全文获取类型
收费全文 | 239561篇 |
免费 | 19334篇 |
国内免费 | 9001篇 |
专业分类
耳鼻咽喉 | 1759篇 |
儿科学 | 3357篇 |
妇产科学 | 2634篇 |
基础医学 | 37041篇 |
口腔科学 | 3790篇 |
临床医学 | 17737篇 |
内科学 | 47476篇 |
皮肤病学 | 3248篇 |
神经病学 | 17302篇 |
特种医学 | 5002篇 |
外国民族医学 | 54篇 |
外科学 | 16589篇 |
综合类 | 30911篇 |
现状与发展 | 23篇 |
一般理论 | 6篇 |
预防医学 | 12454篇 |
眼科学 | 2801篇 |
药学 | 36493篇 |
51篇 | |
中国医学 | 9563篇 |
肿瘤学 | 19605篇 |
出版年
2024年 | 582篇 |
2023年 | 4217篇 |
2022年 | 9041篇 |
2021年 | 11097篇 |
2020年 | 8581篇 |
2019年 | 8096篇 |
2018年 | 7778篇 |
2017年 | 7640篇 |
2016年 | 7753篇 |
2015年 | 9009篇 |
2014年 | 13997篇 |
2013年 | 15696篇 |
2012年 | 13630篇 |
2011年 | 15703篇 |
2010年 | 12705篇 |
2009年 | 12925篇 |
2008年 | 12615篇 |
2007年 | 11797篇 |
2006年 | 10510篇 |
2005年 | 9203篇 |
2004年 | 7749篇 |
2003年 | 6968篇 |
2002年 | 5585篇 |
2001年 | 4687篇 |
2000年 | 3954篇 |
1999年 | 3572篇 |
1998年 | 3273篇 |
1997年 | 3132篇 |
1996年 | 2723篇 |
1995年 | 2471篇 |
1994年 | 2220篇 |
1993年 | 1866篇 |
1992年 | 1581篇 |
1991年 | 1436篇 |
1990年 | 1174篇 |
1989年 | 997篇 |
1988年 | 931篇 |
1987年 | 779篇 |
1986年 | 707篇 |
1985年 | 1361篇 |
1984年 | 1416篇 |
1983年 | 1049篇 |
1982年 | 1030篇 |
1981年 | 890篇 |
1980年 | 767篇 |
1979年 | 648篇 |
1978年 | 497篇 |
1977年 | 389篇 |
1976年 | 426篇 |
1975年 | 366篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
P.A. GARA P. MARTINEZ L. SANCHEZ R. VILLUENDAS J.L. ORRADRE H. OLIVA M.A. PIRIS 《Histopathology》1991,19(1):69-76
Hodin's disease, lymphocyte predominance type (nodular paragranuloma), is of germinal centre origin and the tumours cells have a B-cell phenotype. As the t(14;18) translocation, and the subsequent expression of bcl-2 protein by germinal centre cells, is the most characteristic finding of centroblastic-centrocytic lymphoma, we have tested a series of 11 cases of lymphocyte predominance Hodgkin's disease, using Southern blot analysis for the major breakpoint region and the minor breakpoint cluster region, polymerase chain reaction with primers for the major and minor breakpoint cluster region, and immunohistological studies with a monoclonal antibody specific for the bcl-2 protein. All three techniques gave negative results in the cases of Hodgkin's disease, establishing a clear differentiation from centroblastic-centrocytic lymphoma. These findings are useful in the differential diagnosis between the two entities and raise the question of the non-clonal nature of lymphocyte predominance Hodgkin's disease. 相似文献
103.
2-chloroprocaine antagonism of epidural morphine analgesia 总被引:2,自引:0,他引:2
Background: 2-chloroprocaine (2-CP) used for lumbar epidural anesthesia (LEA) reportedly decreases the efficacy of epidural morphine (EM) administered for post-cesarean section (CS) analgesia. The amount of supplemental i.v. morphine self-administered by the patient via the patient-controlled analgesia device (PCA) is used to study the interaction between EM and 2-CP.
Methods: Forty-two patients scheduled for elective CS were randomly divided into 3 equal groups, and received 2-CP, 2-CP+epinephrine (Epi, 5 μg ml-1 ) or 2% lidocaine (Lido) with Epi for LEA. All patients received 5 mg EM and i.v. PCA morphine for postoperative pain. Cumulative amount of i.v. morphine used in the first 24 hours as well as the amount of the drug used during each 2-h period were noted. Nonparametric analysis of variance and Chi-squared analysis were used for statistical comparisons.
Results: The mean cumulative 24-h i.v. PCA morphine requirement in the 2-CP, 2-CP+Epi and Lido+Epi groups respectively was 20.5±24, 33.1.5±27 and 4.07±6.3 (mean±SD). The Lido+Epi group used significantly less morphine ( P = 0.01) compared to either of the 2-CP groups with no significant difference between the 2-CP groups. The maximum i.v. PCA morphine use occurred in the first 4 hours following surgery in all three groups.
Conclusion: Analgesic efficacy of EM is decreased when 2-CP is used for LEA compared to when Lido+Epi is used. 相似文献
Methods: Forty-two patients scheduled for elective CS were randomly divided into 3 equal groups, and received 2-CP, 2-CP+epinephrine (Epi, 5 μg ml
Results: The mean cumulative 24-h i.v. PCA morphine requirement in the 2-CP, 2-CP+Epi and Lido+Epi groups respectively was 20.5±24, 33.1.5±27 and 4.07±6.3 (mean±SD). The Lido+Epi group used significantly less morphine ( P = 0.01) compared to either of the 2-CP groups with no significant difference between the 2-CP groups. The maximum i.v. PCA morphine use occurred in the first 4 hours following surgery in all three groups.
Conclusion: Analgesic efficacy of EM is decreased when 2-CP is used for LEA compared to when Lido+Epi is used. 相似文献
104.
HCVRNA阳性的丙型肝炎46例,均经临床和/或组织学确诊。治疗组24例用IFNa-nl或a-2b3×106IU,隔日一次;对照组22例用一般护肝药物。HCVRNA12周转阴率治疗组为83.3%,对照组为9.0%(P<0.001)。ALT和AST复常率治疗组也优于对照组(P<0.05)。随访观察满48周者治疗组15例中HCVRNA持续转阴11例(73.3%).对照组5例均持续阳性。治疗组中5例做了Ⅰ~Ⅲ型HCV基因分型,结果均为Ⅱ型。同时对急、慢性丙型肝炎的发病过程和病理诊断作了讨论。 相似文献
105.
刘建勋 《中国激光医学杂志》1992,1(2):109-111
本文较详细地介绍了应用激光技术即用CO_2及Nd:YAG激光手术刀治疗各种类型痔的临床观察。我院自1988年应用CO_2及Nd,YAG(以下简称激光手术刀)的技术治疗各种痔1376例均取得满意的治疗效果,治愈率达100%,并对有关问题进行探讨。 相似文献
106.
107.
Kaisa Heiskanen Pirjo Lindstr m-Sepp Leena Haataja Sirkka-Liisa Vaittinen Terttu Vartiainen Hannu Komulainen 《Toxicology》1995,100(1-3):121-128
Activities of the xenobiotic metabolizing enzymes were measured in the liver, kidney, duodenum and lung microsomes and cytosol fractions of Wistar rats after subchronic administration of 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), a potent bacterial mutagen in chlorinated drinking water. MX was administered by gavage at the dose level of 30 mg/kg for 18 weeks (low dose), or at the dose level which was raised gradually from 45 mg/kg for 7 weeks via 60 mg/kg for 2 weeks to a clearly toxic dose of 75 mg/kg for 5 weeks (high dose). Microsomal and cytosolic preparations were made and the activities of 7-ethoxyresorufin-O-deethylase (EROD), pentoxyresorufin-O-dealkylase (PROD), NADPH-cytochrome-c-reductase, UDP-glucuronosyltransferase (UDPGT) and glutathione-S-transferase (GST) were measured. Kidneys were affected most. A dose-dependent decrease was observed in EROD (90% in males, 80% in females at the high dose) and in PROD (58% in females, at the high dose) in kidneys. An increase was, however, detected in kidney NADPH-cytochrome-c-reductase (66% in females at high dose), UDPGT (89% in males and 97% in females at high dose) and GST activities (56% in males and 50% in females at high dose). MX caused only a few changes in the enzyme activities of the liver. The EROD activity was decreased 25% to 37%, both in the livers of males and females, but the total content of P450s was not altered. Hepatic GST activity was elevated in females in a dose-dependent manner (31% and 44%). GST activity was elevated in duodenum in females (59%) at the high dose. There were no marked changes in the enzyme activities in the lungs. MX was a weak inhibitor of EROD activity both in the liver and kidney microsomes in vitro, decreasing the EROD activity by 53% and 43%, respectively at the concentration of 0.9 mM. The results indicate that MX decreases the activity of phase I metabolism enzymes, but induces phase II conjugation enzyme activities, particularly in kidneys in vivo. It is possible that these changes contribute to metabolism of MX in kidneys and renders them susceptible to MX in the course of repeated exposure. 相似文献
108.
109.
A protein C deficient woman, with a past history of recurrent thrombosis and purpura fulminans, was successfully treated with protein C concentrate in the peripartum period. © 1992 Wiley-Liss, Inc. 相似文献
110.
Alan L Whone Sarah Von Spiczak Mark Edwards Enza-Maria Valente Alexander Hammers Kailash P Bhatia David J Brooks 《Movement disorders》2004,19(12):1498-1503
The opioid transmitters enkephalin and dynorphin are known to regulate pallidal output and consequently cortical excitability. Indeed, abnormal basal ganglia opioid transmission has been reported in several involuntary movement disorders, including levodopa-induced dyskinesias in Parkinson's disease (PD), tardive dyskinesias/dystonia, Huntington's disease, and Tourette's syndrome. Moreover, a previous 11C-diprenorphine PET study investigating levodopa-induced dyskinesias found reduced opioid receptor availability in PD with but not without dyskinesias. We wished to investigate if a similar alteration in basal ganglia opioid binding was present in DYT1 primary torsion dystonia (PTD). Regional cerebral 11C-diprenorphine binding was investigated in 7 manifesting carriers of the DYT1 gene and 15 age-matched normal controls using a region-of-interest (ROI) approach and statistical parametric mapping (SPM). No difference in regional mean 11C-diprenorphine binding was found between DYT1-PTD and controls, and no correlation between the severity of dystonia and opioid binding was seen. We conclude that aberrant opioid transmission is unlikely to be present in DYT1-PTD and altered opioid transmission is not a common mechanism underlying all disorders of involuntary movement. 相似文献