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   2545篇
  免费   92篇
  国内免费   8篇
耳鼻咽喉   10篇
儿科学   42篇
妇产科学   16篇
基础医学   323篇
口腔科学   58篇
临床医学   169篇
内科学   686篇
皮肤病学   37篇
神经病学   214篇
特种医学   115篇
外科学   378篇
综合类   5篇
预防医学   79篇
眼科学   49篇
药学   216篇
中国医学   10篇
肿瘤学   238篇
  2024年   3篇
  2023年   9篇
  2022年   21篇
  2021年   39篇
  2020年   22篇
  2019年   32篇
  2018年   29篇
  2017年   23篇
  2016年   40篇
  2015年   41篇
  2014年   64篇
  2013年   86篇
  2012年   127篇
  2011年   143篇
  2010年   79篇
  2009年   74篇
  2008年   120篇
  2007年   150篇
  2006年   154篇
  2005年   182篇
  2004年   174篇
  2003年   184篇
  2002年   168篇
  2001年   58篇
  2000年   39篇
  1999年   52篇
  1998年   52篇
  1997年   41篇
  1996年   37篇
  1995年   37篇
  1994年   35篇
  1993年   29篇
  1992年   46篇
  1991年   32篇
  1990年   26篇
  1989年   34篇
  1988年   28篇
  1987年   27篇
  1986年   22篇
  1985年   17篇
  1984年   12篇
  1983年   10篇
  1982年   13篇
  1981年   4篇
  1980年   3篇
  1979年   7篇
  1976年   4篇
  1975年   2篇
  1974年   3篇
  1964年   2篇
排序方式: 共有2645条查询结果,搜索用时 15 毫秒
41.
Aim: In Caucasians in northern Europe and North America, type 1 autoimmune hepatitis is characterized by susceptibility to human leukocyte antigens DR3 and DR4, and patients with zone III necrosis more frequently have an acute onset of the disease and a lower frequency of cirrhosis than those without. In Japanese patients, however, type 1 autoimmune hepatitis is primarily associated with DR4, and there are almost no DR3-positive patients. Thus, the clinical features of Japanese patients with type 1 autoimmune hepatitis and zone III necrosis may be different from those reported previously for Caucasians. Methods: We investigated 160 consecutive patients with type 1 autoimmune hepatitis (20 males and 140 females; median age, 55 years; range, 16-79 years). Results: Forty-seven patients (29%) had zone III necrosis, and these patients had lower serum levels of albumin and higher serum levels of total bilirubin, aspartate aminotransferaseand alanine aminotransferase. Histologically, zone III necrosis was found more frequently in patients with acute hepatitis than in those with chronic hepatitis. However, there was no difference in the frequency of cirrhosis between patients with and without zone III necrosis. In addition, normalization of serum alanine aminotransferase levels within six months after the introduction of corticosteroid treatment was slightly more frequent in patients with zone III necrosis (95% vs. 88%). Conclusion: In Japanese patients, zone III necrosis may reflect not only acute autoimmune hepatitis, but also acute exacerbation of pre-existing chronic disease. Furthermore, patients with zone III necrosis may respond better to corticosteroid treatment than those without.  相似文献   
42.
OBJECTIVE: To evaluate the long-term effects of pulmonary rehabilitation in elderly COPD patients, we monitored patients for 1 year after they completed a 2-week inpatient pulmonary rehabilitation program. We also compared the effects of pulmonary rehabilitation on young-elderly (age 65-74 years) and old-elderly (age 75 years or over) COPD patients. METHODOLOGY: Fifty-nine elderly COPD patients (mean age 72.8 years) were studied. They underwent a comprehensive 2-week inpatient pulmonary rehabilitation program incorporating 10 exercise sessions, each of which included endurance training of the lower extremities, peripheral muscle conditioning training of the upper and lower extremities, and stretching, along with various education sessions. The effects of pulmonary rehabilitation were evaluated at 3, 6, and 12 months after completion of the program. RESULTS: Overall, patient health-related quality of life (HRQoL) as assessed by a QoL scale, and dyspnoea as assessed by an oxygen cost diagram, improved significantly over the 12-month period. Exercise capacity assessed by a 6-min walking distance test (6MWD) was similarly significantly improved. However, there was some fall-off in terms of the distance walked 12 months after pulmonary rehabilitation. The improvements in exercise capacity, dyspnoea, and HRQoL did not differ between the two groups, with the exception that the 6MWD (P < 0.01) and the QoL scale (P < 0.05) at 3 months post-pulmonary rehabilitation were significantly higher in the old-elderly group. CONCLUSIONS: Pulmonary rehabilitation is an effective treatment in terms of improving dyspnoea, exercise capacity and HRQoL in elderly COPD patients, and the benefits are almost comparable for young-elderly and old-elderly patients.  相似文献   
43.
Fifty-six lambda gt11-random-primed-cDNA recombinants of which translation products react with antibodies in the serum drawn from patients with hepatitis C (blood-borne non-A, non-B hepatitis) were cloned from serum pooled from donors presumably infected with hepatitis C. The specificity of these clones for hepaitits C infection was determined using 3 test panels. Of these 29 clones were determined to be specific for Japanese hepatitis C infection. However one of the 29 clones was positive for 1 out of 5 normals in an American test panel while 12 clones were positive for the American panel as well. The remaining 28 clones reacted well with serum from transfusion associated chronic hepatitis C comparing to the sporadic cases in the Japanese panel. When they were tested with normal donors, another clone reacted with a distinct donor group with which the other clones did not react. These results may suggest the presence of heterogeneity in Japanese hepatitis C.  相似文献   
44.
45.
In a 43-year-old Japanese Brazilian who came to Japan in 2001, since subjective symptoms such as cough, sputum, and dyspnea on exertion had become severe, he was referred to our hospital because of suspicion of pulmonary tuberculosis in chest radiography and CT findings. A chest radiograph of initial examination showed interstitial shadows in both lungs with nodular, infiltrative or cavitary changes. No Mycobacterium tuberculosis was found. The mycetocyte with multipolar budding resembling the steerage of a ship, which was characteristic of Paracoccidioides was observed in sputum and transbronchial lung biopsy specimens. We cultured a fungus to show dimorphism of temperature dependency, and a diagnosis of chronic lung paracoccidioidomycosis was arrived at. By administration of ITCZ 200 mg/day, the chest radiography findings and clinical manifestations were improved. This case seems to be worthy of reporting in Japan since the affected site or organ was limited to the two lungs with multiple cavitary lesions and fibrotic changes on radiographic examination, and final diagnosis was made by cytology of sputum and pathology of TBLB specimens.  相似文献   
46.
This study was designed to clarify the mechanism of tolerance that occurs during prolonged administration of a beta-agonist in relation to membrane phospholipid degradation and to elucidate the effect of diltiazem, a calcium antagonist. Guinea pigs were divided into 3 groups: (1) control—physiological saline (0.5 ml) was injected once a day for 7 successive days; (2) metaproterenol (Mp)—Mp was injected intraperitoneally (10 mg/kg/day) for 7 successive days; (3) Mp + diltiazem—diltiazem was injected intraperitoneally (20 mg/kg/day) 30 min before Mp injection for 7 successive days. The number of beta-adrenoceptors and the 10−5 M (−)-isoproterenol-stimulated adenylate cyclase activity were significantly decreased in the metaproterenol group. Diltiazem reduced these decreases. Phospholipase activity was increased and phosphatidylcholine and phosphatidylethanolamine levels were decreased in the metaproterenol group. Diltiazem also reduced these changes. These results suggest that the degradation of membrane phospholipids by phospholipase may be involved in a decrease in beta-adrenergic response caused by successive administration of metaproterenol. Diltiazem protects membrane phospholipids from phospholipase attack, which in turn maintains beta-adrenergic responsiveness. Part of this study was presented at the Annual Meeting of the American Thoracic Society, May 12, 1987, New Orleans, Louisiana  相似文献   
47.
48.
BackgroundCUL3 encodes cullin-3, a core component of a ubiquitin E3 ligase. CUL3 mutations have recently been associated with autism spectrum disorder (ASD); however, the detailed clinical courses have been described in only a limited number of patients with CUL3 mutations and neurodevelopmental diseases, including ASD.Case reportA 21-month-old Japanese girl presented with febrile status epilepticus and thereafter exhibited developmental regression, including loss of her verbal ability, eye contact, and skills in activities of daily living. Trio-based exome sequencing identified a de novo two-base insertion in CUL3, c.1758_1759insTG, p.(Thr587*).ConclusionWe report a case of a patient with ASD and a stop-gain CUL3 variant. Screening of CUL3 variants is worth considering for patients with ASD, especially those with Rett-like developmental regression.  相似文献   
49.
Giant vesicles (GVs) have attracted attention as functional materials because they can encapsulate both hydrophilic and hydrophobic compounds. For next generation functional GVs, both tolerance and stimuli-sensitivity are needed. So far, vesicles tolerant to acidic or basic conditions were generated using a mixture of cationic lipids and fatty acids. Here, to create functional GVs that are tolerant to a wide pH range but sensitively respond at below a specific pH, the behaviour of GVs composed of a cationic lipid with an imine bond and oleic acid was investigated. Even though the GVs prepared by the film swelling method were tolerant to strongly acidic conditions, GVs without oleic acid gradually shrank, accompanied by the generation of oil droplets at the same pH. 1H NMR analysis revealed that during hydration of the film, the imine bond hydrolysed to provide a cationic surfactant and an oil component in the presence of oleic acid due to its own Lewis basicity, suggesting the dissociation of oleic acid. The results of fluorescence spectroscopy using an environment-responsive probe and IR spectroscopy indicated that the GV tolerance originated from the intermolecular interactions of cationic lipids and anionic oleate.

Giant vesicles composed of cationic lipids having an imine linkage and oleic acid were stable at strong acidic conditions.  相似文献   
50.
A 52-year-old man without a history of asthma or allergic diseases died of ventricular fibrillation early in the morning. His autopsy revealed no significant findings, except for a mild mural-thickening localized at the proximal region of the right coronary artery. Microscopic examination showed periarteritis with infiltration of numerous eosinophils in the adventitia. No significant vasculitis was found in any other organs. Based on the findings this seems to be the second reported case of isolated eosinophilic coronary periarteritis.  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