全文获取类型
收费全文 | 587篇 |
免费 | 36篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 30篇 |
妇产科学 | 1篇 |
基础医学 | 48篇 |
口腔科学 | 33篇 |
临床医学 | 48篇 |
内科学 | 123篇 |
皮肤病学 | 17篇 |
神经病学 | 9篇 |
特种医学 | 99篇 |
外科学 | 88篇 |
综合类 | 24篇 |
预防医学 | 29篇 |
眼科学 | 4篇 |
药学 | 49篇 |
中国医学 | 1篇 |
肿瘤学 | 25篇 |
出版年
2021年 | 18篇 |
2020年 | 7篇 |
2019年 | 2篇 |
2018年 | 7篇 |
2017年 | 6篇 |
2016年 | 11篇 |
2015年 | 11篇 |
2014年 | 13篇 |
2013年 | 28篇 |
2012年 | 26篇 |
2011年 | 14篇 |
2010年 | 28篇 |
2009年 | 28篇 |
2008年 | 17篇 |
2007年 | 18篇 |
2006年 | 23篇 |
2005年 | 12篇 |
2004年 | 12篇 |
2003年 | 14篇 |
2002年 | 12篇 |
2001年 | 10篇 |
2000年 | 8篇 |
1999年 | 19篇 |
1998年 | 36篇 |
1997年 | 25篇 |
1996年 | 21篇 |
1995年 | 13篇 |
1994年 | 22篇 |
1993年 | 23篇 |
1992年 | 7篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 13篇 |
1988年 | 15篇 |
1987年 | 9篇 |
1986年 | 14篇 |
1985年 | 7篇 |
1984年 | 8篇 |
1983年 | 6篇 |
1982年 | 9篇 |
1981年 | 12篇 |
1980年 | 12篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 9篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1957年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有630条查询结果,搜索用时 0 毫秒
51.
52.
M Tavassoli S Javadi R Firozi F Rezaei AR Khezri M Hadian 《Iranian Journal of Parasitology》2012,7(4):110-115
Background
We tried to investigate the hair contamination of pet dogs and farm sheepdog with Toxocara eggs in terms of the different sex and age groups in north-west of Iran (Urmia and its suburbs).Methods
Hair samples were collected from a total of 138 pet and farm sheepdogs from November 2008 to June 2009 in Urmia City and the suburb (West Azerbaijan-Iran) and examined for the presence of T. canis eggs.Results
T. canis eggs found in 60 samples altogether (pet and shepherd dogs) showed a contamination rate of 36.2%. The number of observed T. canis eggs in each microscope field was varied from 1 to > 400. The age of the dog was found a significant factor to influence the prevalence and intensity of contamination, with 82% of all the eggs recovered from puppies (six months and younger). Additionally, the numbers of eggs in farm sheepdogs were significantly higher than pet dogs (P<0.05).Conclusion
This report shows that direct contact with T. canis infected dogs, particularly puppies from shepherd dogs, may pose a serious hazard to human. Besides, as they may harbor a considerable number of eggs on their hair, they can contaminate the soil and the environment. 相似文献53.
Background
Hadjelia truncata is a nematode that causes lesions in the gizzard lining of pigeons, which may even lead to death. The aim of this study was to introduce Alphitobius diaperinus as a new intermediate host for Hadjelia truncata.Methods
H. truncata infection was identified in a pigeon flock in Ahvaz City, Khuzestan Province, Iran by performing fecal examination and autopsy. Adult and larval stages of beetles were collected from the litter of pigeon houses, and identified morphologically. The beetle larvae were cultured in a medium, containing feces of the infected pigeons. Nematode larval stages from naturally and experimentally (culturally) infected adult beetles were fed to two groups of pigeonsResults
The collected beetles were identified as Alphitobius diaperinus. Average length and width of the adult beetles were 6.31 mm and 2.88 mm respectively. Infection rates of naturally and experimentally infected beetles with larval stages of the nematode were 66.2% and 45.1% respectively. The adult nematodes collected from gizzards of experimentally infected pigeons were identified as H. truncata. Nematode infection rates in pigeons after feeding the infective larvae collected from naturally and experimentally infected beetles were 44.7% and 32.5% respectively.Conclusion
A. diaperinus can serve as a natural intermediate host for H. truncata. 相似文献54.
In vitro evaluation of prothrombin complex concentrates in a thrombin generation assay, using DAPA and purified components of the prothrombinase complex, demonstrated significant levels of coagulant- active "phospholipid replacing" activity. Quantification of this activity showed a significant correlation (r = 0.8747, p less than 0.01) with thrombogenicity measured in vivo in a stasis model in rabbits. Extracted lipid material retained full phospholipid replacing activity in the vitro assay. Thin-layer chromatographic characterization confirmed the presence of phospholipids with known coagulant activity in vitro. In vivo, the extracted material was nonthrombogenic but augmented the thrombogenicity of purified factor Xa. Substitution of a synthetic coagulant-active phospholipid (phosphatidylcholine-phosphatidylserine lipid vesicles) for the extracted phospholipid produced a similar augmentation of a factor-Xa- induced thrombogenicity in vivo. It is concluded that the coagulant- active phospholipid content of prothrombin complex concentrates is a major determinant of thrombogenicity but requires the presence of activated clotting factors for its expression in vivo. 相似文献
55.
Drug-induced thrombocytopenia is associated with increased binding of IgG to platelets both in vivo and in vitro 总被引:3,自引:0,他引:3
Kelton JG; Meltzer D; Moore J; Giles AR; Wilson WE; Barr R; Hirsh J; Neame PB; Powers PJ; Walker I; Bianchi F; Carter CJ 《Blood》1981,58(3):524-529
Thrombocytopenia is a common serious adverse effect of drug treatment. A variety of in vitro diagnostic techniques to confirm the diagnosis are available, but the majority lack sufficient sensitivity to detect all cases of drug-induced thrombocytopenia. We studied 19 patients with suspected drug-induced thrombocytopenia and demonstrated that platelet- associated IgG (PAIgG) was elevated in all at the time of thrombocytopenia, and PAIgG returned to normal levels as the thrombocytopenia resolved. In the majority of patients, the platelet count rapidly returned to normal after the drug was discontinued; however, in six patients, the thrombocytopenia persisted well beyond the period of time that the offending drug would be expected to be cleared from the blood. In 13 patients, serum obtained after recovery was used to identify the drug responsible for the thrombocytopenia in an in vitro assay. In all cases, the addition of the drug historically associated with the thrombocytopenic episode was associated with an increased binding of IgG to control platelets. For uncertain reasons, the concentration of drug required to increase the in vitro binding of IgG to test platelets was often more than the concentration usually achieved in vivo. Wider application of these techniques may provide better understanding of the clinical characteristics and mechanisms responsible for drug-induce thrombocytopenia. 相似文献
56.
Dammacco F; Sansonno D; Han JH; Shyamala V; Cornacchiulo V; Iacobelli AR; Lauletta G; Rizzi R 《Blood》1994,84(10):3336-3343
Type II mixed cryoglobulinemia (MC) is an often progressive vasculitis characterized by circulating cold-precipitable proteins that usually consists of polyclonal IgG and monoclonal IgM kappa with rheumatoid factor (RF) activity. Its etiology is unknown, although recent evidence strongly suggests that hepatitis C virus (HCV) plays a major role. Plasmapheresis, corticosteroids, and cytotoxic drugs have been used in the therapy of MC patients. Recently, favorable results with recombinant interferon-alpha (rIFN alpha) have been reported. To further assess its effectiveness, we studied the effects of natural human interferon-alpha (nIFN alpha), alone and in combination with 6- methyl-prednisolone (PDN), in a prospective, randomized, controlled trial in patients with symptomatic MC. Sixty-five patients were enrolled onto the trial, 52 (80%) of whom presented serum anti-HCV antibodies and specific genomic RNA sequences. Fifteen patients received nIFN alpha (3 MU) intramuscularly (IM) three times weekly, whereas 17 patients also received 16 mg/d of PDN orally on non-IFN days. Moreover, 18 patients received 16 mg/d of PDN only, and 15 were untreated. Treatment was discontinued after 1 year and patients were monitored for 8 to 17 months (mean, 13). A complete response was achieved in eight of 15 patients (53.3%) treated with nIFN alpha and nine of 17 (52.9%) treated with nIFN alpha plus PDN, as compared with three of 18 patients (16.7%) who received PDN only (P < .05) and one of 15 (6.7%) untreated controls (P < .01). Partial response occurred in two of 15 (13.3%) patients treated with nIFN alpha, three of 17 (17.6%) who received nIFN alpha plus PDN, one of 18 (5.5%) who received PDN only, and one of 15 (6.7%) controls. A complete response in six patients (66.7%) was achieved within 3 months in the group that received nIFN alpha plus PDN, as compared with two patients (25%) of those who received nIFN alpha alone (P < .02). In anti-HCV-positive patients, the clinical response occurred in step with reduced or undetectable levels of HCV RNA and transaminase normalization. Quantification of circulating HCV RNA represented a good predictive response marker. The probability of relapse within 3 months after treatment was 100% (three of three patients) and 75% (six of eight patients), respectively, in patients who received PDN alone or nIFN alpha alone as compared with none of those who received nIFN alpha plus PDN (P < .001).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
57.
Chemoattractant-induced changes in surface expression and redistribution of a functional ligand for P-selectin on neutrophils 总被引:4,自引:0,他引:4
Adhesion between platelets and neutrophils is mediated through the interaction of P-selectin on activated platelets with a carbohydrate- containing structure on neutrophils, and occurs under both static and shear conditions. Recent studies using flow chambers have shown that neutrophils become activated after binding to surface-adherent platelets expressing P-selectin. The objective of the present study was to investigate the effect of such activation on the interactions of platelet P-selectin with its ligand on neutrophils. Flow cytometric analyses using P-selectin chimeras revealed that activation induced a rapid and marked reduction in chimera binding, with levels of binding decreased by 71% after 15 minutes of stimulation with the chemotactic agent, FMLP. Using a visual assay of platelet-neutrophil rosetting, we showed that the P-selectin ligand was translocated and clustered at the uropod of neutrophils following the shape changes and polarization induced by chemotactic stimulation. Activated neutrophils bound to surface-adherent platelets also displayed the clustering of P-selectin ligand at the uropod, and these neutrophils detached from the platelets when a shear stress (2 dynes/cm2) was applied through the adhesion chamber. These results indicate that chemotactic stimulation of neutrophils induces changes in the surface expression and distribution of a biologically relevant ligand for P-selectin, and that these changes might influence the adhesive interactions occurring between neutrophils and activated platelets. 相似文献
58.
Rossi GB; Migliaccio AR; Migliaccio G; Lettieri F; Di Rosa M; Peschle C; Mastroberardino G 《Blood》1980,56(1):74-79
Addition of prostaglandins of the E series (PGE1, PGE2) in methylcellulose cultures of murine marrow results in a dose-dependent inhibition of the cloning efficiency of both BFU-E and CFU-C. However, CFU-E growth is unaffected. The inhibitory action of PGE is progressively overcome by increasing amounts of colony-stimulating factor (CSF), and with some limitations, also of erythropoietin (Ep). Addition of PGF2 alpha' associated or not with indomethacin, does not exert any significant effect on these hemopoietic precursors. In an attempt to unvail the mechanism(s) underlying these phenomena, dibutyryl-cyclic AMP (db-cAMP), theophylline (an inhibitor of phosphodiesterase), or theophylline + PGE were plated at various concentrations. Both db-cAMP and theophylline induce an inhibitory influence on both BFU-E and CFU-C growth, which mimicks that by PGEs; additionally, theophylline potentiates the inhibitory action of PGE1. In all these studies, the CFU-E number was not significantly modified. PGE action on BFU-E proliferation is clearly species-dependent, since PGE1 addition to human marrow methylcellulose cultures induces a significant enhancement of the number of both BFU-E and CFU-E derived colonies. This action was abolished upon removal of adherent cells, thus suggesting that PGE1 evokes a release of factor(s) enhancing human erythroid colony growth by adherent cells. 相似文献
59.
A canine model of hemophilic (factor VIII:C deficiency) bleeding 总被引:8,自引:4,他引:8
A model of bleeding due to clotting factor deficiency has been developed in dogs. Normal and hemophilic (factor VIII:C deficient) animals were used. Bleeding was induced in lightly anesthetized animals by severing the apex of the nail cuticle using a guillotine device. In normal animals, bleeding usually ceased spontaneously after 2-8 min. In contrast, in hemophilic animals, bleeding continued for up to 20 min and necessitated either cauterization or the application of topical thrombin to achieve hemostasis. Pretreatment of the hemophilic animals with canine cryoprecipitate corrected the cuticle bleeding time to within the range noted for normal animals. The method is simple and reproducible and has the advantage that a number of observations can be made sequentially on the same animal. Rebleeding of the cauterized cuticle of the hemophilic animals did not usually occur. This model has considerable potential for the preclinical testing of products considered to bypass or replace factor VIII:C in patients with acquired inhibitors of factor VIII:C and may be adapted to the study of other mechanisms involved in normal and abnormal hemostasis. 相似文献
60.