全文获取类型
收费全文 | 20720篇 |
免费 | 1156篇 |
国内免费 | 116篇 |
专业分类
耳鼻咽喉 | 224篇 |
儿科学 | 431篇 |
妇产科学 | 460篇 |
基础医学 | 2655篇 |
口腔科学 | 579篇 |
临床医学 | 1629篇 |
内科学 | 5510篇 |
皮肤病学 | 514篇 |
神经病学 | 1844篇 |
特种医学 | 532篇 |
外国民族医学 | 3篇 |
外科学 | 3276篇 |
综合类 | 102篇 |
现状与发展 | 1篇 |
一般理论 | 4篇 |
预防医学 | 1494篇 |
眼科学 | 391篇 |
药学 | 1039篇 |
中国医学 | 43篇 |
肿瘤学 | 1261篇 |
出版年
2023年 | 152篇 |
2022年 | 295篇 |
2021年 | 805篇 |
2020年 | 350篇 |
2019年 | 700篇 |
2018年 | 809篇 |
2017年 | 462篇 |
2016年 | 476篇 |
2015年 | 555篇 |
2014年 | 760篇 |
2013年 | 1066篇 |
2012年 | 1735篇 |
2011年 | 1638篇 |
2010年 | 950篇 |
2009年 | 884篇 |
2008年 | 1382篇 |
2007年 | 1413篇 |
2006年 | 1330篇 |
2005年 | 1300篇 |
2004年 | 1056篇 |
2003年 | 1002篇 |
2002年 | 951篇 |
2001年 | 132篇 |
2000年 | 70篇 |
1999年 | 136篇 |
1998年 | 144篇 |
1997年 | 141篇 |
1996年 | 119篇 |
1995年 | 121篇 |
1994年 | 101篇 |
1993年 | 83篇 |
1992年 | 64篇 |
1991年 | 67篇 |
1990年 | 44篇 |
1989年 | 40篇 |
1988年 | 39篇 |
1987年 | 36篇 |
1986年 | 39篇 |
1985年 | 41篇 |
1984年 | 39篇 |
1983年 | 22篇 |
1982年 | 29篇 |
1981年 | 38篇 |
1980年 | 26篇 |
1979年 | 32篇 |
1978年 | 33篇 |
1977年 | 21篇 |
1976年 | 28篇 |
1974年 | 21篇 |
1969年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
Autonomic nervous control of the heart rate response to dynamic incremental exercise: evaluation of the Rosenblueth-Simeone model 总被引:1,自引:0,他引:1
Jorge Pinto Ribeiro José Manuel Ibáñez Ricardo Stein 《European journal of applied physiology》1991,62(2):140-144
Summary To evaluate the validity of the Rosenblueth-Simeone model for the heart rate response to incremental dynamic exercise, 11 healthy men performed maximal exercise tests on a cycle ergometer after administration of placebo, propranolol, atropine or both propranolol and atropine. The model showed that the influence of sympathetic activity on heart rate increased at intensities up to those which resulted in a heart rate 70% maximal heart rate on placebo, and levelled off at higher intensities, while there was a progressive withdrawal of the parasympathetic activity. The ratio between heart rate predicted by the model and the recorded heart rate following placebo treatment tended to be less than 1.0 at lower exercise intensities, and approached the unit at intensities above those which resulted in a heart rate higher than 70% of maximal heart rate on placebo. There was a strong correlation (r=0.94,P<0.01) between the heart rate on placebo and the heart rate estimated by the model. Nevertheless, there was some scattering of the data around the identity line, with a standard error of the estimate for the regression line of 11 beats · min–1. Thus, during incremental exercise, the influence of sympathetic activity on heart rate does not become progressively more important at higher exercise intensities. The application of the Rosenblueth-Simeone model shows limitations during incremental exercise, particularly at low exercise intensities. 相似文献
142.
Stefanie Kreutmair Susanne Unger Nicolás Gonzalo Núñez Florian Ingelfinger Chiara Alberti Donatella De Feo Sinduya Krishnarajah Manuel Kauffmann Ekaterina Friebel Sepideh Babaei Benjamin Gaborit Mirjam Lutz Nicole Puertas Jurado Nisar P. Malek Siri Goepel Peter Rosenberger Helene A. Häberle Ikram Ayoub Burkhard Becher 《Immunity》2021,54(7):1578-1593.e5
- Download : Download high-res image (233KB)
- Download : Download full-size image
143.
Sandra Sabatini Venkateswararao Alla Allen Wilson Manuel Cruz-Soto April de White Neil A. Kurtzman Jose A. L. Arruda 《Pflügers Archiv : European journal of physiology》1982,393(3):262-268
Complete papillary necrosis in rats can be induced within 1 month following a single injection of 2-bromoethylamine hydrobromide (BEA) (50 mg, i.v.). Utilizing a combination of clearance and balance techniques the effects of complete absence of the papilla was examined as regards urinary acidification, whole kidney glomerular filtration rate (GFR), single nephron GFR, and morphology. Whole kidney GFR was not different from control, however, the percent filtering juxtamedullary nephrons was markedly diminished (87.2±2.1 vs. 31.5±3.6% filtering, control vs. BEA, respectively,P<0.001) and significantly reduced in the superficial nephrons (80.6±3.6 vs. 62.2±6.1% filtering, control vs. BEA, respectively,P<0.05). There was a significant decrease in juxtamedullary single nephron GFR and an increase in the superficial single nephron GFR as assessed by the quantitative Hanssen's technique in the animals with chronic papillary necrosis. Complete papillary necrosis was associated with normal arterial bicarbonate concentration, pH, and plasma electrolyte concentrations. At the same degree of acidemia (induced by NH4Cl administration) minimal urinary pH, ammonium excretion, and titratable acid excretion were not different than seen in age matched controls. The response to Na2SO4 infusion and phosphate infusion was the same in both groups of animals. The urineblood (U-B)pCO2, an index of urinary acidification, was identical in BEA and control animals. Scanning electron microscopy showed scarring of the juxtamedullary glomeruli one month after BEA. The papilla was sloughed and lying free in the renal pelvis in every experimental animal. These data demonstrate that complete papillary necrosis is not associated with acidosis nor a defect in urinary acidification. 相似文献
144.
Fernando de Ory José Manuel Echevarría George Kafatos Cleo Anastassopoulou Nick Andrews Josephine Backhouse Guy Berbers Blazena Bruckova Daniel I Cohen Hester de Melker Irja Davidkin Giovanni Gabutti Louise M Hesketh Kari Johansen Sari Jokinen Lindsay Jones Anika Linde Elisabeth Miller Jo?l Mossong Anthony Nardone Maria Cristina Rota Andreas Sauerbrei Fran?ois Schneider Zahava Smetana Annedore Tischer Athanassios Tsakris Robert Vranckx 《Journal of clinical virology》2006,36(2):111-118
BACKGROUND: The aim of the European Sero-Epidemiology Network (ESEN2) is to harmonise the serological surveillance of vaccine-preventable diseases in Europe. OBJECTIVE: To allow comparison of antibody prevalence in different countries by standardising results into common units. STUDY DESIGN: For varicella zoster virus (VZV), a reference laboratory established a panel of 148 samples, characterised by indirect enzyme-immunoassay (ELISA), indirect immunofluorescence, and complement fixation test. Fifty-seven samples were also studied by the fluorescence antibody to membrane antigen test. The geometric mean of the antibody activity (GMAA) obtained from four ELISA determinations was used to characterise each sample of the panel as positive (GMAA: >100 mIU/ml), equivocal (GMAA: 50-100 mIU/ml) or negative (GMAA: <50 mIU/ml) for antibody to VZV (anti-VZV). Thirteen laboratories, using five different ELISA tests, tested the panel. RESULTS: Agreement with the reference laboratory was above 85% in all cases, and the R(2) values obtained from regression analysis of the quantitative results were always higher than 0.87. Finally, the regression equations could be used to convert national values into a common unitage. CONCLUSION: This study confirmed that results for anti-VZV obtained by different ELISA methods can be converted into common units, enabling the comparison of the seroprevalence profiles obtained in the participant countries. 相似文献
145.
Luft AR Kaelin-Lang A Hauser TK Buitrago MM Thakor NV Hanley DF Cohen LG 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2002,142(4):562-569
It is assumed that somatosensory input is required for motor learning and recovery from focal brain injury. In rodents and other mammals, corticocortical projections between somatosensory and motor cortices are modified by patterned input. Whether and how motor cortex function is modulated by somatosensory input to support motor learning is largely unknown. Recent human evidence suggests that input changes motor excitability. Using transcranial magnetic stimulation (TMS), this study tested whether motor cortex excitability is affected by patterned somatosensory stimulation in rodents. Motor potentials evoked in gastrocnemius muscles in response to TMS (MEP(TMS)) and to cervical electrical stimulation (MEP(CES)) were recorded bilaterally. Initially, the first negative peak of the MEP(TMS) was identified as a cortical component because it disappeared after decortication in three animals. Subsequently, we studied the effects of 2 h of electrical stimulation of one sciatic nerve on the cortical component of the MEP(TMS), i.e., on motor cortex excitability. After stimulation, its amplitude increased by 117 +/- 45% ( P<0.01) in the stimulated limb. A significantly smaller effect was found in the unstimulated limb ( P<0.02) and no effect was observed in unstimulated control animals. The subcortically evoked MEP(CES) were not affected by stimulation. It is concluded that somatosensory input increases motor excitability in rat. This increase outlasts the stimulation period and is mediated by supraspinal structures, likely motor cortex. Modulation of motor cortex excitability by somatosensory input may play a role in motor learning and recovery from lesion. 相似文献
146.
Emilie Croisier Linda B Moran David T Dexter Ronald KB Pearce Manuel B Graeber 《Journal of neuroinflammation》2005,2(1):14
Background
The role of both microglial activation and alpha-synuclein deposition in Parkinson's disease remain unclear. We have tested the hypothesis that if microglia play a primary role in Parkinson's disease pathogenesis, the microglial "activated" phenotype should be associated with histopathological and/or clinical features of the disease. 相似文献147.
148.
149.
Ramos-Casals M García-Carrasco M Brito Zerón MP Cervera R Font J 《Autoimmunity reviews》2002,1(4):238-243
Patients with hepatitis C virus (HCV) chronic infection present some extrahepatic manifestations that may mimic the clinical, immunologic and histological manifestations of primary Sj?gren's syndrome (SS). Thus, HCV patients with sicca symptomatology and positive autoantibodies could be misdiagnosed as a 'primary' SS. Nevertheless, there are several clinical and immunologic features that could help us differentiate both processes. 相似文献
150.
Cloning and analysis of the murine Fanconi anemia group C cDNA 总被引:7,自引:1,他引:7
Fanconi anemia (FA) is one of a group of disorders characterizedat the cellular level by a combination of hypersensitivity toDNA-damaging agents, chromosomal instability, and defectiveDNA repair. Clinical features of FA include pancytopenia, oftenaccompanied by specific congenital malformations, and a predispositionto leukemia. Since the hematological manifestations are thecritical defect in terms of prognosis, FA is a candidate diseasefor gene replacement therapy, and the development of a mousemodel system is essential for the initial stages of this work.Previously, we have cloned the gene defective in FA group Cby complementation of the intrinsic sensitivity of FA cellsto DNA cross-linking agents. We have now cloned the murine homologueof the human FACC cDNA. The mouse cDNA (Facc) shares 79% aminoacid sequence similarity with the human gene product. The expressionof the mouse cDNA in human FA(C) cells restores the cellulardrug sensitivity to normal levels. Thus, the function of theprotein has been conserved despite the significant sequencedivergence. PCR analysis of mouse tissue RNA reveals that thegene is expressed in all adult tissues, while in situ RNA hybridizationexperiments show tissue specific expression at late stages offetal development. Cross-hybridizing sequences exist in DNAfrom other mammals, chicken and Drosophila. These results supportthe hypothesis that the FACC gene product has a role in a basicaspect of cellular protection against DNA damaging agents andthat this function has been conserved during evolution. 相似文献