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   2939165篇
  免费   222568篇
  国内免费   33167篇
耳鼻咽喉   37015篇
儿科学   89794篇
妇产科学   75518篇
基础医学   401605篇
口腔科学   75483篇
临床医学   285753篇
内科学   562225篇
皮肤病学   66248篇
神经病学   230191篇
特种医学   113057篇
外国民族医学   960篇
外科学   417285篇
综合类   119632篇
现状与发展   91篇
一般理论   994篇
预防医学   222766篇
眼科学   66815篇
药学   227117篇
  439篇
中国医学   29530篇
肿瘤学   172382篇
  2022年   22608篇
  2021年   37731篇
  2020年   26636篇
  2019年   31915篇
  2018年   40934篇
  2017年   33913篇
  2016年   36520篇
  2015年   45734篇
  2014年   60745篇
  2013年   78722篇
  2012年   107361篇
  2011年   115147篇
  2010年   71811篇
  2009年   66026篇
  2008年   99467篇
  2007年   103954篇
  2006年   104742篇
  2005年   100125篇
  2004年   90666篇
  2003年   87653篇
  2002年   82791篇
  2001年   135829篇
  2000年   138667篇
  1999年   118031篇
  1998年   36323篇
  1997年   32787篇
  1996年   32027篇
  1995年   30976篇
  1994年   28078篇
  1993年   25331篇
  1992年   87250篇
  1991年   83424篇
  1990年   80357篇
  1989年   77421篇
  1988年   70577篇
  1987年   69004篇
  1986年   64351篇
  1985年   61073篇
  1984年   45251篇
  1983年   38166篇
  1982年   22569篇
  1979年   39062篇
  1978年   27491篇
  1977年   23291篇
  1976年   21521篇
  1975年   22835篇
  1974年   26818篇
  1973年   25393篇
  1972年   23780篇
  1971年   21970篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The severity of illness in transplant patients and the complexity of transplant operations results in significant postoperative morbidity and mortality. Remarkable efforts have been made by transplant physicians to study and improve organ allocation, graft and patient survival, immunosuppression and the long-term management of post-transplant complications. Less effort has been spent studying the actual transplant operation and systems of acute transplant care. The National Surgical Quality Improvement Program (NSQIP) has provided a standardized approach to quality improvement and has demonstrated significant potential for a reduction in postoperative morbidity and mortality in other surgical disciplines. Medical centers are under increasing pressure to measure surgical quality and the nexus of transplant surgical quality improvement should not lie in the hands of CMS or JACHO, but rather it should be created and developed within the transplant community. The time has come for a national transplant surgical quality improvement program based on the NSQIP infrastructure. Such a proactive approach toward quality improvement from the transplant community is an excellent investment for patients, providers and health care payers.  相似文献   
992.
(加味)柴芍承气汤对重症急性胰腺炎及其并发症的作用   总被引:2,自引:1,他引:1  
目的探讨(加味)柴芍承气汤对重症急性胰腺炎(SAP)及其并发症的防治作用。方法65例SAP患者分为中药组35例,对照组30例。2组的内科治疗相同,中药组一经确诊即予柴芍承气汤加味银杏叶治疗,每剂煎成100~150m l,自鼻胃管内注入或口服,每日2~3次,直至患者腹痛缓解、腹胀基本消失、肠鸣恢复。分别观察2组患者治疗72 h后的PaO2、SaO2肾功能、脑病、局部并发症情况、腹痛缓解时间、肠鸣恢复时间、病死率,以及血清中血小板活化因子(PAF)、肿瘤坏死因子(TNF-α)、白介素-1(IL-1)水平变化。结果治疗72 h后中药组与对照组低氧血症的发生率分别为45.71%、73.73%,P<0.05;肾损害、脑病、局部并发症发生率以及病死率均低于对照组,但无统计学差异;腹痛缓解时间、肠鸣恢复时间均优于对照组(P<0.05);中药组血清中PAF、TNF-α、IL-1水平显著降低(P<0.01),而对照组则无明显变化。结论该汤剂对SAP及其并发症有较好的防治作用。抑制细胞因子或炎症介质可能是该汤剂治疗SAP的重要机制。  相似文献   
993.
994.
995.
The pharmacokinetics (PK) of moxifloxacin in healthy white New Zealand rabbits was studied following intravenous (IV) and subcutaneous (SC) administration routes as well as a SC long‐acting poloxamer 407 gel formulation (SC‐P407). Moxifloxacin concentrations were determined by high‐performance liquid chromatography assay with fluorescence detection. Mean half‐life for IV, SC and SC‐P407 routes was 2.15, 5.41 and 11.09 h. Clearance value after IV dosing was 0.78 l/kg/h. After SC administration, the mean absolute bioavailability was 117% and the Cmax was 1.61 ± 0.49 mg/l. After SC‐P407 administration, the bioavailability was 44% and the Cmax 1.83 was ±0.62 mg/l. No adverse effects were observed in any of the rabbits following IV, SC and SC‐P407 administration of moxifloxacin. Minimal inhibitory concentrations of moxifloxacin against different strains of Staphylococcus aureus from different european countries were used to compute the main pharmacodynamic (PD) surrogate markers of efficacy. The high tolerability of this SC‐P407 formulation and the favourable PK behaviour such as the long half‐life, acceptable bioavailability and excellent PK–PD ratios achieved indicate that it is likely to be effective in rabbits.  相似文献   
996.
997.
SETTING: Diabetes mellitus is a known risk factor for tuberculosis (TB), but no studies have been reported from South-East Asia, which has a high burden of TB and a rapidly growing prevalence of diabetes. OBJECTIVE: To examine if and to what extent diabetes is associated with an increased risk of TB in an urban setting in Indonesia. DESIGN: Case-control study comparing the prevalence of diabetes mellitus (fasting blood glucose level >126 mg/dl) among newly diagnosed pulmonary TB patients and matched neighbourhood controls. RESULTS: Patients and control subjects had a similar age (median 30 years) and sex distribution (52% male), but malnutrition was more common among TB patients (median body mass index 17.7 vs. 21.5 kg/m2). HIV infection was uncommon (1.5% of patients). Diabetes mellitus was present in 60 of 454 TB patients (13.2%) and 18 of 556 (3.2%) control subjects (OR 4.7; 95%CI 2.7-8.1). Adjustment for possible confounding factors did not reduce the risk estimates. Following anti-tuberculosis treatment, hyperglycaemia reverted in a minority (3.7%) of TB patients. CONCLUSION: Diabetes mellitus is strongly associated with TB in young and non-obese subjects in an urban setting in Indonesia. This may have implications for TB control and patient care in this region.  相似文献   
998.
999.
During the last 10 years the knowledge about rostral anterior cingulate cortex (ACC) activity in major depression has substantially increased. Several groups have independently described a relationship between resting activity in this area and response to antidepressant treatment. We have recently confirmed a relationship between resting activity of rostral ACC activity and response in a group of 20 patients with major depression using resting theta activity. In this earlier study regions of interest (ROI) were defined in order to establish regional specificity. Differences between responders and nonresponders were only found in the ACC-ROI, but not in the posterior cingulate region. We have now reanalyzed our data using a whole brain voxelwise approach, in order not to miss any other relevant functional differences. In addition to major differences between responders and nonresponders in the rostral ACC, we have identified a nearby region in the midline orbito-frontal region.  相似文献   
1000.
BACKGROUND: The incidence of malignant melanoma of the skin has risen in every part of the world where reliable cancer registration data are found. OBJECTIVE: Our study aims to describe the changing incidence of and survival from invasive cutaneous malignant melanoma in Malta, by analysing the data from the 211 cases that were registered at the Malta National Cancer Registry between 1993 and 2002. RESULTS: The age standardized incidence rates for invasive cutaneous malignant melanoma rose from 3.7 per 100,000 population per year for males and 5.1 for females in the first 5-year period, to 8.0 per 100,000 population per year for males and 5.9 for females in the second 5-year period. In both sexes, numbers of thin (< or = 1.0 mm) invasive melanomas increased significantly between 1993 and 2002; males also registered a significant increase in intermediate-thickness (1.01-4.0 mm) melanomas. The increase in numbers of thin and intermediate-thickness melanomas between the two 5-year periods was greatest in patients aged 60 years and over. The overall absolute 5-year survival rate for the first period was 74% and for the second period 92%. CONCLUSION: Numbers of reported cases of invasive cutaneous malignant melanoma in Malta have more than doubled during the 10-year study period. This is mostly due to a marked rise in the diagnosis of thin melanomas in both sexes, occurring mainly in patients aged 60 years and over. As thin melanomas are of low metastasizing potential, this has resulted in an increase in survival between the two 5-year study periods.  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