全文获取类型
收费全文 | 3844篇 |
免费 | 456篇 |
国内免费 | 82篇 |
专业分类
耳鼻咽喉 | 13篇 |
儿科学 | 32篇 |
妇产科学 | 49篇 |
基础医学 | 449篇 |
口腔科学 | 140篇 |
临床医学 | 206篇 |
内科学 | 637篇 |
皮肤病学 | 50篇 |
神经病学 | 372篇 |
特种医学 | 120篇 |
外国民族医学 | 1篇 |
外科学 | 701篇 |
综合类 | 143篇 |
现状与发展 | 1篇 |
预防医学 | 91篇 |
眼科学 | 171篇 |
药学 | 156篇 |
1篇 | |
中国医学 | 39篇 |
肿瘤学 | 1010篇 |
出版年
2024年 | 13篇 |
2023年 | 97篇 |
2022年 | 169篇 |
2021年 | 257篇 |
2020年 | 214篇 |
2019年 | 195篇 |
2018年 | 195篇 |
2017年 | 192篇 |
2016年 | 194篇 |
2015年 | 239篇 |
2014年 | 302篇 |
2013年 | 285篇 |
2012年 | 170篇 |
2011年 | 204篇 |
2010年 | 133篇 |
2009年 | 170篇 |
2008年 | 167篇 |
2007年 | 155篇 |
2006年 | 143篇 |
2005年 | 106篇 |
2004年 | 82篇 |
2003年 | 94篇 |
2002年 | 84篇 |
2001年 | 82篇 |
2000年 | 52篇 |
1999年 | 30篇 |
1998年 | 51篇 |
1997年 | 46篇 |
1996年 | 32篇 |
1995年 | 35篇 |
1994年 | 40篇 |
1993年 | 31篇 |
1992年 | 20篇 |
1991年 | 15篇 |
1990年 | 18篇 |
1989年 | 12篇 |
1988年 | 6篇 |
1987年 | 11篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 9篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有4382条查询结果,搜索用时 515 毫秒
1.
2.
目的 对学龄期近视进展儿童进行调节功能的客观检查与分析,观察调节功能与近视进展之间的相关性。方法 选取2017年至2018年在首都医科大学附属北京同仁医院视光学门诊定期就诊的71名学龄期儿童为研究对象,根据受试者近年的屈光度进展速度,按≤0.50 D·a-1、>0.50~1.00 D·a-1、>1.00~1.50 D·a-1、>1.50 D·a-1分为4组,使用人眼调节分析仪对受试者进行调节功能的客观测量与分析,记录不同调节刺激视标下4组的客观调节反应值和客观调节微波动值,并作对比。结果 在所有调节视标上,各组随着调节刺激幅度增加,客观调节反应值也逐渐增加,4组在不同调节刺激视标下的客观调节反应值及平均的客观调节反应值差异均无统计学意义(均为P>0.05)。≤0.50 D·a-1、>0.50~1.00 D·a-1、>1.00~1.50 D·a-1、>1.50 D·a-1近视进展速度组调节微波动值分别为(62.2±5.6)D、(62.5±5.3)D、(66.5±6.0)D和(58.0±6.5)D,4组间差异有统计学意义(F=6.424,P=0.001),在+0.50~-0.50 D、-2.00 D调节刺激视标下,4组的客观调节微波动值比较差异均有统计学意义(均为P<0.05),在其余调节刺激视标下差异均无统计学意义(均为P>0.05)。结论 对于学龄期儿童的近视进展速度,客观调节微波动值相对于客观调节反应值可能是一个更为敏感的相关指标。 相似文献
3.
《Journal of vascular and interventional radiology : JVIR》2020,31(1):25-34
PurposeTo investigate the safety of yttrium-90 radioembolization in combination with checkpoint inhibitor immunotherapy for the treatment of hepatocellular carcinoma (HCC).Materials and MethodsThis single-center retrospective study included 26 consecutive patients with HCC who received checkpoint inhibitor immunotherapy within 90 days of radioembolization from April 2015 to May 2018. Patients had preserved liver function (Child-Pugh scores A–B7) and either advanced HCC due to macrovascular invasion or limited extrahepatic disease (21 patients) or aggressive intermediate stage HCC that resulted in earlier incorporation of systemic immunotherapy (5 patients). Clinical documentation, laboratory results, and imaging results at 1- and 3-month follow-up intervals were reviewed to assess treatment-related adverse events and treatment responses.ResultsThe median follow-up period after radioembolization was 7.8 months (95% confidence interval [CI], 5.6–11.8). There were no early (30-day) mortality or grades 3/4 hepatobiliary or immunotherapy-related toxicities. Delayed grades 3/4 hepatobiliary toxicities (1–3 months) occurred in 2 patients in the setting of HCC disease progression. One patient developed pneumonitis. The median overall survival from first immunotherapy was 17.2 months (95% CI, 10.9–23.4). The median overall survival from first radioembolization was 16.5 months (95% CI, 6.6–26.4). From first radioembolization, time to tumor progression was 5.7 months (95% CI, 4.2–7.2), and progression-free survival was 5.7 months (95% CI, 4.3–7.1).ConclusionsRadioembolization combined with checkpoint inhibitor immunotherapy in cases of HCC appears to be safe and causes limited treatment-related toxicity. Future prospective studies are needed to identify the optimal combination treatment protocols and evaluate the efficacy of combination therapy. 相似文献
4.
《Clinical Lymphoma, Myeloma & Leukemia》2020,20(8):e461-e467
IntroductionVon Willebrand factor (vWF) cleaving protease ADAMTS-13 has a key role for maintaining normal size of vWF. A deficiency or dysfunction of vWF cleaving protease is associated with ultra large vWF multimers and thrombotic microangiopathy. Patients with cancers have reduced levels of vWF cleaving protease. In this pilot study, we have evaluated whether or not deficiencies of ADAMTS-13 were present in myelodysplastic syndromes (MDS). Moreover, we assessed if a reduction in basal levels of ADAMTS-13 may play a role in the prognosis of MDS.Patients and MethodsWe measured and compared the levels of vWF cleaving protease ADAMTS-13 in 100 patients with MDS and 35 healthy controls. Patients were divided into 2 groups according to the International Prognostic Scoring System: group I consisting of 44 patients with low-risk MDS and group II of 56 patients with high-risk MDS. Patients with high-risk and low-risk MDS presented significantly lower levels of ADAMTS-13 than controls (P < .001 and P = .0177, respectively). High-risk patients had significantly lower levels of ADAMTS-13 when compared with the low-risk group (P < .001).ResultsWe found that reduced levels of ADAMTS-13 have a relationship with overall survival (P < .001). Statistical analysis showed that ADAMTS-13 correlates with cytogenetics (P < .001) and a tendency of slight correlation with platelet count and basal levels of ADAMTS-13 (R, 0.35; P value, 0.001). Moreover, we found that levels of ADAMTS-13 have correlation with response to treatment (P < .001).ConclusionsADAMTS-13 in MDS might represent a surrogate marker of prognosis, response to therapy, or disease progression. Further studies are needed. 相似文献
5.
Renal fibrosis and the origin of the renal fibroblast. 总被引:4,自引:0,他引:4
Many studies have determined that the extent of tubulointerstitialinvolvement, particularly fibrosis, correlates better with renalfunction than glomerular changes do, thus, the extent of tubulointerstitialdamage in any given renal biopsy has important implicationsfor the renal prognosis of the patient (summarized in [1]).Tubulointerstitial fibrosis is characterized by the accumulationof extracellular matrix components including collagen typesI, III, IV, proteoglycans and fibronectin. In recent years,much controversy has been created in the nephrology communityregarding the origin of matrix-producing cells in the kidney.Several possibilities exist, including activation of residentinterstitial fibroblasts, migrating haematopoietic or mesenchymalstem cells from the bone marrow, periadventitial cells and epithelialmesenchymaltransition (EMT) of tubular epithelial cells. This review summarizesrecent data indicating the possible origin of matrix-producingcells in the kidney, and illustrates from a clinical point of 相似文献
6.
The genetic program that drives tumor metastasis and the mode and timing of its initiation are of great practical significance to clinical management. Modern technical advances open new opportunities for gaining useful relevant information. Gene expression profiles of histologically‐verified viable tissue from lymph node metastases were compared with those of matched primary breast cancers from 10 different patients, among samples from over 400 cases, using high‐throughput oligonucleotide arrays comprising probes for 22,000 genes. It was observed that metastases have very similar expression signatures to their parent tumors. However, detailed computational analysis revealed that a small number of genes were consistently differentially expressed between 100% of tumors and metastases, suggesting that these are mechanistically important. Lists of such candidate genes, of potential clinical interest, are provided. We interpret these results in the framework of a meta‐analysis of previous investigations by others and ourselves and of existing clinical knowledge on the behavior of human tumors. The collective data show that metastases resemble their primary tumors but the signatures obtained in different studies are not sufficiently reproducible or informative to be prognostically useful, although they do give valuable insights into the pathogenesis and biology of human tumor metastasis. The findings indicate that the genetic program encoding metastasis is implemented progressively over time although, occasionally, this evolution can occur rapidly, early in the life of the neoplasm. The important clinical significance of this deduction is that, in most patients, early detection provides time for appropriate therapeutic intervention to be effective in obstructing metastasis. 相似文献
7.
8.
LYSOSOMAL IRON ACCUMULATION AND TUBULAR DAMAGE IN RAT PUROMYCIN NEPHROSIS AND AGEING 总被引:1,自引:0,他引:1
David C. H. Harris Ching Tay Brian J. Nankivell 《Clinical and experimental pharmacology & physiology》1994,21(2):73-81
1. Energy dispersive X-ray spectrometry was used to examine the relationship between proteinuria and increased urinary iron excretion, and structural and functional damage in puromycin nephrosis. 2. After 11–12 days rats treated with puromycin (10 mg/100g, i.v.i.) had greater proteinuria (211.6 ± 35.7 mg/day, mean ± s.e.m.) and urinary iron excretion (15.4 ± 2.2 μg/day) than salinetreated controls (14.5 ± 1.4 mg/day and 1.1 ± 0.2 μg/day, respectively, both P<0.001). 3. On day 13, mean lysosomal iron concentration of proximal tubular cells (306.6 ± 64.5 vs 11.9 ± 8.6 mg%, P<0.001), and proximal tubular cell damage assessed semi-quantitively (1.17 ± 0.10 vs 0.62 ± 0.10, P<0.001) were higher and creatinine clearance (0.15 ± 0.01 vs 0.29 ± 0.02 mL/min perg kidney weight, P<0.001) lower than in control rats. 4. At days 35, 60 and 360 there were no differences in any of the measured parameters between rats treated with puromycin or saline, and in both groups proteinuria, tissue damage and lysosomal iron concentration increased with time. 5. Lysosomal iron accumulation was the only independent predictor of both functional and structural damage. 6. In conclusion, the apparent association between proteinuria and tubulo-interstitial damage in puromycin nephrosis, and with ageing, is best explained by factors associated with accumulation of iron within lysosomes of proximal tubule cells. 相似文献
9.
Long-term effects of tacrine (THA) on cognitive functions of very mild AD patients were studied. The stability of possible positive changes following prolonged treatment and the effect of increased dose was also studied. Three patients were treated with tacrine (80 mg/day) and the effect on cognitive functions was measured with a neuropsychological test battery. Two of the patients (Pats 1 and 4) showed clear positive changes in all parameters measured. The third patient (Pat 5) did not show as clear positive responses. The effect of the initial treatment dose diminished over time. After raising the dose two of the patients showed improvement in cognitive tests reaching their initial level of performance or even better in most of the tests. This positive effect was not as clear in patient 5. After 13 months of tacrine all patients still showed positive changes in some of the tests. Compared to a hypothetical progression curve for untreated AD patients the patients treated with tacrine seemed to have slower progression. In conclusion, it seems that long-term positive effects on cognitive functions of AD patients can be reached with tacrine and it seems to be possible to slow down the progression of the disease. However, to reach long-term positive effects increasing doses seem to be needed. AD patients seem to differ in their response to tacrine. 相似文献
10.
左侧气胸的心电图特征及原因分析 总被引:4,自引:0,他引:4
目的探讨左侧气胸致心电图改变的特征及产生原因。方法回顾性分析50例左侧气胸患者的心电图和X线胸片资料。结果50例(100%)均呈R波逆递增,V1 ̄V6导联QRS波平均振幅呈V2>V3>V4>V5。左侧胸导联低电压39例(78%),而II、III、aVF导联QRS波振幅全部>0.5mV。顺钟向转位38例(76%),胸导联QRS波振幅随呼吸周期性改变31例(62%),胸导联QRS波振幅最大/最小的比值与气胸肺组织压缩程度呈正相关(p<0.05)。结论胸导联R波逆递增是左侧气胸最重要的特征性心电图改变,气胸的严重程度与胸导联QRS波振幅最大/最小的比值呈正比。 相似文献