全文获取类型
收费全文 | 1913篇 |
免费 | 98篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 26篇 |
儿科学 | 75篇 |
妇产科学 | 126篇 |
基础医学 | 264篇 |
口腔科学 | 128篇 |
临床医学 | 150篇 |
内科学 | 281篇 |
皮肤病学 | 29篇 |
神经病学 | 202篇 |
特种医学 | 143篇 |
外科学 | 184篇 |
综合类 | 11篇 |
预防医学 | 103篇 |
眼科学 | 3篇 |
药学 | 162篇 |
中国医学 | 1篇 |
肿瘤学 | 129篇 |
出版年
2023年 | 18篇 |
2022年 | 20篇 |
2021年 | 44篇 |
2020年 | 25篇 |
2019年 | 40篇 |
2018年 | 39篇 |
2017年 | 42篇 |
2016年 | 35篇 |
2015年 | 45篇 |
2014年 | 49篇 |
2013年 | 66篇 |
2012年 | 112篇 |
2011年 | 123篇 |
2010年 | 69篇 |
2009年 | 61篇 |
2008年 | 88篇 |
2007年 | 85篇 |
2006年 | 87篇 |
2005年 | 98篇 |
2004年 | 84篇 |
2003年 | 58篇 |
2002年 | 68篇 |
2001年 | 58篇 |
2000年 | 57篇 |
1999年 | 70篇 |
1998年 | 39篇 |
1997年 | 30篇 |
1996年 | 21篇 |
1995年 | 20篇 |
1994年 | 14篇 |
1993年 | 12篇 |
1992年 | 21篇 |
1991年 | 21篇 |
1990年 | 19篇 |
1989年 | 33篇 |
1988年 | 19篇 |
1987年 | 19篇 |
1986年 | 25篇 |
1985年 | 12篇 |
1984年 | 11篇 |
1983年 | 17篇 |
1982年 | 14篇 |
1981年 | 15篇 |
1980年 | 9篇 |
1978年 | 11篇 |
1976年 | 10篇 |
1975年 | 9篇 |
1972年 | 11篇 |
1969年 | 10篇 |
1968年 | 9篇 |
排序方式: 共有2017条查询结果,搜索用时 15 毫秒
151.
E Benfenati R Fanelli E Bosone C Biffi R Caponi M Cianetti P Farina 《Drug metabolism and disposition》1991,19(5):913-916
The compound IBI-P-01028, or R,S-cis-6-(6'-carboxyhexyl)-7-trans-n-hexyl-1,3-diazaspiro-[4-4]-nona n-2,4- dione, is a new cytoprotective agent under development. To study the metabolites of this compound in laboratory animals, we administered it to dogs and rats, and analyzed extracts from dog and rat urine, and from dog plasma, by GC-MS. The metabolic profiles were different in the rat and dog. In the dog (plasma and urine), one metabolite was found, and in the rat urine two other metabolites were found. The unmetabolized drug was found only in the dog plasma and urine. 相似文献
152.
Mechanistic and prognostic significance of aberrant methylation in the molecular pathogenesis of human hepatocellular carcinoma 总被引:8,自引:0,他引:8 下载免费PDF全文
Calvisi DF Ladu S Gorden A Farina M Lee JS Conner EA Schroeder I Factor VM Thorgeirsson SS 《The Journal of clinical investigation》2007,117(9):2713-2722
Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide, accounting for an estimated 600,000 deaths annually. Aberrant methylation, consisting of DNA hypomethylation and/or promoter gene CpG hypermethylation, is implicated in the development of a variety of solid tumors, including HCC. We analyzed the global levels of DNA methylation as well as the methylation status of 105 putative tumor suppressor genes and found that the extent of genome-wide hypomethylation and CpG hypermethylation correlates with biological features and clinical outcome of HCC patients. We identified activation of Ras and downstream Ras effectors (ERK, AKT, and RAL) due to epigenetic silencing of inhibitors of the Ras pathway in all HCC. Further, selective inactivation of SPRY1 and -2, DAB2, and SOCS4 and -5 genes and inhibitors of angiogenesis (BNIP3, BNIP3L, IGFBP3, and EGLN2) was associated with poor prognosis. Importantly, several epigenetically silenced putative tumor suppressor genes found in HCC were also inactivated in the nontumorous liver. Our results assign both therapeutic and chemopreventive significance to methylation patterns in human HCC and open the possibility of using molecular targets, including those identified in this study, to effectively inhibit HCC development and progression. 相似文献
153.
Mixed lymphocyte reactivity and cell-mediated lympholysis to trinitrophenyl-modified autologous lymphocytes in C57BL/10 congenic and B10.A recombinant mouse strains 下载免费PDF全文
GM Shearer EC Lozner TG Rehn A Schmitt-Verhulst 《The Journal of experimental medicine》1975,141(4):930-934
Cell-mediated lympholysis (CML) to trinitrophenyl (TNP)-modified autologous splenic lymphocytes has been recently reported in the mouse (1). Both the sensitization and effector phases of this phenomenon were shown to be T-cell mediated. Effector cell specificity studies indicated that modification of the target cells is a necessary but insufficient requirement for cytolysis, and suggested that altered cell surface components controlled by genes mapping in the mouse major histocompatibility H-2 complex (MHC) are important in the specificity of the cytotoxic reaction (1). In allogeneic models the generation of cytotoxic effector cells has been shown to be preceded or accompanied by immunogen- induced proliferation of responding lymphocytes, i.e. a mixed lymphocyte reaction (MLR) (2-5), although the generation of effectors may not necessarily always be the consequence of extensive cell proliferation (5). If the induction of cytotoxic effector lymphocytes by modified syngeneic spleen cells is characteristic of sensitization with cellular alloantigens, one would expect to find that sensitization with TNP-modified autologous cells would also induce thymidine incorporation by the responding cells in the culture. The present report demonstrates that both stimulation of thymidine incorporation and generation of cytotoxic effector cells are part of the in vitro response to TNP-modified autologous lymphocytes. However, the MLR to TNP- modified autologous cells consistently appeared to be less pronounced when compared with an allogeneic MLR, whereas the cytotoxic activity of the effector cells generated by sensitization against TNP-modified autologous cells was frequently as high as that detected against H-2 alloantigens. These two components of reactivity to “modified self” are verified in several C57BL/10 congenic and B10.A recombinant mouse strains. 相似文献
154.
JB Gorlin ; EC Vamvakas ; E Cooke ; D Galacki ; R Geha ; D Humphreys ; P Kent 《Transfusion》1996,36(10):879-885
Background: Recruitment of progenitors during a large-volume collection, as defined by increasing relative and absolute numbers of progenitors (colony-forming units-granulocyte-macrophage [CFU-GM] of CD34+ cells), has been reported previously. Study Design and Methods: To ascertain whether intra-apheresis recruitment occurs in pediatric patients who have undergone mobilization with chemotherapy and granulocyte-colony-stimulating factor (G-CSF), each hour's portion of a 4-hour leukapheresis was collected into separate bags, and assessed by complete blood count, CFU-GM, and CD34+ cell assays. Seven pediatric patients (median age, 7; range, 2–19) were studied in connection with 2 to 4 collections each, for a total of 21 collections (with hourly samples). The collections lasted for 4 hours, at an inlet rate of 1 to 3 mL per kg per minute, for daily processing totals of 5 to 12 blood volumes. (One blood volume [mL] is estimated by the patient's weight in kg × 70 mL/kg.) Smaller (younger) patients had inlet rates exceeding 2 mL per kg per minute, and larger (older) patients had rates of 1 to 1.5 mL per kg per minute. CFU-GM and CD34+ cell counts obtained each hour of the collection and divided by the first hour's value were compared by nonparametric repeated-measures ANOVA. Results: Second-, third- and fourth-hour CD34+ progenitor cell counts were arithmetically higher than first-hour counts, but the trend did not reach significance (p = 0.1561). Second-hour counts were higher than first-hour counts in the overall analysis (mean ± standard error [SE], 1.00 and 1.39 ± 0.1, respectively; p = 0.0525) and in children older than 5 years (1.00 vs. 1.70 ± 0.30, respectively; p = 0.0259), but not in children younger than 5 years (p = 0.8125). CFU-GM counts did not differ among the 4 hours of collection (p = 0.1717) or between the first and second hour (p = 0.9587). Conclusion: In larger (older) patients, from whom fewer blood volumes were collected, there is a trend toward intra-apheresis recruitment, although less than reported previously. In the smaller (younger) patients, from whom more blood volumes were collected, no trend was observed. Lack of (or submaximal) prior mobilization in previously reported studies may have facilitated intracollection recruitment. Alternatively, the larger number of blood volumes collected from the smaller (younger) patients may have masked intra-apheresis recruitment. The study documents the feasibility of large-volume, 4-hour leukapheresis in pediatric patients. 相似文献
155.
CRIPTO promotes an aggressive tumour phenotype and resistance to treatment in hepatocellular carcinoma 下载免费PDF全文
Peter C Gray Lanpeng Chen Irena Klima Joël Grosjean Mark C Burgmans Arantza Farina‐Sarasqueta Ewa B Snaar‐Jagalska Deborah M Stroka Luigi Terracciano Bart van Hoek Alexander F Schaapherder Susan Osanto George N Thalmann Hein W Verspaget Minneke J Coenraad Marianna Kruithof‐de Julio 《The Journal of pathology》2018,245(3):297-310
Hepatocellular carcinoma (HCC) is the third leading cause of cancer‐related death worldwide. Despite increasing treatment options for this disease, prognosis remains poor. CRIPTO (TDGF1) protein is expressed at high levels in several human tumours and promotes oncogenic phenotype. Its expression has been correlated to poor prognosis in HCC. In this study, we aimed to elucidate the basis for the effects of CRIPTO in HCC. We investigated CRIPTO expression levels in three cohorts of clinical cirrhotic and HCC specimens. We addressed the role of CRIPTO in hepatic tumourigenesis using Cre‐loxP‐controlled lentiviral vectors expressing CRIPTO in cell line‐derived xenografts. Responses to standard treatments (sorafenib, doxorubicin) were assessed directly on xenograft‐derived ex vivo tumour slices. CRIPTO‐overexpressing patient‐derived xenografts were established and used for ex vivo drug response assays. The effects of sorafenib and doxorubicin treatment in combination with a CRIPTO pathway inhibitor were tested in ex vivo cultures of xenograft models and 3D cultures. CRIPTO protein was found highly expressed in human cirrhosis and hepatocellular carcinoma specimens but not in those of healthy participants. Stable overexpression of CRIPTO in human HepG2 cells caused epithelial‐to‐mesenchymal transition, increased expression of cancer stem cell markers, and enhanced cell proliferation and migration. HepG2‐CRIPTO cells formed tumours when injected into immune‐compromised mice, whereas HepG2 cells lacking stable CRIPTO overexpression did not. High‐level CRIPTO expression in xenograft models was associated with resistance to sorafenib, which could be modulated using a CRIPTO pathway inhibitor in ex vivo tumour slices. Our data suggest that a subgroup of CRIPTO‐expressing HCC patients may benefit from a combinatorial treatment scheme and that sorafenib resistance may be circumvented by inhibition of the CRIPTO pathway. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. 相似文献
156.
A Borean M De Prà G Farina P Nalin P Rizzotti 《Clinical chemistry and laboratory medicine》2000,38(6):489-493
We monitored the efficacy of therapy with clodronate, a bisphosphonate drug, in women with postmenopausal osteoporosis, using urinary immunoenzymatic assay of C-telopeptide of collagen type I, an eight amino acid fragment (collagen fragment) of the C-telopeptide of the alpha1-chain of collagen type I (EKAHDGGR). The analysis of the dynamics of collagen fragment concentrations (a marker of bone resorption) during treatment suggests the possibility of early modulation and customization of therapy based on the levels of this marker. This could enable improved control over secondary effects and side effects of clodronate therapy. Pharmacologic inhibition of bone resorption by osteoclasts could be indirectly responsible for the increase in parathyroid hormone found during treatment with clodronate. Increased levels of parathyroid hormone are probably necessary to stimulate residual osteoclast activity and are sufficient for the maintenance of calcium-phosphate homeostasis in a new pharmacologically-induced equilibrium. Outside this context the levels of parathyroid hormone of certain patients would be considered pathologic. 相似文献
157.
Narcolepsy syndrome is a common, although often misdiagnosed, neurological disorder, whose clinical features are excessive daytime somnolence with sleep attacks, caplexy, sleep paralysis and hypnagogic hallucinations. The clinical manifestation have been interpreted as the expression of a sudden intrusion of dissociated REM phenomena in wakefulness. Sometimes the clinical manifestations may include only some of the symptoms: in particular, the cases in which the only symptom is excessive daytime somnolence may be difficult to diagnose. The etiopathogenesis of narcolepsy syndrome is still poorly understood. Recent experimental evidences suggest that a protein, called "orexin", which is supposed to play a role in the control mechanisms of both sleep and eating behaviour, is involved in its pathogenesis. The treatment of narcolepsy has been, up to now, exclusively symptomatic, and in some way empirical and unsatisfactory, especially regarding to daytime sleepiness. Recently, new pharmacological agents, acting on the serotoninergic and/or noradrenergic systems, allow a better control of the cataplectic attacks. The recent development of modafinil, a central nervous system stimulant, devoid of the serious side effects of amphetamines and other compounds, allows to hope in a better control of daytime somnolence and sleep attacks. The aim of the paper is to describe the recent advances in the diagnosis and treatment of narcolepsy. 相似文献
158.
Today it is known that severe burns can be accompanied by the phenomenon of vasoplegic syndrome (VS), which is manifested by persistent and diffuse vasodilation, hypotension and low vascular resistance, resulting in circulatory and respiratory failure. The decrease in systemic vascular resistance observed in VS is associated with excessive production of nitric oxide (NO). In the last 2 decades, studies have reported promising results from the administration of an NO competitor, methylene blue (MB), which is an inhibitor of the soluble guanylate cyclase (sGC), in the treatment of refractory cases of vasoplegia. This medical hypothesis rationale is focused on the tripod of burns/vasoplegia catecholamine resistant/methylene blue. This article has 3 main objectives: 1) to study the guanylate cyclase inhibition by MB in burns; 2) to suggest MB as a viable, safe and useful co-adjuvant therapeutic tool of fluid resuscitation, and; 3) to suggest MB as burns hypotensive vasoplegia amine-resistant treatment.
相似文献
相似文献
159.
Zappa A Canuti M Frati E Pariani E Perin S Ruzza ML Farina C Podestà A Zanetti A Amendola A Tanzi E 《Journal of medical virology》2011,83(1):156-164
The discovery of human Metapneumovirus (hMPV) and human Bocavirus (hBoV) identified the etiological causes of several cases of acute respiratory tract infections in children. This report describes the molecular epidemiology of hMPV and hBoV infections observed following viral surveillance of children hospitalized for acute respiratory tract infections in Milan, Italy. Pharyngeal swabs were collected from 240 children ≤3 years of age (130 males, 110 females; median age, 5.0 months; IQR, 2.0-12.5 months) and tested for respiratory viruses, including hMPV and hBoV, by molecular methods. hMPV-RNA and hBoV-DNA positive samples were characterized molecularly and a phylogenetical analysis was performed. PCR analysis identified 131/240 (54.6%) samples positive for at least one virus. The frequency of hMPV and hBoV infections was similar (8.3% and 12.1%, respectively). Both infections were associated with lower respiratory tract infections: hMPV was present as a single infectious agent in 7.2% of children with bronchiolitis, hBoV was associated with 18.5% of pediatric pneumonias and identified frequently as a single etiological agent. Genetically distinct hMPV and hBoV strains were identified in children examined with respiratory tract infections. Phylogenetic analysis showed an increased prevalence of hMPV genotype A (A2b sublineage) compared to genotype B (80% vs. 20%, respectively) and of the hBoV genotype St2 compared to genotype St1 (71.4% vs. 28.6%, respectively). Interestingly, a shift in hMPV infections resulting from A2 strains has been observed in recent years. In addition, the occurrence of recombination events between two hBoV strains with a breakpoint located in the VP1/VP2 region was identified. 相似文献
160.
Francesca BaglioValeria Blasi Andrea FaliniElisabetta Farina Federica MantovaniFabrizio Olivotto Giuseppe ScottiRaffaello Nemni Marco Bozzali 《Neurobiology of aging》2011,32(1):115-124
Motor impairment represents the main clinical feature of Parkinson's disease (PD). Cognitive deficits are also frequently observed in patients with PD, with a prominent involvement of executive functions and visuo-spatial abilities. We used event-related functional MRI (fMRI) and a paradigm based on visual attention and motor inhibition (Go/NoGO-task) to investigate brain activations in 13 patients with early PD in comparison with 11 healthy controls. The two groups did not report behavioural differences in task performance. During motor inhibition (NoGO-effect), PD patients compared to controls showed an increased activation in the prefrontal cortex and in the basal ganglia. They also showed a reduced and less coherent hemodynamic response in the occipital cortex. These results indicate that specific cortico-subcortical functional changes, involving not only the fronto-striatal network but also the temporal-occipital cortex, are already present in patients with early PD and no clinical evidence of cognitive impairment. We discuss our findings in terms of compensatory mechanisms (fronto-striatal changes) and preclinical signs of visuo-perceptual deficits and visual hallucinations. 相似文献