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   49638篇
  免费   4251篇
  国内免费   1496篇
耳鼻咽喉   94篇
儿科学   1061篇
妇产科学   590篇
基础医学   2496篇
口腔科学   667篇
临床医学   5832篇
内科学   14180篇
皮肤病学   221篇
神经病学   1021篇
特种医学   698篇
外科学   3085篇
综合类   10459篇
现状与发展   3篇
一般理论   2篇
预防医学   3216篇
眼科学   3266篇
药学   5063篇
  31篇
中国医学   3161篇
肿瘤学   239篇
  2024年   157篇
  2023年   959篇
  2022年   1425篇
  2021年   2261篇
  2020年   2067篇
  2019年   1634篇
  2018年   1774篇
  2017年   1791篇
  2016年   1935篇
  2015年   1934篇
  2014年   3473篇
  2013年   3577篇
  2012年   3254篇
  2011年   3627篇
  2010年   2743篇
  2009年   2569篇
  2008年   2476篇
  2007年   2449篇
  2006年   2097篇
  2005年   1919篇
  2004年   1570篇
  2003年   1255篇
  2002年   985篇
  2001年   944篇
  2000年   782篇
  1999年   673篇
  1998年   589篇
  1997年   563篇
  1996年   444篇
  1995年   406篇
  1994年   355篇
  1993年   348篇
  1992年   326篇
  1991年   244篇
  1990年   203篇
  1989年   220篇
  1988年   183篇
  1987年   151篇
  1986年   142篇
  1985年   166篇
  1984年   118篇
  1983年   58篇
  1982年   112篇
  1981年   69篇
  1980年   72篇
  1979年   40篇
  1978年   50篇
  1977年   33篇
  1976年   23篇
  1973年   26篇
排序方式: 共有10000条查询结果,搜索用时 333 毫秒
61.
AIM: To undertake a systematic review of the diagnostic performance of clinical examination, sample acquisition and sample analysis in infected foot ulcers in diabetes. METHODS: Nineteen electronic databases plus other sources were searched. To be included, studies had to fulfil the following criteria: (i) compare a method of clinical assessment, sample collection or sample analysis with a reference standard; (ii) recruit diabetic individuals with foot ulcers; (ii) present 2 x 2 diagnostic data. Studies were critically appraised using a 12-item checklist. RESULTS: Three eligible studies were identified, one each on clinical examination, sample collection and sample analysis. For all three, study groups were heterogeneous with respect to wound type and a small proportion of participants had foot ulcers due to diabetes. No studies identified an optimum reference standard. Other methodological problems included non-blind interpretation of tests and the time lag between index and reference tests. Individual signs or symptoms of infection did not prove to be useful tests when assessed against punch biopsy as the reference standard. The wound swab did not perform well when assessed against tissue biopsy. Semiquantitative analysis of wound swab might be a useful alternative to quantitative analysis. The limitations of these findings and their impact on recommendations from relevant clinical guidelines are discussed. CONCLUSION: Given the importance of this topic, it is surprising that only three eligible studies were identified. It was not possible to describe the optimal methods of diagnosing infection in diabetic patients with foot ulceration from the evidence identified in this systematic review.  相似文献   
62.
It has been reported that poor glycaemic control predisposes to oral candidal infection in diabetic patients. For instance, the carriage of Candida species and the density of candidal growth in the oral cavity is frequently claimed to be increased in patients with diabetes mellitus. However, the validity of these observations remains controversial. Hence, we review and discuss here the clinical data in the literature on the relationship between diabetes and oral candidal carriage and infection, and possible mechanisms associated with its pathogenicity.  相似文献   
63.
糖尿病是心血管病重要的独立高危因素。糖尿病增加心肌缺血损伤的危险性,引起心肌本身和心肌内小血管病变,抑制心肌缺血预处理的作用。现就糖尿病对心血管病的影响及糖尿病病人围术期的处理进展作一综述。  相似文献   
64.
目的研究糖尿病状态下血管吻合口愈合规律的特点及影响因素。方法将8周病程的糖尿病组和对照组SD大鼠各20只的双侧颈总动脉切断后行间断缝合,于吻合术后1d、3d、7d、14d分别取材,观察其通畅情况,并对血管吻合口行组织学、超微结构观察和图像分析。同时,各时间点检测血清TNF-α浓度变化。结果对照组吻合口血管内膜损伤小,管壁各层次结构清晰,炎症反应轻;糖尿病组血管内膜损伤重,管壁各层次结构紊乱,有断裂痕迹,管壁周围肉芽组织增生明显。吻合术后7d糖尿病组吻合口血管内膜平均再内皮化明显延迟(3745.18±1045.31μm2比1298.21±224.66μm2,p<0.01);吻合术后14d,糖尿病组血管吻合口内膜增生明显,I/M值达0.71±0.05。与对照组比较,血清TNFα浓度显著增加(术后7d:5.48±0.34ng/ml比0.73±0.09ng/ml,p<0.05;术后14d:5.15±0.12ng/ml比0.51±0.03ng/ml,p<0.05),血清TNF-α浓度与血管吻合口部位内膜增生程度呈正相关。结论糖尿病改变了血管吻合口正常的愈合规律,使正常的吻合口愈合过程转变为慢性炎性、纤维增殖过程,血管吻合口部位的重塑呈现病理性,其中TNF-α在糖尿病血管吻合口重塑过程中发挥了核心作用。  相似文献   
65.
BACKGROUND: Researches on diabetic nervous system lesion are mainly focus on peripheral nerve and vegetative nerve, so there are few investigations on diabetic pseudotabes. OBJECTIVE: To investigate the electrophysiological examinations on the diagnosis of diabetic pseudotabes. DESIGN: Case study. SETTING: Department of Electrophysiology and Department of Neurology, Zhongshan Hospital Affiliated to Xiamen University. PARTICIPANTS: A total of 4 patients with type 2 diabetes mellitus, including 3 males and 1 female aged from 50 to 72 years, were selected from Department of Neurology, Zhongshan Hospital Affiliated to Xiamen University from March 2002 to February 2005. All accepted subjects met the modified diagnostic criteria of diabetes mellitus, which was set by American Diabetes Mellitus Association (ADA) in 1997. Otherwise, the subjects had typical symptoms and physical signs of spinal posterior funiculus damage. However, patients with spinal cord lesion which was caused by other factors were excluded. All accepted subjects provided the confirmed consent. METHODS: Nicolet NT electromyography (EMG)/evoked potential meter (made in the USA) was used to detect spinal cord conduction velocity (SCCV), somatosensory evoked potential (SEP) of lower limbs, motor nerve conduction velocity (MNCV) and sensory nerve conduction velocity (SNCV) of extremities. Determining criteria: Measurements were performed based on the laboratory standards. SCCV, which was less than lower limit of normal value (T2–12: 40–55 m/s, T12–L4: 20–41 m/s, T2–L4: 36–45 m/s), was regarded as abnormal. SEP value of lower limbs: P40, P60 and PF, which were more than standard deviation of normal value (x(—)+2.5), were regarded as the abnormality. Normal value of P40, P60 and PF latencies (x(—)±s) in this study: P40, P60 and PF in males were (37.6±1.9) ms, (59.8±3.9) ms and (7.6±0.9) ms, respectively; meanwhile, those in females were (35.5±1.7) ms, (55.2±2.7) ms and (6.3±0.7) ms, respectively. MNCV and SNCV, which were less than 50 m/s in upper limbs and 40 m/s in lower limbs, were regarded as the abnormality. MAIN OUTCOME MEASURES: Electrophysiological examinations. RESULTS: All 4 patients with type 2 diabetes mellitus were involved in the final analysis. ① SCCV: Among 4 patients, SCCV of three patients was decreased in T2–12, T12–L4 and T2–L4, and that of the other one was decreased in T2–12 and T2–L4; however, SCCV in T12–L4 was normal. There was significant difference as compared with normal value (P < 0.01). ② SEP of lower limbs: SEP values of lower limbs were abnormal in all 4 patients. Among them, P40, P60 and PF latencies of two patients were delayed; P40 of one patient was delayed and PF was not drained out; P40 and P60 of the last one were delayed and PF was normal. ③ MNCV and SNCV: The MNCV and SNCV were normal in one patient and abnormal in three patients. The results demonstrated that MNCV and SNCV of extremities decreased; especially, sensory nerve action potential (SNAP) of both lower extremities of one patient were not drained out. CONCLUSION: Detections of SCCV, SEP of lower limbs, MNCV and SNCV of extremities are helpful to investigate whether peripheral nerve and deep sensory passage are damaged or not and determine whether deep sensory damage is caused by peripheral nerve and spinal posterior funiculus.  相似文献   
66.
HYPOTHESIS: Based on recent findings on the association between vascular risk factors and hippocampal atrophy, we hypothesized that hypertension and diabetes mellitus (DM) are associated with medial temporal lobe atrophy (MTA) in subjects without disability, independent of the severity of white matter hyperintensities. METHODS: In the Leukoaraiosis And DISability in the elderly (LADIS) study, we investigated the relationships between DM, hypertension, blood pressure and MTA in 582 subjects, stratified by white matter hyperintensity severity, using multinomial logistic regression. MTA was visually scored for the left and right medial temporal lobe (score 0-4), and meaned. RESULTS: Mean age was 73.5 years (sd 5.1), 54% was female. Of the subjects, 15% had DM, and 70% had a history of hypertension. The likelihood of having MTA score 3 was significantly higher in subjects with DM (OR 2.9; 95% CI: 1.1-7.8) compared with an MTA score of 0 (no atrophy). The odds ratio for MTA score 2 was not significantly increased (OR 1.8; CI: 0.9-4). Systolic and diastolic blood pressure and a history of hypertension were not associated with MTA. There was no interaction between DM and hypertension. Stratification on white matter hyperintensities (WMH) did not alter the associations. CONCLUSION: Our study strengthens the observation that MTA is associated with DM, independently of the amount of small vessel disease as reflected by WMH.  相似文献   
67.
目的 观察葛根素对糖尿病周围神经病变的临床疗效。方法 在治疗糖尿病的同时 ,用0 9%氯化钠注射液 30 0mL 葛根素 0 4g静脉滴注 ,每天 1次 ,10d为 1疗程 ,共 3个疗程。结果 用葛根素治疗糖尿病周围神经病变 5 3例 ,显效 31例 ,有效 12例 ,总有效率达 81% ,无明显副作用。结论 葛根素治疗糖尿病周围神经病变效果较好 ,副作用小 ,值得推广运用  相似文献   
68.
目的:探讨不同方案治疗早期糖尿病视网膜病变的经济效果,找出既经济又有效的方案。方法:对目前临床常用的4种不同治疗方案(导升明、胰激肽原酶、复方血栓通胶囊、复方丹参滴丸,治疗时间均为90d)运用药物经济学方法进行成本-效果分析。结果:4种方案所需费用分别为1417.50元、810.00元、891.00元、656.10元;治疗有效率分别为94.25%、85.09%、85.17%、83.53%;成本-效果比分别为15.04、9.52、10.46、7.85。结论:复方丹参滴丸治疗效果较好,不良反应少,成本低廉。  相似文献   
69.
The identification of angiotensin-converting enzyme (ACE)2 opened new recognition of renin-angiotensin system (RAS). ACE2 degrades Ang Ⅱ to Ang (1-7), maintains homeostasis of RAS with ACE. Studies have revealed that ACE2 has important functions in diabetic nephropathy. It may be a target for drug and is used as gene therapy for diabetic nephropathy. Amplifying ACE2 activity may have a potential therapeutic role for diabetic nephropathy.  相似文献   
70.
中、老年代谢综合征患者的临床特点分析   总被引:1,自引:0,他引:1  
目的 比较中、老年代谢综合征(MS)患者的临床特点.方法 收集1996~2006年在解放军总医院门诊查体且符合中国人MS诊断标准(CDS)的947例中、老年患者的临床资料.其中老年人679例,中年人268例.分析中、老年患者MS各组分的差异,以及各组分的相关因素等.结果 947例患者中,男性582例(老年423例,中年159例),女性365例(老年256例,中年109例).老年男性患者的年龄大于老年女性(81.5±6.5 vs 74.5±8.8岁,P<0.01),老年男性的体重指数(BMI)高于中年男性(27.14±2.51 vs 25.98±2.38,P<0.01).老年患者的空腹、餐后血糖和收缩压均高于同性别的中年患者,而舒张压无显著差异.中年男性的甘油三酯高于老年男性.中年女性的高密度脂蛋白胆固醇高于男性.多元回归分析显示,男女患者空腹血糖均与餐后2h血糖有相关性(男性R2=0.463,P<0.05;女性R2=0.613,P<0.05).餐后2h血糖与年龄存在相关性(男性,R2=0.522,P<0.01;女性R2=0.716,P<0.05).收缩压与多种指标均有相关性,男性患者收缩压与年龄(R2=0.396,P<0.01)和舒张压(R2=0.535,P<0.05)均有相关性;女性患者的收缩压与BMI(R2=0.557,P<0.05)、舒张压(R2=0.434,P<0.05)、餐后2h血糖(R2=0.434,P<0.01)及空腹血糖(R2=0.473,P<0.05)均有相关性.Logistic回归分析示年龄(OR=2.1,95%CI:1.3~2.7)、空腹血糖(OR=1.7,95%CI:1.2~3.1)和收缩压(OR=1.4,95%CI:1.2~2.9)是预测代谢综合征组分含量的影响因素.结论 中老年代谢综合征患者的代谢指标有差异,年龄、空腹血糖和收缩压可作为代谢综合征的筛选指标.  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