全文获取类型
收费全文 | 142340篇 |
免费 | 13317篇 |
国内免费 | 8818篇 |
专业分类
耳鼻咽喉 | 1161篇 |
儿科学 | 1936篇 |
妇产科学 | 2107篇 |
基础医学 | 16530篇 |
口腔科学 | 2698篇 |
临床医学 | 18924篇 |
内科学 | 23436篇 |
皮肤病学 | 1767篇 |
神经病学 | 8394篇 |
特种医学 | 4318篇 |
外国民族医学 | 61篇 |
外科学 | 14264篇 |
综合类 | 21309篇 |
现状与发展 | 24篇 |
一般理论 | 22篇 |
预防医学 | 10272篇 |
眼科学 | 4166篇 |
药学 | 14033篇 |
151篇 | |
中国医学 | 8029篇 |
肿瘤学 | 10873篇 |
出版年
2024年 | 398篇 |
2023年 | 1989篇 |
2022年 | 5159篇 |
2021年 | 7725篇 |
2020年 | 5681篇 |
2019年 | 4935篇 |
2018年 | 5323篇 |
2017年 | 4564篇 |
2016年 | 4258篇 |
2015年 | 6387篇 |
2014年 | 8062篇 |
2013年 | 7755篇 |
2012年 | 11480篇 |
2011年 | 12560篇 |
2010年 | 7931篇 |
2009年 | 6491篇 |
2008年 | 8152篇 |
2007年 | 7927篇 |
2006年 | 7665篇 |
2005年 | 7420篇 |
2004年 | 4895篇 |
2003年 | 4704篇 |
2002年 | 3881篇 |
2001年 | 2386篇 |
2000年 | 2418篇 |
1999年 | 2473篇 |
1998年 | 1712篇 |
1997年 | 1612篇 |
1996年 | 1325篇 |
1995年 | 1197篇 |
1994年 | 990篇 |
1993年 | 650篇 |
1992年 | 707篇 |
1991年 | 582篇 |
1990年 | 544篇 |
1989年 | 490篇 |
1988年 | 409篇 |
1987年 | 334篇 |
1986年 | 278篇 |
1985年 | 228篇 |
1984年 | 126篇 |
1983年 | 92篇 |
1982年 | 99篇 |
1981年 | 102篇 |
1980年 | 60篇 |
1979年 | 61篇 |
1978年 | 21篇 |
1977年 | 32篇 |
1976年 | 31篇 |
1975年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
141.
142.
目的:建立一种简单、稳定、可靠的PON1基因多态性分析法。方法:取外周静脉血100μl,用ROSE法提取基因组DNA,用两对引物:P192F 5′-TAT TGT TGC TGT GGG ACC TGA G-3′,P192R 5′-CAC GCT AAA CCC AAA TAC ATC TC-3′;P55F 5′-GAA GAG TGA TGT ATA GCC CCA G-3′,P55R 5′-TTT AAT CCA GAG CTA ATG AAA GCC-3分别进行PCR扩增,用限制性内切酶AlwI,NlaⅢ对两种PCR产物分别进行酶切,3%琼脂糖凝胶电泳。结果:扩增的两个PCR产物在192、55多态性位点大小分别为99bp、170bp。Alw I酶切后,凝胶电脉得到完全酶切(66bp,33bp),部分酶切(99bp、66bp、33bp),未被酶切(99bp)三种类型DNA片段(RR,QR,QQ基因型);NlaⅢ酶切后,凝胶电脉得到部分酶切(170bp,126bp,44bp),未被酶切(170bp)两种类型DNA片段(LM,LL基因型)。经双盲重复检测,结果一致。应用此方法对胃癌患者血样标本检测,发现其PON1基因多态性在192位点频率较高。结论:采用一步PCR-RFLP技术可以建立简单、稳定、可靠的PON1基因多态性分析法。 相似文献
143.
【目的】了解手术创伤对术后全身炎症反应综合征 (SIRS)的影响。【方法】搜集外科重症监护室 (SICU) 335例患者的术后资料 ,分析不同手术组SIRS发病率 ;手术时间、失血量与SIRS持续时间的关系 ;SIRS持续时间与术后并发症的关系。【结果】术后SIRS发病率为 75 8% ,大手术高达 92 4 % ;无并发症患者失血量与SIRS持续时间呈正相关 (r1=0 783,P<0 0 1) ,手术时间与SIRS持续时间呈正相关 (r2 =0 398,P <0 0 1) ;随着SIRS持续时间延长 ,并发症发病率显著增高 (P<0 0 5 )。【结论】术后SIRS发生、发展与手术创伤密切相关 ;监测SIRS进程有助于及早发现并发症 相似文献
144.
大鼠脑组织单胺类递质及其代谢产物的检测方法研究 总被引:13,自引:0,他引:13
目的 :研究大鼠脑组织中单胺类递质及其代谢产物的高效液相反相离子对色谱测定法。方法 :采用LiChrosorbC18,10 μm色谱柱 ,流动相为甲醇 :水 (4 0 :60 ) ,含 0 .0 2 8g LEDTANa2 ,0 .15g LSDS ,0 .2ml LH2 SO4(pH 2 .5~ 3 ) ,荧光检测波长 :λEX=2 85 ,λEM=3 3 3。结果 :对 87只大鼠脑组织中 4种单胺类递质及其代谢产物的含量进行了同时测定 ,高香草酸 (HVA) 2 .5 0~ 40 .0 μg ml、去甲肾上腺素 (NE) 0 .0 1~ 0 .5 0 μg ml、多巴胺 (DA)0 .0 5~ 1.0 0 μg ml、5 羟色胺 (5 HT) 0 .0 2 5~ 0 .5 0 μg ml,峰面积与其含量呈良好的线性关系。 结论 :该法操作简便、快速、准确 ,为组织中单胺类递质及其代谢产物检测的一种理想方法 ,并适用于临床相关研究。 相似文献
145.
目的 探讨在多柔比星 (阿霉素 )肾病综合征 (NS)幼年大鼠肾损伤过程中核因子 (NF) κB和血管紧张素ATⅠ、ATⅡ的表达及其相关性。方法 4周龄雄性Wistar大鼠单侧肾切除加腹腔注射阿霉素造成NS模型 ,分别以免疫组织化学和原位杂交检测ATⅠ、ATⅡ和NF κB。结果 肾病组随着病变时间的延长 ,NF κB和ATⅠ、ATⅡ表达的强度和部位均呈增强趋势 ,治疗组在相同时间点则两者都有不同程度下调 (P <0 .0 5 )。结论 在阿霉素肾病损伤过程中NF κB和ATⅠ、ATⅡ起着介导作用。 相似文献
146.
Adrenergic signalling between rat taste receptor cells 总被引:2,自引:0,他引:2
Scott Herness† Fang-li Zhao Namik Kaya Shao-gang Lu Tiansheng Shen Xiao-Dong Sun‡ 《The Journal of physiology》2002,543(2):601-614
In taste buds, synaptic transmission is traditionally thought to occur from taste receptor cells to the afferent nerve. This communication reports the novel observation that taste receptor cells respond to adrenergic stimulation. Noradrenaline application inhibited outward potassium currents in a dose-dependent manner. This inhibition was mimicked by the β agonist isoproterenol and blocked by the β antagonist propranolol. The α agonists clonidine and phenylephrine both inhibited the potassium currents and elevated intracellular calcium levels. Inwardly rectifying potassium currents were unaffected by adrenergic stimulation. Experiments using the RT-PCR technique demonstrate that lingual epithelium expresses multiple α (α1a, α1b, α1c, α1d, α2a, α2b, α2c) and β (β1, β2) subtypes of adrenergic receptors, and immunocytochemistry localized noradrenaline to a subset of taste receptor cells. Collectively, these data imply strongly that adrenergic transmission within the taste bud may play a paracrine role in taste physiology. 相似文献
147.
Ming Zhao Cheng Simon C F Rawlinson Andrew A Pitsillides Gul Zaman Subburaman Mohan David J Baylink Lance E Lanyon 《Journal of bone and mineral research》2002,17(4):593-602
The mechanism by which mechanical strain and estrogen stimulate bone cell proliferation was investigated using monolayer cultures of human osteoblastic TE85 cells and female human primary (first-passage) osteoblasts (fHOBs). Both cell types showed small but statistically significant dose-dependent increases in [3H]thymidine incorporation in response to 17beta-estradiol and to a single 10-minute period of uniaxial cyclic strain (1 Hz). In both cell types, the peak response to 17beta-estradiol occurred at 10(-8) - 10(-7) M and the peak response to strain occurred at 3500 microstrain ((mu)epsilon). Both strain-related and 17beta-estradiol-related increases in [3H]thymidine incorporation were abolished by the estrogen receptor (ER) modulator ICI 182,780 (10-8 M). Tamoxifen (10(-9) - 10(-8) M) increased [3H]thymidine incorporation in both cell types but had no effect on their response to strain. In TE85 cells, tamoxifen reduced the increase in [3H]thymidine incorporation associated with 17beta-estradiol to that of tamoxifen alone but had no such effect in fHOBs. In TE85 cells, strain increased medium concentrations of insulin-like growth factor (IGF) II but not IGF-I, whereas 17beta-estradiol increased medium concentrations of IGF-I but not IGF-II. Neutralizing monoclonal antibody (MNAb) to IGF-I (3 microg/ml) blocked the effects of 17beta-estradiol and exogenous truncated IGF-I (tIGF-I; 50 ng/ml) but not those of strain or tIGF-II (50 ng/ml). Neutralizing antibody to IGF-II (3 microg/ml) blocked the effects of strain and tIGF-II but not those of 17beta-estradiol or tIGF-I. MAb aIR-3 (100 ng/ml) to the IGF-I receptor blocked the effects on [3H]thymidine incorporation of strain, tIGF-II, 17beta-estradiol, and tIGF-I. HOBs and TE85 cells, act similarly to rat primary osteoblasts and ROS 17/2.8 cells in their dose-related proliferative responses to strain and 17beta-estradiol, both of which can be blocked by the ER modulator ICI 182,780. In TE85 cells (as in rat primaries and ROS 17/2.8 cells), the response to 17beta-estradiol is mediated by IGF-I, and the response to strain is mediated by IGF-II. Human cells differ from rat cells in that tamoxifen does not block their response to strain and reduces the response to 17beta-estradiol in TE85s but not primaries. In both human cell types (unlike rat cells) the effects of strain and IGF-II as well as estradiol and IGF-I can be blocked at the IGF-I receptor. 相似文献
148.
多层螺旋CT胸部低剂量扫描对气道三维重建的应用研究 总被引:5,自引:1,他引:4
目的:比较低剂量与常规剂量条件下中央气道三维重建图像的差别,探讨低剂量螺旋CT扫描进行中央气道三维重建的可行性。材料和方法:32例病例行低剂量(50mAs)平扫及常规剂量(195mAs)平扫(1例)及增强扫描(31例),将两组原始数据分别普通算法及高分辨算法重叠重建出4组横断面图像,并进行气道SSD及VR重建,由两名放射科医师分析4组图像的质量、支气管显示情况、支气管病变检出情况,将结果进行统计学分析。结果:①图像质量:两组剂量间SSD图像质量无明显差异,高分辨重建图像质量≥普通算法重建图像质量;VR图像质量两种剂量之间无明显差异,高分辨算法图像质量≥标准算法重建图像质量。②支气管显示:两名医生评价结果均表明对段以上支气管显示方面无论SSD图像还是VR图像,低剂量与常规剂量组以及两种算法图像之间均无明显差异。③病变检出:无论SSD还是VR图像4组图像对支气管病变的检出无差异。④剂量差别:低剂量扫描比常规剂量扫描辐射剂量大大降低(13.6~3.6mGy)。结论:与常规剂量扫描相比,低剂量薄层扫描气道三维重建图像质量、对中央气道显示及病变检出都无明显差异,而病人接受的辐射剂量却大大降低,因此低剂量薄层扫描气道三维重建可以代替常规剂量重建图像应用于临床气道病变显示。 相似文献
149.
Su-Ping Sun Ye-Ning Jin Hong-Peng Yang Yi Wei Zhao Dong 《World journal of gastroenterology : WJG》2007,13(39)
AIM: To evaluate the relationship between changes in serum transforming growth factor β1 (TGFβ1) level and curative effect of radiotherapy (RT) in patients with esophageal carcinoma.METHODS: Ninety patients with histologically confirmed esophageal carcinoma were enrolled. Serum samples for TGFβ1 analysis were obtained before and at the end of RT. An enzyme-linked immunosorbent assay was used to measure serum TGFβ1 level. Multivariate analysis was performed to investigate the relationship between disease status and changes in serum TGFβ1 level.RESULTS: Serum TGFβ1 level in patients with esophageal carcinoma before RT was significantly higher than that in healthy controls (P < 0.001). At the end of RT, serum TGFβ1 level was decreased in 67.82% (59/87) of the patients. The overall survival rate at 1,3 and 5 years was 48.28% (42/87), 19.54% (17/87)and 12.64% (11/87), respectively. Main causes of death were local failure and regional lymph node metastasis.In patients whose serum TGFβ1 level decreased after RT,the survival rate at 1, 3 and 5 years was 61.02% (36/59),28.81% (17/59) and 18.64% (11/59), respectively. The survival rate at 1 year was 17.86% (5/28) in patients whose serum TGFβ1 level increased after RT, and all died within 18 mo (P < 0.01).CONCLUSION: Serum TGFβ1 level may be a useful marker for monitoring disease status after RT in patients with esophageal carcinoma. 相似文献
150.
目的观察初诊T2DM短期胰岛素强化治疗的疗效。方法对40例初诊T2DM患者采用三餐前皮下注射短效胰岛素和睡前注射中效胰岛素2wk,并检测治疗2wk前后FPG、PPG、GHbA1C及血脂等值进行比较。结果两组治疗后FPG、PPG、GHbA1C及血脂各值均显著低于治疗前p〈0.05(x^2=4.940—11.544)。结论胰岛13细胞功能异常和(或)胰岛素抵抗是T2DM发病的基本环节,早期强化胰岛素治疗能获得血糖的有效控制,减少或延缓并发症的发生。 相似文献