic MeHg poisoning patients complained of paresthesia at the distal parts of their extremities and around the lips even 30 years after the cessation of exposure to MeHg of anthropogenic origin. The persisting somatosensory disorders after the discontinuation of exposure to MeHg were induced by diffuse damage to the somatosensory cortex, but not by damage to the peripheral nervous system, as previously believed. Based on these findings, symptoms and lesions in MeHg poisoning are reappraised.  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