全文获取类型
收费全文 | 1010篇 |
免费 | 63篇 |
出版年
2022年 | 11篇 |
2021年 | 24篇 |
2020年 | 7篇 |
2019年 | 10篇 |
2018年 | 25篇 |
2017年 | 10篇 |
2016年 | 22篇 |
2015年 | 40篇 |
2014年 | 60篇 |
2013年 | 68篇 |
2012年 | 42篇 |
2011年 | 57篇 |
2010年 | 41篇 |
2009年 | 30篇 |
2008年 | 50篇 |
2007年 | 48篇 |
2006年 | 27篇 |
2005年 | 26篇 |
2004年 | 38篇 |
2003年 | 33篇 |
2002年 | 17篇 |
2001年 | 30篇 |
2000年 | 22篇 |
1999年 | 19篇 |
1998年 | 10篇 |
1997年 | 5篇 |
1996年 | 8篇 |
1995年 | 10篇 |
1993年 | 5篇 |
1992年 | 22篇 |
1991年 | 22篇 |
1990年 | 18篇 |
1989年 | 21篇 |
1988年 | 13篇 |
1987年 | 16篇 |
1986年 | 21篇 |
1985年 | 20篇 |
1984年 | 7篇 |
1981年 | 12篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 10篇 |
1976年 | 11篇 |
1975年 | 9篇 |
1973年 | 4篇 |
1972年 | 6篇 |
1971年 | 4篇 |
1970年 | 7篇 |
1969年 | 5篇 |
1967年 | 5篇 |
排序方式: 共有1073条查询结果,搜索用时 15 毫秒
131.
132.
133.
134.
Peter JD Andrews Helen Louise Sinclair Claire G Battison Kees H Polderman Giuseppe Citerio Luciana Mascia Bridget A Harris Gordon D Murray Nino Stocchetti David K Menon Haleema Shakur Daniel De Backer 《Trials》2011,12(1):1-13
Background
Severe malaria remains a major cause of global morbidity and mortality. Despite the use of potent anti-parasitic agents, the mortality rate in severe malaria remains high. Adjunctive therapies that target the underlying pathophysiology of severe malaria may further reduce morbidity and mortality. Endothelial activation plays a central role in the pathogenesis of severe malaria, of which angiopoietin-2 (Ang-2) has recently been shown to function as a key regulator. Nitric oxide (NO) is a major inhibitor of Ang-2 release from endothelium and has been shown to decrease endothelial inflammation and reduce the adhesion of parasitized erythrocytes. Low-flow inhaled nitric oxide (iNO) gas is a US FDA-approved treatment for hypoxic respiratory failure in neonates.Methods/Design
This prospective, parallel arm, randomized, placebo-controlled, blinded clinical trial compares adjunctive continuous inhaled nitric oxide at 80 ppm to placebo (both arms receiving standard anti-malarial therapy), among Ugandan children aged 1-10 years of age with severe malaria. The primary endpoint is the longitudinal change in Ang-2, an objective and quantitative biomarker of malaria severity, which will be analysed using a mixed-effects linear model. Secondary endpoints include mortality, recovery time, parasite clearance and neurocognitive sequelae.Discussion
Noteworthy aspects of this trial design include its efficient sample size supported by a computer simulation study to evaluate statistical power, meticulous attention to complex ethical issues in a cross-cultural setting, and innovative strategies for safety monitoring and blinding to treatment allocation in a resource-constrained setting in sub-Saharan Africa.Trial Registration
ClinicalTrials.gov Identifier: NCT01255215 相似文献135.
136.
137.
Omenn GS States DJ Adamski M Blackwell TW Menon R Hermjakob H Apweiler R Haab BB Simpson RJ Eddes JS Kapp EA Moritz RL Chan DW Rai AJ Admon A Aebersold R Eng J Hancock WS Hefta SA Meyer H Paik YK Yoo JS Ping P Pounds J Adkins J Qian X Wang R Wasinger V Wu CY Zhao X Zeng R Archakov A Tsugita A Beer I Pandey A Pisano M Andrews P Tammen H Speicher DW Hanash SM 《Proteomics》2005,5(13):3226-3245
HUPO initiated the Plasma Proteome Project (PPP) in 2002. Its pilot phase has (1) evaluated advantages and limitations of many depletion, fractionation, and MS technology platforms; (2) compared PPP reference specimens of human serum and EDTA, heparin, and citrate-anti-coagulated plasma; and (3) created a publicly-available knowledge base (www.bioinformatics.med.umich.edu/hupo/ppp; www.ebi.ac.uk/pride). Thirty-five participating laboratories in 13 countries submitted datasets. Working groups addressed (a) specimen stability and protein concentrations; (b) protein identifications from 18 MS/MS datasets; (c) independent analyses from raw MS-MS spectra; (d) search engine performance, subproteome analyses, and biological insights; (e) antibody arrays; and (f) direct MS/SELDI analyses. MS-MS datasets had 15 710 different International Protein Index (IPI) protein IDs; our integration algorithm applied to multiple matches of peptide sequences yielded 9504 IPI proteins identified with one or more peptides and 3020 proteins identified with two or more peptides (the Core Dataset). These proteins have been characterized with Gene Ontology, InterPro, Novartis Atlas, OMIM, and immunoassay-based concentration determinations. The database permits examination of many other subsets, such as 1274 proteins identified with three or more peptides. Reverse protein to DNA matching identified proteins for 118 previously unidentified ORFs. We recommend use of plasma instead of serum, with EDTA (or citrate) for anticoagulation. To improve resolution, sensitivity and reproducibility of peptide identifications and protein matches, we recommend combinations of depletion, fractionation, and MS/MS technologies, with explicit criteria for evaluation of spectra, use of search algorithms, and integration of homologous protein matches. This Special Issue of PROTEOMICS presents papers integral to the collaborative analysis plus many reports of supplementary work on various aspects of the PPP workplan. These PPP results on complexity, dynamic range, incomplete sampling, false-positive matches, and integration of diverse datasets for plasma and serum proteins lay a foundation for development and validation of circulating protein biomarkers in health and disease. 相似文献
138.
Saurí A Saksena S Salgado J Johnson AE Mingarro I 《The Journal of biological chemistry》2005,280(27):25907-25912
The current model for cell-to-cell movement of plant viruses holds that transport requires virus-encoded movement proteins that intimately associate with endoplasmic reticulum membranes. We have examined the early stages of the integration into endoplasmic reticulum membranes of a double-spanning viral movement protein using photocross-linking. We have discovered that this process is cotranslational and proceeds in a signal recognition particle-dependent manner. In addition, nascent chain photocross-linking to Sec61alpha and translocating chain-associated membrane protein reveal that viral membrane protein insertion takes place via the translocon, as with most eukaryotic membrane proteins, but that the two transmembrane segments of the viral protein leave the translocon and enter the lipid bilayer together. 相似文献
139.
Kinetics of iron release from ferric binding protein (FbpA): mechanistic implications in bacterial periplasm-to-cytosol Fe3+ transport 总被引:1,自引:0,他引:1
The ferric binding protein (FbpA) transports iron across the periplasmic space of certain Gram-negative bacteria and is an important component involved in iron acquisition by pathogenic Neisseria spp. (Neisseria gonorrheae and Neisseria meningitidis). Previous work has demonstrated that the synergistic anion, required for tight Fe(3+) sequestration by FbpA, also plays a key role in inserting Fe(3+) into the FbpA binding site. Here, we investigate the iron release process from various forms of holo-FbpA, Fe(3+)FbpA-X, during the course of a chelator competition reaction using EDTA and Tiron. Fe(3+)FbpA-X represents the protein assembly complex with different synergistic anions, X = PO(4)(3)(-) and NTA. Stepwise mechanisms of Fe(3+) release are proposed on the basis of kinetic profiles of these chelator competition reactions. Fe(3+)FbpA-PO(4) and Fe(3+)FbpA-NTA react differently with EDTA and Tiron during the Fe(3+)-exchange process. EDTA replaces PO(4)(3)(-) and NTA from the first coordination shell of Fe(3+) and acts as a synergistic anion to give a spectroscopically distinguishable intermediate, Fe(3+)FbpA-EDTA, prior to pulling Fe(3+) out of the protein. Tiron, on the other hand, does not act as a synergistic anion but is a more efficient competing chelator as it removes Fe(3+) from FbpA at rate much faster than EDTA. These results reaffirm the contribution of the synergistic anion to the FbpA iron transport process as the anion, in addition to playing a facilitative role in iron binding, appears to have a "gatekeeper" role, thereby modulating the Fe(3+) release process. 相似文献
140.
Curcumin ameliorates oxidative stress during nicotine-induced lung toxicity in Wistar rats 总被引:3,自引:0,他引:3
Nicotine, a major toxic component of cigarette smoke has been identified as a major risk factor for lung related diseases. In the present study, we evaluated the protective effects of curcumin on lipid peroxidation and antioxidants status in bronchoalveolar lavage fluid (BALF) and bronchoalveolar lavage (BAL) of nicotine treated Wistar rats. Lung toxicity was induced by subcutaneous injection of nicotine at a dose of 2.5 mg/kg body weight (5 days a week, for 22 weeks) and curcumin (80 mg/kg body weight) was given simultaneously by intragastric intubation for 22 weeks. Measurement of biochemical marker enzymes: alkaline phosphatase, lactate dehydrogenase, lipid peroxidation and antioxidants were used to monitor the antiperoxidative effects of curcumin. The increased biochemical marker enzymes as well as lipid peroxides in BALF and BAL of nicotine treated rats was accompanied by a significant decrease in the levels of glutathione, glutathione peroxidase, superoxide dismutase and catalase. Administration of curcumin significantly lowered the biochemical marker enzymes, lipid peroxidation and enhanced the antioxidant status. The results of the present study suggest that curcumin exert its protective effect against nicotine-induced lung toxicity by modulating the biochemical marker enzymes, lipid peroxidation and augmenting antioxidant defense system. 相似文献