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   894篇
  免费   59篇
  国内免费   9篇
耳鼻咽喉   4篇
儿科学   63篇
妇产科学   10篇
基础医学   144篇
口腔科学   2篇
临床医学   57篇
内科学   182篇
皮肤病学   2篇
神经病学   76篇
特种医学   51篇
外科学   125篇
预防医学   28篇
眼科学   127篇
药学   19篇
中国医学   3篇
肿瘤学   69篇
  2022年   7篇
  2021年   13篇
  2020年   7篇
  2019年   13篇
  2018年   20篇
  2017年   15篇
  2016年   12篇
  2015年   17篇
  2014年   25篇
  2013年   38篇
  2012年   41篇
  2011年   54篇
  2010年   19篇
  2009年   19篇
  2008年   44篇
  2007年   42篇
  2006年   49篇
  2005年   56篇
  2004年   47篇
  2003年   47篇
  2002年   43篇
  2001年   25篇
  2000年   17篇
  1999年   14篇
  1998年   9篇
  1997年   7篇
  1996年   8篇
  1995年   8篇
  1994年   5篇
  1993年   10篇
  1992年   21篇
  1991年   21篇
  1990年   18篇
  1989年   24篇
  1988年   18篇
  1987年   16篇
  1986年   15篇
  1985年   21篇
  1984年   14篇
  1983年   18篇
  1982年   5篇
  1981年   2篇
  1979年   7篇
  1978年   5篇
  1976年   3篇
  1975年   2篇
  1974年   5篇
  1973年   5篇
  1968年   3篇
  1966年   2篇
排序方式: 共有962条查询结果,搜索用时 46 毫秒
101.
Sarcopenia (SP) is a syndrome characterized by age-associated loss of skeletal muscle mass and function. SP worsens both acute and late radiation-induced toxicity, prognosis, and quality of life. Myosteatosis is a pathological infiltration of muscle tissue by adipose tissue which often precedes SP and has a proven correlation with prognosis in cancer patients. Sarcopenic obesity is considered a “hidden form” of SP (due to large fat mass) and is independently related to higher mortality and worse complications after surgery and systemic treatments with worse prognostic impact compared to SP alone. The evaluation of SP is commonly based on CT images at the level of the middle of the third lumbar vertebra. On this scan, all muscle structures are contoured and then the outlined surface area is calculated. Several studies reported a negative impact of SP on overall survival in patients undergoing RT for tumors of the head and neck, esophagus, rectum, pancreas, cervix, and lung. Furthermore, several appetite-reducing side effects of RT, along with more complex radiation-induced mechanisms, can lead to SP through, but not limited to, reduced nutrition. In particular, in pediatric patients, total body irradiation was associated with the onset of SP and other changes in body composition leading to an increased risk of cardiometabolic morbidity in surviving adults. Finally, some preliminary studies showed the possibility of effectively treating SP and preventing the worsening of SP during RT. Future studies should be able to provide information on how to prevent and manage SP before, during, or after RT, in both adult and pediatric patients.  相似文献   
102.
A 39-year-old healthy woman presented for decreased vision at distance and near for 4 years. She also noted a decrease in her color vision. Her best-corrected visual acuities were 20/70 in each eye. Her visual fields were abnormal, and she had bilateral sluggish pupils, impaired color vision, and optic disc pallor. The magnetic resonance imaging of the brain, heavy metal screen, autoimmune work-up, B12, B6, folate, erythrocyte sedimentation rate, rapid plasma reagin, and Lyme titer were all normal. Optical coherence tomography of the macula and electroretinogram were normal; the visual evoked potential was unrecordable in both eyes. She denied a family history of similar ocular issues, and genotyping of the OPA1 gene revealed a novel previously unreported mutation at IVS12+10T >C.  相似文献   
103.
Recent evidences suggest that B-cell chronic lymphocytic leukemia (B-CLL) may have heterogeneous biological and clinical features. Immunological phenotype may be useful for distinguishing these different forms of disease.

We used a quantitative flow cytometric approach to analyze the expression of several membrane molecules (CD19, CD20, CD22, CD23, CD11c, CD5, CD79b) commonly used to diagnose and characterize B-CLL in a choort of 84 consecutive B-CLL patients diagnosed according to morphological and immunological findings. We found that morphologically so-called “atypical” B-CLL displayed a significantly higher number of CD20 and CD22 molecules than typical forms. On the other hand, CD19 was found to be more expressed in typical B-CLL, although without reaching statistical significance. Finally, no difference was detected with respect to CD23, CD79b, CD11c and CD5 number of molecules/per cell between typical and atypical B-CLL. Other clinico-biological features, such as surface membrane immunoglobulin density, percentage of CD79b and FMC7 expression, peripheral blood lymphocytosis, trisomy 12 and advanced clinical stages were also found to be more frequent in atypical B-CLL. In conclusion, our data confirm the hypothesis that atypical B-CLL is a disease sustained by more mature B-cells, closely related but, at the same time, clearly distincted from neoplastic cells of typical B-CLL.  相似文献   
104.
The introduction of spiral multislice or multidetector CT (MSCT) has led to significant results in coronary diagnostic imaging. In fact with MSCT, isotropic (cubic voxel) three-dimensional imaging of large volumes (e.g. the entire cardiac volume) was possible in a single breath-hold. Moreover, with dedicated reconstruction algorithms, temporal resolution and scannable volume could be optimized, limiting the artifacts associated with the spiral technique. The quantification of calcium deposits in the coronary walls and, in particular, the morphologic study of these vessels represent an important challenge to this technique. Multislice CT with retrospective gating is now a relevant diagnostic instrument in coronary heart disease; however only most recent CT devices with 16 rows of detectors enable a real solution of problems of spatial (isotropic, submillimetric imaging) and temporal (< 0.5 s rotation time) required for correct identification of stenosis and plaque characterization, which are the two main goals of noninvasive coronary imaging.  相似文献   
105.
106.
107.
The presence of anatomical endonasal variants (concha bullosa, nasal septal deviation, or hypertrophic turbinates) may cause more complications in patients with epiphora who have external dacryocystorhinostomy (DCR). The purpose of this study was to assess the results of surgical placement of a stent in 28 patients. They were randomised into two groups and had either DCR or placement of a Song's polyurethane stent. They were followed up for 18 months. Twenty-six patients had a good result. The success rate was 13/14 for those who had DCR and 13/14 for those who had a stent. Operating time was significantly less for placing a stent (mean (SD) 15 (2) minutes) compared with 40 (3) minutes for DCR (p <0.01). Placement of a polyurethane stent is an effective and short procedure for nasolacrimal obstruction, which is suitable for patients with unusual intranasal conditions.  相似文献   
108.
Color Doppler imaging was used to evaluate a patient with gaze-induced amaurosis caused by an intraconal orbital mass. The time-velocity waveform demonstrated abnormally high vascular resistance in the central retinal artery of the affected eye in the primary position. Abduction of the affected eye resulted in transient visual loss with an unreactive pupil. This same maneuver during color Doppler imaging resulted in a dramatic reduction of blood flow in the central retinal artery. Two months after surgical excision of the mass, the gaze-evoked amaurosis was no longer present, and color Doppler imaging demonstrated normal blood flow in the central retinal artery. This suggests that impaired retinal and optic nerve blood flow are responsible for gaze-induced amaurosis from compressive orbital lesions.  相似文献   
109.
A 26-year-old woman with a Chiari-I malformation and intermittent symptoms of intracranial pressure elevation is described. Clinically, papilledema was accompanied by midperipheral retinal hemorrhages. Repeat computed tomographic scans and lumbar puncture showed normal results. Posterior fossa-directed magnetic resonance image scanning revealed the Chiari-I malformation. Intraventricular monitoring was necessary to demonstrate the marked but unsustained elevation of intracranial pressure.  相似文献   
110.
Bilateral acute visual loss characterized by cecocentral scotomas and acquired dyschromatopsia developed in a patient receiving large oral doses of ciprofloxacin hydrochloride (Cipro). The visual defects improved after cessation of this antibiotic. To our knowledge, this association has not been described previously. The use of this medication in high doses must be accompanied by careful monitoring of optic nerve function.  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