全文获取类型
收费全文 | 4727篇 |
免费 | 288篇 |
国内免费 | 121篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 76篇 |
妇产科学 | 99篇 |
基础医学 | 303篇 |
口腔科学 | 10篇 |
临床医学 | 744篇 |
内科学 | 899篇 |
皮肤病学 | 53篇 |
神经病学 | 362篇 |
特种医学 | 63篇 |
外科学 | 482篇 |
综合类 | 868篇 |
预防医学 | 133篇 |
眼科学 | 47篇 |
药学 | 807篇 |
4篇 | |
中国医学 | 99篇 |
肿瘤学 | 83篇 |
出版年
2024年 | 8篇 |
2023年 | 43篇 |
2022年 | 64篇 |
2021年 | 126篇 |
2020年 | 114篇 |
2019年 | 112篇 |
2018年 | 124篇 |
2017年 | 120篇 |
2016年 | 128篇 |
2015年 | 175篇 |
2014年 | 342篇 |
2013年 | 401篇 |
2012年 | 290篇 |
2011年 | 299篇 |
2010年 | 232篇 |
2009年 | 199篇 |
2008年 | 222篇 |
2007年 | 228篇 |
2006年 | 198篇 |
2005年 | 175篇 |
2004年 | 180篇 |
2003年 | 159篇 |
2002年 | 148篇 |
2001年 | 144篇 |
2000年 | 102篇 |
1999年 | 85篇 |
1998年 | 70篇 |
1997年 | 74篇 |
1996年 | 64篇 |
1995年 | 45篇 |
1994年 | 64篇 |
1993年 | 31篇 |
1992年 | 25篇 |
1991年 | 39篇 |
1990年 | 29篇 |
1989年 | 22篇 |
1988年 | 23篇 |
1987年 | 20篇 |
1986年 | 21篇 |
1985年 | 30篇 |
1984年 | 30篇 |
1983年 | 30篇 |
1982年 | 31篇 |
1981年 | 9篇 |
1980年 | 21篇 |
1979年 | 8篇 |
1978年 | 5篇 |
1977年 | 9篇 |
1976年 | 10篇 |
1975年 | 4篇 |
排序方式: 共有5136条查询结果,搜索用时 15 毫秒
1.
K. KARNICKI† R. D. MCBANE II † R. S. MILLER† R. J. Leadley JR ¶ J. MORSER W. G. OWEN†‡ J. H. CHESEBRO§ 《Journal of thrombosis and haemostasis》2004,2(12):2162-2169
BACKGROUND/OBJECTIVE: The efficacy of a direct factor (F)Xa inhibitor, ZK-807834, was compared with indirect inhibition by enoxaparin for inhibition and deaggregation of acute platelet-rich thrombi in a well-characterized porcine carotid injury model. METHODS: A crush injury was performed on a randomly chosen carotid artery and the thrombus allowed to propagate for 30 min. Pigs then received intravenous drug for 35 min: ZK-807834-Dose 1 (40 microg kg(-1) bolus + 1.5 microg kg(-1) min(-1) infusion, n=6); ZK-807834-Dose 2 (20 microg kg(-1) bolus + 0.75 microg kg(-1) min(-1) infusion; n=6); enoxaparin (1 mg kg(-1) bolus; n=6); or saline (n=6). Five minutes after drug initiation, the contralateral artery was injured. Thrombus size was monitored by scintillation detection of autologous 111In-platelets. RESULTS: The prothrombin time ratio was 2.2 +/- 0.1; 1.4 +/- 0.3; 1.2 +/- 0.9 and 1.1 +/- 0.2, respectively. ZK-807834-Dose 1 significantly inhibited carotid platelet deposition (525 +/- 226 x 10(6) cm(-2); P = 0.008), whereas ZK-807834-Dose 2 (2325 +/- 768) and enoxaparin (1236 +/- 383) were not different from saline (2776 +/- 642). Thrombus deaggregation was greatest for animals receiving ZK-807834-Dose 1 (473 +/- 185). Neither ZK-807834-Dose 2 (1588 +/- 480) nor enoxaparin (1618 +/- 686) was different from saline control (2222 +/- 598). CONCLUSIONS: Direct FXa inhibition with ZK-807834, at a prothrombin time ratio of 2.2, effectively inhibits thrombosis and promptly deaggregates thrombi induced by arterial injury. In contrast, indirect FXa inhibition with enoxaparin was ineffective. 相似文献
2.
Factor Xa-activated whole blood clotting time (Xa-ACT) for bedside monitoring of dalteparin anticoagulation during haemodialysis. 总被引:1,自引:1,他引:0
Rolf Dario Frank Vincent M Brandenburg Regina Lanzmich Jürgen Floege 《Nephrology, dialysis, transplantation》2004,19(6):1552-1558
BACKGROUND: Low molecular weight heparins (LMWH) like dalteparin are increasingly used for anticoagulation during haemodialysis (HD). The available laboratory tests for monitoring LMWH anticoagulation are time-consuming and expensive, and the suitability of the conventional activated clotting time (ACT) is controversial. A simple and cheap bedside test would be useful. METHODS: We studied the factor Xa-activated whole blood clotting time (Xa-ACT) in vitro and in vivo in nine patients undergoing chronic HD with i.v. dalteparin bolus anticoagulation and compared it with the conventional ACT. Plasma anti-factor Xa (antiXa) activity was determined with a chromogenic assay. Thrombin-antithrombin complexes were measured to detect coagulation activation. RESULTS: Xa-ACT and ACT were prolonged with rising dalteparin concentration. In vitro, both clotting times were strongly correlated with the antiXa levels (r = 0.94 and 0.89, respectively). Nevertheless, compared with the ACT, the Xa-ACT was considerably more sensitive to the LMWH in vitro (healthy blood: Xa-ACT 90 s/U vs ACT 26 s/U; uraemic blood: Xa-ACT 96 s/U vs ACT 31 s/U) as well as in vivo (Xa-ACT 81 s/U vs ACT 22 s/U) and reflected different intensities of anticoagulation. An initial dalteparin bolus of 80+/-11 U/kg body weight was able to prevent coagulation activation for up to 4 h of HD. CONCLUSION: For monitoring LMWH anticoagulation the Xa-ACT was superior to the conventional ACT in vitro as well as in vivo during HD. The Xa-ACT can be useful as a LMWH bedside test. The ACT was not sensitive enough to serve as a LMWH monitoring tool. 相似文献
3.
O. F. M. SELLEVOLD T. M. BERG K. A. REIN O. W. LEVANG O–J. IVERSEN K. BERGH 《Acta anaesthesiologica Scandinavica》1994,38(4):372-379
A prospective randomized study was performed to investigate the effect of surface coating with covalently endpoint–attached heparin (Carmeda Bio Active Surface) and reduced general heparinization on haematological indices and complement C5 activation. Care was taken to optimize the rheological design of the system using centrifugal pump and a closed system without venting or machine suction. Twenty patients scheduled for aortocoronary bypass grafting (EF > 0.5) participated in the study. Ten patients were randomized to be treated with heparin–coated equipment (CBAS) and reduced i.v. heparin (1.5 mg kg-1) while 10 patients treated with identical but noncoated equipment and full heparinization (3 mg–kg-1) served in a Control group. A vacuum suction was used to collect the blood from the operating field and it was autotransfused at weaning from extracorporeal circulation (ECC). Blood samples were obtained from the venous (precircuit) and arterial (postcircuit) side. We used a new and very specific method for detection of C5a based on monoclonal antibodies. The concentration of C5a was low in both groups during the operation but a significant increase was seen on days 1 and 2. In the Control group there was an increase from 10.2 ngml-1±1.2 to 27.5 ng ml-1 ± 4.8 on day 2 and in the CBAS group from 10.7 ng ml-1 ± 1.2 to 35.6 ng ml-1 ± 11.6 on day 2 (NS between groups). The granulocytes and total leukocyte count increased at the end of ECC and was maintained at the elevated level throughout the study period. The amount of free haemoglobin was high in the autotransfused blood in both groups. The present results confirm the feasibility of reducing general heparin when using heparin–coated systems but the study does not support the superiority of such coating with regard to biocompatibility in short procedures with a Theologically optimized circuit. The potential benefit from reduced heparin and protamine has not been fully evaluated. 相似文献
4.
M. J. Ray P. A. Carroll S. J. E. Just G. A. T. Hawson J. H. N. Belt 《Journal of clinical monitoring and computing》1994,10(2):97-100
Objective. The Ciba Corning 512 coagulation monitor (CC512) can be used to monitor heparin therapy by performing an activated
partial thromboplastin time (APTT) at the patient’s bedside. This study was designed to compare the CC512 results to results
using the laboratory system. The relative sensitivities of both systems to the effect of oral anticoagulant therapy also was
investigated.Methods. Activated partial thromboplastin times were performed with both the CC512 and laboratory system on 74 specimens from patients
receiving IV heparin therapy, and on 14 specimens from patients on warfarin only. Heparin assays were performed on 43 of the
specimens from the heparinized patients.Results. When a patient was receiving heparin only, the APTT results of the CC512 proved to be similar to existing laboratory methods.
The CC512 APTT results of patients on warfarin only were markedly prolonged, whereas the laboratory APTTs were only slightly
affected.Conclusion. The CC512 results were comparable to the laboratory system. However, the CC512 APTT was more sensitive to the effect of
warfarin than the laboratory APTT system used in this study. CC512 APTT results on a patient receiving both oral and intravenous
anticoagulation could be misleading.
The authors wish to thank D.M. O’Brien and the nursing staff of the Coronary Care Unit for providing CC512 data and laboratory
specimens, and I. Smith for the preparation of graphics. We also wish to thank Australian Diagnostics Corporation, which provided
consumables. 相似文献
5.
Influence of heparin on fibrinogen and D-dimer plasma levels in acute myocardial infarction treated with streptokinase 总被引:5,自引:0,他引:5
SALVIONE A.; MARENZI G. C.; AGOSTONI P.; GRAZI S.; GUAZZI M. D. 《European heart journal》1994,15(5):654-659
The purpose of this study was to investigate whether, to whatextent, and through which mechanisms intravenous heparin, administeredbefore and after streptokinase, affects the plasma levels ofD-dimer and fibrinogen in myocardial infarction. Data concerningmortality and incidence of coronary recanalization in patientsreceiving heparin and thrombolytic therapy after acute myocardialinfarction are controversial; furthermore, the mechanisms throughwhich heparin acts in combination with thrombolytic therapyare unclear. Thirty-eight patients with acute myocardial infarctiontreated with streptokinase were considered. Nineteen of themreceived, immediately before the beginning of thrombolytic treatment,a bolus of heparin (100 U. kg1 intravenously) and, 2 h later,intravenous heparin in doses raising the partial thromboplastintime to 2-2.5 times the normal value (Group 1); the remaining19 did not receive anticoagulant treatment (Group 2). Multipledeterminations of plasma D-dimer and fibrinogen levels wereobtained in all patients before, and in the seven days followingthrombolytic treatment. Six hours after streptokinase, fibrinogendecreased from 304 ± 34 to 61 ± 34 mg. dt1 inGroup 1 and from 312 ± 29 to 38 ±21 mg. dt1 inGroup 2 (P<002 versus Group 1). The same difference betweengroups persisted at the 12th and at the 18th hour. D-dimer values,from 0-5 ± 01 \ig. dl1 in Group 1 and 04 ±01 fig.dt1 in Group 2, increased at the 1st hour to 37.2 ± 36.5fig. dt1 and 52.2 ± 39.8 µg. dl1, respectively.A peak value was reached in both groups at the 6th hour, whichwas followed by a slow decrease. A significant difference betweenthe two groups (P<0.05) was observed at the 1st, 2nd, 4thand 6th hour. An inverse correlation between maximal changesof fibrinogen and of D-dimer was found in both groups (r= 0.89,P<0.001 in Group 1; r=-0.81, P<0.001 in Group 2). The relationship between D-dimer and fibrinogen variations afterstreptokinase and changes induced by heparin, support the hypothesisthat the decrease of fibrinogen, following thrombolysis, isnot only the consequence of its direct degradation, but alsothe result of its transformation by streptokinase into fibrin,fibrin cross-linked (with facilitation of thrombogenic condition)and then into the stable catabolite, D-dimer. These data confirma thrombogenic effect of streptokinase therapy; this tendencycan be limited by prompt use of high doses of heparin. 相似文献
6.
颜程光 《实用临床医学(江西)》2006,7(9):38-39
目的:探讨低分子肝素治疗不稳定型心绞痛(UA)的临床疗效。方法:对41例不稳定型心绞痛病例,治疗前均常规治疗。在此基础上低分子肝素(体重≤60 kg为5 000 U,体重>60 kg为7 500 U),12 h 1次皮下注射,连用7~14 d,分别于用药前30 min,用药后48 h采血测定活化部分凝血活酶时间(APTT),凝血酶原时间(PT)。结果:显效9例,有效24例,总有效率80.5%。结论:低分子肝素具有高比例的抗因子Xa和抗因子Ⅱa活性,由于其分子量小,与血浆蛋白和内皮细胞结合减少,所以生物利用度高,血浆半衰期长。疗效可取得与肝素同样甚至更高抗凝血酶效果,并且有发生严重出血事件低的优点。 相似文献
7.
Sher Geoffrey; Feinman Michael; Zouves Christo; Kuttner Gordon; Maassarani Ghanima; Salem Rifaat; Matzner William; Ching Wendell; Chong Penny 《Human reproduction (Oxford, England)》1994,9(12):2278-2283
This study was undertaken to explore whether intervention withheparin and aspirin (H/A) in selected patients undergoing in-vitrofertilization (TVF) and embryo transfer could improve fecundityrates. Specifically, it explored the possibility that womendiagnosed with organic pelvic disease who demonstrated antiphospholipidantibodies (APA) could benefit from H/A administration in asimilar manner to that used in patients with recurrent pregnancyloss. We used an enzymelinked immunosorbent assay forsix different phospholipids to identify patients who expressedAPA before they underwent IVF/embryo transfer. This study wasconfined to the first IVF/embryo transfer cycle that followedassessment of APA status and accordingly, the number of IVF/embryotransfer cycles corresponds with the number of patients treated.APA seropositive patients were treated with aspirin, 81 mg orallyq.d., and heparin 5000 IU s.c. b.i.d., beginning on day 1 ofcontrolled ovarian stimulation. The endpoint for success wasa live birth or an ultrasound confirming fetal cardiac activity(a viable pregnancy). The prevalence of APA in patients diagnosedwith organic pelvic disease (53%) was much higher than in thosewithout female pathology (14%). The administration of H/A toAPA seropositive patients significantly (P < 0.05) improvedthe viable pregnancy rate (49%) compared to the untreated APAseropositive group (16%). The viable pregnancy rate for APAseropositive women treated with H/A was also significantly (P< 0.001) higher than for untreated APA seronegative patients(27%). We conclude that all women undergoing IVF/embryo transfershould be tested for APA prior to initiating ovarian stimulation,and those with APA seropositivity should be treated with H/A. 相似文献
8.
目的探讨低分子肝素联合辛伐他汀治疗不稳定型心绞痛的疗效。方法将100例不稳定型心绞痛患者随机分为对照组50例和观察组50例。对照组仅采取常规治疗(硝酸酯类、β-受体阻滞剂、钙拮抗剂、阿司匹林等),观察组在常规治疗的基础上加用低分子肝素和辛伐他汀,观察比较各组的疗效。结果观察组总有效率为90.0%,对照组总有效率为60.0%,两组疗效比较差异有显著性意义(P〈0.05)。结论低分子肝素联合辛伐他汀治疗不稳定型心绞痛取得满意的疗效。 相似文献
9.
综述了低分子量肝素的化学和生物活性的不均一性,以及药理作用,药物动力学、临床应用等方面的差异。 相似文献
10.
N. P. Kock H. -J. Gabius J. Schmitz J. Schottelius 《Tropical medicine & international health : TM & IH》1997,2(9):863-874
By employing neoglycoproteins (NGP) and glycosaminoglycans, the detection of endogenous glycoligand-binding sites has become possible. Monitoring specific binding of 11 of these sugar receptor-specific tools, 13 trypanosomatids of monogenetic genera Blastocrithidia, Crithidia, Herpetomonas , and Leptomonas and digenetic genera Endotrypanum , Leishmania , and Sauroleishmania were analysed by agglutination and fluorescence assays. NGP showed agglutination reactions only with the digenetic but not with the monogenetic species. Sensitive flow cytofluorimetric investigations revealed that the apparently different reactivity to NGP is due to a pronounced quantitative difference in expression of binding sites between mono- and digenetic flagellates. Moreover, flow cytofluorimetry was used to demonstrate the occurrence of receptor sites for heparin on the cell surfaces of all trypanosomatids. An indication for a correlation of the binding capacity for the NGP N-acetyl-β-d-glucosamine and heparin to differences in the pathogenicity of parasites was observed for Leishmania donovani as well as Leishmania enriettii . Infective populations of these species contained a significantly higher number of cells which had bound N-acetyl-β-d-glucosamine and heparin than noninfective (long-term in vitro -cultured) populations. The results of the present report additionally support the hypothesis that lectin–carbohydrate interactions with neutral sugar moieties and heparin or heparin-like molecules participate in the interactions between trypanosomatids and host (cells), and that the detected binding sites for carbohydrates and heparin may thus be referred to as potential virulence factors. 相似文献