全文获取类型
收费全文 | 777篇 |
免费 | 33篇 |
国内免费 | 47篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 41篇 |
妇产科学 | 3篇 |
基础医学 | 72篇 |
口腔科学 | 12篇 |
临床医学 | 113篇 |
内科学 | 231篇 |
皮肤病学 | 21篇 |
神经病学 | 48篇 |
特种医学 | 144篇 |
外科学 | 34篇 |
综合类 | 25篇 |
预防医学 | 8篇 |
眼科学 | 5篇 |
药学 | 59篇 |
中国医学 | 3篇 |
肿瘤学 | 36篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2017年 | 8篇 |
2016年 | 5篇 |
2015年 | 22篇 |
2014年 | 20篇 |
2013年 | 21篇 |
2012年 | 17篇 |
2011年 | 16篇 |
2010年 | 33篇 |
2009年 | 30篇 |
2008年 | 19篇 |
2007年 | 50篇 |
2006年 | 20篇 |
2005年 | 17篇 |
2004年 | 10篇 |
2003年 | 4篇 |
2002年 | 21篇 |
2001年 | 23篇 |
2000年 | 13篇 |
1999年 | 11篇 |
1998年 | 45篇 |
1997年 | 48篇 |
1996年 | 55篇 |
1995年 | 31篇 |
1994年 | 31篇 |
1993年 | 21篇 |
1992年 | 9篇 |
1991年 | 13篇 |
1990年 | 8篇 |
1989年 | 34篇 |
1988年 | 27篇 |
1987年 | 21篇 |
1986年 | 21篇 |
1985年 | 15篇 |
1984年 | 14篇 |
1983年 | 6篇 |
1982年 | 16篇 |
1981年 | 12篇 |
1980年 | 14篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1976年 | 6篇 |
1975年 | 8篇 |
1922年 | 1篇 |
排序方式: 共有857条查询结果,搜索用时 0 毫秒
11.
12.
13.
14.
MUHAMMAD N RAZA MUHAMMAD HADID CHARLES E KEEN CORALIE BINGHAM ANDREW HJ SALMON 《Nephrology (Carlton, Vic.)》2012,17(8):748-753
Background: The use and timing of steroids in the management of acute tubulointerstitial nephritis (ATIN) remains debatable. Aims: To determine the incidence and aetiology of ATIN in our unit, and to examine trends in the use of steroids and their impact on renal outcomes. Methods: Patients with a histological diagnosis of ATIN over a 9‐year period were identified and divided into steroid‐treated (StG) and steroid‐naïve groups (SnG). Mean change in estimated glomerular filtration rate (eGFR) was determined. Results: Forty‐nine patients had ATIN as their main diagnosis, 67% of cases were drug‐induced, and proton pump inhibitors (PPI) were the second commonest implicated drug category. Majority (75%) of patients received steroids, and eGFR improved to a significantly greater degree in these steroid‐treated patients (3.4‐fold improvement vs 2.0‐fold in SnG; P < 0.05, unpaired t‐test). Despite comparable eGFR at presentation (StG: 11.7; SnG: 15.4), steroid‐treated patients were less likely to receive dialysis, although not significantly so (OR 0.27; 95% CI 0.06–1.15, P = 0.066, chi‐squared test). However, there was no significant relation between the degree of eGFR improvement and delay in starting steroids (Pearson r = ?0.25, P > 0.45), and no difference in eGFR at the time of last follow‐up (StG: 33 ± 3; SnG: 32 ± 7; P > 0.9, unpaired t‐test). Conclusion: StG patients had a greater degree of improvement in renal function, but with no correlation between degree of improvement in eGFR and delay in starting steroids, and similar eGFR values at final follow‐up. PPI were the second commonest drug category among drug‐induced cases. 相似文献
15.
16.
Expression of fibrinogen receptors during activation and subsequent desensitization of human platelets by epinephrine 总被引:2,自引:0,他引:2
Epinephrine causes platelet aggregation and secretion by interacting with alpha 2-adrenergic receptors on the platelet surface. Platelet aggregation requires the binding of fibrinogen to a specific receptor on the membrane glycoprotein IIb-IIIa complex. Although the IIb-IIIa complex is identifiable on the surface of resting platelets, the fibrinogen receptor is expressed only after platelet activation. The current studies were designed to examine the effect of occupancy of platelet alpha 2-adrenergic receptors by epinephrine on the expression of fibrinogen receptors and on the aggregation of platelets. The ability of epinephrine to induce the expression of fibrinogen receptors was studied under two different conditions: acute stimulation (less than 1 min) and prolonged stimulation (50 to 90 min), the latter of which is associated with a reduction or "desensitization" of the platelet aggregation response. Expression of the fibrinogen receptor was monitored with 125I-fibrinogen as well as with 125I-PAC-1 (PAC-1), a monoclonal antibody that binds to the glycoprotein IIb-IIIa complex only after platelets are activated. Epinephrine caused an immediate increase in PAC-1 and fibrinogen binding that was dependent on occupancy of the alpha 2-receptor by epinephrine and on the presence of extracellular free Ca (KCa = 30 mumol/L). By itself, 1 mmol/L Mg was unable to support induction of the fibrinogen receptor by epinephrine. However, it did decrease the Ca requirement by about two orders of magnitude. Prolonged stimulation of unstirred platelets by epinephrine led to a 70% decrease in the aggregation response when the platelets were subsequently stirred. Despite their decreased aggregation response, desensitized platelets bound PAC-1 and fibrinogen normally, indicating that the loss of aggregation was not due simply to a decrease in fibrinogen receptor expression. Although desensitization was not affected by pretreatment of the platelets with aspirin, it was partially prevented when extracellular Ca was chelated by EDTA during the long incubation with epinephrine. These studies demonstrate that once platelet alpha 2-adrenergic receptors are occupied by epinephrine, extracellular Ca is involved in initiating the aggregation response by supporting the induction of the fibrinogen receptor and the binding of fibrinogen. Furthermore. Ca-dependent reactions subsequent to fibrinogen binding may be necessary for maximal platelet aggregation and are impaired when platelets become desensitized to epinephrine. 相似文献
17.
Engraftment of dogs with Ia-positive marrow cells isolated by avidin- biotin immunoadsorption 总被引:3,自引:0,他引:3
Berenson RJ; Bensinger WI; Kalamasz D; Schuening F; Deeg HJ; Graham T; Storb R 《Blood》1987,69(5):1363-1367
Previous work has shown failure of engraftment in lethally irradiated dogs when autologous marrow was depleted of Ia-positive cells with an anti-Ia antibody and complement before infusion. In the current study, we have utilized an avidin-biotin immunoadsorption procedure to obtain a population of highly enriched Ia-positive cells for autologous bone marrow transplantation in dogs given lethal irradiation. Dog marrow cells (2.4 to 7.0 X 10(9) cells) that contained 8.6% to 19.9% Ia- positive cells were treated successively with monoclonal antibody 7.2, which reacts with a framework determinant of Ia-antigen, and biotin- conjugated goat antimouse immunoglobulin. These treated cells were passed over a column of avidin-Biogel (polyacrylamide) and the adherent cells removed by mechanical agitation. Seven lethally irradiated dogs were transplanted with 5.9 to 33.4 X 10(6) recovered adherent cells per kilogram of which 69.0% to 88.0% were Ia-positive. All dogs had hematologic recovery; six are alive and well with durable engraftment and one died on day 15 posttransplant. They are immunologically normal as determined by lymph node and bone marrow biopsies, lymphocyte function, and immunophenotyping of peripheral blood and bone marrow cells. These data provide further evidence that canine hematopoietic stem cells express Ia-like antigens and that these cells are capable of complete hematopoietic and immunologic reconstitution in an autologous model. 相似文献
18.
背景目前已开展了对重性精神病患者进提供连续性服务的研究。目的探讨基层对有抑郁症风险患者提供连续性服务的水平,并与对心力衰竭患者的服务水平进行对比。方法采用抑郁症风险患者与心力衰竭患者对比的探索性研究。采用患者问卷评估服务的持续性,包含如下内容:(1)联系的服务提供者数(个人连续性);(2)诊所内服务提供者之间的合作(团队连续性)(6个项目,分数1~5分);(3)诊所外全科医师与服务提供者之间的合作(跨界连续性)(4个项目,分数1~5分)。结果大多数抑郁症风险患者在过去1年中寻遍整个服务提供界联系了几个服务提供者,曾遇到过高水平团队连续性服务及低水平跨界连续性服务。在诊所中可接触到的不同服务提供者要明显多于心力衰竭患者服务提供者(P<0.01)。抑郁症风险患者的服务提供者之间的合作更好一些,每项平均得分4.3分,心力衰竭患者得分为4.0分(P=0.03)。然而,跨界连续性服务方面正好相反:抑郁症风险患者每项平均得分3.5分,心力衰竭患者得分为4.0分(P=0.01)。结论抑郁症风险患者与心力衰竭患者之间的探索性对比显示:体验服务连续性方面的差距不大。对此还应行进一步分析。 相似文献
19.
Julia C Bartsch Pawel Fidzinski Jojanneke HJ Huck Heide H?rtnagl Richard Kovács Agustin Liotta Josef Priller Christian Wozny Joachim Behr 《Neuropsychopharmacology》2015,40(4):987-995
Dopaminergic hyperfunction and N-methyl-D-aspartate receptor (NMDAR) hypofunction have both been implicated in psychosis. Dopamine-releasing drugs and NMDAR antagonists replicate symptoms associated with psychosis in healthy humans and exacerbate symptoms in patients with schizophrenia. Though hippocampal dysfunction contributes to psychosis, the impact of NMDAR hypofunction on hippocampal plasticity remains poorly understood. Here, we used an NMDAR antagonist rodent model of psychosis to investigate hippocampal long-term potentiation (LTP). We found that single systemic NMDAR antagonism results in a region-specific, presynaptic LTP at hippocampal CA1-subiculum synapses that is induced by activation of D1/D5 dopamine receptors and modulated by L-type voltage-gated Ca2+ channels. Thereby, our findings may provide a cellular mechanism how NMDAR antagonism can lead to an enhanced hippocampal output causing activation of the hippocampus-ventral tegmental area-loop and overdrive of the dopamine system. 相似文献
20.
Gastric cytoprotection by antacids and papaverine in rats 总被引:1,自引:0,他引:1
J Hagel H Renner M Hirsch G Weig B Kaduk H Ruppin W Domschke 《Hepato-gastroenterology》1982,29(6):271-274
Prostaglandin E2 (PGE2) prevented hemorrhagic ulceration of rat stomach mucosa induced by various procedures when given orally at a non-antisecretory dose. This effect of PGE2 is called gastric cytoprotection. We used absolute ethanol, 0.6 N hydrochloric acid and 0.2 N sodium hydroxide as damaging agents. Ranitidine at an antisecretory dose did not exhibit any cytoprotective effect. However, the poorly absorbable antacids, magnesium hydroxide plus aluminium hydroxide and aluminium phosphate inhibited the development of hemorrhagic lesions significantly. A similar protective effect was seen after intragastric administration of papaverine, which is known to stimulate endogenous prostaglandin synthesis. However, the question as to whether or not stimulation of endogenous prostaglandin synthesis is the mode of action of the cytoprotective effect of papaverine and poorly absorbable antacids, cannot yet be answered. 相似文献