全文获取类型
收费全文 | 59217篇 |
免费 | 5450篇 |
国内免费 | 4194篇 |
专业分类
耳鼻咽喉 | 646篇 |
儿科学 | 642篇 |
妇产科学 | 570篇 |
基础医学 | 6039篇 |
口腔科学 | 885篇 |
临床医学 | 7544篇 |
内科学 | 8152篇 |
皮肤病学 | 586篇 |
神经病学 | 2789篇 |
特种医学 | 2507篇 |
外国民族医学 | 36篇 |
外科学 | 6382篇 |
综合类 | 10815篇 |
现状与发展 | 13篇 |
一般理论 | 3篇 |
预防医学 | 4175篇 |
眼科学 | 1631篇 |
药学 | 6361篇 |
53篇 | |
中国医学 | 4139篇 |
肿瘤学 | 4893篇 |
出版年
2024年 | 251篇 |
2023年 | 855篇 |
2022年 | 2312篇 |
2021年 | 2946篇 |
2020年 | 2394篇 |
2019年 | 1872篇 |
2018年 | 2019篇 |
2017年 | 1996篇 |
2016年 | 1797篇 |
2015年 | 2891篇 |
2014年 | 3624篇 |
2013年 | 3348篇 |
2012年 | 4844篇 |
2011年 | 5187篇 |
2010年 | 3609篇 |
2009年 | 2927篇 |
2008年 | 3381篇 |
2007年 | 3162篇 |
2006年 | 3048篇 |
2005年 | 2819篇 |
2004年 | 1842篇 |
2003年 | 1742篇 |
2002年 | 1443篇 |
2001年 | 1193篇 |
2000年 | 1114篇 |
1999年 | 1063篇 |
1998年 | 705篇 |
1997年 | 622篇 |
1996年 | 542篇 |
1995年 | 497篇 |
1994年 | 384篇 |
1993年 | 308篇 |
1992年 | 322篇 |
1991年 | 317篇 |
1990年 | 228篇 |
1989年 | 190篇 |
1988年 | 217篇 |
1987年 | 188篇 |
1986年 | 126篇 |
1985年 | 109篇 |
1984年 | 76篇 |
1983年 | 42篇 |
1982年 | 41篇 |
1981年 | 53篇 |
1980年 | 42篇 |
1979年 | 44篇 |
1978年 | 22篇 |
1977年 | 26篇 |
1976年 | 15篇 |
1975年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Vincent Chung Liang Liu Zhaoxiang Bian Zhongzhen Zhao Wai Leuk Fong Wan Fung Kum Jing Gao Min Li 《Movement disorders》2006,21(10):1709-1715
The objective of this study is to assess the efficacy and safety of herbal medicines (HMs), as a monotherapy or adjunct therapy, compared to placebo or conventional approaches in the treatment of idiopathic Parkinson's disease (PD). We conducted a systematic review of randomized controlled trials from both conventional and alternative medicine sources. Outcome measures were overall improvement, quality of life, reduction of levodopa dose, and adverse events. Nine studies were included, each testing a different HM. Six of the trials had limited internal validity due to major flaws in design, including the lack of proper randomization; insufficient blinding; unclear inclusive criteria in terms of diagnostic criteria, baseline staging, and duration of disease; lack of proper sample size calculation; and insufficient data analysis. Imbalances in gender and ethnicity among the patients in the included trials were observed. No major adverse events emerged, and no specific pattern was detected from the trials describing such data. In addition to major methodological defects, heterogeneity in (1) HM tested, (2) control treatment, and (3) outcome measure hindered in-depth data analysis and synthesis. Current evidence is insufficient to evaluate the efficacy and safety of various HMs. Further studies with improved trial design and reporting, with assessment on cost-effectiveness, quality of life, and qualitative data are warranted. 相似文献
2.
3.
4.
多囊卵巢综合征患者卵巢间质胰岛素样生长因子受体的表达 总被引:3,自引:0,他引:3
目的:探讨肥胖及非肥胖多囊卵巢综合征(PCOS)患者卵巢间质胰岛素样生长因子(IGF-Ⅰ)受体基因的定量表达。方法:用逆转录基因扩增技术(RT-PCR),检测35例PCOS患者(肥胖组15例,非肥胖组20例)及20例正常妇女(对照组)卵巢间质细胞IGF-Ⅰ受体mRNA的表达量(灰度比值)。并对IGF-Ⅰ受体基因mRNA逆转录的cDNA产物进行限制性内切酶酶切分析。结果:PCOS两组IGF-Ⅰ受体基因的表达量显著高于对照组,PCOS两组灰度比值为1.184±0.240,对照组灰度比值为0.999±0.086(P<0.001)。非肥胖组(1.238±0.387)明显大于肥胖组(1.058±0.109,P<0.1)。酶切分析证实,3组IGF-Ⅰ受体基因扩增片段相同,PCOS两组未发现明显的碱基突变存在。结论:PCOS患者卵巢间质IGF-Ⅰ受体基因呈过度表达。且PCOS非肥胖患者局部IGF-I受体表达高于PCOS肥胖患者。 相似文献
5.
6.
The granulocyte colony-stimulating factor (G-CSF) has been shown to accelerate recovery from severe neutropenia and to decrease the incidence of documented infections after intensive chemotherapy in cancer patients. However, the routine prophylactic use of G-CSF is expensive. This study was conducted to determine the role of G-CSF as adjunct therapy for septicemia following neutropenia caused by chemotherapy in children with acute leukemia. Fifty consecutive episodes of septicemia were studied involving 34 episodes of Gram-negative, 7 episodes of Gram-positive, 5 episodes of polymicrobial bacterial septicemia, one episode of fungemia, and 3 episodes of disseminated fungal infection. In the first 25 episodes, G-CSF was not used (group A). For the next 16 episodes, G-CSF 200 μg per square meter per day subcutaneously was given immediately after the septicemia was documented until the absolute neutrophil count was maintained at more than 1,500 per cubic millimeter (group B). Thereafter, G-CSF at the same dose as that of group B was prophylactically used in all the children who received high-dose cytosine arablnc-side-containing regimens. Nine episodes of septicemia occurred (group C). The incidences of mortality per episode of septicemia in groups A, B, and C were 12.0% (3/25), 12.5% (2/16) and 0% (0/9), respectively. Statistically, there was no difference between the three groups overall and in pair-wise comparisons (all P > 0.5). The durations of G-CSF administration in group B ranged from 6 to 26 days with a median of 12 days and the durations of G-CSF administration in group C ranged from 10 to 23 days with a median of 19 days. With or without G-CSF, there may be no significant difference in the mortality of septicemia following neutropenia caused by chemotherapy in children with acute leukemia. 相似文献
7.
目的:观察环境温度的改变对MⅡ期人卵纺锤体结构的影响.方法:40例非男性因素的不孕妇女,将常规体外授精后未受精的MⅡ期卵子置于室温(23~25℃)直至纺锤体消失.于纺锤体消失后,将卵子分成3个实验组:1组纺锤体消失后立即复温(n=8);2组纺锤体消失后室温下静置5 min再复温(n=6);3组纺锤体消失后室温下静置10 min再复温(n=6).卵子复温后5 min,10 min,2 h分别观察纺锤体的复现情况.结果:20个未受精的MⅡ期卵子置于室温下5 min内纺锤体均消失.1组中的8个卵子,2组中的6个卵子复温后再次观测到了MⅡ期纺锤体.3组中的6个卵子只有3个卵子再次出现了MⅡ期纺锤体.对照组的18个卵子放置于37℃恒温板上观察30 min,纺锤体均未见消失.结论:MⅡ期卵子纺锤体对环境温度的改变非常敏感.温度降低将导致纺锤体消失,随着时间的延长,纺锤体复现几率明显减少. 相似文献
8.
Kuo-Sheng Hung MD Phd Chung-Ling Liang MD Cheng-Haung Wang MD Hsueh-Wen Chang PhD Naeun Park MS Suh-Hang Hank Juo MD PhD 《Journal of clinical neuroscience》2004,11(8):849-853
Frontal intracerebral haemorrhage (ICH) is a common result of cranial trauma. Outcome differences between bilateral and unilateral frontal ICH are not well studied but would be valuable to predict prognosis in clinical practice. Two aims are proposed in this study: first to compare the risk of developing delayed ICH after bilateral or unilateral frontal ICH, and second to determine the variables helpful to predict outcome according to the Glasgow Outcome Scale (GOS). Between January 1993 and December 1997, 694 consecutive patients with traumatic ICH were admitted to the Chang Gung Medical Center within 24 h of the trauma. Patients with ICH in sites other than the frontal lobes were excluded. A total of 161 cases (mean age 46.3+/-20.3 years), including 57 bilateral (mean age 52.5+/-18.7 years) and 104 unilateral (mean age 42.9+/-20.5 years) traumatic frontal ICH were studied. Twenty-eight of 57 patients (49%) with bifrontal ICH versus 17 of 104 patients (16%) with unilateral frontal ICH had a further, delayed ICH. In 42 of 45 patients (93%) with delayed ICH, this occurred within 5 days of the initial trauma. Multivariate logistic regression was used to select significant predictors of outcome. We found that delayed ICH (p<0.001), age (p=0.004) and mechanism of injury (p=0.001) explained the worse outcome in patients with bifrontal ICH. The best-fitting logistic regression model included three variables: delayed ICH (p=0.011), initial GCS (p=0.023), and a sum score of clinical and radiological variables (p=0.003). Bifrontal ICH tended to occur in older patients after a fall and was associated with a higher risk of developing delayed ICH or brain stem compression compared to unilateral ICH damage. Using these three variables - delayed ICH, initial GCS, and the sum score - in a logistical regression model is useful to predict outcome in patients with traumatic frontal ICH and may aid patient management. 相似文献
9.
浅谈基因治疗的现状及其面临的困境 总被引:1,自引:0,他引:1
基因治疗将在未来的疾病治疗中扮演重要的角色,然而这一新颖的技术却面临着诸多问题,本文论述了基因治疗的发展现状及其所面临的技术难题。 相似文献
10.
左双腔支气管导管管端位置与吸气峰压变化的关系 总被引:13,自引:3,他引:10
目的 观测无隆突钩双腔支气管导管(DLT)管端位置与吸气峰压(Ppeak)以及肺顺应性环形状改变的关系,探讨用Ppeak和顺应性环的变化评估DLT管端位置的可行性。方法 拟行右侧剖胸手术的成年患者32例,静脉诱导后插入左Mallinckrodt DLT,吸入氧化亚氮和地氟醚维持麻醉。按纤维支气管镜(FOB)确认DLT管端位置和通气方式将观测过程分为四个阶段:第一阶段(S1),管端位置正确的双肺通气;第二阶段(S2),管端位置正确的左侧单肺通气;第三阶段(S3),管端插入左下支气管(置管过深)的左侧单肺通气;第四阶段(S。),管端处在左支气管开口(置管偏浅)的左侧单肺通气。每阶段均机械通气15min。结果 回归方程预计插管深度与FOB检查符合者占71.9%。S2时Ppeak值比S1时增加50.8%,肺顺应性(Cdyn)值减少36.2%;S3时Ppeak值比S1时增加87.4%,Cdyn值减少56.8%。PV环曲线斜率向右明显移位,环体显著延长。结论 用无隆突钩DLT行肺隔离,在无FOB定位的条件时,联合应用听诊法、回归方程预计插管深度、动态监测气道峰压和P-V环的变化综合评估,可提高DLT管端的正确到位率。单肺通气的气道峰压超过双肺通气时的1.65倍,且气道峰压超过25cm H2O.应高度怀疑DLT管端发生过深移位。 相似文献