全文获取类型
收费全文 | 969篇 |
免费 | 78篇 |
专业分类
1047篇 |
出版年
2023年 | 5篇 |
2022年 | 9篇 |
2021年 | 20篇 |
2020年 | 12篇 |
2019年 | 11篇 |
2018年 | 18篇 |
2017年 | 16篇 |
2016年 | 32篇 |
2015年 | 45篇 |
2014年 | 55篇 |
2013年 | 55篇 |
2012年 | 72篇 |
2011年 | 75篇 |
2010年 | 38篇 |
2009年 | 44篇 |
2008年 | 52篇 |
2007年 | 46篇 |
2006年 | 56篇 |
2005年 | 41篇 |
2004年 | 34篇 |
2003年 | 38篇 |
2002年 | 27篇 |
2001年 | 21篇 |
2000年 | 12篇 |
1999年 | 16篇 |
1998年 | 15篇 |
1997年 | 14篇 |
1996年 | 6篇 |
1995年 | 2篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1992年 | 10篇 |
1991年 | 16篇 |
1990年 | 24篇 |
1989年 | 11篇 |
1988年 | 10篇 |
1987年 | 9篇 |
1986年 | 5篇 |
1985年 | 8篇 |
1984年 | 3篇 |
1983年 | 6篇 |
1982年 | 2篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1977年 | 5篇 |
1974年 | 4篇 |
1967年 | 5篇 |
1966年 | 5篇 |
1960年 | 1篇 |
排序方式: 共有1047条查询结果,搜索用时 9 毫秒
991.
AAM Coelho-Castelo AP Trombone RS Rosada RR Santos Jr VLD Bonato A Sartori CL Silva 《Genetic vaccines and therapy》2006,4(1):1-10
In order to assess a new strategy of DNA vaccine for a more complete understanding of its action in immune response, it is important to determine the in vivo biodistribution fate and antigen expression. In previous studies, our group focused on the prophylactic and therapeutic use of a plasmid DNA encoding the Mycobacterium leprae 65-kDa heat shock protein (Hsp65) and achieved an efficient immune response induction as well as protection against virulent M. tuberculosis challenge. In the present study, we examined in vivo tissue distribution of naked DNA-Hsp65 vaccine, the Hsp65 message, genome integration and methylation status of plasmid DNA. The DNA-Hsp65 was detectable in several tissue types, indicating that DNA-Hsp65 disseminates widely throughout the body. The biodistribution was dose-dependent. In contrast, RT-PCR detected the Hsp65 message for at least 15 days in muscle or liver tissue from immunized mice. We also analyzed the methylation status and integration of the injected plasmid DNA into the host cellular genome. The bacterial methylation pattern persisted for at least 6 months, indicating that the plasmid DNA-Hsp65 does not replicate in mammalian tissue, and Southern blot analysis showed that plasmid DNA was not integrated. These results have important implications for the use of DNA-Hsp65 vaccine in a clinical setting and open new perspectives for DNA vaccines and new considerations about the inoculation site and delivery system. 相似文献
992.
R. Eduardo Palma Dusan Boric‐Bargetto J. Pablo Jayat David A. Flores Horacio Zeballos Víctor Pacheco Ricardo A. Cancino Fernando D. Alfaro Enrique Rodríguez‐Serrano Ulyses F. J. Pardiñas 《Zoologica scripta》2014,43(3):217-234
The mouse opossums of the genus Thylamys constitute a group of species mainly adapted to open xeric‐like habitats and restricted to the southern portion of South America. We used molecular data (mitochondrial and nuclear sequences) to evaluate the phylogenetic and biogeographical relationships of all currently known living species of the genus, recognizing a new taxon from the middle and high elevations of the Peruvian Andes and evaluating the phylogenetic structuring within T. pallidior and T. elegans, as well as the validity of T. sponsorius, T. cinderella and T. tatei, and the haplogroups recognized within T. pusillus. Our results confirm the monophyly of the genus and that the Caatinga and the Cerrado inhabitants Thylamys karimii and T. velutinus are the most basal species in the radiation of Thylamys. We also calibrated a molecular clock which hypothesized a time of origin of the genus of about 24 My, with most species differentiating in middle and late Miocene and Plio‐Pleistocene times of South America. 相似文献
993.
994.
Acid phosphatase purified from maize scutellum showed a kinetic transition from negative cooperativity at pH 5.4, to Michaelian behavior at pH 6.7. The 相似文献
995.
996.
Ana LS Vanz Gaby Renard Mario S Palma Jocelei M Chies Sérgio L Dalmora Luiz A Basso Diógenes S Santos 《Microbial cell factories》2008,7(1):13
Background
Biopharmaceutical drugs are mainly recombinant proteins produced by biotechnological tools. The patents of many biopharmaceuticals have expired, and biosimilars are thus currently being developed. Human granulocyte colony stimulating factor (hG-CSF) is a hematopoietic cytokine that acts on cells of the neutrophil lineage causing proliferation and differentiation of committed precursor cells and activation of mature neutrophils. Recombinant hG-CSF has been produced in genetically engineered Escherichia coli (Filgrastim) and successfully used to treat cancer patients suffering from chemotherapy-induced neutropenia. Filgrastim is a 175 amino acid protein, containing an extra N-terminal methionine, which is needed for expression in E. coli. Here we describe a simple and low-cost process that is amenable to scaling-up for the production and purification of homogeneous and active recombinant hG-CSF expressed in E. coli cells. 相似文献997.
M Scaramuzzi C Amorotti M De Palma A M Falchi D De Maria P Casolo 《The International journal of biological markers》1990,5(1):35-37
We have investigated the possible relation between serum levels of CA 15.3 and disease status in 110 patients after radical mastectomy for breast cancer, with metastatic diffusion. Its persistent elevation was usually related to a very poor prognosis. In patients who died within 18 months the marker was always elevated. In case of progression of the disease, the marker level appeared to be consistently correlated with the general clinical condition. In healthy patients with stable disease the marker remained near the normal range. 相似文献
998.
Summary The investigated biocatalyst consists of gelatin-entrapped cells of Saccharomyces cerevisiae retaining invertase activity. Comparative examination of pH profile, apparent Km, saturation velocity and activation energy indicates that the entrapment procedure did not influence invertase affinity with sucrose but lead to some loss of activity probably due to either enzyme inactivation or cell-wall impairment as well as to substrate diffusion limitation in the gel matrix. 相似文献
999.
P Martelletti P Cugini C Letizia L Di Palma P Battisti M Granata D Scavo M Giacovazzo 《Chronobiologia》1990,17(1):59-64
This investigation is devoted to explore the 24-h patterns of serum angiotensin converting enzyme (ACE) activity in clinically healthy subjects and migraine patients taking as reference the adrenal cycle. Time data series have been analyzed by means of chronobiologic procedures. The biostatistical approach has documented that the enzymatic activity of serum ACE in clinically healthy subjects changes with a circadian periodicity. The chronobiologic approach has additionally revealed that the enzymatic activity of serum ACE activity is circadianly aperiodic in migraine patients, while plasma cortisol shows a preserved cyclicity along 24-h scale. The aperiodicity suggests that the enzymatic degradation of the ACE-dependent substrate is inappropriate over the 24-h span. 相似文献
1000.
Claudia A.N. Kobayashi Thelma L. Silva Fábio C.S. Nogueira Mario S. Palma Marília A.R. Buzalaf 《Chemico-biological interactions》2009,180(2):305-311
Two-dimensional gel electrophoresis (2-DE) was used to better understand alterations in renal metabolism induced by fluoride (F). Three groups of weanling male Wistar rats were treated with drinking water containing 0 (control), 5, or 50 ppm F for 60 days (n = 6/group). Kidneys were collected for proteomic and histological (HE) analysis. After protein isolation, renal proteome profiles were examined using 2-DE and Colloidal Coomassie Blue staining. Protein spots with a 2-fold significant difference as detected by quantitative intensity analysis (Image Master Platinum software) and t-test (p < 0.05) were excised and analyzed by MALDI-TOF MS (matrix assisted laser desorption ionization-time-of-flight mass spectrometry). The histological analysis revealed no damage in kidneys induced by F, except for a vascular congestion in the 50 ppm F group. Between control vs 50 ppm F, and control vs 5 ppm F groups, 12 and 6 differentially expressed proteins were detected, respectively. Six proteins, mainly related with metabolism, detoxification and housekeeping, were successfully identified. At the high F group, pyruvate carboxylase, a protein involved in the formation of oxaloacetate was found to be downregulated, while enoyl coenzyme A hydratase, involved in fatty acids oxidation, was found to be upregulated. Thus, proteomic analysis can provide new insights into the alterations in renal metabolism after F exposure, even in low doses. 相似文献