全文获取类型
收费全文 | 1863篇 |
免费 | 123篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 16篇 |
儿科学 | 45篇 |
妇产科学 | 22篇 |
基础医学 | 188篇 |
口腔科学 | 119篇 |
临床医学 | 105篇 |
内科学 | 483篇 |
皮肤病学 | 22篇 |
神经病学 | 107篇 |
特种医学 | 113篇 |
外科学 | 307篇 |
综合类 | 5篇 |
一般理论 | 1篇 |
预防医学 | 64篇 |
眼科学 | 88篇 |
药学 | 115篇 |
肿瘤学 | 196篇 |
出版年
2023年 | 15篇 |
2022年 | 25篇 |
2021年 | 51篇 |
2020年 | 32篇 |
2019年 | 48篇 |
2018年 | 72篇 |
2017年 | 40篇 |
2016年 | 43篇 |
2015年 | 59篇 |
2014年 | 81篇 |
2013年 | 70篇 |
2012年 | 118篇 |
2011年 | 123篇 |
2010年 | 66篇 |
2009年 | 81篇 |
2008年 | 114篇 |
2007年 | 111篇 |
2006年 | 108篇 |
2005年 | 105篇 |
2004年 | 109篇 |
2003年 | 104篇 |
2002年 | 106篇 |
2001年 | 17篇 |
2000年 | 14篇 |
1999年 | 20篇 |
1998年 | 18篇 |
1997年 | 21篇 |
1996年 | 18篇 |
1995年 | 17篇 |
1994年 | 19篇 |
1993年 | 9篇 |
1992年 | 10篇 |
1991年 | 11篇 |
1990年 | 9篇 |
1989年 | 5篇 |
1988年 | 5篇 |
1987年 | 9篇 |
1986年 | 9篇 |
1985年 | 6篇 |
1984年 | 14篇 |
1983年 | 13篇 |
1982年 | 11篇 |
1981年 | 9篇 |
1980年 | 3篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1908年 | 2篇 |
1907年 | 2篇 |
排序方式: 共有1996条查询结果,搜索用时 531 毫秒
1.
2.
3.
Background
The mitogen-activated protein kinases, MAPKs for short, constitute cascades of signalling pathways involved in the regulation of several cellular processes that include cell proliferation, differentiation and motility. They also intervene in neurological processes like fear conditioning and memory. Since little remains known about the MAPK-Activated Protein Kinase, MAPKAPK5, we constructed the first MAPKAPK knockin mouse model, using a constitutive active variant of MAPKAPK5 and analyzed the resulting mice for changes in anxiety-related behaviour. 相似文献4.
Martin Zeier Jolanta Perz Reinhold P Linke Ugo Donini Rüdiger Waldherr Konrad Andrassy Anthony D Ho Hartmut Goldschmidt 《Nephrology, dialysis, transplantation》2003,18(12):2644-2647
BACKGROUND: High-dose chemotherapy followed by autologous blood stem cell transplantation induces remission of plasma cell dyscrasia in patients with AL amyloidosis. The impact of this treatment on the glomerular amyloid mass is still unknown. METHODS: In the present study, the quantity of the renal amyloid mass before and more than 3 years after high-dose melphalan treatment and autologous blood stem cell transplantation was assessed in two patients. At the time of the second renal biopsy, both patients were in complete remission without detectable serum and urinary monoclonal IgA-lambda and a normal percentage of plasma cells in the bone marrow. RESULTS: In both patients with biopsy-proven AL amyloidosis, urinary protein excretion decreased from 7 g/24 h to <2 g/24 h more than 3 years after autologous blood stem cell transplantation. In contrast, glomerular amyloid deposits persisted, as shown in the second biopsy. CONCLUSION: Despite complete remission of the plasma cell dyscrasia and improvement of glomerular permeability, the amount of glomerular amyloid mass did not regress. 相似文献
5.
Andrea Sagripanti Adamasco Cupisti Ugo Baicchi Marco Ferdeghini Giuliano Barsotti 《International Journal of Clinical & Laboratory Research》1994,24(2):113-116
Summary Intraglomerular fibrin deposition has been implicated as an important pathogenetic mechanism in patients with glomerular diseases
and the nephrotic syndrome. To investigate fibrin formation and degradation in nephrosis, we measured fibrinopeptide A by
radio-immunoassay and D-dimer by enzyme-linked immunosorbent assay in the plasma of 30 consecutive adult patients with the
nephrotic syndrome; in 10 the serum creatinine was more than 2 mg/dl. Both fibrinopeptide A and D-dimer were abnormally elevated
in the majority of nephrotics (P<0.001 vs. healthy controls), providing evidence of increased fibrin generation and lysis “in vivo.” A positive correlation
was found between fibrinopeptide A and D-dimer (correlation coefficient 0.64,P<0.001), suggesting a close relationship between fibrin formation and degradation. Calcium heparin, administered to 12 nephrotics,
caused a marked decrease in plasma fibrinopeptide A, due to a reduction of in vivo thrombin activity. As enhanced thrombin
activity can favor fibrin deposition within the renal parenchyma, as well as vascular complications, it is reasonable to assume
that an antithrombotic treatment aimed at controlling thrombin generation may ameliorate the natural history of nephrosis. 相似文献
6.
Carlo Piccinni Chiara Sacripanti Elisabetta Poluzzi Domenico Motola Lara Magro Ugo Moretti Anita Conforti Nicola Montanaro 《European journal of clinical pharmacology》2010,66(2):199-206
Aim
The aim of the present study was to collect and compare cases of drug-induced PML in order to contribute to the debate about the role of the underlying diseases and/or drug immunosuppression in PML occurrence. 相似文献7.
Onelio Geatti Brahm Shapiro Pier Giuseppe Orsolon Gianni Proto Ugo Paolo Guerra Francesco Antonucci Daniele Gasparini 《European journal of nuclear medicine and molecular imaging》1994,21(1):17-22
Technetium-99m methoxyisobutylisonitrile (MIBI), like thallium-201, has recently been introduced as a myocardial perfusion agent and is now also showing very promising results in parathyroid scintigrapy. The results of 201Tl/99mTc-pertechnetate and 99mTc-MIBI/99mTc-pertechnetate subtraction scintigraphy, ultrasonography and computed tomography are presented in a series of 43 patients operated on for hyperparathyroidism. All four imaging modalities were confirmed to be reliable, scintigraphy being the most accurate. Sensitivities ranged from 81% to 95%, that of 99mTc-MIBI being the highest. Moreover this tracer, which has more favourable physical and also biochemical properties, yielded images of superior quality. This allowed localization of the lesion by visual inspection only in as many as 86% of the patients with positive 99mTc-MIBI/99mTc-pertechnetate subtraction scintigraphy. We believe that the higher sensitivity, superior image quality and lower cost of 99mTc-MIBI imaging will make 99mTc-MIBI the new radiopharmaceutical of choice for parathyroid scintigraphy (when one takes into account the stability of labelling with large activities it is possible to perform three or four cardiac studies together with one parathyroid scintigraphic examination using one lyophililzed vial). 相似文献
8.
F Berti G Rossoni R Niada G Folco C Omini C Tondo 《Journal of cardiovascular pharmacology》1986,8(2):235-240
Defibrotide, a simple strand polydeoxyribonucleotide of mammalian origin with a molecular weight of 20,000 daltons, given intravenously to the rabbit before and after production of left ventricular infarction, prevents the alteration of the contractile response to postsynaptic adrenergic stimulation tested in isolated perfused heart preparations 3 days after coronary artery occlusion. According to the dose-response curves for isoproterenol and tyramine, left ventricular dP/dtmax was significantly depressed in infarcted hearts, whereas the dose-response curve for the inotropic effect of phenylephrine was markedly enhanced. These alterations were prevented by pretreatment of the rabbits with defibrotide (32 mg/kg/h i.v. for 6 h). In fact the potency ratios, calculated from the dose-response curves related to dP/dtmax of isoproterenol, tyramine, and phenylephrine in infarcted and control hearts excised from defibrotide treated and shamoperated rabbits, are nearly 1. The observed alterations in myocardial contractility in infarcted hearts seem to be specific for postsynaptic alpha and beta-adrenoceptors since the dose-response curve of left ventricular dP/dtmax for histamine is not different from control. The results obtained with defibrotide reflect the ability of this substance to protect the myocardial tissue from ischemic damage: this is also supported by the capacity of defibrotide (8 mg/kg/h i.v. for 6.5 h) to prevent the reduction of CPK-activity in the infarcted ventricle. Finally, we suggest that the observed beneficial effect of defibrotide in rabbit heart may also be explained by the antithrombotic effect of this substance, which is based on its profibrinolytic activity and PGI2-release. 相似文献
9.
Ann F. Welton Herman J. Crowley Giancarlo Folco Teresa Viganó 《Inflammation research》1982,12(4):438-442
Ro 21-7634 has previously been shown to inhibit histamine and SRS-A release from actively-sensitized guinea pig lung fragments upon antigen challenge. In the studies described herein, it was observed that Ro 21-7634 does not decrease SRS-A release but instead acts to inhibit the synthesis of this mediator. This was confirmed by studying SRS-A synthesisin vitro in rat peritoneal cells after challenge with ionophore A23187. In the peritoneal cell system, Ro 21-7634 exhibited an IC50 of 500 M, in comparison with 5,8,11,14-eicosatetraynoic acid, phenidone and BW755C (IC50's of 2, 100, and 100 M, respectively). When studied at 10–4 and 10–3
M in perfused guinea pig lung, Ro 21-7634 inhibited antigen-induced thromboxane A2 production by 68 and 96%, respectively. In this system, antigen is believed to induce thromboxane A2 production through the release of histamine and SRS-A from lung tissue. These mediators then interact at receptor sites in the lung parenchyma to induce thromboxane A2 synthesis. Ro 21-7634 could thus be inhibiting thromboxane A2 production by preventing the release of histamine and synthesis of SRS-A in the perfused lung system. Such a mechanism is suggested by the fact that although Ro 21-7634 was effective in inhibiting antigen-induced thromboxane production, it was ineffective in inhibiting thromboxane A2 production induced in the guinea pig lung system by the direct perfusion of histamine or SRS-A through the lung. 相似文献
10.
Giovanni Perego Gabriele Lugli Ugo Pedretti Giuseppe Allegra 《Macromolecular chemistry and physics.》1988,189(11):2687-2701
The crystal structure of iodine/trans-polyacetylene complexes (CHIy)x (y = 0,009, 0,035, 0,17 and 0,30) was investigated by X-ray diffraction analysis of highly oriented samples. An iodine-containing phase (PAI) was observed in all cases, accompanied by residual crystallinity due to pristine polyacetylene (PA) for y < 0,17. A structural model is proposed for PAI, consisting of blocks of iodine-saturated PA (PAIs) and blocks of PA, arranged in a mosaic-like lattice, paracrystalline in character. PAIs, corresponding to (CHI0,40)x, is formed by layers of (CH)x chains alternating with layers containing polyiodide chains, the latter being characterized by ordered stacking of sequentially disordered (I3?-I5?-I3?) groups. I… C non-bonded interactions are identified in the lattice, which may be responsible for the electron transfer from the polymer to the polyiodide anions. Short-range transverse correlation occurs within the polyiodide layers with a resulting quasi-regular two-dimensional lattice of iodines. The iodine and the polymer lattices are incommensurate along c. The model fits the experimental data from an X-ray fibre diagram. A mathematical expression is derived, which allows to evaluate the intensity scattered by the iodine lattice. An approximate expression of the non-equatorial intensity along the ξ reciprocal direction was obtained, which accounts for the modulation of the streaks observed in the fibre pattern. 相似文献