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   2876篇
  免费   167篇
  国内免费   68篇
耳鼻咽喉   26篇
儿科学   72篇
妇产科学   105篇
基础医学   283篇
口腔科学   51篇
临床医学   334篇
内科学   560篇
皮肤病学   46篇
神经病学   186篇
特种医学   246篇
外科学   442篇
综合类   60篇
一般理论   7篇
预防医学   262篇
眼科学   48篇
药学   227篇
肿瘤学   156篇
  2022年   19篇
  2021年   61篇
  2020年   33篇
  2019年   44篇
  2018年   61篇
  2017年   37篇
  2016年   44篇
  2015年   46篇
  2014年   70篇
  2013年   116篇
  2012年   128篇
  2011年   102篇
  2010年   91篇
  2009年   80篇
  2008年   124篇
  2007年   188篇
  2006年   134篇
  2005年   126篇
  2004年   111篇
  2003年   118篇
  2002年   112篇
  2001年   92篇
  2000年   86篇
  1999年   75篇
  1998年   45篇
  1997年   50篇
  1996年   42篇
  1995年   36篇
  1994年   36篇
  1993年   29篇
  1992年   43篇
  1991年   43篇
  1990年   41篇
  1989年   40篇
  1988年   53篇
  1987年   50篇
  1986年   31篇
  1985年   43篇
  1984年   25篇
  1983年   23篇
  1982年   25篇
  1981年   20篇
  1980年   21篇
  1979年   28篇
  1978年   18篇
  1977年   28篇
  1976年   18篇
  1973年   24篇
  1972年   21篇
  1970年   22篇
排序方式: 共有3111条查询结果,搜索用时 343 毫秒
51.
X-linked hypohidrotic ectodermal dysplasia (XLHED; ectodysplasin deficiency) has been classically described as affecting hair, sweat glands, and dentition. What may be underappreciated is the effect ectodysplasin deficiency has on glands surrounding the airways and eyes and the resulting chronic health issues. In this study, 12 male children (age range 6–13 years) and 14 male adults with XLHED (18–58 years of age) were investigated by pulmonary function tests, measurement of fractional exhaled nitric oxide, and by ophthalmologic assessments. Twelve healthy individuals (six children, six adults) served as controls. Signs of airway constriction and inflammation were detected in eight children with XLHED, including the youngest subject, and in ten adult XLHED patients. Increased tear osmolarity, reduced tear film break-up time, and other ocular abnormalities were also present at an early age. Five of 12 XLHED subjects not reporting a history of asthma and 7 of the 12 patients not reporting a history of dry eye issues showed at least two abnormal test results in the respective organ system. The presence of residual sweat ducts, suggestive of partial ectodysplasin gene expression, correlated with milder disease in two XLHED subjects with mutations affecting the collagen-like domain of ectodysplasin. Conclusion: The high prevalence of asthma-like symptoms in XLHED patients as young as 6 years and a similar prevalence of dry eye problems indicate that screening evaluation, regular monitoring, and consideration of therapeutic intervention should begin in early childhood.  相似文献   
52.
53.
54.
The objective was to investigate the relationship between the presence of different types of antinuclear antibodies (ANA) in patients with systemic sclerosis (SSc) and the presence of clinical features. Sera from 230 patients with SSc were tested for the presence of ANA, including anticentromere antibodies (ab), antitopoisomerase I ab, anti- U1 RNP ab and antinucleolar ab, including anti-Th RNP, anti-U3 RNP and anti-U17 RNP. Clinical features were registered prospectively in a clinical database. Eighty-two per cent of the patients were women. The median age was 58 yr (45-67, quartiles) and median age at disease onset was 44 (30-55) yr. ANA were found in 86% of the patients (anticentromere: 34%; antitopoisomerase I: 14%; anti-U1 RNP: 6.5%; antinucleolar total: 16%; anti-Th RNP: 2.2%; anti-U3 RNP: 3.5%; anti- U17 RNP: 0%). Anticentromere ab were found to be related to a high prevalence of calcinosis, telangiectasia, digital ulcers, acrosclerosis, primary biliary cirrhosis, isolated reduction of pulmonary diffusing capacity, and a low prevalence of radiological evidence of pulmonary fibrosis. Antitopoisomerase I ab were associated with a high prevalence of digital joint deformity, distal osteolysis, radiological signs of pulmonary fibrosis, a low prevalence of calcinosis and late onset of disease. Anti-U1 RNP ab were related to a high prevalence of arthritis and myositis, a low prevalence of calcinosis, and early disease onset. The presence of antinucleolar ab, including anti-U3 RNP and anti-Th RNP, was not significantly related to any particular clinical features in this study; possibly due to the small number of patients with these ab. The presence of anticentromere, antitopoisomerase I and anti-U1 RNP ab in the serum was also found to have previously described clinical correlations in a group of Danish SSc patients.   相似文献   
55.
56.
取样胶囊主要是吸取人体消化道内的消化液进行研究,本文以胃液为例,对取样胶囊吸取消化液进行探讨,分析在取样胶囊的研究中选取何种吸附材料最合适.首先对胃液成分进行分析,然后配置模拟胃液,选取六种不同吸附材料进行了吸附实验,并按实验结果绘制了不同的吸附曲线.由实验结果,对各种材料的吸附量、吸附稳定性和可靠性等进行了对比分析,同时还对取样机构模型设计的简单化因素进行分析.最后得出结论,认为德制胶棉在各个因素上都有明显的优势,适宜作为取样胶囊中的吸附材料.  相似文献   
57.
Endocarditis in the drug addict   总被引:4,自引:0,他引:4  
  相似文献   
58.
Cystic fibrosis (CF) is characterized by defective cystic fibrosis transmembrane regulator (CFTR) expression and function, associated with abnormal ion transport and mucociliary clearance, and clinical lung disease. Triphosphate nucleotides such as uridine-5'-triphosphate (UTP) and INS 365, may be useful for CF through actions, mediated via P2Y(2) extracellular receptors, on chloride and liquid secretion, and ciliary beat frequency. INS 365 may offer chemical stability advantages over UTP. In a randomized, double-blind, multicenter phase I study, we studied the safety and maximally tolerated dose of escalating, single doses of aerosolized INS 365, in adult and pediatric patients with mild to moderate CF lung disease (FEV(1) > or = 45% predicted). In four successive dose cohorts of adult patients (n = 12 per cohort, age > or = 18 years) and four successive pediatric dose cohorts (n = 12 per cohort, age 5-12 years), patients were randomized 3:1 active/placebo (0.9% saline) to evaluate doses of 20, 40, 80, and 100 mg INS 365 delivered by nebulizer (Pari Star ). Sputum was collected pre- and post-dosing to obtain preliminary results on clinical efficacy. After each dose cohort, a Data Safety Monitoring Committee (DSMC) reviewed the data. Forty-eight adult and 36 pediatric patients completed the protocol (up to 100 mg for adults, 80 mg for pediatric patients). The predominant adverse events were cough, wheezing, chest tightness, and a decrease in FEV(1) (occurring in 8/48 adults, and 5/36 pediatric patients), which occurred predominantly in the 80-mg and 100-mg dose cohorts. Though a few adult patients had a tendency to increase sputum production, there was little consistent effect noted on sputum production in this acute, single-dose study. The data suggest that aerosolized INS 365 is safe when delivered at single doses of up to 40 mg in adults and children with CF, but that higher doses are unlikely to be tolerated.  相似文献   
59.

Background:

Monoamine reuptake inhibitors exhibit unique clinical profiles that reflect distinct engagement of the central nervous system (CNS) transporters.

Methods:

We used a translational strategy, including rodent pharmacokinetic/pharmacodynamic modeling and positron emission tomography (PET) imaging in humans, to establish the transporter profile of TD-9855, a novel norepinephrine and serotonin reuptake inhibitor.

Results:

TD-9855 was a potent inhibitor of norepinephrine (NE) and serotonin 5-HT uptake in vitro with an inhibitory selectivity of 4- to 10-fold for NE at human and rat transporters. TD-9855 engaged norepinephrine transporters (NET) and serotonin transporters (SERT) in rat spinal cord, with a plasma EC50 of 11.7ng/mL and 50.8ng/mL, respectively, consistent with modest selectivity for NET in vivo.Accounting for species differences in protein binding, the projected human NET and SERT plasma EC50 values were 5.5ng/mL and 23.9ng/mL, respectively. A single-dose, open-label PET study (4–20mg TD-9855, oral) was conducted in eight healthy males using the radiotracers [11C]-3-amino-4- [2-[(di(methyl)amino)methyl]phenyl]sulfanylbenzonitrile for SERT and [11C]-(S,S)-methylreboxetine for NET. The long pharmacokinetic half-life (30–40h) of TD-9855 allowed for sequential assessment of SERT and NET occupancy in the same subject. The plasma EC50 for NET was estimated to be 1.21ng/mL, and at doses of greater than 4mg the projected steady-state NET occupancy is high (>75%). After a single oral dose of 20mg, SERT occupancy was 25 (±8)% at a plasma level of 6.35ng/mL.

Conclusions:

These data establish the CNS penetration and transporter profile of TD-9855 and inform the selection of potential doses for future clinical evaluation.  相似文献   
60.
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