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   707篇
  免费   70篇
  国内免费   3篇
耳鼻咽喉   1篇
儿科学   13篇
妇产科学   4篇
基础医学   75篇
口腔科学   19篇
临床医学   64篇
内科学   230篇
皮肤病学   9篇
神经病学   117篇
特种医学   12篇
外科学   69篇
综合类   6篇
预防医学   30篇
眼科学   11篇
药学   38篇
中国医学   1篇
肿瘤学   81篇
  2023年   13篇
  2022年   25篇
  2021年   49篇
  2020年   25篇
  2019年   30篇
  2018年   35篇
  2017年   24篇
  2016年   24篇
  2015年   32篇
  2014年   24篇
  2013年   33篇
  2012年   42篇
  2011年   59篇
  2010年   18篇
  2009年   17篇
  2008年   31篇
  2007年   17篇
  2006年   30篇
  2005年   22篇
  2004年   17篇
  2003年   30篇
  2002年   30篇
  2001年   21篇
  2000年   19篇
  1999年   22篇
  1998年   5篇
  1997年   3篇
  1996年   8篇
  1995年   6篇
  1993年   9篇
  1992年   12篇
  1991年   8篇
  1990年   5篇
  1989年   9篇
  1988年   6篇
  1987年   9篇
  1986年   4篇
  1985年   1篇
  1984年   1篇
  1983年   3篇
  1979年   2篇
排序方式: 共有780条查询结果,搜索用时 15 毫秒
11.
12.
X-ray radiotherapy activates tumor antigen-specific T-cell responses, and increases in the serum levels of high mobility group box 1 (HMGB1) induced by X-ray irradiation play a pivotal role in activating anti-tumor immunity. Here, we examined whether carbon-ion beams, as well as X-rays, can induce HMGB1 release from human cancer cell lines. The study examined five human cancer cell lines: TE2, KYSE70, A549, NCI-H460 and WiDr. The proportion of cells surviving X- or carbon-ion beam irradiation was assessed in a clonogenic assay. The D10, the dose at which 10% of cells survive, was calculated using a linear–quadratic model. HMGB1 levels in the culture supernatants were assessed by an ELISA. The D10 dose for X-rays in TE2, KYSE70, A549, NCI-H460 and WiDr cells was 2.1, 6.7, 8.0, 4.8 and 7.1 Gy, respectively, whereas that for carbon-ion beams was 0.9, 2.5, 2.7, 1.8 and 3.5 Gy, respectively. X-rays and carbon-ion beams significantly increased HMGB1 levels in the culture supernatants of A549, NCI-H460 and WiDr cells at 72 h post-irradiation with a D10 dose. Furthermore, irradiation with X-rays or carbon-ion beams significantly increased HMGB1 levels in the culture supernatants of all five cell lines at 96 h post-irradiation. There was no significant difference in the amount of HMGB1 induced by X-rays and carbon-ion beams at any time-point (except at 96 h for NCI-H460 cells); thus we conclude that comparable levels of HMGB1 were detected after irradiation with iso-survival doses of X-rays and carbon-ion beams.  相似文献   
13.
Lymphangioma of the mesocolon is very rare. We report two cases of surgically resected and histologically proven mesocolic lymphangioma in adults. In both cases, ultrasound revealed a large cystic mass with multiple thin septa in the lower abdomen. A peculiar finding was the large craniocaudal sliding movement of the mass synchronized with the patient's respiration, which was a clue to the diagnosis of mesenteric lymphangioma. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 46 :78–81, 2018;  相似文献   
14.
A 44-year-old man diagnosed with idiopathic dilated cardiomyopathy was admitted to our hospital with acute decompensated heart failure. Seven years before this admission, the first introduction of medication resulted in left ventricular (LV) recovery, which was sustained for several years. However, the patient stopped taking his medication, resulting in worsening of the LV function. Despite the second introduction of medication, the LV function did not improve. We performed cardiac magnetic resonance imaging and an endomyocardial biopsy, which revealed the significant development of cardiac fibrosis that had not been present at the time of the initial diagnosis.  相似文献   
15.
A 69-year-old man was admitted to our hospital for progressive muscle weakness in both lower limbs and limb ataxia (day 0). Nerve conduction studies showed low compound muscle action potential amplitudes at rest and increased amplitudes after maximum voluntary contraction. Blood testing revealed SOX-1 antibodies. He was diagnosed with paraneoplastic cerebellar degeneration and Lambert-Eaton myasthenic syndrome (PCD-LEMS). He died from aspiration pneumonia on day 9. Small-cell lung carcinoma (SCLC), which had not been obvious on computed tomography, was found during the autopsy. Patients with PCD-LEMS who test positive for SOX-1 antibodies should be carefully evaluated for SCLC.  相似文献   
16.
An 80-year-old woman was admitted with cardiogenic shock; she arrived in a deep coma with systolic blood pressure of 44 mmHg. An electrocardiogram showed ST elevation in I, aVL, V5 and V6, suggesting myocardial infarction in the lateral area of the left ventricle. A chest roentgenogram showed right pulmonary edema without cardiomegaly. Transthoracic and transesophageal echocardiograms revealed severe mitral regurgitation and a flailing anterior mitral valve leaflet, suggesting a ruptured papillary muscle. The patient was initially treated with high-dose dopamine, dobutamine and norepinephrine. Intraaortic balloon pumping was initiated after the patient's condition stabilized. She underwent emergency mitral valve replacement with a prosthetic valve. Complete rupture of the anterior papillary muscle was confirmed. Histological examination revealed necrosis of the anterior papillary muscle with inflammatory changes. She recovered uneventfully. Postoperative coronary angiography demonstrated subtotal occlusion of the first diagonal branch, and left ventriculography demonstrated akinesis of the lateral segment. This was a rare case in which subtotal occlusion of the first diagonal branch caused rupture of an anterior papillary muscle leading to severe mitral regurgitation.  相似文献   
17.

Background

Hyperthymic temperament has been generally accepted as one of premorbid temperament of bipolar disorders. Although several studies indicate that subjects with hyperthymic temperament receive more illuminance, our recent study suggests that the threshold of brightness and darkness judgment is not different between more and less hyperthymic subjects, and that hyperthymic temperament may be associated with left inferior orbitofrontal cortex, which has been reported to be associated with bipolar disorder. Therefore, at the next stage, it can be hypothesized that hyperthymic subjects may prefer brightness (i.e., heliotropism) and thereby seek illuminance, and that percent signal changes of left inferior orbitofrontal cortex during the preference task may be associated with hyperthymic temperament scores.

Methods

We compared brightness preference and un-preference between more and less hyperthymic subjects, and investigated percent signal changes of left inferior orbitofrontal cortex during brightness preference judgment, brightness un-preference judgment, and control task by using functional Magnetic Resonance Imaging (fMRI).

Results

There were significant differences in brightness preference judgment and un-preference judgment, showing that more hyperthymic subjects preferred brighter illuminace levels and un-preferred darker illuminance levels than less hyperthymic subjects. Moreover, fMRI signal changes of left inferior orbitofrontal cortex was significantly and negatively associated with hyperthymic temperament scores.

Limitations

It is unknown why left but not right inferior orbitofrontal cortex was associated with hyperthymic temperament scores.

Conclusions

The present findings suggest that more hyperthymic subjects may prefer brightness and un-prefer darkness than less hyperthymic subjects (i.e., heliotropism), and reconfirm that hyperthymic temperament may be associated with left inferior orbitofrontal cortex, which have been reported to be associated with bipolar disorders.  相似文献   
18.
Mechanical loading of cardiac and skeletal muscles in vivo and in vitro causes rapid activation of a number of immediate-early (IE) genes and hypertrophy of muscle cells. However, little is known as to how muscle cells sense mechanical load and transduce it into intracellular signals of gene regulation. We examined roles of putative cellular mechanotransducers, mechanosensitive ion channels, the cytoskeleton, and contractile activity in stretch-induced hypertrophy of cardiac myocytes grown on a deformable silicone sheet. Using the patch-clamp technique, we found a single class of stretch-activated cation channel that was completely blocked by gadolinium (Gd3+). Inhibition of this channel by Gd3+ did not affect either the stretch-induced expression of IE genes or the increase in protein synthesis. Neither disruption of microtubules with colchicine nor that of actin microfilaments by cytochalasin D prevented the stretch-induced IE gene expression and increase in protein synthesis. Arresting contractile activity of myocytes by high K+, tetrodotoxin, or Ba2+ did not affect the stretch-induced IE gene expression. Tetrodotoxin-arrested myocytes could increase protein synthesis in response to stretch. These results suggest that Gd(3+)-sensitive ion channels, microtubules, microfilaments, and contractile activity may not be necessary for transduction of mechanical stretch into the IE gene expression and hypertrophy. The stimulus of membrane stretch may be transmitted to the cell nucleus through some mechanisms other than electrical or direct mechanical transduction in cardiac myocytes.  相似文献   
19.
Most mediastinal abscesses result from infections after thoracotomy, esophageal perforation or penetrating chest trauma. This disease is rarely caused by closed blunt chest trauma. All previously reported such cases after closed blunt chest trauma presented with hematoma and sternal osteomyelitis resulting from sternal fracture. Here we report a 15-year-old sumo wrestler who presented with an anterior mediastinal abscess without any mediastinal fracture. The mediastinal abscess resulted from the hematogenous spread of Staphylococcus aureus to a hematoma that might have been caused by a closed blunt chest trauma incurred during sumo wrestling exercises.  相似文献   
20.
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