全文获取类型
收费全文 | 3667篇 |
免费 | 270篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 32篇 |
儿科学 | 143篇 |
妇产科学 | 84篇 |
基础医学 | 616篇 |
口腔科学 | 97篇 |
临床医学 | 322篇 |
内科学 | 762篇 |
皮肤病学 | 131篇 |
神经病学 | 470篇 |
特种医学 | 71篇 |
外科学 | 349篇 |
综合类 | 11篇 |
一般理论 | 1篇 |
预防医学 | 290篇 |
眼科学 | 50篇 |
药学 | 265篇 |
中国医学 | 4篇 |
肿瘤学 | 258篇 |
出版年
2024年 | 8篇 |
2023年 | 68篇 |
2022年 | 116篇 |
2021年 | 185篇 |
2020年 | 99篇 |
2019年 | 150篇 |
2018年 | 134篇 |
2017年 | 104篇 |
2016年 | 121篇 |
2015年 | 147篇 |
2014年 | 167篇 |
2013年 | 169篇 |
2012年 | 291篇 |
2011年 | 293篇 |
2010年 | 147篇 |
2009年 | 124篇 |
2008年 | 207篇 |
2007年 | 174篇 |
2006年 | 166篇 |
2005年 | 183篇 |
2004年 | 130篇 |
2003年 | 153篇 |
2002年 | 123篇 |
2001年 | 52篇 |
2000年 | 47篇 |
1999年 | 33篇 |
1998年 | 23篇 |
1997年 | 26篇 |
1996年 | 17篇 |
1995年 | 13篇 |
1994年 | 10篇 |
1993年 | 12篇 |
1992年 | 12篇 |
1991年 | 10篇 |
1990年 | 20篇 |
1989年 | 18篇 |
1988年 | 15篇 |
1987年 | 18篇 |
1986年 | 16篇 |
1985年 | 10篇 |
1984年 | 15篇 |
1983年 | 7篇 |
1982年 | 8篇 |
1981年 | 8篇 |
1980年 | 11篇 |
1978年 | 15篇 |
1977年 | 15篇 |
1975年 | 7篇 |
1971年 | 5篇 |
1929年 | 5篇 |
排序方式: 共有3956条查询结果,搜索用时 15 毫秒
1.
T Schaub H M Dittrich A Antoniadis P Wolff P Gutjahr 《R?ntgen-Bl?tter; Zeitschrift für R?ntgen-Technik und medizinisch-wissenschaftliche Photographie》1986,39(10):287-290
Spinal Ewing's sarcomas are rare and cause problems in differential diagnosis. The radiologic, nuclear medicine and CT findings in two children with histologically proven Ewing's sarcoma are presented and problems in differential diagnosis discussed. Biopsy should be done early. 相似文献
2.
Cody JD Semrud-Clikeman M Hardies LJ Lancaster J Ghidoni PD Schaub RL Thompson NM Wells L Cornell JE Love TM Fox PT Leach RJ Kaye CI Hale DE 《American journal of medical genetics. Part A》2005,137(1):9-15
Most individuals with constitutional deletions of chromosome 18q have developmental delays, dysmyelination of the brain, and growth failure due to growth hormone deficiency. We monitored the effects of growth hormone treatment by evaluating 23 individuals for changes in growth, nonverbal intelligence quotient (nIQ), and quantitative brain MRI changes. Over an average of 37 months, the treated group of 13 children had an average nIQ increase of 17 points, an increase in height standard deviation score of 1.7, and significant change in T1 relaxation times in the caudate and frontal white matter. Cognitive changes of this magnitude are clinically significant and are anticipated to have an effect on the long-term outcomes for the treated individuals. 相似文献
3.
Angelo Agostoni Bianca Marasini Marco Cicardi Giancarlo Martignoni Lilj Uziel Maurezio Pietrogrande 《Allergy》1978,33(4):216-221
Prophylactic treatment with antifibrinolytic agents, epsilon-aminocapriod and tranexamic acid, reduces the incidence and severits of attacks in patients with hereditary angioedema. Long-term ellectivenessor risk of antifibrinolytic agents has not been established. Sixteen patients needing continuous prophylaxis because of frequency and severity of attacks were treated with tranexamic acid. In four patients this treatment was ineffective and the drug was withdrawn after 2 months. A remission or reduction in the frequency or serverity of attacks was observed in 12 patients treated for a period ranging from 8 to 34 months. Hepatic tests and blood fibrinolytic activity were not influenced by long term oral treatment with tranexamic acid. 相似文献
4.
Analysis of cell type-specific responses mediated by the type IV secretion system of Helicobacter pylori 下载免费PDF全文
Helicobacter pylori persistently infects the human stomach and can cause gastritis, gastric ulceration, and gastric cancer. The type IV secretion system (TFSS) of virulent H. pylori strains translocates the CagA protein, inducing the dephosphorylation of host cell proteins and leading to changes in the morphology or shape of AGS gastric epithelial cells. Furthermore, the TFSS is involved in the induction of proinflammatory cytokines. While the H. pylori genes required for TFSS function have been investigated systematically, little is known about possible host cell factors involved. We infected 19 different mammalian cell lines individually with H. pylori and analyzed CagA translocation, dephosphorylation of host cell proteins, chemokine secretion (interleukin-8 and macrophage inflammatory protein 2), and changes in cellular phenotypes. Our results demonstrate that not only bacterial but also host cell factors determine the cellular response to infection. The identification of such unknown host cell factors will add to our understanding of host-pathogen interactions and might help in the development of new therapeutic strategies. 相似文献
5.
6.
The Arabidopsis PILZ group genes encode tubulin-folding cofactor orthologs required for cell division but not cell growth 总被引:5,自引:0,他引:5
Steinborn K Maulbetsch C Priester B Trautmann S Pacher T Geiges B Küttner F Lepiniec L Stierhof YD Schwarz H Jürgens G Mayer U 《Genes & development》2002,16(8):959-971
Plant microtubules are organized into specific cell cycle-dependent arrays that have been implicated in diverse cellular processes, including cell division and organized cell expansion. Mutations in four Arabidopsis genes collectively called the PILZ group result in lethal embryos that consist of one or a few grossly enlarged cells. The mutant embryos lack microtubules but not actin filaments. Whereas the cytokinesis-specific syntaxin KNOLLE is not localized properly, trafficking of the putative auxin efflux carrier PIN1 to the plasma membrane is normal. The four PILZ group genes were isolated by map-based cloning and are shown to encode orthologs of mammalian tubulin-folding cofactors (TFCs) C, D, and E, and associated small G-protein Arl2 that mediate the formation of alpha/beta-tubulin heterodimers in vitro. The TFC C ortholog, PORCINO, was detected in cytosolic protein complexes and did not colocalize with microtubules. Another gene with a related, although weaker, embryo-lethal phenotype, KIESEL, was shown to encode a TFC A ortholog. Our genetic ablation of microtubules shows their requirement in cell division and vesicle trafficking during cytokinesis, whereas cell growth is mediated by microtubule-independent vesicle trafficking to the plasma membrane during interphase. 相似文献
7.
Baker W Schneider BA Kulkarni A Sloan G Schaub R Sypek J Cannon JG 《Journal of leukocyte biology》2004,76(2):352-358
This investigation sought to determine if P-selectin-mediated mechanisms contributed to macrophage localization in damaged muscle, an essential process for muscle regeneration. Mice were injected intravenously (i.v.) with soluble P-selectin glycoprotein ligand-1 (sPSGL-1) at 5, 50, or 200 microg/mouse or with 100 microl vehicle alone, and then, lengthening contractions were induced in hindlimb plantar-flexor muscles. The contractions caused fiber damage in soleus muscles, with maximal invasion by CD11b+ mononuclear cells at 24 h post-injury and substantial accumulation of CD11b+ mononuclear cells in the extracellular matrix up to 7 days post-injury. sPSGL-1 treatment caused a dose-dependent decrease in the number of regenerating fibers (P=0.021), as determined by developmental myosin heavy chain (dMHC) expression. This expression was reduced 93% at 7 days post-injury by the highest dose of sPSGL-1, which had no significant influence on intrafiber or extracellular accumulation of cells expressing CD11b, a general marker for phagocytic cells. Additional mice were injected i.v. with 20 microg anti-P-selectin or isotype-control immunoglobulin G and were then subjected to lengthening contractions as before. At 7 days post-injury, soleus muscles from anti-P-selectin-treated mice contained 48% fewer mononuclear cells that bound ER-BMDM1 (P=0.019), a marker for mature macrophages and dendritic cells, and 84% fewer fibers expressing dMHC (P = 0.006), compared with muscles from isotype-injected, control mice. The number of CD11b+ cells was not significantly different between groups. The results are consistent with the concept that P-selectin is involved in the recruitment, maturation, and/or activation of cells that are critical for muscle fiber regeneration. 相似文献
8.
Tanja Schlereth Jan Oliver Dittmar Bianca Seewald Frank Birklein 《The Journal of physiology》2006,576(3):823-832
Neuropeptides are the mediators of neurogenic inflammation. Some pain disorders, e.g. complex regional pain syndromes, are characterized by increased neurogenic inflammation and by exaggerated sudomotor function. The aim of this study was to explore whether neuropeptides have a peripheral effect on human sweating. We investigated the effects of different concentrations of calcitonin gene-related peptide (CGRP), vasoactive intestinal peptide (VIP) and substance P (SP) on acetylcholine-induced axon reflex sweating in healthy subjects (total n = 18). All substances were applied via dermal microdialysis. The experiments were done in a parallel setting: ACh alone and ACh combined with CGRP, VIP or SP in various concentrations were applied. Acetylcholine (10−2 m ) always elicited a sweating response, neuropeptides alone did not. However, CGRP significantly enhanced ACh-induced sweating ( P < 0.01). Post hoc tests revealed that CGRP in physiological concentrations of 10−7 –10−9 m was most effective. VIP at any concentration had no significant effect on axon reflex sweating. The duration of the sweating response ( P < 0.01), but not the amount of sweat, was reduced by SP. ACh-induced skin blood flow was significantly increased by CGRP ( P < 0.01), but unaltered by VIP and SP. The results indicate that CGRP amplifies axon reflex sweating in human skin. 相似文献
9.
PURPOSE OF REVIEW: Obesity is a major cause of morbidity accounting for approximately 300 000 deaths each year and about 7% of the health care budget with an economic impact greater than US dollar 100 billion annually in the United States. Obesity and its sequelae such as cardiovascular disease, diabetes, arthritis or cancer have been on the rise over the last decades. The parallel time trend with an increasing prevalence of asthma has induced a lively debate about a potential link between both conditions. RECENT FINDINGS: A number of prospective studies have shown that weight gain can antedate the development of asthma. Effect modification by sex may occur as some studies have shown effects of body mass index on asthma only among females. However, sex differences are not consistent. Several hypotheses have been proposed to explain the epidemiological associations including alterations in airway mechanics and immune responses, hormonal influences and genetic factors. SUMMARY: There is evidence that obesity and overweight are associated with the development of asthma. Yet, the mechanisms underlying this relation are unclear. Weight reduction among asthmatic patients can result in improvements of lung function demonstrating the potential clinical impact of the findings. 相似文献
10.
Nijhuis-van der Sanden MW Smits-Engelsman BC Eling PA Nijhuis BJ Van Galen GP 《Developmental neuropsychology》2002,22(3):643-670
The article aims to discriminate between 2 features that in principle both may be characteristic of the frequently observed poor motor performance in girls with Turner's syndrome (TS). On the one hand, a reduced movement speed that is independent of variations in spatial accuracy demands and therefore suggests a problem in motor execution. On the other hand, a disproportional slowing down of movement speed under spatial-accuracy demands, indicating a more central problem in motor programming. To assess their motor performance problems, 15 girls with TS (age 9.6-13.0 years) and 14 female controls (age 9.1-13.0 years) were tested using the Movement Assessment Battery for Children (MABC). In additionally, an experimental procedure using a variant of Fitts' graphic aiming task was used to try and disentangle the role of spatial-accuracy demands in different motor task conditions. The results of the MABC reestablish that overall motor performance in girls with TS is poor. The data from the Fitts' task reveal that TS girls move with the same accuracy as their normal peers but show a significantly lower speed independent of task difficulty. We conclude that a problem in motor execution is the main factor determining performance differences between girls with TS and controls. 相似文献