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   18130篇
  免费   999篇
  国内免费   99篇
耳鼻咽喉   130篇
儿科学   325篇
妇产科学   330篇
基础医学   2992篇
口腔科学   384篇
临床医学   1466篇
内科学   3297篇
皮肤病学   711篇
神经病学   1983篇
特种医学   1258篇
外科学   2308篇
综合类   80篇
一般理论   6篇
预防医学   736篇
眼科学   309篇
药学   1720篇
中国医学   23篇
肿瘤学   1170篇
  2023年   63篇
  2022年   130篇
  2021年   208篇
  2020年   191篇
  2019年   233篇
  2018年   250篇
  2017年   246篇
  2016年   323篇
  2015年   412篇
  2014年   495篇
  2013年   638篇
  2012年   976篇
  2011年   1122篇
  2010年   692篇
  2009年   701篇
  2008年   1138篇
  2007年   1206篇
  2006年   1163篇
  2005年   1142篇
  2004年   1128篇
  2003年   1178篇
  2002年   1135篇
  2001年   243篇
  2000年   174篇
  1999年   254篇
  1998年   306篇
  1997年   256篇
  1996年   225篇
  1995年   195篇
  1994年   176篇
  1993年   177篇
  1992年   126篇
  1991年   110篇
  1990年   100篇
  1989年   103篇
  1988年   115篇
  1987年   90篇
  1986年   74篇
  1985年   76篇
  1984年   98篇
  1983年   88篇
  1982年   96篇
  1981年   98篇
  1980年   104篇
  1979年   56篇
  1978年   59篇
  1977年   79篇
  1976年   61篇
  1975年   58篇
  1974年   67篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Enteral feeding causes an increase of intestinal oxygen demand depending on the amount administered. The aim of this study presented was to evaluate, whether intraoperative duodenal feeding might put patients at risk developing splanchnic O(2)-imbalance due to an intraoperatively compromised intestinal perfusion based on stress and unrecognized hypovolemia. In 18 severely burned patients, the CO(2)-gap between the arterial and gastric CO(2), as a parameter for the intestinal O(2)-balance, was measured during the first operation. All operations were performed on day 3-5 after admission and lasted for 4-5h. Half of the patients (nine patients) were fed intraoperatively, whereas in the other nine patients feeding was suspended beginning 1h prior to surgery until 6h after surgery. CO(2)-gap measurements were carried out prior to surgery, hourly during the operation and 5h postoperatively. Measurements 3 and 4h after beginning of the operation revealed significantly higher CO(2)-gap values in the fasting group. All other measurements showed no significant difference between both groups. Therefore, intraoperative enteral nutrition, at least in the early postburn phase, is not only necessary for reducing caloric deficits, but also seems to have a protective effect on gut oxygen balance.  相似文献   
992.
Pseudoaneurysms in the visceral arteries are rare complications of pancreatitis. In the reported case, a 42-year-old man with a splenic pseudoaneurysm was successfully treated by computed tomography (CT)-guided direct thrombin injection into the pseudoaneurysm lumen. Selective catheterization of the splenic artery had proven technically impossible. During the procedure, contrast medium was injected via a pigtail catheter into the aorta for planning, correct positioning of the needle tip, and control imaging after injection. CT examinations 1 day, 3 weeks, and 6 months after treatment demonstrated complete occlusion shrinkage of the pseudoaneurysm, and the patient was symptom-free.  相似文献   
993.
994.
995.
Context  Up to 40% of thoracotomies performed for non–small cell lung cancer are unnecessary, predominantly due to inaccurate preoperative detection of lymph node metastases and mediastinal tumor invasion (T4). Mediastinoscopy and the novel, minimally invasive technique of transesophageal ultrasound–guided fine-needle aspiration (EUS-FNA) target different mediastinal lymph node stations. In addition, EUS can identify tumor invasion in neighboring organs if tumors are located adjacent to the esophagus. Objective  To investigate the additional value of EUS-FNA to mediastinoscopy in the preoperative staging of patients with non–small cell lung cancer. Design, Setting, and Patients  Prospective, nonrandomized multicenter trial performed in 1 referral and 5 general hospitals in the Netherlands. During a 3-year period (2000-2003), 107 consecutive patients with potential resectable non–small cell lung cancer underwent preoperative staging by both EUS-FNA and mediastinoscopy. Patients underwent thoracotomy with tumor resection if mediastinoscopy was negative. Surgical-pathological staging was compared with preoperative findings and the added benefit of the combined strategy was assessed. Intervention  The EUS-FNA examination was performed as an additional staging test to mediastinoscopy in all patients. Main Outcome Measure  Detection of mediastinal tumor invasion (T4) and lymph node metastases (N2/N3) comparing the combined staging by both EUS-FNA and mediastinoscopy with staging by mediastinoscopy alone. Results  The combination of EUS-FNA and mediastinoscopy identified more patients with tumor invasion or lymph node metastases (36%; 95% confidence interval [CI], 27%-46%) compared with either mediastinoscopy alone (20%; 95% CI, 13%-29%) or EUS-FNA (28%; 95% CI, 19%-38%) alone. This indicated that 16% of thoracotomies could have been avoided by using EUS-FNA in addition to mediastinoscopy. However, 2% of the EUS-FNA findings were false-positive. Conclusion  These preliminary findings suggest that EUS-FNA, when added to mediastinoscopy, improves the preoperative staging of lung cancer due to the complementary reach of EUS-FNA in detecting mediastinal lymph node metastases and the ability to assess mediastinal tumor invasion.   相似文献   
996.
The management of patients with coexisting diseases who undergo cardiac surgery is a subject to controversial discussions as the operative mortality is thought to be increased by simultaneous procedures. Traditionally, the surgical procedures have been staged with the cardiac surgery performed first followed by the visceral operation at a later date. However, especially in cases of malignant disease (e. g. pulmonary or abdominal) the curative treatment is delayed and the additional costs of two settings have to be considered.  相似文献   
997.
AIM: This study was designed to analyse the relationship between myocardial lactate--determined by microdialysis--and hemodynamics during coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB). METHODS: Twenty consecutive patients with coronary artery disease were enrolled for this prospective, observational study. Microdialysis measurements were performed in the apical region of the heart during periods of 15 to 20 min before, during, and after CPB; hemodynamics and plasma lactate concentrations were determined correspondingly. Correlation analysis revealed a relationship between myocardial lactate concentration and right ventricular ejection fraction at baseline (Spearman's r: 0.6; P=0.02). Patients were thus grouped according to the myocardial lactate concentration at baseline into a high-lactate group (2.5+/-0.7 mmol.l(-1), n=10) and low-lactate group (0.9+/-0.5 mmol.l(-1), n=10). RESULTS: Preoperative left ventricular ejection fraction was not different between the groups (high-lactate group: 53+/-16%; low-lactate group: 57+/-15%; P=n.s.) Patients in the high-lactate-group had a lower stroke volume index (P=0.005) and right ventricular ejection fraction (P=0.04) before, and higher central venous and pulmonary artery pressures (P<0.01) after CPB. Plasma lactate was significantly higher during CPB in the high-lactate-group (P<0.05). No correlation was observed between myocardial and plasma lactate. Six patients in the high-lactate but none in the low-lactate-group needed inotropic support after weaning from CPB (P=0.01). CONCLUSIONS: These data are suggestive of an association between subtle myocardial ischemia--detected by microdialysis--and perioperative myocardial dysfunction in patients undergoing CABG. The microdialysis technique may be a valuable adjunct for monitoring myocardial metabolism during cardiac surgery.  相似文献   
998.
OBJECTIVE: To evaluate the satisfaction level of patients and partners after implantation of a Mentor Alpha-1 inflatable penile prosthesis (IPP) for the treatment of erectile dysfunction (ED). MATERIAL AND METHODS: A questionnaire was sent to 46 patients who had been operated on for ED with implantation of a Mentor Alpha-1 IPP. The investigation was designed to evaluate patient and partner satisfaction. RESULTS: Eighty-five percent of the questionnaires were returned. Sexual desire had not changed but the quality of sexual activity had significantly improved. Acceptance by the partner was good. Overall satisfaction among both patients and partners was high. In total, 95% of patients said that they would recommend the procedure to other patients in the same situation. CONCLUSIONS: Patient and partner satisfaction with the Mentor Alpha-1 IPP was high, with the exception of the minority of patients who experienced unacceptable complications. Infection and mechanical failure are important risks which patients should be informed of before agreeing to implantation surgery.  相似文献   
999.
BACKGROUND: Contradictory reports on the value of intraoperative quick parathyroid hormone (PTH) monitoring in renal hyperparathyroidism have been published. METHODS: Thirty-five consecutive patients underwent total parathyroidectomy, central neck dissection, bilateral thymectomy, and immediate autotransplantation. PTH levels were measured by PTH assay at induction of anesthesia (baseline level) and in 5-minute intervals after excision of the last parathyroid gland. Parathyroidectomy was considered "total" in patients with PTH levels <10 pg/mL (subgroup 1), "subtotal" between 10 and 65 pg/mL (subgroup 2) and "insufficient" at >65 pg/mL (subgroup 3) within the first postoperative week. RESULTS: Fifteen minutes after excision of the last gland, PTH levels dropped to 19.4 +/- 15.7% (subgroup 1), 14.9 +/- 5.9% (subgroup 2), and 18 +/- 6.7% (subgroup 3) from baseline among 22 patients on hemodialysis, to 22.1 +/- 18.7% and 17.5% in 9 patients (subgroups 1 and 2) after successful kidney transplantation, and to 10.7% and 17.5% (subgroup 1) and 12.8% and 31.4% (subgroup 2) in 4 patients with reduced renal function after kidney transplantation. CONCLUSIONS: Currently available QPTH assays are not useful to predict insufficient resection of hyperfunctioning parathyroid tissue.  相似文献   
1000.
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