全文获取类型
收费全文 | 5547篇 |
免费 | 290篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 48篇 |
儿科学 | 184篇 |
妇产科学 | 181篇 |
基础医学 | 791篇 |
口腔科学 | 161篇 |
临床医学 | 453篇 |
内科学 | 1168篇 |
皮肤病学 | 89篇 |
神经病学 | 416篇 |
特种医学 | 166篇 |
外科学 | 716篇 |
综合类 | 20篇 |
一般理论 | 2篇 |
预防医学 | 348篇 |
眼科学 | 37篇 |
药学 | 373篇 |
中国医学 | 10篇 |
肿瘤学 | 684篇 |
出版年
2023年 | 32篇 |
2022年 | 91篇 |
2021年 | 137篇 |
2020年 | 65篇 |
2019年 | 133篇 |
2018年 | 157篇 |
2017年 | 88篇 |
2016年 | 98篇 |
2015年 | 135篇 |
2014年 | 169篇 |
2013年 | 256篇 |
2012年 | 364篇 |
2011年 | 380篇 |
2010年 | 202篇 |
2009年 | 202篇 |
2008年 | 317篇 |
2007年 | 320篇 |
2006年 | 285篇 |
2005年 | 306篇 |
2004年 | 286篇 |
2003年 | 268篇 |
2002年 | 173篇 |
2001年 | 108篇 |
2000年 | 140篇 |
1999年 | 139篇 |
1998年 | 62篇 |
1997年 | 39篇 |
1996年 | 28篇 |
1995年 | 27篇 |
1994年 | 30篇 |
1993年 | 24篇 |
1992年 | 68篇 |
1991年 | 70篇 |
1990年 | 66篇 |
1989年 | 61篇 |
1988年 | 61篇 |
1987年 | 63篇 |
1986年 | 62篇 |
1985年 | 56篇 |
1984年 | 43篇 |
1983年 | 39篇 |
1982年 | 16篇 |
1981年 | 22篇 |
1980年 | 14篇 |
1979年 | 30篇 |
1978年 | 20篇 |
1976年 | 10篇 |
1975年 | 15篇 |
1973年 | 13篇 |
1972年 | 8篇 |
排序方式: 共有5847条查询结果,搜索用时 15 毫秒
31.
Microalbuminuria is a predictor of renal and cardiovascular disease in both type 1 (insulin-dependent) and type 2 (insulin-independent) diabetes. We report on a screening programme for microalbuminuria at a diabetes clinic in Italy. All diabetic patients without Albustix-positive proteinuria attending the clinic between April and September 1991 were screened. Microalbuminuria was defined as a urinary albumin/creatinine ratio, on an early morning sterile urine sample, >3 in at least two consecutive urine collections. Three hundred and fifty patients, 45 (20 female, 25 female) type 1 and 305 (145 male, 160 female) type 2 diabetics, were examined. The age range was 18–42 years and 36–73 years and duration of diabetes 1–24 and 1–35 years for type 1 and type 2 diabetic patients respectively. Blood pressure, lipids, glycosylated haemoglobin, body mass index and insulin dose, where appropriate, were measured in all patients. Microalbuminuria was found in 8 (22%) of the type 1 diabetics. These patients had a longer duration of diabetes (17.5 vs 7.4 years,P<0.001), higher diastolic blood pressure (86±2.1 vs 76±2.6 mmHg,P<0.05) and an increased total serum cholesterol level (203±23 vs 180±25 mg/dl,P<0.05) compared with diabetic patients with microalbuminuria. Of the type 2 diabetic patients 95 (33%) were found to have microalbuminuria and 210 (69%) nor-moalbumiuria. The prevalence of hypertension (defined blood pressure >140/90 mmHg or antihypertensive treatment) and of dyslipidaemia (defined as total cholesterol >200 and triglycerides >170 or hypolipidaemic treatment) were significantly higher (P<0.001 and 0.01 respectively) in patients with microalbuminuria. This study shows a prevalence of microalbuminuria in type 1 and type 2 diabetic patients similar to that reported in surveys of diabetes clinic outpatients in northern Europe. The association between microalbuminuria and recognized risk factors for cardiovascular and renal disease justifies screening programmes for microalbuminuria for early detection of at-risk diabetic patients and for the implementation of preventive therapeutic measures. 相似文献
32.
Tesarik J Ubaldi F Rienzi L Martinez F Iacobelli M Mendoza C Greco E 《Human reproduction (Oxford, England)》2004,19(2):254-261
BACKGROUND: Germ cell elimination and sperm DNA fragmentationin men with primary testiculopathies involve apoptosis-relatedprocesses whose mechanisms are poorly understood. This studyexamines the participation of typical (caspase-dependent) andatypical (caspase-independent) pathways in these processes.METHODS: Caspase activity and DNA fragmentation were evaluatedin Sertoli and germ cells from 63 men with non-obstructive azoospermiaand with different histological diagnoses who were undergoingtesticular biopsy for an assisted reproduction attempt. In eightof these men, phosphatidylserine externalization was also examined.RESULTS: The percentage of Sertoli cells showing caspase activityand DNA fragmentation was low and uniform in all diagnoses.In germ cells that remained tightly associated with Sertolicells despite vigorous mechanical treatment, the incidence ofboth caspase activity and DNA fragmentation was high, particularlyin men with maturation arrest. In Sertoli cell-free germ cells,high incidence of DNA fragmentation contrasted with low incidenceof caspase activity and phosphatidylserine externalization.CONCLUSIONS: In men with primary testicular failure, apoptosisof Sertoli cells is insignificant. Some germ cells undergo caspase-dependentapoptosis, show phosphatidylserine externalization and are tightlyassociated with Sertoli cells. Other germ cells show caspase-independentDNA fragmentation, do not externalize phosphatidylserine andlack a tight association with Sertoli cells. 相似文献
33.
Angiotensin-(1–7) stimulates water transport in rat inner medullary collecting duct: evidence for involvement of vasopressin V2 receptors 总被引:1,自引:0,他引:1
Magaldi AJ Cesar KR de Araújo M Simões e Silva AC Santos RA 《Pflügers Archiv : European journal of physiology》2003,447(2):223-230
The peptide angiotensin-(1–7) [Ang-(1–7)] is known to enhance water transport in rat inner medullary collecting duct (IMCD). The aim of this study was to determine the mechanism of the Ang-(1–7) effect on osmotic water permeability (P
f). P
f was measured in the normal rat IMCD perfused in vitro in presence of agonists [Ang-(1–7), arginine vasopressin (AVP) and Ang-(3–8)], and antagonists of the angiotensin and the vasopressin cascade. Ang-(1–7), but not Ang-(3–8), increased P
f significantly. The effect of Ang-(1–7) on P
f was abolished by its selective antagonist, A-779, added before or after Ang-(1–7). Prostaglandin E2 and the protein kinase A inhibitor H8 also blocked the Ang-(1–7) effect. Blockade of vasopressin V1 receptors by antagonists did not change the Ang-(1–7) effect, but pre-treatment with a V2 antagonist abolished the effect of Ang-(1–7) on P
f. Similarly, pre-treatment with A-779 inhibited AVPs effect on P
f. Forskolin-stimulated P
f was blocked both by A-779 and by the V2 antagonist. Finally, Ang-(1–7) increased cAMP levels in fresh IMCD cell suspensions whilst the forskolin-stimulated cAMP synthesis was decreased by A-779 and the V2 antagonist. These data provide evidence that Ang-(1–7) interacts via its receptor with the AVP V2 system through a mechanism involving adenylate-cyclase activation. 相似文献
34.
35.
Impact of intranasal budesonide on immune inflammatory responses and epithelial remodeling in chronic upper airway inflammation 总被引:3,自引:0,他引:3
Mastruzzo C Greco LR Nakano K Nakano A Palermo F Pistorio MP Salinaro ET Jordana M Dolovich J Crimi DN Vancheri C 《The Journal of allergy and clinical immunology》2003,112(1):37-44
BACKGROUND: Histologic and immunohistologic features of nasal polyps (NP) are similar to those observed in asthma, thus suggesting a similar immunopathology. OBJECTIVE: The primary objective of this study was to further understand the anti-inflammatory and immunoregulatory effects of locally delivered corticosteroids. To this end, the effect of intranasal budesonide on the expression of specific cytokines, lymphocyte subsets, and epithelial remodeling in this model of airway tissue inflammation were studied. METHODS: We used immunohistochemical techniques to examine nasal mucosae (NM) from healthy individuals and nasal polyp (NP) tissues from patients with nasal polyposis obtained before and after intranasal budesonide treatment. RESULTS: First, the density of CD8(+) cells was markedly increased in NP tissues after intranasal budesonide treatment from 16.1 +/- 8.4 (M +/- SEM) per mm(2) to 39.9 +/- 24.1. Second, the density of cells immunoreactive for IL-4, IL-5, IFN-gamma, IL-12, and TGF-beta in NP was significantly greater than in control NM tissues. The density of IL-4(+) and IL-5(+) cells in NP tissues significantly decreased after budesonide treatment from 40 +/- 12 to 17.8 +/- 8 and from 19.3 +/- 11 to 10.4 +/- 7, respectively. In contrast, the density of IFN-gamma(+) and IL-12(+) cells remained unchanged. In addition, we found that the density of TGF-beta(+) cells significantly increased after intranasal budesonide from 18 +/- 5 to 41 +/- 9. Third, damage to the entire length of the NP epithelium was quantified using a grading system. The epithelium of untreated NP was substantially damaged; remarkable epithelial restitution with no apparent changes in stromal collagen deposition was observed after intranasal budesonide treatment. CONCLUSIONS: These findings demonstrate that intranasal budesonide induced an increase in CD8 population and a selective regulatory effect on tissue cytokine expression. Furthermore, intranasal budesonide promoted epithelial remodeling. We hypothesize that these immunoregulatory and remodeling effects elicited by steroids might be, at least in part, mediated by the induction of TGF-beta. 相似文献
36.
I Get by with a Little Help from my Family and Friends: Adolescents' Support for Diabetes Care 总被引:5,自引:6,他引:5
La Greca Annette M.; Auslander Wendy F.; Greco Peggy; Spetter Dante; Fisher Edwin B. Jr.; Santiago Julio V. 《Journal of pediatric psychology》1995,20(4):449-476
Evaluated and compared the support provided by family membersand friends for adolescents' diabetes care. Family and friendsupport also were examined in relation to other measures ofsocial support, to demographic variables (age, gender, durationof diabetes) and to adherence. Using a structured interview,74 adolescents with diabetes described the ways that familymembers and friends provided support for diabetes management(insulin shots, blood glucose monitoring, eating proper meals,exercise), and for helping them to "feel good about their diabetes."Families provided more support than friends for three managementtasks (insulin injections, blood glucose monitoring, meals);this support was largely instrumental. In contrast, friendsprovided more emotional support for diabetes than families.Greater family support was related to younger age, shorter diseaseduration, and better treatment adherence. Implications of thefindings include encouraging parents to remain involved in adolescents'treatment management, and involving peers as supportive companionsfor meals and exercise. 相似文献
37.
Marcie R Finney Nicholas J Greco Stephen E Haynesworth Joseph M Martin David P Hedrick Jimmy Z Swan Daniel G Winter Suzanne Kadereit Matthew E Joseph Pingfu Fu Vincent J Pompili Mary J Laughlin 《Biology of blood and marrow transplantation》2006,12(5):585-593
Endothelial precursor cells (EPCs) cultured from adult bone marrow (BM) have been shown to mediate neovasculogenesis in murine models of vascular injury. We sought to directly compare umbilical cord blood (UCB)- and BM-derived EPC surface phenotypes and in vivo functional capacity. UCB and BM EPCs derived from mononuclear cells (MNC) were phenotyped by surface staining for expression of stromal (Stro-1, CXCR4, CD105, and CD73), endothelial (CD31, CD146, and vascular endothelial [VE]-cadherin), stem cell (CD34 and CD133), and monocyte (CD14) surface markers and analyzed by flow cytometry. The nonobese diabetic/severe combined immunodeficiency murine model of hind-limb ischemia was used to analyze the potential of MNCs and culture-derived EPCs from UCB and BM to mediate neovasculogenesis. Histologic evaluation of the in vivo studies included capillary density as a measure of neovascularization. Surface CXCR4 expression was notably higher on UCB-derived EPCs (64.29%+/-7.41%) compared with BM (19.69%+/-5.49%; P=.021). Although the 2 sources of EPCs were comparable in expression of endothelial and monocyte markers, BM-derived EPCs contained higher proportions of cells expressing stromal cell markers (CD105 and CD73). Injection of UCB- or BM-derived EPCs resulted in significantly improved perfusion as measured by laser Doppler imaging at days 7 and 14 after femoral artery ligation in nonobese diabetic/severe combined immunodeficiency mice compared with controls (P<.05). Injection of uncultured MNCs from BM or UCB showed no significant difference from control mice (P=.119; P=.177). Tissue samples harvested from the lower calf muscle at day 28 demonstrated increased capillary densities in mice receiving BM- or UCB-derived EPCs. In conclusion, we found that UCB and BM-derived EPCs differ in CXCR4 expression and stromal surface markers but mediate equivalent neovasculogenesis in vivo as measured by Doppler flow and histologic analyses. 相似文献
38.
Protection of killer antiidiotypic antibodies against early invasive aspergillosis in a murine model of allogeneic T-cell-depleted bone marrow transplantation 总被引:5,自引:0,他引:5
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Cenci E Mencacci A Spreca A Montagnoli C Bacci A Perruccio K Velardi A Magliani W Conti S Polonelli L Romani L 《Infection and immunity》2002,70(5):2375-2382
Antiidiotypic monoclonal antibodies (MAbs) representing the internal image of a yeast killer toxin (KT) have therapeutic potential against several fungal infections. The efficacy of KT MAbs against Aspergillus fumigatus was investigated in a mouse model of T-cell-depleted allogeneic bone marrow transplantation (BMT) with invasive pulmonary aspergillosis. Mice were highly susceptible to infection at 3 days post-BMT, when profound neutropenia was observed both in the periphery and in the lungs. Treatment with KT MAbs protected the mice from infection, as judged by the long-term survival and decreased pathology associated with inhibition of fungal growth and hyphal development in the lungs. In vitro, similar to polymorphonuclear neutrophils, KT MAbs significantly inhibited the hyphal development and metabolic activity of germinated Aspergillus conidia. These results indicate that mimicking the action of neutrophils could be a strategy through which KT MAbs exert therapeutic efficacy in A. fumigatus infections. 相似文献
39.
Bottini N Otsu A Borgiani P Saccucci P Stefanini L Greco E Fontana L Hopkins JM Mao XQ 《Clinical genetics》2003,63(3):228-231
Protein tyrosine phosphatases (PTPases) have recently been recognized as important modulators of various signal transduction pathways in immune cells. Genetic polymorphisms have been described in genes codifying for members of this family of enzymes, and the genetics of PTPases is predicted to play an important role in the etiology of immune diseases and of their clinical variability. The low molecular weight protein tyrosine phosphatase (ACP1 or LMPTP) is one of the few PTPases with a known genetic polymorphism, and has been proposed to be associated with atopic dermatitis in a small sample from an Italian population. In this paper we describe the association of the ACP1 polymorphism with total IgE levels in two independent samples from English and Italian populations. In both the samples the mean value of serum IgE is lower among subjects carrying the BC genotype than in other ACP1 genotypes. The BC genotype is associated with the highest total ACP1 enzymatic activity. Our data suggest that one or both of the ACP1 isoforms exert an inhibitory role on some signal transduction pathway relevant for IgE hyperproduction. 相似文献
40.