全文获取类型
收费全文 | 18841篇 |
免费 | 1302篇 |
国内免费 | 875篇 |
专业分类
耳鼻咽喉 | 180篇 |
儿科学 | 415篇 |
妇产科学 | 335篇 |
基础医学 | 1861篇 |
口腔科学 | 233篇 |
临床医学 | 1826篇 |
内科学 | 3363篇 |
皮肤病学 | 190篇 |
神经病学 | 1182篇 |
特种医学 | 888篇 |
外科学 | 3485篇 |
综合类 | 2673篇 |
一般理论 | 6篇 |
预防医学 | 761篇 |
眼科学 | 293篇 |
药学 | 1418篇 |
9篇 | |
中国医学 | 723篇 |
肿瘤学 | 1177篇 |
出版年
2024年 | 34篇 |
2023年 | 215篇 |
2022年 | 529篇 |
2021年 | 617篇 |
2020年 | 559篇 |
2019年 | 566篇 |
2018年 | 684篇 |
2017年 | 629篇 |
2016年 | 579篇 |
2015年 | 604篇 |
2014年 | 1201篇 |
2013年 | 1094篇 |
2012年 | 1152篇 |
2011年 | 1351篇 |
2010年 | 1139篇 |
2009年 | 1157篇 |
2008年 | 1250篇 |
2007年 | 1212篇 |
2006年 | 992篇 |
2005年 | 920篇 |
2004年 | 706篇 |
2003年 | 618篇 |
2002年 | 519篇 |
2001年 | 373篇 |
2000年 | 290篇 |
1999年 | 248篇 |
1998年 | 179篇 |
1997年 | 158篇 |
1996年 | 142篇 |
1995年 | 150篇 |
1994年 | 133篇 |
1993年 | 107篇 |
1992年 | 100篇 |
1991年 | 92篇 |
1990年 | 63篇 |
1989年 | 52篇 |
1988年 | 51篇 |
1987年 | 42篇 |
1986年 | 51篇 |
1985年 | 61篇 |
1984年 | 57篇 |
1983年 | 34篇 |
1982年 | 47篇 |
1981年 | 31篇 |
1980年 | 40篇 |
1979年 | 31篇 |
1978年 | 20篇 |
1977年 | 31篇 |
1976年 | 28篇 |
1974年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
J. G. Boonstra Johan W. van der Pijl Yves F. C. Smets Herman H. P. J. Lemkes Jan Ringers Leendert A. van Es F. J. van der Woude Jan A. Bruijn 《Transplant international》1997,10(6):451-456
To examine the incidence of interstitial and vascular
rejection in pancreas allografts and its impact on graft survival, we studied 36 percutaneous pancreas biopsies and 10 pancreas
transplantectomy specimens from 32 patients who had undergone simultaneous pancreas-kidney transplantation. Interstitial rejection
(IR) was predominantly found in the biopsies, while vascular rejection (VR) was most prominent in the transplantectomies.
Pancreas graft survival was significantly decreased for pancreas grafts that had suffered from vascular rejection when compared
to those with only interstitial rejection. Potential rejection markers, i. e., serum amylase, glucose, creatinine, and urinary
amylase, did not correlate with histological signs of rejection, although increased levels of serum amylase were, in all but
one case, associated with rejection.We conclude that a percutaneous pancreas biopsy remains the most reliable method to determine
pancreas rejection, and that by distinguishing between IR andVR, a pancreas biopsy may provide important diagnostic as well
as prognostic information.
Received: 6 March 1997 Received after revision: 5 June 1997 Accepted: 30 June 1997 相似文献
52.
54只大白鼠随机分三组,用不同方法修复坐骨神经缺损,术后60天和90天取材,作电生理、组织学和电镜观察的比较,结果表明:游离神经移植+血管植入方法和带血管蒂神经移植效果同样好,二者均显著优于单纯游离神经移植。 相似文献
53.
de Caro R. Parenti A. Capitanio G. Ori C. Bracco F. Ricchieri G. L. 《Acta neurochirurgica》1990,104(1-2):73-76
Summary A vascular malformation, consisting of a venous vessel bridgeing the right inferior petrosal sinus and the anterior spinal veins, was found in the posterior fossa. The vessel presented a ring-like course around the right trigeminal root, and it was parallel and dorsal to the basilar artery. The malformation was associated with cutaneous and hepatic angiomas and peri-osteal lipomas. It had been clinically silent for 52 years, when it thrombosed causing death. The authors think that, within a general mesenchymopatic state, this is a result of the persistence of an embryonal cerebral venous pattern. 相似文献
54.
Claudia Linde Cornelia Löffler Christina Kessler U. Quast 《Naunyn-Schmiedeberg's archives of pharmacology》1997,356(4):467-474
In vascular smooth muscle, openers of ATP-dependent potassium channels (K
ATP channels), such as P1075 (N-cyano-N’-(1,1-dimethylpropyl)-N’’-3-pyridylguanidine), produce relaxation. In this study we have investigated the effects of thiol-modifying agents on the
binding of P1075 and on the 86Rb+ efflux stimulating and vasorelaxant effects of the opener in rat aortic rings. The increase in 86Rb+ efflux induced by P1075 was taken as a qualitative measure of K+ channel opening. The hydrophilic SH-group-oxidizing substance, thimerosal (1 to 100μM), abolished specific binding of [3H]-P1075 with an IC50 value of 7.6±1.2μM; at 30μM, the half time for inhibition was 38min. Two other thiol-oxidizing agents, PMB (4-hydroxy-mercuribenzoic
acid) and DTBNP (2,2’-dithio-bis(5-nitropyridine)), inhibited binding up to 86% and 44%, respectively. The disulphide bond
reducing substance, DTT (1,4-dithiothreitol, 0.1 to 1mM), reduced [3H]-P1075 binding by up to 20% and partially reversed the inhibitory effect of thimerosal. In 86Rb+ efflux experiments, thimerosal (3 to 100μM) concentration-dependently increased basal efflux but inhibited P1075-stimulated
tracer efflux with an IC50 value of 7±1μM. The inhibitory effect occurred with a half-time of approximately 8min and was essentially reversed by DTT.
In rings precontracted with noradrenaline, thimerosal inhibited the vasorelaxant effect in a noncompetitive manner, shifting
the concentration-relaxation curves to the right and reducing maximum relaxation.The data show that oxidation of thiol groups
interferes with the binding of the K
ATP channel opener, P1075; concomitantly, the 86Rb+ efflux stimulating and the vasorelaxant effects are inhibited. Reduction of disulphide bonds by DTT has only minor effects
on the action of P1075. Collectively, the results suggest that intact thiol groups are essential for the functioning of the
KATP channel in rat aorta. The different kinetics governing the inhibition of opener binding and of opener-stimulated 86Rb+ efflux suggest that the SH-groups involved in the two processes differ in their accessibility to thimerosal and/or in their
reactivity.
Received: 7 April / Accepted: 9 July 1997 相似文献
55.
The effect of established infection with penicillin-resistant staphylococcus aureus on m'icrbarterial anastomosis was studied in an experimental model. The infection was treated with wound debridement and systemic antibiotics before the surgical procedure. It was found that the anastomotic patency rate of microarte-rial repair was 95.1%. The presence of established infection, if properly treated, should not be a contraindication to microarterial surgery. 相似文献
56.
细胞内钙信号的变化调节血管平滑肌细胞增殖 总被引:4,自引:0,他引:4
目的探讨细胞内钙信号的变化对大鼠血管平滑肌细胞(VSMC)增殖作用的影响及其对细胞内信号转导机制的变化。方法以培养的大鼠VSMC为模型,用雷尼丁(RY)剌激VSMC内贮Ca2 释放入胞浆,用3H亮氨酸及3H胸腺嘧啶掺入量作为反应VSMC增殖的指标,加入不同的细胞内信号转导阻断剂,观察对RY效应的影响。结果与对照组相比,RY浓度依赖性地促进细胞内游离钙浓度的增高,差异显著(P<0.05或0.01)。RY剌激组蛋白核酸合成速率明显增高,与对照组相比差异显著(P<0.01);尼卡地平(Nicardipine),蛋白激酶C抑制剂(H7),钙调素激酶(CaMPK)抑制剂(W7)和丝裂素活化蛋白激酶(MAPK)抑制剂(PD98059)能明显抑制RY介导的VSMC蛋白核酸合成速率增高,与RY剌激组相比差异显著(P<0.01)。结论细胞内钙信号的变化明显促进VSMC增殖,但其效应可能通过Ca2 、PKC、MAPK来介导。钙离子拮抗剂可抑制血管平滑肌细胞增殖。 相似文献
57.
目的:探讨垂体腺瘤细胞株HP75 VEGF表达与细胞因子IL-1α和IL-6分泌的关系。方法:HP75细胞常规培养,经各种因素处理后,取培养上清液,采用ELISA方法分别检测VEGF、IL-1α和IL-6的分泌水平。结果:①HP75细胞时间依赖性分泌VEGF、IL-1α和IL-6;②较大剂量的IL-1α剂量依赖性的刺激VEGF表达;③所用各种剂量的IL-6对VEGF的分泌均无显著影响;④IL-1α和IL-6中和抗体对VEGF基础分泌无显著影响。结论:VEGF的表达与IL-1α和IL-6的分泌密切相关,提示细胞因子在垂体腺瘤的生长过程中发挥重要作用。 相似文献
58.
子宫肌瘤患者外周静脉与子宫静脉血管内皮细胞生长因子水平测定及临床意义 总被引:3,自引:0,他引:3
目的:探讨血管内皮细胞生长因子(VEGF)在子宫肌瘤发生和肌瘤生长中的作用。方法:手术中暴露子宫静脉后,抽取子宫静脉血3ml,同时抽取非输液肢体外周静脉血3ml。抽取配对正常妇女外周静脉血3ml。ELISA法测定VEGF水平。测量子宫重量、肌瘤总重量、肌瘤数目和最大肌瘤最大径线值。结果:子宫肌瘤患者子宫静脉血和外周静脉血VEGF水平分别为159.38±25.63pg/ml和76.35±26.61pg/ml,对照人群外周静脉血VEGF水平为42.53±29.47pg/ml。子宫静脉血中的VEGF水平明显高于外周静脉血(P=0.019),子宫肌瘤患者外周静脉血中的VEGF水平明显高于对照人群外周静脉血的VEGF水平(P=0.013)。子宫重量、肌瘤总重量、肌瘤数目、最大肌瘤最大径线都与子宫肌瘤患者子宫静脉和外周静脉VEGF呈显著正相关。结论:VEGF可能参与了子宫肌瘤的生长和病情发展。 相似文献
59.
醒脑启智胶囊对学习记忆障碍小鼠行为的影响 总被引:4,自引:2,他引:2
目的观察醒脑启智胶囊对血管性痴呆学习记忆障碍小鼠行为的影响 ,验证醒脑启智胶囊对血管性痴呆的疗效。方法复制脑缺血再灌注血管性痴呆小鼠模型 ,灌胃给药 ,并与银杏叶、尼莫地平对照 ,分别于术后 7天、15天、3 0天 ,采用水迷宫法检测各组小鼠行为学变化。结果模型小鼠学习与记忆能力下降 ,表现为游全程时间延长 ,错误次数增加。醒脑启智胶囊可使模型小鼠游全程时间缩短 ,错误次数减少 ,优于对照药物。结论醒脑启智胶囊对模型小鼠学习与记忆能力下降有提高作用。 相似文献
60.
本文报告2例系非甲亢危象及危象前期的甲状腺功能亢进(简称甲亢)患者,临床突出的症状是:频繁而又顽固的呕吐,例1导致了Mallory-Weiss征,服他巴唑60小时后呕吐明显缓解,96小时后呕吐完全停止。例2由于呕吐误诊为胃神经官能症,服他巴唑治疗一周后呕吐停止。甲亢性呕吐国内未见报告,本文对呕吐的机制进行了分析探讨。 相似文献