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   73493篇
  免费   5983篇
  国内免费   3196篇
耳鼻咽喉   839篇
儿科学   1196篇
妇产科学   826篇
基础医学   8201篇
口腔科学   1303篇
临床医学   8040篇
内科学   12069篇
皮肤病学   831篇
神经病学   4809篇
特种医学   3045篇
外国民族医学   12篇
外科学   9516篇
综合类   10138篇
现状与发展   19篇
一般理论   43篇
预防医学   5901篇
眼科学   1118篇
药学   6839篇
  56篇
中国医学   3306篇
肿瘤学   4565篇
  2024年   215篇
  2023年   821篇
  2022年   1941篇
  2021年   2886篇
  2020年   2260篇
  2019年   1990篇
  2018年   2083篇
  2017年   1967篇
  2016年   1977篇
  2015年   2926篇
  2014年   3606篇
  2013年   4331篇
  2012年   6155篇
  2011年   6395篇
  2010年   4498篇
  2009年   3800篇
  2008年   4790篇
  2007年   4432篇
  2006年   4138篇
  2005年   3606篇
  2004年   2913篇
  2003年   2651篇
  2002年   2267篇
  2001年   1163篇
  2000年   922篇
  1999年   742篇
  1998年   452篇
  1997年   421篇
  1996年   392篇
  1995年   362篇
  1994年   317篇
  1993年   277篇
  1992年   362篇
  1991年   369篇
  1990年   350篇
  1989年   337篇
  1988年   268篇
  1987年   256篇
  1986年   270篇
  1985年   268篇
  1984年   219篇
  1983年   221篇
  1982年   186篇
  1981年   162篇
  1980年   152篇
  1979年   167篇
  1978年   156篇
  1977年   131篇
  1974年   119篇
  1973年   112篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Blood volume, blood pressure, plasma concentrations of atrial natriuretic peptide (ANP), cyclic 3',5'-guanosine monophosphate (cGMP), angiotensin II, aldosterone, and arginine vasopressin (AVP), and urinary excretion rates of cGMP, sodium, and water were determined before and after infusion of human albumin 20%, 3.5 ml/kg body-weight to 12 patients with chronic glomerulonephritis and 19 healthy control subjects (Study 1); and before and after frusemide injection, 0.75 mg/kg to 15 patients with chronic glomerulonephritis and 19 healthy control subjects (Study 2). In Study 1 blood volume was expanded to the same degree in patients (8.8 and 7.5%, medians, after 90 and 180 min) and controls (8.6 and 6.1%). ANP was enhanced in the patients (5.9 to 11.0 pmol/l, P less than 0.01) and the controls (4.9 to 7.1 pmol/l, P less than 0.01), but the elevated level was protracted in the patients simultaneously with a delayed sodium excretion. Plasma cGMP increased, aldosterone decreased and AVP was unchanged in both groups, whereas angiotensin II decreased in the patients (P less than 0.01), but not in the controls. In Study 2 blood volume was reduced to a smaller extent in the patients than in the controls (8.9% versus 9.9%, P less than 0.05). ANP an cGMP decreased, and angiotensin II, aldosterone and AVP increased in both patients and controls. In conclusion, patients with glomerulonephritis respond to albumin- and frusemide induced changes in blood volume with essentially the same counter-regulatory changes in ANP, angiotensin II, aldosterone and AVP as do healthy subjects. The more protracted increase in ANP and the decrease in angiotensin II after albumin, and the smaller blood volume reduction after frusemide suggest an abnormal regulation of blood volume in glomerulonephritis.  相似文献   
42.
43.
羟乙基淀粉容量治疗对高龄病人手术的血流动力学影响   总被引:1,自引:0,他引:1  
目的观察羟乙基淀粉130/0.4氯化纳注射液(6%HES,万汶),应用于老年患者容量治疗时对血流动力学的影响。方法选择30例ASAⅠ~Ⅱ级择期手术的老年患者,给予万汶进行容量治疗,观察术中血流动力学变化。结果所有患者术中血流动力学保持稳定。结论万汶应用于老年患者进行容量治疗时血流动力学保持稳定。  相似文献   
44.
椎管镜技术治疗腰椎间盘突出症并侧隐窝狭窄   总被引:4,自引:0,他引:4  
目的 :探讨椎管镜技术治疗腰椎间盘突出症并侧隐窝狭窄的临床效果。方法 :采用显微内窥镜椎间盘切除系统治疗腰椎间盘突出症并侧隐窝狭窄 860例。结果 :临床疗效参照NaKai分级 ,70 9例获得随访 ,平均 2年 7个月 ,优 ,5 5 9例 ;良 ,12 7例 ;可 ,2 3例。结论 :椎管镜技术是治疗腰椎间盘疾病安全有效的方法 ,住院时间短 ,恢复快 ,但操作技术有待进一步提高。  相似文献   
45.
We examined the time course effects of continuous PTH on cortical bone and mechanical properties. PTH increased cortical bone turnover and induced intracortical porosity with no deleterious effect on bone strength. Withdrawal of PTH increased maximum torque to failure and stiffness with no change in energy absorbed. INTRODUCTION: The skeletal response of cortical bone to parathyroid hormone (PTH) is complex and species dependent. Intermittent administration of PTH to rats increases periosteal and endocortical bone formation but has no known effects on intracortical bone turnover. The effects of continuous PTH on cortical bone are not clearly established. MATERIALS AND METHODS: Eighty-four 6-month-old female Sprague-Dawley rats were divided into three control, six PTH, and two PTH withdrawal (WD) groups. They were subcutaneously implanted with osmotic pumps loaded with vehicle or 40 microg/kg BW/day human PTH(1-34) for 1, 3, 5, 7, 14, and 28 days. After 7 days, PTH was withdrawn from two groups of animals for 7 (7d-PTH/7d-WD) and 21 days (7d-PTH/21d-WD). Histomorphometry was performed on periosteal and endocortical surfaces of the tibial diaphysis in all groups. microCT of tibias and mechanical testing by torsion of femora were performed on 28d-PTH and 7d-PTH/21d-WD animals. RESULTS AND CONCLUSIONS: Continuous PTH increased periosteal and endocortical bone formation, endocortical osteoclast perimeter, and cortical porosity in a time-dependent manner, but did not change the mechanical properties of the femur, possibly because of addition of new bone onto periosteal and endocortical surfaces. Additionally, withdrawal of PTH restored normal cortical porosity and increased maximum torque to failure and stiffness. We conclude that continuous administration of PTH increased cortical porosity in rats without having a detrimental effect on bone mechanical properties.  相似文献   
46.
Early intervention with budesonide is an effective strategy for mild persistent asthma, which has been shown to provide additional clinical benefits at a low incremental cost using USA cost data. The present authors analysed whether this strategy would be cost-effective using cost data for other countries. Based on the 3-yr prospective, randomised, double-blind inhaled Steroid Treatment As Regular Therapy (START) in early asthma study (comparing budesonide and placebo combined with usual asthma therapy), the cost-effectiveness was estimated separately for eight different countries, from both healthcare payer and societal perspectives, of adding budesonide to usual asthma therapy. Local unit costs were applied to data for the total trial population. Incremental cost-effectiveness ratios (ICER) were estimated as cost per symptom-free day (SFD) gained. Budesonide increased SFDs by an average of 14.1 days annually. From a healthcare payer perspective, budesonide would reduce the total cost of asthma care in Australia. In Sweden, Canada, France, Spain, UK, China and the USA, the ICER ranged from US$2.4-11.3 per SFD. From a societal perspective, budesonide would be cost-saving in Australia, Canada and Sweden. In conclusion, for countries where costs with budesonide are higher, the policy implication has to be determined by that health system's willingness to pay for an additional symptom-free day. However, where budesonide therapy increases symptom-free days and reduces total costs, the policy conclusion clearly favours early intervention.  相似文献   
47.
目的 探讨宫腔镜双极汽化切割术的安全性和疗效。方法 术前宫腔镜诊断均为黏膜下肌瘤和肌壁间凸向宫腔肌瘤36例,在宫腔镜下施行双极汽化电切术。结果 手术成功率100%,手术时间10-70分钟,平均32分钟;出血量12-100ml,平均28ml;标本重15-42g,平均31g。术中、术后无并发症。术后满意率94.4%。结论 宫腔镜双极汽化切割术具有手术时间短、出血少、无并发症等优点,疗效满意。  相似文献   
48.
Intraocular pressures and optic disc hemorrhages were studied in all cases of manifest glaucoma detected in a defined population over a decade. High intraocular pressure was found to be an unreliable signat the detection of a glaucomatous visual field defect and an unusual finding 5–10 yearsbefore. The prevalence of optic disc hemorrhages at the detection of a glaucomatous visual field defect was 33%. All but 9 of 44 persons with manifest glaucoma were found to have had at least one optic disc hemorrhage at one time or another.  相似文献   
49.
Radiotherapy has been successful in treating localized prostate cancer; however, a subset of patients will experience disease recurrence. Determination of the recurrence location must be made using pretreatment and posttreatment clinical variables, imaging, and postradiotherapy biopsy. Patients presumed to have local-only recurrence, optimal clinical risk factors, and an extended life expectancy may be considered for salvage local treatment. Current options include salvage surgery, cryoablation, and brachytherapy. Although they are associated with higher morbidity than primary therapy, salvage treatments can be effective and can still provide patients with a good oncologic and functional outcome. As these modalities continue to improve and patient selection is optimized, better results will evolve.  相似文献   
50.
手术示教系统的细节设计   总被引:3,自引:0,他引:3  
手术示教系统已是一个较为成熟的教学系统,本文将根据现时流行的几种设计方案进行分析,并对设计过程和选材中遇到的一些细节问题提出一些意见.  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