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   10123篇
  免费   461篇
  国内免费   30篇
耳鼻咽喉   154篇
儿科学   143篇
妇产科学   112篇
基础医学   1006篇
口腔科学   327篇
临床医学   582篇
内科学   2271篇
皮肤病学   350篇
神经病学   832篇
特种医学   408篇
外科学   1571篇
综合类   40篇
一般理论   1篇
预防医学   366篇
眼科学   135篇
药学   903篇
中国医学   11篇
肿瘤学   1402篇
  2023年   62篇
  2022年   112篇
  2021年   170篇
  2020年   109篇
  2019年   146篇
  2018年   193篇
  2017年   162篇
  2016年   162篇
  2015年   176篇
  2014年   233篇
  2013年   255篇
  2012年   425篇
  2011年   483篇
  2010年   266篇
  2009年   212篇
  2008年   413篇
  2007年   423篇
  2006年   445篇
  2005年   449篇
  2004年   427篇
  2003年   384篇
  2002年   400篇
  2001年   408篇
  2000年   401篇
  1999年   382篇
  1998年   129篇
  1997年   97篇
  1996年   95篇
  1995年   81篇
  1994年   73篇
  1993年   57篇
  1992年   255篇
  1991年   244篇
  1990年   248篇
  1989年   243篇
  1988年   214篇
  1987年   203篇
  1986年   164篇
  1985年   178篇
  1984年   126篇
  1983年   107篇
  1982年   45篇
  1979年   87篇
  1978年   57篇
  1977年   54篇
  1974年   53篇
  1971年   49篇
  1969年   46篇
  1967年   46篇
  1966年   43篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
111.
Results of Yusho annual inspection were reviewed from the view point of correlation of PCBs, PCQs and PCDFs concentration in blood or subcutaneous adipose tissue and clinical findings. To make discussion quantitative, fifteen terms of clinical findings on Yusho disease were quantified on the severity by evaluating (+) as 2 points, (+-) as 1 point and (-) as 0 point. First, the temporal variations of the severity of clinical findings on 5 Yusho patients were figured. Additionally, the temporal variations of blood triglyceride and PCBs concentration, and GOT were also surveyed. The adopted terms of clinical findings were general malaise, cough, sputum, headache, abdominal pain, peripheral neuropathy, soreness of joints, deformity of nails, comedo formation, acne-like eruption, secondary infection, scar formation, disorder of Meibomian glands, edema of eye lids and increased discharge from the eyes. During the investigated period from 1972 to 1988 the total score of clinical findings clearly decreased on two patients who had high score, tended to decrease on two other patients, and was not clear on another patient. Secondly, the correlation coefficients were calculated between each of PCDFs, PCBs or PCQs concentration in subcutaneous adipose tissue or blood and the total score at the year in which the adipose tissue and blood were taken. For the female patients the correlation coefficient of PCDFs concentration in subcutaneous adipose tissue and total score of clinical findings was the highest of all (r = 0.9885). However, for the male patients it was not available because the number of the subjects was only two. Thus far it has been reported that the powers of PCBs gas chromatogram pattern and PCQs concentration as criteria for Yusho diagnosis are low as for the subjects who belonged to the border area between Yusho patients and normal persons. This survey suggests that PCDFs concentration in subcutaneous adipose tissue can be a potent criterion that has a high correlation with the clinical findings of Yusho.  相似文献   
112.
The effect of hapten density on benzylpenicilloyl (BPO)-protein conjugates upon the induction of BPO-specific IgE immune response was investigated in BALB/c and C3H mice. Bovine gamma-globulin (BGG) and ovalbumin (OA) were employed as carrier proteins. In both strains of mice, moderately substituted conjugates (BPO19-BGG, and BPO-OA with an epitope density from 2 to 7.5) elicited a persistent BPO-specific IgE, while heavily substituted conjugates (BPO38-BGG) induced only a transient response. In contrast, lightly substituted conjugates (BPO3.2-, BPO9.5-BGG, and BPO1-OA) failed to produce BPO-specific IgE antibodies. There was no significant difference in carrier-specific IgE immune response among these various conjugates. These results suggest that moderately substituted hapten-protein conjugates are one of the favorable conditions for eliciting hapten-specific IgE immune response in mice.  相似文献   
113.
Migrant workers known in Japanese as "dekasegi" refer to workers who migrate seasonally from their town of residence to areas where work is readily available. The eastern part of Toyama Prefecture is well known as a source of migrant workers who engage in jobs associated with dust exposure such as tunnel projects. Most of these workers suffered from silicosis. A total of 695 migrant workers suffering from silicosis who had underwent health screening between 1977 and 1982 were followed until the end of 1983. For cases of death, the cause and date of death were individually confirmed on the basis of death certificates. Based on these data, the person-years of risk and cause-specific mortality rates were calculated. The mean person-years of risk per person was 4.7. During this period of observation, there were 75 deaths among these silicosis patients, giving a mortality rate of 23.0 per 1,000 person-years of risk. When classified by the Japanese roentgenographic category of pneumoconiosis, the mortality rate was 10.5 for category 1, 21.3 for category 2, 38.6 for category 3 and 49.3 for category 4. The mortality rates of categories 3 and 4 were significantly higher than those of categories 1 and 2. The highest cause-specific mortality rate among silicosis patients per 1,000 person-years was 5.2 for malignant neoplasms followed by 3.7 for pulmonary tuberculosis, 3.1 for both cardiovascular diseases and pneumoconiosis, and 2.8 for pneumonia and bronchitis. High mortality rates in the 50-69 age group were found among silicosis patients belonging to categories 3 and 4. By cause of death, the mortality rates of all malignant neoplasms (especially lung cancer), pulmonary tuberculosis, and cerebrovascular diseases were relatively high in this age group. In the 70-89 age group, the mortality rate of those belonging to categories 2, 3 and 4 was high and by cause of death the mortality rates of pneumoconiosis, pulmonary tuberculosis, all malignant neoplasms (especially lung cancer), cardiovascular diseases and pneumonia and bronchitis were high. The mortality rates of silicosis patients with abnormal findings in %VC, FEV1% and AaDO2 by pulmonary function tests tended to be higher than those of silicosis patients without such abnormalities.  相似文献   
114.
Summary Twenty-eight oligodendrogliomas and seven oligoastrocytomas were immunotested by the peroxidase-antiperoxidase (PAP) method with antiglial fibrillary acidic protein (GFAP) serum, anti-Leu 7 monoclonal antibody (Mab), anti-myelin-associated glycoprotein (MAG) Mab, anti-myelin basic protein (MBP) serum, anti-carbonic anhydrase C (CA C) serum and anti-neuron-specific enolase (NSE) serum. The immunoreactivity of their vascular pattern was studied withUlex europaeus type I lectin (UEA I). According to their morphology and distribution GFAP-positive cells were respectively interpreted as reactive astrocytes, neoplastic astrocytes and neoplastic oligodendrocytes. Reactive astrocytes were found in the tumor, around the tumor and surrounding the supporting blood vessels. Neoplastic astrocytes were mainly found in the oligoastrocytomas and usually closely intermingled with neoplastic oligodendrocytes. GFAP-positive neoplastic oligodendrocytes were found in the typical oligodendrogliomatous areas. They had central nuclei and GFA positivity was mainly found in the perinuclear cytoplasm. They correspond to the gliofibrillary oligodendrocytes described by Herpers and Budka [11]. Of the oligodendrogliomas 91% displayed Leu 7 positivity, but anti-Leu 7 cannot be considered as a specific marker for oligodendrogliomas since other neuroepithelial tumors have been reported to react with this antibody [20]. MAG-, CA C- and NSE-positivities were found in a number of tumor cells in a few oligodendrogliomas. All the tumor cells were MBP-negative, but myelin sheaths and fragments of myelin in the infiltrated white matter were clearly demonstrated by this antiserum. UEA I strikingly demonstrated the vascular pattern of the tumors, and its usefulness as a discriminating marker for the supportive endothelial cells was confirmed.Dedicated to Prof. F. Seitelberger on the occasion of his seventieth birthdaySupported by a grant from the Fondation Suisse de Bourses de Médecine et Biologie (EP) and by Research Grant CA 31271 from the National Cancer Institute, US Department of Health and Human Services (LJR)  相似文献   
115.
Summary Considering the possibility of a paracellular route for edema resolution we studied the microvasculature of the subependymal and subcortical white matter in hydrocephalic rats. Normal adult rats were used as controls. After injection of kaolin suspension into the cisterna magna, the animals were killed at intervals of 1, 2, 4, and 8 weeks. In hydrocephalic rats at 1 week after kaolin injection, widening of the interendothelical cleft between the tight junction (dehiscence) was seen in 27 of 76 (35%) vessels. At 2 weeks after kaolin injection, the number of the dehiscences had increased (39/7:56%) and some were enlarged, forming interendothelial blisters. At 4 weeks in hydrocephalic rats, both dehiscences and blisters were still prominent (45/7363%) and at 8 weeks the dehiscences were still prominent, but the number of the blisters had decreased (25/8131%). The blisters and dehiscences were most pronounced in the corpus callosum and occipital regions. Following i.v. injection of horseradish peroxidase, the interendothelial dehiscences and blisters were completely devoid of the marker substance. These findings indicate that in obstructive hydrocephalus the tight junctions may constitute part of a paracellular pathway for the resorption of interstitial edema fluid.  相似文献   
116.
Matcha, a type of green tea, has a higher amino acid content than other types of tea. We previously examined the ability of matcha to improve cognitive function in older adults and determined that continuous matcha intake improves attention and executive function. This study aimed to compare the effects of matcha and caffeine and clarify the differences between these effects. The study was registered at the University Hospital Medical Information Network (UMIN000036578). The effect of single and continuous intake was compared, and the usefulness of continuous intake was evaluated under the stress condition. The Uchida–Kraepelin test (UKT) was used to induce mild acute stress, and the Cognitrax was used to evaluate cognitive function. A single dose of caffeine improved attentional function during or after stress loading. The reduced reaction time in the Cognitrax, observed following a single dose of matcha, was likely due to caffeine. The matcha group showed an increase in the amount of work after continuous intake, whereas the caffeine group only showed an increase in the amount of work for the UKT after a single dose. Ingesting matcha with caffeine improves both attention and work performance when suffering from psychological stress compared with caffeine alone.  相似文献   
117.
Neurosurgical Review - The present study aimed to determine the incidence of intraprocedural motor-evoked potential (MEP) changes and to correlate them with intraprocedural ischemic complications...  相似文献   
118.
The inner avascular zone of the meniscus has limited healing capacity as the area is poorly vascularized. Although peptide hydrogels have been reported to regenerate bone and cartilage, their effect on meniscus regeneration remains unknown. We tested whether the self‐assembling peptide hydrogel scaffold KI24RGDS stays in the meniscal lesion and facilitates meniscal repair and regeneration in an induced rabbit meniscal defect model. Full‐thickness (2.0 mm diameter) cylindrical defects were introduced into the inner avascular zones of the anterior portions of the medial menisci of rabbit knees (n = 40). Right knee defects were left empty (control group) while the left knee defects were transplanted with peptide hydrogel (KI24RGDS group). Macroscopic meniscus scores were significantly higher in the KI24RGDS group than in the control group at 2, 4, and 8 weeks after surgery. Histological examinations including quantitative and qualitative scores indicated that compared with the control group, the reparative tissue in the meniscus was significantly enhanced in the KI24RGDS group at 2, 4, 8, and 12 weeks after surgery. Immunohistochemical staining showed that the reparative tissue induced by KI24RGDS at 12 weeks postimplantation was positive for Type I and II collagen. KI24RGDS is highly biocompatible and biodegradable, with strong stiffness, and a three dimensional structure mimicking native extracellular matrix and RGDS sequences that enhance cell adhesion and proliferation. This in vivo study demonstrated that KI24RGDS remained in the meniscal lesion and facilitated the repair and regeneration in a rabbit meniscal defect model.  相似文献   
119.
120.
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