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   19706篇
  免费   899篇
  国内免费   146篇
耳鼻咽喉   216篇
儿科学   414篇
妇产科学   150篇
基础医学   2459篇
口腔科学   343篇
临床医学   1221篇
内科学   5254篇
皮肤病学   492篇
神经病学   1620篇
特种医学   648篇
外科学   3155篇
综合类   61篇
一般理论   4篇
预防医学   441篇
眼科学   631篇
药学   1346篇
中国医学   30篇
肿瘤学   2266篇
  2023年   98篇
  2022年   267篇
  2021年   490篇
  2020年   254篇
  2019年   301篇
  2018年   372篇
  2017年   315篇
  2016年   421篇
  2015年   464篇
  2014年   561篇
  2013年   668篇
  2012年   1208篇
  2011年   1285篇
  2010年   750篇
  2009年   657篇
  2008年   1136篇
  2007年   1266篇
  2006年   1193篇
  2005年   1327篇
  2004年   1325篇
  2003年   1177篇
  2002年   1221篇
  2001年   334篇
  2000年   271篇
  1999年   355篇
  1998年   311篇
  1997年   244篇
  1996年   239篇
  1995年   211篇
  1994年   180篇
  1993年   191篇
  1992年   169篇
  1991年   135篇
  1990年   161篇
  1989年   155篇
  1988年   134篇
  1987年   97篇
  1986年   92篇
  1985年   89篇
  1984年   70篇
  1983年   74篇
  1982年   46篇
  1981年   54篇
  1980年   35篇
  1979年   55篇
  1978年   43篇
  1977年   34篇
  1974年   23篇
  1972年   18篇
  1966年   17篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
OBJECTIVE: This study retrospectively explored the late-life functional status of Okinawan centenarians. METHODS: Activities of daily living were measured retrospectively at five time points (10, 5, 3, and 1 year prior and present) for 22 centenarians in relation to seven physical, two sensory, and two cognitive functions using the Inoue Index. RESULTS: In all, 82% of individuals were still functioning independently at a mean age of 92 years and almost two-thirds were still functioning independently at a mean age of 97 years. CONCLUSION: Preliminary analyses suggest high functional status in Okinawan centenarians throughout their 90 s. The genetic and environmental factors contributing to this successful aging phenomenon deserve further investigation.  相似文献   
32.
Transrectal hyperthermia was performed on 30 patients with benign prostatic hyperplasia twice a week for a total of ten times with the temperature of the prostatic tissue set at 43.0 degrees C. In our in vitro experiment using an agar phantom, the highest temperature was observed at approx. 1.5 cm from the point where the 915-MHz microwave was generated. Our histopathological study of the prostatic tissue, resected at open surgery after three days of hyperthermia, indicated that the effect of hyperthermia first occurred in the interstitial tissues, and then extended to the epithelial cells. Subjective symptoms and objective findings were evaluated. In almost all cases, improvement was observed in subjective symptoms after completion of the treatment. The residual urine volume improved significantly. Also, significant improvement was observed in our urodynamics study. In 16 out of 30 cases (53%), both subjective symptoms and objective findings were still improved after six months.  相似文献   
33.
A 75‐year‐old male was admitted to the gastroenterology unit of Nagoya City University Hospital due to epigastralgia after surgical treatment for right renal cancer. Endoscopy revealed advanced type 1 gastric cancer in the corpus of the stomach and multiple polypoid lesions in the stomach and duodenum. X‐ray examination of the small intestine using barium showed multiple polyps in the upper jejunum. Faint pigmentation on the palm was also detected. Peutz‐Jeghers syndrome (PJS) was diagnosed, despite a lack of family history. Total gastrectomy, resection of part of the upper jejunum and intraoperative endoscopic polypectomy of duodenal polyps was performed. This is the second reported case of PJS associated with renal cancer. We also detected a missense mutation in the tumor suppressor gene STK11 that, when mutated, is causative for PJS.  相似文献   
34.
1. This study was undertaken to evaluate the preventive effects of locally administered argatroban, a competitive inhibitor of thrombin-induced platelet activation, on restenosis after balloon angioplasty. 2. A hydrogel-coated balloon catheter was immersed three times in argatroban/saline solution (1 mg/mL) for 60 s, inflated to a pressure of 606 kPa and left in the rabbit common carotid artery for 1 min. The same procedure was performed, without drug, as a control. The pharmacokinetics of delivered argatroban in the arterial wall were assessed using [14C]-argatroban. Platelet deposition 2h after balloon injury was quantified by fluorescence studies using antiplatelet antibody. Vascular smooth muscle cell (VSMC) proliferation 3 days after balloon injury was assessed by immunohistochemical staining for proliferative cell nuclear antigen (PCNA). In a clinical study, we divided 50 elective patients into two groups: argatroban and control. 3. In the experimental study, the mean quantities of argatroban at 0, 2 and 6 h after deflation wer. 24.63, 0.49 and 0.11 nmol/g wet weight of artery, respectively. Argatroban was undetected 24 h after deflation. Two hours after deflation, argatroban-treated arteries showed less platelet adhesion than saline-treated controls. The mean number of PCNA-positive cells was 16.9 and 43.8% in the argatroban and control groups, respectively (P < 0.01). In the clinical study, the mean late gain loss was 8.2 and 27.3% in the argatroban and control groups, respectively (P < 0.05). The mean late restenosis rate was 11.1 and 41.4% in the argatroban and control groups, respectively (P<0.05). 4. These data suggest that blood coagulation plays a significant role in VSMC proliferation after balloon injury and that locally administered argatroban using hydrogel-coated balloon catheter may prevent post-percutaneous transluminal coronary angioplast. restenosis.  相似文献   
35.
Background: The effects of inhalational anesthetics on the microcirculation, including leukocyte dynamics, remain to be clarified. The authors investigated halothane and sevoflurane anesthesia to determine if these agents evoked leukocyte adhesion through endothelial cell-dependent mechanisms involving such adhesion molecules.

Methods: Rats were anesthetized with halothane or sevoflurane in 100% oxygen and the lungs were mechanically ventilated. Leukocyte behavior in mesenteric venules was recorded through intravital video microscopy under monitoring microvascular hemodynamics. To examine the mechanisms for leukocyte rolling and adhesion, these studies were repeated after animals were pretreated with a monoclonal antibody against P-selectin (MAb PB1.3) or against intracellular adhesion molecule-1 (ICAM-1; MAb 1A29): P-selectin required for rolling of circulating leukocytes and ICAM-1 for firm adhesive interactions with leukocyte integrins.

Results: Under baseline anesthetic conditions (1 minimum alveolar concentration [MAC]), venular wall shear rates, an index of the disperse force on marginating leukocytes, in the sevoflurane-treated rats were about two times higher than those with halothane. At 2 MAC, halothane caused a marked arteriolar constriction and decreasing shear rates concurrent with an increasing density of venular leukocyte adhesion. Sevoflurane at 2 MAC induced leukocyte rolling and adhesion, which were attenuated by PB1.3 and 1A29, without alterations in the wall shear rates. Halothane-induced leukocyte adhesion was not prevented by PB1.3 but it was by 1A29.  相似文献   

36.
We used morphological, biochemical and immunohistochemical methods to assess the response of Müller cells after experimental lensectomy-vitrectomy in rabbits. We observed widened intercellular spaces between the Müller cells and nerve fibers of ganglion cells, and increased electron opacity in the Müller cells of eyes injected with silicone oil. No apparent morphological changes were detected in the Müller cells of air-injected eyes. The specific and total activities of Müller cell-marker enzymes (glucose 6-phosphatase and glutamine synthetase) showed an initial increase, followed by a decrease. Glial fibrillary acidic protein immunoreactivity was not found in the Müller cells of the normal rabbit retina but was exhibited after surgery. Our results showed that markers of Müller cells associated with glycogenolysis and/or gluconeogenesis, glutamate-glutamine cycle and cytoskeletal protein metabolism were affected by the experimental lensectomy-vitrectomy.  相似文献   
37.
The present study was designed to investigate the presynaptic alpha 2-adrenoceptor function to inhibit norepinephrine (NE) release in blood vessels of reduced renal mass salt hypertensive rats (Na-loaded HT). Isolated perfused mesenteric vasculatures were prepared from Na-loaded HT and normotensive control rats (NT-control), and the NE release and vascular responsiveness were examined. Periarterial nerve stimulation caused a significantly greater release of NE and pressor responses in Na-loaded HT than in NT-control. Yohimbine, a potent alpha 2-adrenoceptor antagonist, demonstrated the facilitatory effects on NE release during nerve stimulation. The effects were significantly attenuated in Na-loaded HT compared with NT-control. These results demonstrate that vascular sympathetic nervous activity might be enhanced in Na-loaded HT. Furthermore, the increased NE release from vascular adrenergic neurons in Na-loaded HT could partially depend on impaired presynaptic alpha 2-adrenoceptor-mediated modulation, which might contribute to the pathogenesis and maintenance of this form of salt-dependent hypertension.  相似文献   
38.
We experienced a case of mediastinal lipoma, which is considered to be a relatively rare disease. A 3-year-old girl was referred to Gifu University hospital because of fever and an abnormal shadow on her chest X-ray. The chest X-ray clearly showed a well-delineated tumor shadow which seemed to oppress the diaphragm and the right atrium in the right lower lung area. A computed tomogram (CT) of the chest showed a homogeneous mass localized on the right diaphragm and adjoining the right anterior chest wall and heart. The mass showed a fat density measuring about-100 HU. Magnetic resonance imaging (MRI) showed a high-intensity mass which was almost the same level as the subcutaneous fat on both the T1-weighted and T2-weighted images. Thoracotomy was performed and a fatty tumor was found. It arose from the right side of the pericardium and adjoined the diaphragm, the anterior chest wall, and the thymus. There was no adhesion between the tumor and the surrounding organs. It was resected easily and its contents were yellowish and homogeneous. The patient made an uneventful recovery and was discharged 10 days after the operation. Light microscopy showed a lipoma consisting of mature adipose tissue and no malignancy was found.  相似文献   
39.
40.
In order to determine predictive factors of early seizures (ES) after acute stroke and to estimate prognosis, we retrospectively examined clinical data of 1,743 consecutive patients with acute ischemic stroke. The subjects were divided into two groups; an ES group (19 patients) and a non-ES group (1,724 patients). Multivariate statistical analysis revealed that the NIH-Stroke Scale score on admission (/10, OR, 1.1: 95% CI 1.04 to 1.13) and positive past history of cerebrovascular disease or brain injury (OR, 3.85: 95% CI 1.49 to 9.95) are significant factors to predict ES. There was no significant difference in the outcome between the two groups. A recurrence of seizures, after follow up for 4 to 40 months, was observed only in one patient with a history of ES.  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