全文获取类型
收费全文 | 654篇 |
免费 | 73篇 |
专业分类
727篇 |
出版年
2023年 | 4篇 |
2021年 | 18篇 |
2020年 | 10篇 |
2019年 | 15篇 |
2018年 | 12篇 |
2017年 | 12篇 |
2016年 | 15篇 |
2015年 | 25篇 |
2014年 | 23篇 |
2013年 | 45篇 |
2012年 | 41篇 |
2011年 | 46篇 |
2010年 | 26篇 |
2009年 | 29篇 |
2008年 | 31篇 |
2007年 | 24篇 |
2006年 | 26篇 |
2005年 | 27篇 |
2004年 | 22篇 |
2003年 | 22篇 |
2002年 | 16篇 |
2001年 | 20篇 |
2000年 | 20篇 |
1999年 | 17篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 9篇 |
1991年 | 11篇 |
1990年 | 11篇 |
1989年 | 15篇 |
1988年 | 10篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1979年 | 6篇 |
1977年 | 5篇 |
1975年 | 3篇 |
1973年 | 7篇 |
1972年 | 5篇 |
1971年 | 8篇 |
1970年 | 4篇 |
1969年 | 3篇 |
1968年 | 5篇 |
1967年 | 3篇 |
1966年 | 4篇 |
1965年 | 7篇 |
排序方式: 共有727条查询结果,搜索用时 15 毫秒
61.
Tanno B Negroni A Vitali R Pirozzoli MC Cesi V Mancini C Calabretta B Raschellà G 《The Journal of biological chemistry》2002,277(26):23172-23180
62.
Venturoli S Paradisi R Bagnoli A Colombo FM Ravaioli B Vianello F Mancini F Gualerzi B Porcu E Seracchioli R 《Hormone research》2001,56(1-2):25-31
OBJECTIVE: To evaluate the safety and efficacy of a low dose of flutamide (125 mg/day) in maintaining the clinical results already obtained using a higher dose (250 mg/day), in women suffering from hirsutism. METHOD: Forty-three women suffering from hirsutism of varying origin received 250 mg/day of flutamide as an initial treatment for 12 months and, subsequently, 125 mg/day of flutamide for an additional 12 months as a maintenance treatment. Hirsutism was evaluated by the Ferriman-Gallwey score, and hair diameter and hair growth rate were determined by a special image analysis processor. Biochemical, clinical and hormonal parameters were evaluated in basal conditions and every 2-6 months. RESULTS: The significant decrease in the hirsutism score, hair diameter and hair growth rate during the initial treatment period was confirmed at the end of the maintenance treatment period. Androgen levels decreased up to the end of the initial treatment period and partially decreased during the maintenance treatment. During the initial treatment period, 4 subjects showed an increase of aspartate aminotransferase and alanine aminotransferase and dropped out. During the maintenance treatment period, no side effects or complications were observed. CONCLUSION: Satisfactory management of hirsutism with flutamide seems to be represented by an initial treatment period using 250 mg/day to achieve satisfactory results, followed by a long maintenance treatment period using 125 mg/day. 相似文献
63.
Continuous antiretroviral therapy is currently the most effective way to treat HIV infection. Unstructured interruptions are quite common due to side effects and toxicity, among others, and cannot be prevented. Several attempts to structure these interruptions failed due to an increased morbidity compared to continuous treatment. The cause of this failure is poorly understood and often attributed to drug resistance. Here we show that structured treatment interruptions would fail regardless of the emergence of drug resistance. Our computational model of the HIV infection dynamics in lymphoid tissue inside lymph nodes, demonstrates that HIV reservoirs and evasion from immune surveillance themselves are sufficient to cause the failure of structured interruptions. We validate our model with data from a clinical trial and show that it is possible to optimize the schedule of interruptions to perform as well as the continuous treatment in the absence of drug resistance. Our methodology enables studying the problem of treatment optimization without having impact on human beings. We anticipate that it is feasible to steer new clinical trials using computational models. 相似文献
64.
J Guay J P Falgueyret A Ducret M D Percival J A Mancini 《European journal of biochemistry》2000,267(20):6311-6318
The prodomains of several cysteine proteases of the papain family have been shown to be potent inhibitors of their parent enzymes. An increased interest in cysteine proteases inhibitors has been generated with potential therapeutic targets such as cathepsin K for osteoporosis and cathepsin S for immune modulation. The propeptides of cathepsin S, L and K were expressed as glutathione S-transferase-fusion proteins in Escherichia coli. The proteins were purified on glutathione affinity columns and the glutathione S-transferase was removed by thrombin cleavage. All three propeptides were tested for inhibitor potency and found to be selective within the cathepsin L subfamily (cathepsins K, L and S) compared with cathepsin B or papain. Inhibition of cathepsin K by either procathepsin K, L or S was time-dependent and occurred by an apparent one-step mechanism. The cathepsin K propeptide had a Ki of 3.6-6.3 nM for each of the three cathepsins K, L and S. The cathepsin L propeptide was at least a 240-fold selective inhibitor of cathepsin K (Ki = 0.27 nM) and cathepsin L (Ki = 0.12 nM) compared with cathepsin S (Ki = 65 nM). Interestingly, the cathepsin S propeptide was more selective for inhibition of cathepsin L (Ki = 0.46 nM) than cathepsin S (Ki = 7.6 nM) itself or cathepsin K (Ki = 7.0 nM). This is in sharp contrast to previously published data demonstrating that the cathepsin S propeptide is equipotent for inhibition of human cathepsin S and rat and paramecium cathepsin L [Maubach, G., Schilling, K., Rommerskirch, W., Wenz, I., Schultz, J. E., Weber, E. & Wiederanders, B. (1997), Eur J. Biochem. 250, 745-750]. These results demonstrate that limited selectivity of inhibition can be measured for the procathepsins K, L and S vs. the parent enzymes, but selective inhibition vs. cathepsin B and papain was obtained. 相似文献
65.
Marcello Mancini Adelaide Greco Enrico Tedeschi Giuseppe Palma Monica Ragucci Maria Grazia Bruzzone Anna Rita Daniela Coda Enza Torino Alessandro Scotti Ileana Zucca Marco Salvatore 《PloS one》2015,10(6)
To characterize the anatomy of the venous outflow of the mouse brain using different imaging techniques. Ten C57/black male mice (age range: 7-8 weeks) were imaged with high-frequency Ultrasound, Magnetic Resonance Angiography and ex-vivo Microcomputed tomography of the head and neck. Under general anesthesia, Ultrasound of neck veins was performed with a 20MHz transducer; head and neck Magnetic Resonance Angiography data were collected on 9.4T or 7T scanners, and ex-vivo Microcomputed tomography angiography was obtained by filling the vessels with a radiopaque inert silicone rubber compound. All procedures were approved by the local ethical committee. The dorsal intracranial venous system is quite similar in mice and humans. Instead, the mouse Internal Jugular Veins are tiny vessels receiving the sigmoid sinuses and tributaries from cerebellum, occipital lobe and midbrain, while the majority of the cerebral blood, i.e. from the olfactory bulbs and fronto-parietal lobes, is apparently drained through skull base connections into the External Jugular Vein. Three main intra-extracranial anastomoses, absent in humans, are: 1) the petrosquamous sinus, draining into the posterior facial vein, 2) the veins of the olfactory bulb, draining into the superficial temporal vein through a foramen of the frontal bone 3) the cavernous sinus, draining in the External Jugular Vein through a foramen of the sphenoid bone. The anatomical structure of the mouse cranial venous outflow as depicted by Ultrasound, Microcomputed tomography and Magnetic Resonance Angiography is different from humans, with multiple connections between intra- and extra- cranial veins. 相似文献
66.
Many aberrant or unassembled proteins synthesized in the endoplasmic reticulum (ER) are degraded by cytosolic proteasomes. To investigate how soluble glycoproteins destined for degradation are retrotranslocated across the ER membrane, we analyzed the fate of two IgM subunits, mu and J, retained in the ER by myeloma cells that do not synthesize light chains. Degradation of mu and J is prevented by proteasome inhibitors, suggesting that both chains are retrotranslocated to be disposed of by proteasomes. Indeed, when proteasomes are inhibited, some deglycosylated J chains that no longer contain intrachain disulfide bonds accumulate in the cytosol. However, abundant glycosylated J chains are still present in the ER at time points in which degradation would have been almost complete in the absence of proteasome inhibitors, suggesting that retrotranslocation and degradation are coupled events. This was confirmed by protease protection and cell fractionation assays, which revealed that virtually all mu chains are retained in the ER lumen in a glycosylated state when proteasomes are inhibited. Association with calnexin correlated with the failure of mu chains to dislocate to the cytosol. Taken together, these results suggest that active proteasomes are required for the extraction of Ig subunits from the ER, though the requirements for retrotranslocation may differ among individual substrates. 相似文献
67.
Tempera I Cipriani R Campagna G Mancini P Gatti A Guidobaldi L Pantellini F Mandosi E Sensi M Quesada P Mario UD D'Erme M Morano S 《Journal of cellular physiology》2005,205(3):387-392
Poly(ADP-ribose)polymerase (PARP-1), a nuclear enzyme activated by DNA strand breaks, is involved in DNA repair, aging, inflammation, and neoplastic transformation. In diabetes, reactive oxygen and nitrogen species occurring in response to hyperglycemia cause DNA damages and PARP-1 activation. Because circulating mononuclear cells (MNCs) are involved in inflammation mechanisms, these cells were chosen as the experimental model to evaluate PARP-1 levels and activity in patients with type 2 diabetes. MNCs were isolated from 25 diabetic patients (18 M, 7 F, age, 63.5 +/- 10.2 years, disease duration 17.7 +/- 8.2 years) and 11 age and sex matched healthy controls. PARP-1 expression and activity were analyzed by semi-quantitative PCR, Western and activity blot, and immunofluorescence microscopy. PARP-1-mRNA expression was increased in MNCs from all diabetic patients versus controls (P < 0.01), whereas PARP-1 content and activity were significantly lower in diabetic patients (P < 0.0001). To verify whether low PARP-1 levels and activity were due to a proteolytic effect of caspase-3 like, the latter activation was measured by a fluorimetric assay. Caspase-3 activity in MNCs was significantly higher in diabetic patients versus control subjects (P < 0.0001). The different PARP-1 behavior in MNCs from patients with type 2 diabetes could therefore be responsible for the abnormal inflammation and infection responses in diabetes. 相似文献
68.
Justin Mancini Brooke Weckselblatt Yoonjie K. Chung Julia C. Durante Steven Andelman Jessica Glaubman Justin D. Dorff Samhita Bhargava Rebeccah S. Lijek Katherine P. Unger Iruka N. Okeke 《Journal of bacteriology》2011,193(18):4813-4820
Heat-resistant agglutinin 1 (Hra1) is an accessory colonization factor of enteroaggregative Escherichia coli (EAEC) strain 042. Tia, a close homolog of Hra1, is an invasin and adhesin that has been described in enterotoxigenic E. coli. We devised a PCR-restriction fragment length polymorphism screen for the associated genes and found that they occur among 55 (36.7%) of the enteroaggregative E. coli isolates screened, as well as lower proportions of enterotoxigenic, enteropathogenic, enterohemorrhagic, and commensal E. coli isolates. Overall, 25%, 8%, and 3% of 150 EAEC strains harbored hra1 alone, tia alone, or both genes, respectively. One EAEC isolate, 60A, produced an amplicon with a unique restriction profile, distinct from those of hra1 and tia. We cloned and sequenced the full-length agglutinin gene from strain 60A and have designated it hra2. The hra2 gene was not detected in any of 257 diarrheagenic E. coli isolates in our collection but is present in the genome of Salmonella enterica serovar Heidelberg strain SL476. The cloned hra2 gene from strain 60A, which encodes a predicted amino acid sequence that is 64% identical to that of Hra1 and 68% identical to that of Tia, was sufficient to confer adherence on E. coli K-12. We constructed an hra2 deletion mutant of EAEC strain 60A. The mutant was deficient in adherence but not autoaggregation or invasion, pointing to a functional distinction from the autoagglutinin Hra1 and the Tia invasin. Hra1, Tia, and the novel accessory adhesin Hra2 are members of a family of integral outer membrane proteins that confer different colonization-associated phenotypes. 相似文献
69.
Adelaide Greco Monica Ragucci Anna Rita Daniela Coda Alessandro Rosa Sara Gargiulo Raffaele Liuzzi Matteo Gramanzini Sandra Albanese Sabina Pappatà Marcello Mancini Arturo Brunetti Marco Salvatore 《PloS one》2013,8(10)
Background
Ultrasound is a valuable non-invasive tool used in obstetrics and gynecology to monitor the growth and well being of the human fetus. The laboratory mouse has recently emerged as an appropriate model for fetal and perinatal studies because morphogenetic processes in mice exhibit adequate homology to those in humans, and genetic manipulations are relatively simple to perform in mice. High-frequency ultrasound (HFUS) has recently become available for small animal preclinical imaging and can be used to study pregnancy and development in the mouse. The objective of the current study was to assess the main applications of HFUS in the evaluation of fetal growth and placental function and to better understand human congenital diseases.Methodology/Principal Findings
On each gestational day, at least 5 dams were monitored with HFUS; a total of ∼200 embryos were examined. Because it is not possible to measure each variable for the entire duration of the pregnancy, the parameters were divided into three groups as a function of the time at which they were measured. Univariate analysis of the relationship between each measurement and the embryonic day was performed using Spearman’s rank correlation (Rs). Continuous linear regression was adopted for multivariate analysis of significant parameters. All statistical tests were two-sided, and a p value of 0.05 was considered statistically significant.Conclusions/Significance
The study describes the main applications of HFUS to assess changes in phenotypic parameters in the developing CD1 mouse embryo and fetus during pregnancy and to evaluating physiological fetal and placental growth and the development of principal organs such as the heart, kidney, liver, brain and eyes in the embryonic mouse. A database of normal structural and functional parameters of mouse development will provide a useful tool for the better understanding of morphogenetic and cardiovascular anomalies in transgenic and mutant mouse models. 相似文献70.