全文获取类型
收费全文 | 27116篇 |
免费 | 2382篇 |
国内免费 | 500篇 |
专业分类
耳鼻咽喉 | 270篇 |
儿科学 | 380篇 |
妇产科学 | 236篇 |
基础医学 | 2390篇 |
口腔科学 | 481篇 |
临床医学 | 3559篇 |
内科学 | 2958篇 |
皮肤病学 | 175篇 |
神经病学 | 1936篇 |
特种医学 | 1597篇 |
外国民族医学 | 4篇 |
外科学 | 3013篇 |
综合类 | 4136篇 |
现状与发展 | 1篇 |
一般理论 | 2篇 |
预防医学 | 2817篇 |
眼科学 | 544篇 |
药学 | 3146篇 |
39篇 | |
中国医学 | 1120篇 |
肿瘤学 | 1194篇 |
出版年
2024年 | 80篇 |
2023年 | 394篇 |
2022年 | 695篇 |
2021年 | 1051篇 |
2020年 | 1021篇 |
2019年 | 928篇 |
2018年 | 977篇 |
2017年 | 965篇 |
2016年 | 862篇 |
2015年 | 986篇 |
2014年 | 1870篇 |
2013年 | 1848篇 |
2012年 | 1694篇 |
2011年 | 1774篇 |
2010年 | 1598篇 |
2009年 | 1337篇 |
2008年 | 1282篇 |
2007年 | 1362篇 |
2006年 | 1278篇 |
2005年 | 950篇 |
2004年 | 911篇 |
2003年 | 795篇 |
2002年 | 737篇 |
2001年 | 507篇 |
2000年 | 428篇 |
1999年 | 413篇 |
1998年 | 326篇 |
1997年 | 282篇 |
1996年 | 245篇 |
1995年 | 220篇 |
1994年 | 217篇 |
1993年 | 154篇 |
1992年 | 147篇 |
1991年 | 150篇 |
1990年 | 152篇 |
1989年 | 141篇 |
1988年 | 126篇 |
1987年 | 113篇 |
1986年 | 104篇 |
1985年 | 136篇 |
1984年 | 119篇 |
1983年 | 99篇 |
1982年 | 87篇 |
1981年 | 103篇 |
1980年 | 80篇 |
1979年 | 53篇 |
1978年 | 40篇 |
1977年 | 32篇 |
1976年 | 37篇 |
1975年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Akira Ishih Toshio Miyase Tohru Suzuki Francis W. Muregi Mamoru Terada 《Journal of natural medicines》2007,61(2):213-216
Febrifugine and isofebrifugine alkaloid mixtures extracted from the leaves and buds of Hydrangea macrophylla var. Otaksa, collected during different months, in Japan, were quantified using high-performance liquid chromatography. Leaves collected
during the flowering season, namely from June to August, contained 0.16–0.31 mg/g of the alkaloid mixture, whereas those collected
from September to December had less than 0.03 mg/g of the mixture. However, extracts of buds harvested from October to February
contained a consistently larger amount (more than 0.49 mg/g) of the alkaloids. Hot-water extracts from the leaves and buds
collected during different seasons were evaluated for antimalarial activity against Plasmodium yoelii 17XL in mice. The extract of leaves collected in August demonstrated high antimalarial activity, and all mice that received
the extract survived the infection. In contrast, the extract of leaves collected in December showed little activity. The extract
of buds collected in December cleared parasites, but with subsequent mortality to mouse. The present results show that the
amount of antimalarial agent—febrifugine and isofebrifugine mixture—in H. macrophylla var. Otaksa is both part- and season-dependent, suggesting that the choice of plant parts and their harvesting season are important factors
worth considering in the pharmacological use of medicinal plants. 相似文献
62.
ZusammenfassungEinleitung In unserer Klinik wird seit über 30 Jahren die operative Behandlung von Klumpfüßen über einen dorsomedialen Zugang durchgeführt. Postoperativ erfolgt zunächst eine Gipsbehandlung, dann eine konsequente Nachbehandlung mit Orthesen und Winkeleinlagen.Material und Methode Zwischen dem 1. 6. 1986 und dem 31. 12. 2000 wurden 130 primäre Klumpfußweichteiloperationen bei 86 Patienten durchgeführt. 119 (92%) Füße konnten nach durchschnittlich 4,5 Jahren klinisch-radiologisch nachuntersucht werden. Das durchschnittliche Alter bei der Operation betrug 7,6 Monate. Klassifikation nach Dimeglio und Score nach Laaveg und Ponseti dienten zur Beurteilung. Die gemessenen Winkel in den belasteten Röntgenbildern des Fußes a.p. und seitlich prä- und postoperativ wurden verglichen, Komplikationen und Rezidive dokumentiert.Ergebnisse 29 (22,3%) Füße wiesen einen Schweregrad IV nach Dimeglio, 58 (44,6%) Grad III und 43 (33,1%) Grad II auf. Ein Klumpfußrezidiv war bei 9 (7,6%) Fällen zu beobachten. Alle Winkel verbesserten sich signifikant. Bei der Nachuntersuchung wurden durchschnittlich 95,4±9,2 Punkte nach dem Score von Laaveg und Ponseti erzielt.Schlussfolgerung Der von uns verwendete dorsomediale Zugangsweg erlaubt eine ausgezeichnete Klumpfußkorrektur mit geringer Rezidiv- und Komplikationsrate. 相似文献
63.
Two thousand nine hundred and ninety-four reports of OSHA-reportable occupational injury or illness cases in 1984 from member companies of a national trade association of semiconductor manufacturing firms were analyzed. The 37 participating manufacturing facilities represented 16 companies employing over 95,000 persons, or approximately one-third of the U.S. work force for this industry in 1984. The annual incidence rate for all reportable injuries and illnesses was 2.7 per 100 full-time employees (FTE) for men and 3.7 per 100 FTE for women. Strains, sprains, or dislocations were the most frequently reported incidents (N = 956 [31.9%]), followed by cuts, lacerations, punctures, scratches, and abrasions (N = 445 [14.9%]), and chemical burns (N = 401 [13.4%]). Increased work-loss days per case were associated with manufacturing sites that did not have an employee health clinic on the premises, with custodial occupations, and with female gender. 相似文献
64.
目的探讨重症脓毒症患者免疫治疗及各免疫指标的变化对严重脓毒症患者预后的影响。方法将20例腹部无明显感染的患者、20例腹部脓毒症患者不伴器官功能障碍、18例腹部严重脓毒症及脓毒性休克患者分为A、B、C组,A组术前及A、B、C组术后第1、3、7天,各抽取外周静脉血5ml于肝素管内,分别测定T淋巴细胞亚群(CD3、CD4、CD8、CD4/CD8)。同时记录生命体征的变化和预后转归。结果A、B、C三组在术后1、3天,CD3、CD4、CD4/CD8均下降,C组下降明显,与A、B组比较,差异具有显著性意义(P<0.05),术后第7天A、B、C组(病情好转者)均上升,C组恶化者CD3、CD4、CD4/CD8持续低下,与A、B、C组(病情好转者)比较,差异具有显著性意义(P<0.05)。结论手术对T淋巴细胞CD3、CD4抑制明显,术后1、3天抑制明显,7天明显上升至正常。对于术后脓毒症不伴器官功能障碍者对T淋巴细胞亚群影响不大,其变化与手术对机体免疫功能的变化一致。对于术后重症脓毒症及脓毒性休克患者IgA、IgM、IgG,C3、C4及T淋巴细胞亚群CD3、CD4、CD4/CD8明显降低,且随病情恶化,持续在较低水平。 相似文献
65.
This paper presents the use of iterative dynamic programming employing exact penalty functions for minimum energy control problems. We show that exact continuously non-differentiable penalty functions are superior to continuously differentiable penalty functions in terms of satisfying final state constraints. We also demonstrate that the choice of an appropriate penalty function factor depends on the relative size of the time delay with respect to the final time and on the expected value of the energy consumption. A quadratic approximation (QA) of the delayed variables is much better than a linear approximation (LA) of the same for relatively large time delays. The QA improves the rate of convergence and avoids the formation of ‘kinks‘. A more general way of selecting appropriate penalty function factors is given and the results obtained using four illustrative examples of varying complexity corroborate the efficacy of the method. 相似文献
66.
Background The skin microdiallysis technique makes it possible to measure histamine release in intact human skin in vivo directly. In this study we have used the microdialysis technique to characterize histamine release by codeine after intracutaneous injectioin and following skin challenge by a novel atraumatic delivery technique. Objective The purpose of the study was to compare histamine release in human skin by codeine. delivered by an intraprobe drug delivery system (IPD) and intracutaneous injections (ICT), with respect to dose-response relations, kinetics of histamine appearance and decay, corelations between histamine release and skin respones, and reproducibility. Methods Hollow dialysis fibres were inserted intradermally in 12 healthy subjects. Twelve fibres were inserted in each subjects, six fibres in each arm. Each fibre was perfused at a rate of 3 μL/min, and samples were collected in 2 min fractions. By the IPD technique, codeine was administrered to the skin by adding codeine to the perfusion medium. Sequential IPD challenges were performed in one arm. and ICTs were done on the other arm. Results Sixfold serial dilutions of codeine (0.01-3 mg/mL) caused a significant doserelated histamine release by ICT and IPD. Peak histamine release was found within the first 4 min after skin challenge by ICT and IPD, followed by a fast decline with a dialysate histamine half life of approximately 2-3 min. Peak hisamine release was linearly correlates with cumulative release of the 20 min sampling period, and histamine release correlated with weal soze. The coefficient of variation on peak histamine releae was 18.9% and 4.8% for codeine ICT and IPD, respectively. Conclusioin We have described in detail codeine-induced histamine release in intact human skin in vivo by the microdialysis technique. It was possible to administer codeine atraumaticallyl to the skin by intraprobe delivery. The skin microdialysis codeine atraumaticallly to the skin by intraprobe delivery. The skin microdialysis technique opens up possibilities for measurement of infllammatory mediators release in normal and diseases skin, and it will be possible to deliver immunopharmacologically active drugsto the skin by intraprobe delivery. 相似文献
67.
LightCycler实时监测PCR定量分析血清HBV DNA 总被引:2,自引:0,他引:2
目的 检验LightCycler实时监测PCR(real-time detection PCR,RTD-PCR)对血清中HBV DNA定量检测的灵敏性和可重复性,探讨HBV血清标志物与HBV DNA定量的关系。方法 HBV定量按深圳匹基公司乙肝PCR荧光检测试剂盒使用说明,对乙肝标志物已明确的773例血清中HBV DNA定量结果进行统计分析。结果 实时监测PCR对血清中HBV DNA定量检测的灵敏性高,可检测低至1000拷贝/ml血清;可重复性好,批间误差<20%;各种标志物类型的血清HBV DNA含量分布情况表明,HBV血清标志物中HBeAg与HBV DNA含量有明显的关系,一般HBeAg阳性血清HBV DNA含量较高,但也有相当一部分例外。结论 LightCycler实时监测PCR对血清中HBV DNA定量检测灵敏性高可重复性好;仅根据HBV血清标志物往往不能确定乙肝患者HBV DNA复制水平的高低,HBV DNA定量检测具有十分重要的临床意义。 相似文献
68.
李阳春 《南通大学学报(哲学社会科学版)》2002,18(2):117-120
八十年代初中期 ,中国戏剧积极拓展我国传统戏剧的时空观、写意性特征 ,大胆借鉴西方现代戏剧的荒诞化、意象性技巧 ,出现了探索创新、多元发展的崭新局面。其中对“三一律、一堵墙”戏剧观的突破 ,运用意识形象外显人物的内心世界 ,嫁接多种艺术手段将现实时空转化为艺术时空 ,是新时期戏剧艺术探索最突出的三项成就。而过分强调形式技巧 ,脱离观众欣赏习惯 ,致使演出市场萎缩 ,观众锐减 ,无疑是新时期戏剧艺术探索中面临的最大困顿。 相似文献
69.
小切口加脊柱花刀治疗髓核骨化性腰椎间盘突出症 总被引:1,自引:0,他引:1
赵新建 《中国脊柱脊髓杂志》1997,7(6):247-250
为保留腰椎后部结构的完整性,防止术后腰椎不稳,采用小切口单侧小开窗加脊柱花刀治疗旁侧型髓核骨化性腰椎间盘突出症22例,单侧扩大开窗加脊柱花刀治疗中央型髓核骨化性腰椎间盘突出症10例。手术尽可能地保留了腰椎全部结构的完整性,可防止术后腰椎不稳和减少对硬膜和神经根的疤痕粘连。并就32例髓核骨化性腰椎间盘突出症患者CT图像中髓核骨化的形式和形态进行了讨论。 相似文献
70.
Non-invasive tear break-up time (NITBUT) has been proposed as a measure of tear film integrity which is superior to the more commonly used tear break-up time (TBUT), since it does not alter the volume or the physicochemical properties of the tear layer by the addition of fluorescein. We measured NITBUT by measuring the time taken for distortions or discontinuities to appear in the reflected image of a grid pattern which covered about 80 per cent of the corneal surface. NITBUT measures were made 100 times on seven Hong Kong Chinese subjects with up to 20 consecutive measures being made on a single day. We also measured NITBUT on one occasion on an unselected population of 52 Hong Kong Chinese subjects. NITBUT shows a skewed distribution in all subjects, with many shorter values and some extremely long values. There are statistically significant variations in NITBUT from day to day, and from subject to subject. The group of 52 subjects also had a skewed NITBUT distribution with many short values and some very long values. The arithmetic mean does not adequately represent NITBUT data, either for individual subjects or for this group of subjects. As many as five to eight measures may be necessary to gain a stable estimate of the NITBUT and stability of the measure is improved if extreme values are omitted. We recommend the use of nonparametric statistics to compare NITBUT values from day to day in or between subjects. 相似文献