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   12746篇
  免费   682篇
  国内免费   42篇
耳鼻咽喉   89篇
儿科学   432篇
妇产科学   234篇
基础医学   1673篇
口腔科学   212篇
临床医学   988篇
内科学   3183篇
皮肤病学   199篇
神经病学   1310篇
特种医学   661篇
外科学   1643篇
综合类   30篇
一般理论   1篇
预防医学   564篇
眼科学   110篇
药学   898篇
中国医学   16篇
肿瘤学   1227篇
  2023年   50篇
  2022年   53篇
  2021年   241篇
  2020年   154篇
  2019年   211篇
  2018年   251篇
  2017年   194篇
  2016年   229篇
  2015年   239篇
  2014年   372篇
  2013年   480篇
  2012年   688篇
  2011年   777篇
  2010年   422篇
  2009年   386篇
  2008年   645篇
  2007年   679篇
  2006年   596篇
  2005年   571篇
  2004年   530篇
  2003年   501篇
  2002年   488篇
  2001年   399篇
  2000年   411篇
  1999年   421篇
  1998年   143篇
  1997年   105篇
  1996年   96篇
  1995年   85篇
  1994年   84篇
  1993年   79篇
  1992年   273篇
  1991年   259篇
  1990年   264篇
  1989年   249篇
  1988年   188篇
  1987年   164篇
  1986年   183篇
  1985年   207篇
  1984年   120篇
  1983年   97篇
  1982年   67篇
  1981年   47篇
  1979年   107篇
  1977年   56篇
  1976年   53篇
  1975年   53篇
  1974年   47篇
  1973年   56篇
  1971年   47篇
排序方式: 共有10000条查询结果,搜索用时 481 毫秒
1.
2.
3.
4.
5.
Migration of Kirschner (K) wires from the upper extremity joints has often been reported, but it is less common from the lower extremities. In this report, we describe an 85-year-old man treated, during a hip replacement procedure, with a K-wire because of a trochanteric fracture; after one year, the K-wire was found in the popliteal fossa. This report illustrates the first case of K-wire migration in the popliteal area of the knee and suggests avoiding the use of free K-wires without any tension banding.  相似文献   
6.
Eledoisin has been tried as a possible treatment for dry eye based on the hypothesis that it pharmacologically stimulates tear secretion when topically applied to the eye. To determine if topically applied eledoisin pharmacologically stimulates orbital lacrimal secretion, the orbital lacrimal gland excretory duct of normal rabbits was cannulated, and eledoisin was applied topically with and without prior administration of proparacaine. To determine if topically applied eledoisin stimulated accessory lacrimal gland secretion, isotonic buffer with and without eledoisin was tested in a rabbit model with only accessory lacrimal tissue remaining after the administration of proparacaine. Topically applied eledoisin did not pharmacologically stimulate lacrimal secretion but rather increased lacrimal gland secretion only in non-anesthetized eyes through a sensory reflex mechanism that is blocked by proparacaine.  相似文献   
7.
A Serra  G Polese  C Braggion    A Rossi 《Thorax》2002,57(1):50-54
BACKGROUND: Patients with advanced cystic fibrosis can benefit from non-invasive positive pressure ventilation (NPPV) for the treatment of acute decompensation as well as for the management of chronic respiratory failure. This study was undertaken to compare the physiological effects of non-invasive proportional assist ventilation (PAV) and pressure support ventilation (PSV) on ventilatory pattern, transcutaneous blood gas tensions, and diaphragmatic effort in stable patients with cystic fibrosis and chronic CO2 retention. METHODS: In 12 patients two periods of spontaneous breathing were followed randomly by PSV (12 (3) cm H2O) and PAV (flow assist 4.9 (1.3) cm H2O/l.s, volume assist 18.9 (5.1) cm H2O/l) set for the patient's comfort and administered for 40 minutes with 2 cm H2O continuous positive airway pressure. Ventilatory pattern, transcutaneous blood gas tensions, and surface diaphragmatic electromyography were measured in the last 10 minutes of each application. RESULTS: On average, both PSV and PAV improved ventilation (+30%), tidal volume (+30%), and transcutaneous CO2 (-7%) while reducing diaphragmatic activity (-30% with PSV, -20% with PAV). Mean inspiratory airway pressure was lower during PAV than during PSV (9.7 (1.9) and 12.9 (2.7) cm H2O, respectively; p<0.05). The mean coefficient of variation of tidal volume was about 20% (range 11-39%) during spontaneous breathing and did not change with either PAV or PSV. CONCLUSIONS: These results show that short term administration of nasal PAV and PSV to patients with stable cystic fibrosis with chronic respiratory insufficiency is well tolerated, improves ventilation and blood gas tensions, and unloads the diaphragm.  相似文献   
8.
An endoscopic endonasal approach was performed to remove an intra-suprasellar Rathke's cleft cyst. Rathke's cleft cyst are benign lesions, rarely diagnosed because they are often asymptomatic. To the best of our knowledge, at least 475 cases of Rathke's cleft cysts have been reported. They seem to arise from remnants of Rathke's pouch, an invagination of the stomodeum. A 52-year-old woman, complaining of bilateral frontal headaches, was operated on by using an endoscopic endonasal approach, for an intra-suprasellar tumor. The pre-operative diagnosis was non-functioning pituitary adenoma. Intra-operatively a creamy-coloured viscous tissue was found. After the removal of the cyst contents and of the capsule, the suprasellar structures were seen well. The chiasmatic cistern, the chiasm, the pituitary stalk and the pituitary gland were visualized with 0 and 30 degree endoscopes. The pathological findings showed a well-differentiated cuboidal epithelium. The diagnosis was Rathke's cleft cyst. No post-operative complications were observed. The endoscopic technique was particularly suitable in this case, both for the Rathke's cleft features and for an excellent outcome. The Rathke's cleft cyst was easily removed by suction and the cyst wall was entirely removed with curettes and pituitary punches. The hypophysis was distinguished from the cyst and was preserved. The surgical manoeuvres were all done under direct visual control. The absence of nasal packing and of breathing difficulties made comfortable the post-operative outcome. Thus, the endoscopic endonasal approach can be considered the favourite technique in case of either intra- and/or suprasellar Rathke's cleft cysts.  相似文献   
9.
Clinical and biological data were evaluated using Desu univariate analyses or Cox multivariate analyses in a series of 1,777 chronic lymphocytic leukemia (CLL) patients from an Italian Cooperative Group. In univariate analyses, age and sex of patients, presence of bone marrow (BM; greater than or equal to 50%), and peripheral blood (PB; greater than or equal to 60,000/microL) lymphocytosis, anemia (hemoglobin [Hb] less than 11 g/dL), thrombocytopenia (less than 100,000/microL), direct Coombs' test positivity, hepatomegaly, splenomegaly, and extent of lymph node involvement were shown to be of significant prognostic value. Multivariate analyses, through a stepwise procedure, showed that the most important prognostic variables are Hb, hepatomegaly, lymph node involvement, PB lymphocytosis, and age and sex of patients. Further covariates would produce an improvement having a nonsignificant P value. Based on the results of multivariate analyses, a four-step staging using the significant variables of the Cox model is proposed.  相似文献   
10.
This study aimed to assess the ability of global and local systolic parameters measured with gated blood-pool SPECT (GBPS) to diagnose and characterize the severity of diffuse or localized arrhythmogenic right ventricular dysplasia (ARVD). METHODS: Fifty-nine subjects with symptomatic ventricular arrhythmias were prospectively included in the study. With the International Society and Federation of Cardiology criteria for ARVD as a gold standard, these subjects were classified as subjects without ARVD (21 control subjects) and patients with localized ARVD (16 patients) or diffuse ARVD (22 patients). Right ventricular volumes, right ventricular ejection fractions (EF), the SD of local EF (sigma-EF), and the SD of the local times of end systole (sigma-TES) were computed from GBPS data and compared among the groups in the study population. RESULTS: sigma-EF did not differ between control subjects and patients with diffuse or localized ARVD. Right ventricular EF and volumes differed between patients with diffuse ARVD and control subjects, with similar areas under the receiver-operating-characteristic curves, but right ventricular EF and volumes failed to differentiate patients with localized ARVD. In contrast, sigma-TES differed between patients with diffuse or localized ARVD and control subjects. Regression analysis showed that the systolic parameter most strongly associated with the diagnosis of ARVD was sigma-TES. The probabilities of a randomly chosen patient in the diffuse ARVD group and of a randomly chosen patient in the localized ARVD group having sigma-TES values greater than that of a randomly chosen control subject were 98.5% and 96.7%, respectively. For the diagnosis of localized ARVD, a threshold of 80 ms for sigma-TES corresponded to sensitivity, specificity, and positive and negative predictive values of 100%, 81%, 80%, and 100%, respectively. CONCLUSION: With GBPS, both diffuse ARVD and localized ARVD can be accurately diagnosed by computing sigma-TES for all of the pixels on the surface of the right ventricle.  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