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   304939篇
  免费   11296篇
  国内免费   8030篇
耳鼻咽喉   2201篇
儿科学   8169篇
妇产科学   5294篇
基础医学   31316篇
口腔科学   3658篇
临床医学   29383篇
内科学   51443篇
皮肤病学   2125篇
神经病学   23267篇
特种医学   13301篇
外国民族医学   70篇
外科学   42184篇
综合类   22107篇
现状与发展   24篇
一般理论   5篇
预防医学   26067篇
眼科学   6419篇
药学   22384篇
  157篇
中国医学   7097篇
肿瘤学   27594篇
  2024年   1568篇
  2023年   2452篇
  2022年   4877篇
  2021年   6070篇
  2020年   4649篇
  2019年   4397篇
  2018年   25675篇
  2017年   20847篇
  2016年   22733篇
  2015年   6195篇
  2014年   7460篇
  2013年   7025篇
  2012年   16053篇
  2011年   30773篇
  2010年   24787篇
  2009年   16371篇
  2008年   26013篇
  2007年   28178篇
  2006年   7205篇
  2005年   8745篇
  2004年   7819篇
  2003年   8495篇
  2002年   5994篇
  2001年   3498篇
  2000年   3730篇
  1999年   3592篇
  1998年   2433篇
  1997年   2363篇
  1996年   1647篇
  1995年   1553篇
  1994年   1364篇
  1993年   876篇
  1992年   1261篇
  1991年   1156篇
  1990年   1051篇
  1989年   896篇
  1988年   762篇
  1987年   705篇
  1986年   529篇
  1985年   491篇
  1984年   268篇
  1983年   198篇
  1982年   142篇
  1981年   116篇
  1980年   117篇
  1979年   122篇
  1978年   67篇
  1975年   60篇
  1974年   84篇
  1938年   61篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Objective Diabetes mellitus is an independent risk factor for acute myocardial infarction. Thus, a surveillance study was conducted as part of studies to create a national database related to electrocardiogram (ECG)-gated myocardial perfusion single-photon emission computed tomography (SPECT) of ischemic heart disease. Methods Single-photon emission computed tomography was conducted in patients with type 2 diabetes mellitus and their prognoses will be followed for 3 years, stratified by patients’ clinical background and SPECT findings. Results A total of 513 patients from 50 institutions were enrolled in this study, 297 of whom were men (age 66.2 ± 0.4 years, mean ± SEM) and 261 women (age 67.8 ± 0.5 years). They have a history of retinopathy (25.3%), neuropathy (19.9%), cerebrovascular disorder, chronic obstructive pulmonary disease, and photocoagulation. Major risk factors for present disease were hypertension (82.3%) and hyperlipidemia (79.7%). In 244 patients (129 men and 115 women), body mass index (BMI) was 25 or more. Fifty-two of them (10.1%) underwent coronary angiography; of these, 26 (50.0%) had no coronary artery lesions with 75% or more stenosis, and only 1 (1.9%) had a left main trunk with 50% or more stenosis. An overwhelming majority of patients (94.3%) underwent SPECT imaging by a 1-day stress-followed-by-rest procedure. Stress procedure was exercise in most (70.8%) patients, followed by dipyridamole infusion in 14.6%, adenosine infusion in 6.6%, and adenosine triphosphate infusion in 5.7%. Endpoint of stress examination was most often fatigue in lower limbs (40.7%), followed by completion of pharmacological stress protocol (28.7%), and achievement of target heart rate (26.3%). The largest number of patients (198, 38.6%) received 99mTc-tetrofosmin at an initial dosage of 200–300 MBq (mean 331 ± 3 MBq) followed by a second dosage of 700–800 MBq (mean 748 ± 8 MBq). Among them, 491 (95.7%) received some kind of therapeutic drug: hypoglycemic drugs were used by the largest number (83.2%), followed by hypotensive (66.7%), hypolipidemic (40.7%), and antiplatelet drugs (27.7%), vasodilators (5.5%), and antioxidants and others (2.3%). Conclusions This study was designed to clarify the correlation between coronary artery disease and diabetes mellitus as its risk factor based on the clinical and imaging findings. Patient enrollment was closed on September 30, 2005, and follow-up is now under way.  相似文献   
992.
993.
994.
腹股沟斜疝是小儿外科常见疾病。1岁以内婴儿腹股沟斜疝可出现反复嵌顿现象,对睾丸血供造成一定影响,需早期手术治疗。我院于2000年11月-2005年11月共施行1岁以内婴儿腹股沟斜疝手术86例,取得良好疗效,现报告如下。  相似文献   
995.
Introduction Idiopathic granulomatous mastitis (IGM) is a rare benign inflammatory breast disease that presents with variable local manifestations. We describe here the different management protocols based on the clinical presentation of these patients. Methods A retrospective review of 20 histopathologic confirmed cases of IGM seen over a period of 10 years was performed. Results The median age was 34 years (age range: 21–45 years). All were married, parous with history of breast feeding. Ill-defined mass mimicking carcinoma was the commonest presentation (70%); however, with the presence of signs of inflammation like pain (55%), redness (40%), and peau d’orange (40%), an inflammatory process appeared more likely. Axillary lymph node enlargement was infrequently seen (40%). Radiologic findings (mammography and ultrasound) were nonspecific. Histopathology showed the characteristic lobular distribution of granulomatous inflammation in all cases. Surgically, 7 patients had abscess drainage with open biopsy, and 7 patients had lumpectomy. Six patients with diffuse breast involvement were diagnosed by core needle biopsy only. Microbial cultures showed no growth. Antibiotics were given empirically when signs of inflammation where present. Two patients needed further abscess drainage followed by persistent sinus excision 3–6 weeks later. The median follow-up was 24 months (range: 15–42 months). Seventeen patients (85%) were recurrence-free, and 3 patients (15%) were lost to follow-up. Conclusions Management of IGM cases needs to be tailored according to the clinical presentation. Precise radiologic and pathologic data interpretation by a multidisciplinary breast team will facilitate diagnosis and minimize unnecessary intervention.  相似文献   
996.
Spontaneous Regression of a Metastatic Liver Tumor: Report of a Case   总被引:1,自引:0,他引:1  
A 60-year-old man, who suffered from advanced rectal cancer accompanied with liver metastasis, underwent an abdominoperineal resection and a partial hepatectomy. He remained well until 4 months after surgery when he developed a biopsy-proven recurrent intrapelvic mass and multiple liver tumors. At 6 months after surgery, the metastatic liver tumors grew larger and almost completely occupied both lobes of the liver. However, 9 months after surgery, the liver tumors regressed remarkably and his clinical condition improved without any specific treatment for cancer. Although he died of cancerous peritonitis 18 months after surgery, the autopsy findings did not indicate any apparent regrowth of the liver tumors. To date, only one case report of a spontaneous regression of a metastatic liver tumor from colorectal cancer has been published in the English literature. We herein describe this rare case and discuss some of the reasons potentially responsible for the regression. Received: July 16, 2001 / Accepted: March 5, 2002  相似文献   
997.
Postinjury abdominal compartment syndrome (ACS) has evolved during the 1980s together with the introduction of damage control surgery (DCS) principles. DCS made it possible to salvage severely injured trauma patients who previously would have exsanguinated due to uncontrollable coagulopathic bleeding. These patients had severe hemorrhagic shock; their abdomens were tightly packed and had ongoing massive resuscitation. ACS is a lethal complication of the damage control patients. For today the pathophysiological characteristics of ACS are described, the intra-abdominal pressure is measured on many intensive care units. Postinjury ACS (primary and secondary) is one of the better characterized etiological types of ACS: risk factors, diagnostic criteria, independent predictors and preventive strategies are all well documented. Since the mortality of full-blown postinjury ACS is still unacceptably high and does not seem to improve with earlier decompression, prevention is the recommended strategy to decrease the morbidity and mortality. Open abdomen is one of the important preventive strategies but it is not free from morbidity and mortality. With aggressive open abdomen management in postinjury ACS these complications can be minimized. More importantly, timely hemorrhage control and hemostatic resuscitation are the likely solutions for more efficient prevention of the postinjury ACS.  相似文献   
998.
Ren B  Wu H  Zhu J  Li D  Shen Y  Ying R  Dong G  Jing H 《Transplantation proceedings》2006,38(9):2777-2779
Ischemia-reperfusion (I/R) injury may influence graft function following transplantation. Ulinastatin, a urinary trypsin inhibitor has been shown to attenuate I/R injury in various organs such as intestine, heart, and kidney in animals. The present experiment was designed to evaluate the effect of pretreatment with ulinastatin on I/R-induced lung injury. METHODS: After establishing a constant left lung warm ischemia-reperfusion model in rats, 45 animals were randomly divided into three experimental groups: sham group (n = 15), IR group (n = 15), and ulinastatin (5000 U/kg pre-ischemia) + IR group (n = 15). The lung injury was evaluated by tissue myeloperoxidase activity, with simultaneous estimation of the serum concentration of TNFalpha. RESULTS: The ulinastatin-pretreated animals exhibited markedly decreased lung tissue myeloperoxidase activity (P < .05). Blood gas analysis demonstrated, that the treated animals had significantly ameliorated pulmonary oxygenation (P < .05). The serum concentration of TNF-alpha in the ulinastatin-pretreated group was markedly decreased compared with that of the I/R group (P < .05). CONCLUSIONS: Ulinastatin attenuated I/R-induced lung injury. This function is partly related to the capacity of the agent to inhibit myeloperoxidase activity in lung tissue and decrease systemic expression to TNF-alpha.  相似文献   
999.
独活寄生汤加味内服外洗治疗膝关节骨性关节炎   总被引:3,自引:0,他引:3  
[目的]探讨膝关节骨性关节炎有效方法。[方法]对236例膝关节骨性关节炎采用口服独活寄生汤加外洗治疗。[结果]治愈145例(61.4%),显效48例(20.4%),有效31例(13.1%),无效12例(5.1%),总有效率为94.9%。[结论]独活寄生汤加味内服外洗治疗膝关节骨性关节炎有效。  相似文献   
1000.
目的 :探讨机械通气对ICU肺动脉高压伴呼吸衰竭患者血浆脑钠肽(BNP)水平的影响。方法 :挑选82名需要进行机械通气的肺动脉高压伴呼吸衰竭患者,随机分成两组,每组41名成员。无创组在常规治疗的基础上提供面罩呼吸机辅助呼吸,有创组在常规治疗的基础上提供气管切开或气管插管呼吸机辅助呼吸。分别统计治疗前及治疗24h后两组患者血气分析结果、血浆BNP含量及肺动脉压的变化。结果 :治疗24h后两组患者动脉血气分析指标均较治疗前有显著改善,此外有创机械通气组较无创机械通气组动脉血气分析指标略低,同时两者血浆BNP含量及肺动脉压力均明显降低,有创机械通气组患者较无创机械通气组患者下降明显。结论 :有创机械通气治疗ICU肺动脉高压伴呼吸衰竭患者较无创机械通气治疗效果显著。机械通气可以降低BNP浓度,其浓度变化有创机械通气效果优于无创机械通气。  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