全文获取类型
收费全文 | 5734篇 |
免费 | 476篇 |
国内免费 | 154篇 |
专业分类
耳鼻咽喉 | 60篇 |
儿科学 | 110篇 |
妇产科学 | 121篇 |
基础医学 | 683篇 |
口腔科学 | 144篇 |
临床医学 | 619篇 |
内科学 | 1325篇 |
皮肤病学 | 58篇 |
神经病学 | 336篇 |
特种医学 | 136篇 |
外科学 | 815篇 |
综合类 | 287篇 |
一般理论 | 7篇 |
预防医学 | 372篇 |
眼科学 | 114篇 |
药学 | 489篇 |
1篇 | |
中国医学 | 146篇 |
肿瘤学 | 541篇 |
出版年
2023年 | 39篇 |
2022年 | 79篇 |
2021年 | 154篇 |
2020年 | 96篇 |
2019年 | 133篇 |
2018年 | 146篇 |
2017年 | 114篇 |
2016年 | 156篇 |
2015年 | 192篇 |
2014年 | 240篇 |
2013年 | 277篇 |
2012年 | 400篇 |
2011年 | 439篇 |
2010年 | 280篇 |
2009年 | 246篇 |
2008年 | 338篇 |
2007年 | 388篇 |
2006年 | 299篇 |
2005年 | 342篇 |
2004年 | 302篇 |
2003年 | 275篇 |
2002年 | 241篇 |
2001年 | 198篇 |
2000年 | 162篇 |
1999年 | 113篇 |
1998年 | 49篇 |
1997年 | 51篇 |
1996年 | 45篇 |
1995年 | 30篇 |
1994年 | 29篇 |
1993年 | 26篇 |
1992年 | 51篇 |
1991年 | 63篇 |
1990年 | 50篇 |
1989年 | 34篇 |
1988年 | 27篇 |
1987年 | 16篇 |
1986年 | 30篇 |
1985年 | 29篇 |
1984年 | 19篇 |
1983年 | 18篇 |
1982年 | 8篇 |
1981年 | 9篇 |
1980年 | 13篇 |
1979年 | 18篇 |
1978年 | 21篇 |
1977年 | 11篇 |
1976年 | 9篇 |
1974年 | 11篇 |
1973年 | 8篇 |
排序方式: 共有6364条查询结果,搜索用时 31 毫秒
51.
Increased endostatin/collagen XVIII expression correlates with elevated VEGF level and poor prognosis in hepatocellular carcinoma. 总被引:2,自引:0,他引:2
Tsung-Hui Hu Chao-Cheng Huang Chia-Ling Wu Pey-Ru Lin Shang-Yun Liu Jui-Wei Lin Jiin-Haur Chuang Ming Hong Tai 《Modern pathology》2005,18(5):663-672
Liver is the primary source for collagen XVIII, the precursor of angiogenesis inhibitor, endostatin. However, the role of endostatin/collagen XVIII expression during liver carcinogenesis remains elusive. Therefore, we studied its expression in five hepatoma cell lines and 105 hepatocellular carcinoma specimens. The poorly differentiated hepatoma cell lines exhibited increased endostatin/collagen XVIII levels compared with the well-differentiated ones. In hepatoma tissues, endostatin/collagen XVIII expression was detected in various types of liver cells and was significantly stronger in adjacent nontumor tissues than that in tumors (P<0.001). Endostatin/collagen XVIII expression in nontumor tissues correlated with tumor stages (P=0.014) and expression of vascular endothelial growth factor (P=0.007), but not the stages of hepatic fibrosis (P>0.05). Kaplan-Meier analysis showed that patients with higher endostatin/collagen XVIII expression had significantly shorter overall survival (P=0.011) and disease-free survival (P=0.0034). Moreover, endostatin/collagen XVIII level was an independent prognostic factor for tumor recurrence (P=0.034) by multivariate analysis. In conclusion, increased endostatin/collagen XVIII expression correlated with hepatoma progression and predicted poor prognosis for patients with hepatocellular carcinoma. 相似文献
52.
Annexin was purified from rat liver mitochondria to an apparent homogeneity with a molecular weight of 35 kDa as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The purified mitochondrial annexin (AXmito) was identified as annexin I by an immunoblot analysis using anti-annexin I antibody. The inhibitory effect of AXmito I on porcine pancreatic phospholipase A2 activity was as potent as that of bovine lung annexin I. The presence of annexin I in mitochondria was confirmed by an electron-microscopic study. AXmito I was shown to be phosphorylated by intrinsic protein tyrosine kinases on its tyrosine residues. This annexin was also phosphorylated by protein kinase C. 相似文献
53.
Three parametric statistical models have been fully validated for cancer of the larynx for the prediction of long-term 15, 20 and 25 year cancer-specific survival fractions when short-term follow-up data was available for just 1-2 years after the end of treatment of the last patient. In all groups of cases the treatment period was only 5 years. Three disease stage groups were studied, T1N0, T2N0 and T3N0. The models are the Standard Lognormal (SLN) first proposed by Boag (1949 J. R. Stat. Soc. Series B 11 15-53) but only ever fully validated for cancer of the cervix, Mould and Boag (1975 Br. J. Cancer 32 529-50), and two new models which have been termed Tobacco Cancer Risk (TCR) and Absolute Cancer Cure (ACC). In each, the frequency distribution of survival times of defined groups of cancer deaths is lognormally distributed: larynx only (SLN), larynx and lung (TCR) and all cancers (ACC). All models each have three unknown parameters but it was possible to estimate a value for the lognormal parameter S a priori. By reduction to two unknown parameters the model stability has been improved. The material used to validate the methodology consisted of case histories of 965 patients, all treated during the period 1944-1968 by Dr Manuel Lederman of the Royal Marsden Hospital, London, with follow-up to 1988. This provided a follow-up range of 20-44 years and enabled predicted long-term survival fractions to be compared with the actual survival fractions, calculated by the Kaplan and Meier (1958 J. Am. Stat. Assoc. 53 457-82) method. The TCR and ACC models are better than the SLN model and for a maximum short-term follow-up of 6 years, the 20 and 25 year survival fractions could be predicted. Therefore the numbers of follow-up years saved are respectively 14 years and 19 years. Clinical trial results using the TCR and ACC models can thus be analysed much earlier than currently possible. Absolute cure from cancer was also studied, using not only the prediction models which incorporate a parameter for a statistically cured fraction of patients C(SLN), C(TCR) and C(ACC), but because of the long follow-up range of 20-44 years, also by complete life analysis. The survival experience of those who did not die of their original cancer of the larynx was compared to the expected survival experience of a population with the same age, birth cohort and sex structure. To date it has been generally assumed for early stage disease that although for some 5-10 years after treatment the survival experience of this patient subgroup might be no different from that expected in the matched group, thereafter the death rate of this subgroup becomes lower than that of the matched group. This implies that surviving cancer patients cured of their disease tend to die of other conditions at a higher than normal rate as they become older, and therefore cancer is never totally cured. Our conclusion is that at least for cancer of the glottic larynx, the answer to the question: 'Can cancer totally be cured?' is 'Yes to at least 15-years post-treatment and also probably to 25 years.' 相似文献
54.
The pattern and frequency of t(14;18) translocation and immunophenotype in Asian follicular lymphoma 总被引:2,自引:0,他引:2
AIMS: Follicular lymphoma is frequently associated with t(14;18)(q32;q21) translocation. This study was undertaken to determine the pattern of Bcl-2, CD10 and Bcl-6 expression in relation to t(14;18) translocation in follicular lymphoma from a cohort of a multi-ethnic Asian population. METHODS AND RESULTS: Sixty-two cases of follicular lymphoma were retrieved for immunohistochemistry, and t(14;18) translocation analysis by polymerase chain reaction and fluorescent in-situ hybridization techniques. Bcl-2 expression was present in 74% of the cases. CD10 expression was also relatively low (61%), with decreasing frequency of expression in high-grade tumours. Bcl-6 protein was expressed in most of the tumours (88%) regardless of the tumour grade. The t(14;18) translocation was detected in 46 cases (74%) with an extremely high rate of t(14;18) translocation in ethnic Indian cases (100%). CONCLUSION: The frequency of t(14;18) translocation in this series of follicular lymphomas was higher when compared with previous Asian reports, but in accordance with European and North American findings. CD10 expression is strongly associated with a t(14;18) translocation event, but the overall CD10 expression was relatively low, possibly due to the high proportion of high-grade tumours in the series. t(14;18) translocation was not associated with Bcl-2 or Bcl-6 expression. 相似文献
55.
Waters WF Hurry MJ Binks PG Carney CE Lajos LE Fuller KH Betz B Johnson J Anderson T Tucci JM 《Behavioral sleep medicine》2003,1(2):81-101
This investigation compared progressive muscle relaxation plus cognitive distraction (PMR/CD), hypothesized to better improve sleep onset, versus sleep restriction and stimulus control (SR/SC), hypothesized to better improve sleep maintenance, versus a flurazepam (Dalmane) positive contrast condition (MED) and a sleep hygiene education minimal treatment control condition (SHE). Participants with chronic insomnia (N = 53), completed 2 baseline weeks of sleep diaries, and were randomly assigned to a treatment group for 2 more weeks. In the second phase, PMR/CD participants were assigned to 2 weeks of PMR/CD + SR/SC + SHE while SHE participants continued SHE. Results indicated that PMR/CD had greater effect upon sleep onset than SR/SC and SHE, SR/SC had greater effect on sleep maintenance than PMR/CD, and MED was better than the other treatments. In the second phase, the treatment package produced modest additional improvements and SHE performed superior to expectations. 相似文献
56.
Opening of the mitochondrial permeability transition pore has been recognized to be involved in cell death. The present study investigated the effect of beta-carbolines (harmaline and harmalol) on the MPP(+)-induced change in the mitochondrial membrane permeability and cell death in differentiated PC12 cells. beta-Carbolines and antioxidants (superoxide dismutase, catalase, ascorbate or rutin) prevented the loss of cell viability in PC12 cells treated with 250 microM MPP(+), while the effects of N-acetylcysteine and dithiothreitol were not observed. beta-Carbolines reduced the condensation and fragmentation of nuclei caused by MPP(+) in PC12 cells. beta-Carbolines alone did not exhibit a significant cytotoxic effect on PC12 cells. beta-Carbolines (50 microM) inhibited the decrease in mitochondrial transmembrane potential, cytochrome c release, activation of caspase-3, formation of reactive oxygen species (ROS) and depletion of GSH caused by MPP(+) in PC12 cells. beta-Carbolines reduced the hydrogen peroxide- or SIN-1-induced cell death in PC12 cells. The results suggest that beta-carbolines may attenuate the MPP(+)-induced viability loss in PC12 cells by inhibition of change in the mitochondrial membrane permeability and by antioxidant effect. 相似文献
57.
目的研发一种专用于防旋型股骨近端髓内钉置入时的三维导航器。方法选取颈干角为(135±5)°,并且股骨大转子顶点基本与股骨头中心等高的人体股骨骨骼的干标本32例,其中左侧16例,右侧16例。通过股骨头中心、平行于股骨干、垂直于股骨干与股骨颈所在的平面用钢锯将股骨标本的股骨头进行截骨;在股骨大粗隆顶端开口向股骨近端髓腔内插入PFNA主钉,主钉钉尾与股骨头中心点在同一高度上。在本课题所研发的股骨近端髓内钉三维导航器的导引下向股骨头颈部打入动力钉导引针,测量动力钉导引针在股骨头截骨面上的出针点与经股骨头中心点直线的垂直距离作为偏离值。结果利用本课题所研制的三维立体导航器在32例股骨骨骼的干标本上置入导引针,其中14例偏离值为0(占43.75%),最大偏离值为2mm,仅3例(占9.375%),平均误差只有0.69mm。结论本课题所研制的导航器结构简单,操作简便,定位精确,值得进一步在临床上研究应用。 相似文献
58.
目的:探讨一种不影响残存神经自行恢复的产瘫臂丛神经修复新方法。方法:将上干损伤部位行松解,不切除神经瘤,将其近端的颈5或颈7神经根和神经瘤远端的臂丛上干的神经束膜切开窗口,取颈丛皮支或前臂外侧皮神经前成多段(一般每段长约2.0-2.5cm),两端分别与颈5神经根和上干的神经束膜行端侧缝合,结果:8例患儿经术后1-11年(平均3年)的随访,4例的三角肌和肱二头肌骨力达4级和4^-级,4例达3例。3例后期进行了肩关节松解和旋前圆肌肌腱切断,结论:该方法既提供了可使损伤近端颈5神经根的新生纤维生长至上干的神经通道,又未阻断神经瘤内残存神经纤维的自行恢复,是治疗产瘫特别是Tassin2型的新术式。 相似文献
59.
渤海鱼类和头足类异尖科线虫幼虫感染情况调查 总被引:5,自引:0,他引:5
[目的 ]调查渤海鱼类和头足类异尖科线虫幼虫感染情况 .[方法 ]对渤海 2 5种鱼 2 90尾和 3种头足类 10 8尾进行剖检 .[结果 ]发现 19种鱼 15 6尾和 1种头足类 8尾感染异尖科线虫幼虫 6种 ,计73 2 7条 .从 15种鱼 (N =191)中的 12 1尾 ( 63 4 % )和一种头足类 (N =5 4 )中的 8尾 ( 14 8% )体内检出简单异尖线虫幼虫 5 992条 ,占总数的 81 8% ,4种鱼是本幼虫的新发现宿主 .其余 13 3 5条幼虫中 ,15 4( 2 1% )条为鲔蛔线虫B型幼虫 ,采自 4种鱼 2 3尾 ;10 13 ( 13 8% )条为鲔蛔线虫C型幼虫 ,采自 13种鱼79尾 ;164( 2 2 % )条为宫脂线虫中国V型幼虫 ,采自 4种 2 0尾鱼 ;2种鱼感染针蛔虫幼虫 3条 ;仅发现 1条伪新地蛔虫幼虫 . 相似文献
60.
抗角蛋白自身抗体对银屑病裸鼠皮损移植模型的影响 总被引:3,自引:0,他引:3
目的:建立银屑病裸鼠皮损移植模型,观察抗角蛋白自身抗体(AK auto Ab)对银屑病动物模型的影响。方法:将人体银屑病皮损组织块移植于裸鼠背部,移植后一组裸鼠腹腔注射纯化的人体AK auto Ab,另一组裸鼠腹腔注射生理盐水作为对照,从组织病理变化评价银屑病裸鼠皮损移植模型的可行性以及AK auto Ab对移植的银屑病皮片组织学改变的影响。结果:对照组皮损植片相当一段时间内能稳定地维持银屑病的部分重要组织学改变,而AK auto Ab注射组则可使银屑病的组织学特征的维持时间明显缩短。结论:银屑病裸鼠皮损移植模型是银屑病短期内理想的动物模型,AK auto Ab具有促进银屑皮炎恢复的作用。 相似文献