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   12874篇
  免费   647篇
  国内免费   69篇
耳鼻咽喉   197篇
儿科学   200篇
妇产科学   166篇
基础医学   1473篇
口腔科学   533篇
临床医学   983篇
内科学   3391篇
皮肤病学   160篇
神经病学   767篇
特种医学   494篇
外科学   2217篇
综合类   50篇
预防医学   400篇
眼科学   236篇
药学   789篇
中国医学   14篇
肿瘤学   1520篇
  2023年   76篇
  2022年   104篇
  2021年   231篇
  2020年   127篇
  2019年   168篇
  2018年   206篇
  2017年   171篇
  2016年   235篇
  2015年   251篇
  2014年   318篇
  2013年   351篇
  2012年   639篇
  2011年   676篇
  2010年   396篇
  2009年   321篇
  2008年   684篇
  2007年   664篇
  2006年   734篇
  2005年   696篇
  2004年   693篇
  2003年   672篇
  2002年   677篇
  2001年   343篇
  2000年   364篇
  1999年   374篇
  1998年   173篇
  1997年   145篇
  1996年   135篇
  1995年   125篇
  1994年   134篇
  1993年   136篇
  1992年   295篇
  1991年   254篇
  1990年   207篇
  1989年   190篇
  1988年   180篇
  1987年   184篇
  1986年   161篇
  1985年   153篇
  1984年   125篇
  1983年   86篇
  1982年   58篇
  1981年   58篇
  1979年   64篇
  1978年   56篇
  1977年   40篇
  1975年   49篇
  1974年   51篇
  1971年   39篇
  1969年   49篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
Objective We have developed a surgical method for atrial septal defect repair through a limited right lateral thoracotomy in which the incision line begins 2 cm caudal from the lower angle of the scapula and ends at the midaxial line, thereby improving patient satisfaction with the cosmetic results of treatment. Methods We performed a retrospective review of 28 patients who underwent isolated atrial septal defect repair through a limited right lateral thoracotomy between January 2002 and August 2004. The mean age and mean body weight at the time of the operation were 85.8 months (range 9–236 months) and 23.0 kg (range 8.0–56.0 kg), respectively. All repaired defects were the ostium secundum type. Results There was no operative or late mortality and no late morbidity after a mean follow-up of 26 months (range 12–41 months). Echocardiography showed no residual shunt in any of the patients. The mean length of the skin incision was 7.8 cm (range 5.0–11.0 cm), and almost all the patients had satisfactory cosmetic results. Conclusion The atrial septal defect repair through a limited right lateral thoracotomy in pediatric patients showed satisfactory surgical results and excellent cosmetic results.  相似文献   
62.
We reported a 57-year-old female patient recently suffering from frequent seizures such as motionless staring and oral automatism. Electroencephalograms showed spikes in the right sphenoidal derivation and magnetic resonance images revealed an abnormal region, most likely related with a migration disorder such as a focal cortical dysplasia. She was diagnosed as mesiotemporal lobe epilepsy associated with a migration disorder. Seizure disappeared after medication therapy was done. No previous literature has described such a case, thus this is the first report of an epilepsy associated with migration disorder newly onset in a patient older than 50 years old.  相似文献   
63.
Porcine teschovirus (PTV) antigens were detected by a streptavidin‐biotin complex method in formalin‐fixed paraffin‐embedded tissues of 3‐week‐old pigs that had been inoculated intravenously with PTV Talfan strain. PTV antigens were detected in cytoplasm of nerve cells, glial cells and endothelial cells in the cerebellar nuclei, the grey matter of the midbrain, pons and medulla oblongata and the ventral horn of the spinal cord and of ganglion cells in the spinal ganglion corresponding to those lesions characterized as non‐suppurative encephalomyelitis and ganglionitis. The results of this study suggest that nerve cells of the brain stem and spinal cord and ganglion cells of the spinal ganglion permit PTV replication and represent the main target cell population of PTV. This is the first study to demonstrate PTV antigen by immunohistochemistry in formalin‐fixed paraffin‐embedded tissue specimens from pigs infected with PTV.  相似文献   
64.
Background : We have previously shown that eradication of Helicobacter pylori increases acid secretion in H. pylori -associated enlarged fold gastritis.
Aim : To investigate whether locally produced interleukin-1β is possibly involved in the inhibition of acid secretion in H. pylori gastritis.
Methods : IL-1β release from the gastric body mucosa was determined by short-term culture of biopsy specimens in 13 patients with enlarged fold gastritis (all H. pylori -positive), five H. pylori -positive and 10 H. pylori -negative patients without enlarged folds. The acid-inhibitory effect of locally produced IL-1β was examined by [14C]-aminopyrine uptake assay using isolated rabbit gastric glands.
Results : IL-1β release was significantly greater in patients with enlarged fold gastritis, significantly correlated with both basal and tetragastrin-stimulated acid outputs in the H. pylori -positive patients ( r  = −0.591 and r  = −0.641, respectively; P  < 0.01), and significantly decreased with concomitant increases in acid secretions after eradication of H. pylori . [14C]-aminopyrine uptake was inhibited by IL-1β in a dose-dependent manner.
Conclusions : Increased production of IL-1β caused by H. pylori infection is possibly involved in the inhibition of acid secretion in enlarged fold gastritis.  相似文献   
65.
A 6-year-old boy was sent to us due to basal meningoencephalocele detected by MRI. He had had a past history of strabismus and morning glory syndrome since 6 months of age, as well as hypopituitary dwarfism since he was 3 years old. On admission, physical examination revealed hypertelorism and left coloboma. Laryngoscopic examination revealed a round mass covered by normal nasal mucose in the midline of the tegmen of the choana. X-ray tomogram and CT scan demonstrated an isodense mass protruding into the nasopharyngeal cavity through a bony defect of the sella turcica. Right carotid angiogram showed stenosis of the right internal carotid artery and abnormal fine vessels in the basal ganglia similar to basal Moyamoya network. There was an irregular filling of the right anterior cerebral artery. Left carotid angiogram showed an irregular filling of the left middle cerebral artery. MRI showed an anterior part of the third ventricle descending into, and the meningocele protruding into the nasopharyngeal cavity. It also showed a stalk extending from the hypothalamus into the meningocele, but the pituitary gland was not recognized. The meningocele was of the same signal intensity as CSF in both T1 and T2 weighted images. Growth hormone deficiency was confirmed by radioimmunoassay of the peripheral blood. An operation was scheduled transcranial to prevent snoring during sleep at age 9. The stalk was observed behind the chiasm during the operation, but a radical operation was not performed because of a possibility of postoperative hypothalamic-pituitary dysfunction. Transsphenoidal encephalocele is rare. So far as we could see, only 30 cases have been reported.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
66.
The role of endoscopic retrograde cholangiopancreatography (ERCP) in the preoperative assessment of anomalous pancreaticobiliary junction was retrospectively evaluated in 74 consecutive patients (19 males and 55 females; aged 0–80 years). Sixty-three patients had congenital biliary dilatation and 11 did not. Type classification of congenital biliary dilatation was possible by ERCP alone in 45 patients (71%). The main causes of classification failure were previous bilio-enteric anastomosis and restriction of postural changes during ERCP due to general anesthesia in pediatric patients. Classification of anomalous junction was possible in 69 patients (93%). Technical difficulty in ERCP caused classification failure in 5 patients. Neoplastic lesions were found in 12 patients (16%) and all but 1 were correctly diagnosed by ERCP. We conclude that ERCP plays an important role in the preoperative diagnosis and type classification of anomalous pancreaticobiliary junction and congenital biliary dilatation.  相似文献   
67.
We describe herein a rare case of primary malignant melanoma of the rectum in an 85-year-old woman. The patient presented with intermittent rectal bleeding, and a colonoscopy revealed an ulcerated polypoid mass in the rectum, located 5 cm from the anal verge. The lesion was histologically characterized by solid growths of small round cells with scanty cytoplasm and prominent nucleoli. Although no melanin pigment was found in the tumor cells, they were immunohistochemically positive for HMB-45, a monoclonal antibody highly specific for malignant melanoma. Thus, HMB-45 proved very useful to establish a diagnosis of amelanotic malignant melanoma of the rectum.  相似文献   
68.
69.
Analysis of DNA ploidy patterns was performed on 76 diffusely infiltrating carcinomas of the stomach and the results correlated with histologic findings and outcome. Twenty six cases were diploid (34%) and 50 cases were aneuploid. There was no correlation between DNA ploidy and histologic type, depth of invasion, lymphatic invasion, evidence of peritoneal dissemination or curability. In aneuploid tumors, incidence of vascular invasion was significantly higher than that in diploid tumors (p less than 0.05). In addition, the patients with aneuploid tumors had a poor prognosis than with diploid tumors. These results indicate that DNA ploidy patterns may possibly be a useful prognostic marker for diffusely infiltrating carcinomas of the stomach.  相似文献   
70.
OBJECTIVE: The purpose of this study was to determine the association of dry mouth with oral symptoms and function, such as denture instability, discomfort, soreness in denture-bearing tissue, and dissatisfaction with chewing, tasting, or speaking in removable denture wearers. STUDY DESIGN: The subjects were 493 removable denture wearers with a mean age of 67.3 years. Perception of oral dryness was measured by a questionnaire. A multiple logistic regression analysis was used to determine the effect of the dry mouth on oral symptoms and function after controlling for age and gender. RESULTS: Oral dryness during eating was related to dissatisfaction with chewing (odds ratio, 10.5; P < .001) and speaking (odds ratio, 3.5; P < .05) and overall dissatisfaction (odds ratio, 6.3; P < .01) in complete denture wearers. Feeling of dry mouth was likely to be associated with soreness in denture-bearing tissues in both complete and removable partial denture wearers. CONCLUSIONS: There was a significant association of the perception of dry mouth among a group of denture wearers with oral symptoms and 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