全文获取类型
收费全文 | 28278篇 |
免费 | 2557篇 |
国内免费 | 1383篇 |
专业分类
耳鼻咽喉 | 46篇 |
儿科学 | 292篇 |
妇产科学 | 93篇 |
基础医学 | 1173篇 |
口腔科学 | 69篇 |
临床医学 | 6029篇 |
内科学 | 4398篇 |
皮肤病学 | 33篇 |
神经病学 | 7516篇 |
特种医学 | 840篇 |
外科学 | 1152篇 |
综合类 | 4620篇 |
现状与发展 | 5篇 |
预防医学 | 1266篇 |
眼科学 | 393篇 |
药学 | 1935篇 |
33篇 | |
中国医学 | 2278篇 |
肿瘤学 | 47篇 |
出版年
2025年 | 12篇 |
2024年 | 589篇 |
2023年 | 757篇 |
2022年 | 1284篇 |
2021年 | 1737篇 |
2020年 | 1533篇 |
2019年 | 1439篇 |
2018年 | 1442篇 |
2017年 | 1389篇 |
2016年 | 1370篇 |
2015年 | 1173篇 |
2014年 | 2260篇 |
2013年 | 2531篇 |
2012年 | 1661篇 |
2011年 | 1643篇 |
2010年 | 1346篇 |
2009年 | 1241篇 |
2008年 | 1200篇 |
2007年 | 1186篇 |
2006年 | 1082篇 |
2005年 | 830篇 |
2004年 | 691篇 |
2003年 | 605篇 |
2002年 | 584篇 |
2001年 | 436篇 |
2000年 | 367篇 |
1999年 | 301篇 |
1998年 | 248篇 |
1997年 | 189篇 |
1996年 | 150篇 |
1995年 | 133篇 |
1994年 | 121篇 |
1993年 | 93篇 |
1992年 | 76篇 |
1991年 | 51篇 |
1990年 | 60篇 |
1989年 | 47篇 |
1988年 | 53篇 |
1987年 | 44篇 |
1986年 | 49篇 |
1985年 | 39篇 |
1984年 | 41篇 |
1983年 | 29篇 |
1982年 | 44篇 |
1981年 | 19篇 |
1980年 | 12篇 |
1979年 | 11篇 |
1978年 | 10篇 |
1977年 | 6篇 |
1975年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
神经干细胞移植治疗缺氧缺血性脑损伤的实验研究 总被引:23,自引:4,他引:19
目的 研究神经干细胞移植治疗缺氧缺血性脑损伤的可行性。方法 取孕龄为12-16天的母鼠,从胎脑中分离神经细胞,进行培养、鉴定。用出生7天的SD大鼠的新生鼠制作缺氧缺血性脑损伤的动物模型,7天后接受神经干细胞移植(移植组,n=16只),同时设置对照组,只注射磷酸缓冲液(对照组,n=8只),8-10周后,作Y迷宫实验检测大鼠的学习能力和记忆能力。取脑组织作免疫组织化学检查。结果 从大鼠胎脑中成功培养出神经干细胞,培养条件下呈悬浮状态生长,形成神经球,绝大多数的细胞表达神经干细胞的标志物神经巢蛋白(nestin)。接爱神经干细胞移植组大鼠的学习能力、记忆能力和对照组相比,有明显提高,差异具有显著性(P<0.05)。接受神经干细胞移植大鼠组织中可见存活的移植细胞,并和宿主脑组织融合在一起。结论 在体外培养条件下,可从胎脑组织中培养出神经干细胞,移植到缺氧缺血性脑损伤大鼠脑内后,细胞与宿主的脑组织融合在一起,动物的学习、记忆能力有改善。移植神经干细胞是治疗缺氧缺知性脑损伤的有效方法之一。 相似文献
2.
Gazzaniga P. P. Ferroni P. Mina C. Pulcinelli F. M. Rizzo P. A. 《The Italian Journal of Neurological Sciences》1987,8(6):561-566
148 patients with various forms of cerebrovascular disease (CVD) were studied by means of a multiparametric analysis ofin vitro platelet aggregation, based on the following six parameters: ADP and epinephrine primary and secondary aggregation thresholds
and percent maximum aggregation induced by optimal concentrations of ADP and epinephrine. These patients were assigned to
four study groups, according to clinical diagnosis supported by CT scan, of transient ischemic attack and reversible neurological
deficit (TIA-RIND), or completed stroke, in the presence or absence respectively of antiplatelet medical treatment at the
time of the study. A statistically significant increase of thein vitro platelet aggregation was found in 44.4% of the untreated TIA-RIND patients and in 33.9% of the untreated stroke patients.
However this last group showed a higher percentage of very marked hyperaggregation. Differences between the two treated study
groups and controls were not signicant. No difference was found in collagen-and ristocetin-induced aggregation between the
patient groups and the controls.
Sommario 148 pazienti con varie forme di malattia cerebrovascolare, sono stati studiati con analisi multiparametriche dell'aggregazione piastrinica in vitro sulla base dei seguenti sei parametri: le soglie di aggregazione primaria e secondaria e l'aggregazione massima percentuale indotta da ADP ed Epinefrina. Questi pazienti sono stati suddivisi in 4 gruppi di studio in accordo con la diagnosi clinica confortata dai dati della TAC e cioè: TIA, RIND, o rammollimento in presenza o in assenza rispettivamente di un trattamento antiaggregante nel momento dello studio. è stato trovato un aumento statisticamente significativo dell'aggregazione in vitro delle piastrine nel 44.4% dei casi TIA, RIND non trattati e nel 33,9% dei casi di rammollimento non trattati. Quest'ultimo gruppo, però, ha dimostrato una più alta percentuale di iperaggregazione molto marcata. Le differenze tra i 2 gruppi di studio trattati con antiaggreganti e i controlli non erano significative. Inoltre nessuna differenza è stata riscontrata tra i gruppi e i controlli nell'aggregazione indotta da collageno e ristocetina.相似文献
3.
Stroke-induced hemiballismus (HB) has been reported to improve motor function in people with Parkinson's disease (PD). We report on a patient who developed HB from a parietal infarct. The HB was improved by very low-dose clozapine but the HB did not improve the parkinsonism. This suggests that HB itself, whether from a lesion in the subthalamic nucleus or elsewhere, is not what improves motor function in PD; instead, the physiological function of the damaged structure is the determining factor. 相似文献
4.
短暂性脑缺血发作患者血浆中TXB2和PGF1α含量检测 总被引:3,自引:0,他引:3
本文用放射免疫法测定47例短暂性脑缺血发作(TIA)患者血浆中血栓素B_2(TXB_2)和6酮-前列腺F_(1α)(PGF_(1α))的含量。结果发现TIA患者血浆中TXB_2含量增高,PGF_(1α)降低;头颅CT或MRI示有小灶性梗塞者及TIA发作持续时间长于30min者TXB_2升高和PGF_(1α)降低更显著。治疗3个月后,血浆PGF_(1α)显著增高。TXB_2和PGF_(1α)在体内的失平衡是急性脑血管疾病发病的重要机理之一。 相似文献
5.
Tetsuji Kai Yang Il Kim Hirokazu Kitamura Katsunori Kawano Seigo Kitano 《Journal of Hepato-Biliary-Pancreatic Surgery》1997,4(4):423-430
There is a growing body of evidence that the cytokine, tumor necrosis factor-α (TNF-ga), plays an important role in the development
of hepatic ischemia/reperfusion injury. We found that the immunosuppressants, cyclosporine-A (CsA), azathioprine, and FK506,
have protective effects on such injury. The purpose of the present study was to elucidate mechanisms involved in these beneficial
effects of the immunosuppressant, CsA, on liver injury following cold preservation and transplantation, with special reference
to the suppression of TNF-α release. Rat livers were stored in Euro-Collins solution (EC) at 4°C for 6h and orthotopically
transplanted. The animals allotted to two groups: group A (untreated controls) and group B (CsA pretreatment of recipients).
CsA (10 mg/kg, p.o.) was given for 3 consecutive days preoperatively. CsA pretreatment of the recipients significantly improved
the 2-week survival rate (0/6 for group A, 3/6 for group B;P<0.05) and this was associated with a significant decrease in serum TNF-α levels 2h posttransplantation (group A, 69.8±15.7
pg/ml; group B, 22.8±6.8; mean±SEM;n=12 each;P<0.05) and amelioration of sinusoidal endothelial injury, assessed by electron microscopy. Plasma endotoxin levels following
reperfusion of the grafts were not altered by the CsA therapy. Morphologically, CsA pretreatment of the recipients did not
alter activation of Kupffer cells. CsA pretreatment of the recipient aids in preventing cold preservation/reperfusion injury
of the liver graft, possibly by modulating effects of TNF-α. 相似文献
6.
B. Stemper N. Thürauf B. Neundörfer J. G. Heckmann 《European journal of neurology》2003,10(6):743-744
A 76-year old woman was admitted because of severe gait ataxia and dysarthric speech that had worsened over the last 24 h. The patient was initially suspected of having repeated transitory ischemic attacks (TIAs) as her daughter reported a similar episode that had happened 3 weeks prior to admission. The onset of spontaneous twisting, choreoathetotic movements of both hands and arms and worsening of symptoms one hour after admission together with a history of lithium therapy lead to the correct diagnosis and appropriate treatment. 相似文献
7.
8.
Adrià Arboix Lluis García-Eroles Emili Comes Montserrat Oliveres Miquel Balcells Gustavo Pacheco Cecilia Targa 《European journal of neurology》2003,10(4):429-435
We assessed predictors of spontaneous early neurological recovery after acute ischemic stroke by means of multivariate analysis in a cohort of 1,473 consecutive patients treated at one academic center. At hospital discharge, spontaneous neurological improvement or good outcome was defined as grades 0-2 of the Rankin scale, and poor outcome (no improvement or in-hospital death) as grades 3-5. Spontaneous recovery of neurological deficit at the time of discharge from the hospital was observed in 16% of patients with cerebral infarction (n = 238). Dysarthria-clumsy hand syndrome improved in 44% of patients and was the only variable significantly associated with in-hospital functional recovery in three logistic regression models that in addition to lacunar syndromes, included demographic variables, cardiovascular risk factors, and clinical variables [odds ratio (OR) 2.56], neuroimaging findings (OR 2.48), and outcome data (OR 2.39), respectively. Clinical factors related to severity of infarction available at stroke onset have a predominant influence upon in-hospital outcome and may help clinicians to assess prognosis more accurately. Our work gives a contribution into prognostic factors after acute ischemic stroke. With regard to patterns of stroke, dysarthria-clumsy hand syndrome was a significant predictor of spontaneous in-hospital recovery in ischemic stroke patients. 相似文献
9.
M. Vincenzi T. Morlino P. Allegri E. Barbieri F. Cappelletti U. Delio R. Ometto P. Maiolino 《Clinical cardiology》1981,4(1):15-21
Alterations in cardiovascular function induced by the acute intravenous administration of verapamil (5 or 10 mg) in 52 patients (29 with ischemic heart disease and 23 without heart disease) were evaluated with use of invasive techniques (right and left heart catheterization, left ventricular cineangiography, and coronary arteriography). The most significant changes were represented by a decrease in systemic vascular resistance and systemic arterial pressure, and an increase in heart rate and cardiac output. Contractility indexes were not depressed in either group, and altered ventricular wall motion tended to improve to a slightly smaller degree than in patients treated with nitroglycerin. The use of verapamil in patients with ischemic heart disease appears to be safe, and concern about the negative inotropic influences in humans no longer seems justified. 相似文献
10.