全文获取类型
收费全文 | 12345篇 |
免费 | 976篇 |
国内免费 | 574篇 |
专业分类
耳鼻咽喉 | 23篇 |
儿科学 | 181篇 |
妇产科学 | 98篇 |
基础医学 | 1262篇 |
口腔科学 | 57篇 |
临床医学 | 1022篇 |
内科学 | 1544篇 |
皮肤病学 | 126篇 |
神经病学 | 436篇 |
特种医学 | 306篇 |
外国民族医学 | 2篇 |
外科学 | 382篇 |
综合类 | 2548篇 |
预防医学 | 1456篇 |
眼科学 | 152篇 |
药学 | 2628篇 |
6篇 | |
中国医学 | 1441篇 |
肿瘤学 | 225篇 |
出版年
2024年 | 53篇 |
2023年 | 175篇 |
2022年 | 410篇 |
2021年 | 497篇 |
2020年 | 367篇 |
2019年 | 335篇 |
2018年 | 311篇 |
2017年 | 448篇 |
2016年 | 458篇 |
2015年 | 420篇 |
2014年 | 631篇 |
2013年 | 979篇 |
2012年 | 623篇 |
2011年 | 720篇 |
2010年 | 572篇 |
2009年 | 486篇 |
2008年 | 560篇 |
2007年 | 530篇 |
2006年 | 558篇 |
2005年 | 479篇 |
2004年 | 453篇 |
2003年 | 414篇 |
2002年 | 327篇 |
2001年 | 370篇 |
2000年 | 313篇 |
1999年 | 235篇 |
1998年 | 234篇 |
1997年 | 207篇 |
1996年 | 237篇 |
1995年 | 215篇 |
1994年 | 186篇 |
1993年 | 183篇 |
1992年 | 145篇 |
1991年 | 124篇 |
1990年 | 96篇 |
1989年 | 99篇 |
1988年 | 58篇 |
1987年 | 61篇 |
1986年 | 39篇 |
1985年 | 66篇 |
1984年 | 44篇 |
1983年 | 22篇 |
1982年 | 35篇 |
1981年 | 23篇 |
1980年 | 13篇 |
1979年 | 13篇 |
1978年 | 14篇 |
1977年 | 11篇 |
1976年 | 19篇 |
1973年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
硒对二乙基亚硝胺诱发大鼠肝癌生长的抑制作用的观察 总被引:3,自引:0,他引:3
观察硒对二乙基亚硝胺诱发大鼠肝癌的影响。方法;在诱癌过程中,大鼠分别投予含0.2,1.0,3.0×10^-6硒的饲料,检测血,肝组织LPO,GSH-PX活性,观察诱癌率及癌结节面积。结果:补Se后对诱癌率无显著影响,但补充3.0×1-0^-6Se可使癌结节面积显著减少。补Se可显著地减轻诱癌早期血和肝组织中LPO的形成及诱癌过程中血和肝组织中GSH-PX活性的降低。 相似文献
42.
报道52例高血压病人服降压药双氢克尿噻、心得安、复方降压片和硝苯啶1~2月后血脂的变化,结果显示,双克(25~50mg/日)对血脂的主要影响是升高TG,加用心得安(30mg/日)后,TG升高幅度更大;TC有上升趋势,HDL-C变化较小。复降片(3片/日)对血脂的影响较大。不仅TG明显升高、TC也有明显升高,而HDL-C则有显著下降、HDL-C/TC比值下降也十分显著。硝苯啶(30mg/日)对血脂也产生不利影响,血TG浓度上升,TC浓度增加,而HDL-C变化不大。这种变化已被看作为对长期接受这些药物治疗的病人外加了一个致动脉粥样硬化的危险因素。 相似文献
43.
Summary. Superoxide dismutase-like activity (SOD-like), isoenzyme lactate dehydrogenase-C4 (LDH-C4) and NADH-diaphorase activities in spermatozoa have been investigated from 58 normozoospermic and 27 oligozoospermic men. Significantly higher SOD-like, LDH-C4 and diaphorase activities ( P <0.01, P <0.005 and P <0.0001, respectively) were detected in spermatozoa from oligozoospermic men, compared to the activities found in normozoospermic samples. SOD-like activity (mean±SE) in oligozoospermic samples amounted to 8.3±1.6 U 10−8 spermatozoa, while in spermatozoa in normozoospermic men with a sperm concentration above 20 million of spermatozoa per ml amounted to 4.2±0.5 U 10−8 . There was a close correlation between the SOD-like activity and biochemical indicators of the presence of residual cytoplasm i.e. isoenzyme LDH-C4 and NADH-diaphorase (r = 0.53 and r = 0.66 in normozoospermic and r = 0.63 and r = 0.54 in oligozoospermic men, respectively). A positive relationship between SOD-like activity and experimentally-induced lipid peroxidation was detected in 54 infertile men (r = 0.30; P <0.05). These findings suggest that a higher level of superoxide dismutase-like activity may reflect a defect in the development or maturation of spermatozoa and, thereby, a decreased fertility potential. Hence, determination of SOD-like activity may give information on the state of maturity of human spermatozoa, while its role in the antioxidative protection remains to be determined. 相似文献
44.
Aitken R.John; Buckingham Donna W.; Brindle James; Gomez Emelio; Baker H.W.Gordon; Irvine D.Stewart 《Human reproduction (Oxford, England)》1995,10(8):2061-2071
The addition of luminol to unprocessed semen samples resultedin the generation of chemiluminescent signals, the intensityof which was highly correlated with the level of leukocyte contamination.Despite the spontaneous oxidant-generating capacity of seminalleukocytes, no correlations were observed between leukocytecontamination and the fertility status of the subjects or anyaspect of the semen profile, including the motility of the spermatozoaor their performance in a hyaluronate penetration assay. Luminol-dependentchemiluminescence and leukocyte contamination were also correlatedin washed sperm suspensions prepared either by repeated centrifugationor on discontinuous Percoll gradients. However, in such spermsuspensions, the spontaneous generation of oxidants by contaminatingleukocytes (>2x104 leukocytes/ml) was invariably associatedwith a decreased capacity for movement. Moreover, causativeassociations between leukocyte contamination, reactive oxygenspecies generation, lipid peroxidation and impaired sperm motilitywere revealed by experiments involving the selective additionor removal of activated leukocytes. From these observationswe can conclude that low concentrations of leukocytes are acommon feature of the human ejaculate and can impair sperm function,particularly in the absence of seminal plasma. These findingshave implications for our understanding of the importance ofleukocytospermia in defining the fertility of human spermatozoain vivo and in vitro. 相似文献
45.
维生素E对培养心肌细胞脂质过氧化损伤的保护 总被引:3,自引:0,他引:3
应用氢过氧化枯烯引发体外培养的乳鼠心肌细胞脂质过氧化损伤过程,观察了添加维生素E(200mg/L的α-生育酚)的影响。结果显示:维生素E能明显减轻细胞脂质过氧化物的蓄积、细胞内肌酸激酶漏出和DNA断裂,保护细胞膜流动性、肌球蛋白轻链肌酸激酶和头部ATP酶的活性;但对 ̄3H-TdR掺入的影响不显著。表明维生素E具有抵抗脂质过氧化所致心肌细胞损伤的作用。 相似文献
46.
Salahudeen Abdulla K.; Wang Chunyou; Bigler Steven A.; Dai Zhongyi; Tachikawa Hiroyasu 《Nephrology, dialysis, transplantation》1996,11(4):635-642
BACKGROUND AND PURPOSE.: Heme-proteins, besides causing renal tubular obstruction, maycontribute to rhabdomyolysis-induced renal injury through aheme-iron-mediated lipid peroxidation process. In the presentstudy, we compared the combined therapy of a lipid peroxidationinhibitor, 21-aminosteroid (21-AS) and fluid-alkaline-mannitol(FAM) diuresis with either of them alone to determine the efficacyof the combination therapy and to delineate the roles of lipidperoxidation and cast formation. METHODS AND RESULTS.: Employing Raman spectroscopy, we confirmed in vitro the abilityof 21-AS to inhibit iron-induced fatty acid peroxidation. 21-ASwas then administered to rats developing renal failure fromglycerol-induced rhabdomyolysis. Although 21-AS inhibited rhabdomyolysis-inducedplasma and renal lipid peroxidation, renal protection was incomplete.Administration of FAM to inhibit cast formation afforded a betterrenal protection. However, when these therapies were combinedto inhibit both lipid peroxidation and cast formation, therewas a synergistic renal functional protection. This was accompaniedby a maximum inhibition of renal and plasma lipid peroxidation,as well as, renal tubular necrosis and cast formation. Comparedto combination therapy, FAM therapy alone, despite identicalvolume, was accompanied by a higher tubular necrosis and castformation. CONCLUSIONS.: That combining a lipid peroxidation inhibitor with fluid-alkalinediuresis in rhabdomyolysis further lowers renal lipid peroxidation,tubular necrosis and cast formation and synergistically limitsrenal dysfunction (i) supports a role for lipid peroxidationin the pathophysiology of rhabdomyolysis ARF, (ii) underscoresthe role of intratubular heme retention, a cause for tubularobstruction as well a source for prodigious amount of iron,likely involved in the lipid peroxidation, and (iii) raisesthe possibility of interactions between non-oxidant and oxidantmechanisms. 相似文献
47.
EffectofShengmaisan(生脉散)onLipidPeroxidationDamageinAcuteMyocardialinfarctionPatientsLUBao-jing(吕宝经);RONGYe-zhi(荣烨之);ZHAOMei-h... 相似文献
48.
背景 既往研究显示ACAT-1 rs1044925单核苷酸多态性(SNP)与冠心病及缺血性脑卒中的发病风险相关,并且与血脂水平有关。目的 本研究旨在探讨ACAT-1 rs1044925 SNP与急性冠脉综合征(ACS)的关系,以及rs1044925 SNP与ACS患者阿托伐他汀治疗后调脂效果的关系。方法 选择2016年1月—2018年1月在广西壮族自治区人民医院老年心血管内科确诊为ACS并接受经皮冠状动脉介入治疗(PCI)的患者111例作为ACS组(男67例,女44例);患者均接受阿托伐他汀治疗,20 mg/晚;同时服用氯吡格雷75 mg,1次/d(或替格瑞洛90 mg,2次/d),阿司匹林100 mg,1次/d;并在经PCI后常规使用阿托伐他汀,20 mg/晚。对照组为同期体检健康人群,共338例(男170例,女168例)。通过聚合酶链反应和限制性片段长度多态性(PCR-RFLP)对ACAT-1 rs1044925 SNP进行基因分型,检测ACS组和对照组的基线血脂水平,随访检测ACS组患者阿托伐他汀治疗1年后血脂参数。结果 ACS组和对照组受检者的血清总胆固醇(TC)间差异无统计学... 相似文献
49.
型糖尿病常合并脂代谢紊乱,脂代谢紊乱加重胰岛素抵抗,同时也参与糖尿病并发症的发生、发展。新型降糖药钠-葡萄糖耦联转运体-2(SGLT-2)抑制剂通过抑制肾脏对葡萄糖的重吸收发挥降糖作用,进而调控机体糖、脂代谢,改善2型糖尿病患者血脂、异位脂肪沉积及胰岛素抵抗。本文对SGLT-2抑制剂改善2型糖尿病脂代谢的相关研究进展做一综述。 相似文献
50.
目的 探讨不同生长激素分泌状态下矮身材儿童血脂水平的差异,为生长激素缺乏对儿童体脂代谢的影响提供理论依据。方法 收集矮身材儿童188例,依据生长激素药物激发试验峰值分为生长激素完全缺乏(cGHD)组、生长激素部分缺乏(pGHD)组、非生长激素缺乏性(nGHD)组,研究对象均禁食禁水10 h后空腹测定总胆固醇(TC)、三酰甘油(TG)、低密度脂蛋白胆固醇(LDL)和高密度脂蛋白胆固醇(HDL)4项血脂水平。结果 3组儿童HDL水平比较差异无统计学意义(P>0.05);3组儿童TC、TG、LDL、non-HDL水平比较差异均有统计学意义(P<0.05);组间两两比较,cGHD组TC、LDL、non-HDL水平较其他组明显升高(P<0.05),cGHD组TG水平较nGHD明显升高(P<0.05),与pGHD组比较差异无统计学意义(P>0.05)。pGHD、nGHD组高TC、高LDL及高non-HDL的发生率明显低于cGHD组(P<0.05),nGHD组临界高LDL的发生率明显低于cGHD组(P<0.05)。而3组间TG、HDL的异常发生率及TC、TG... 相似文献