全文获取类型
收费全文 | 57194篇 |
免费 | 4910篇 |
国内免费 | 242篇 |
出版年
2023年 | 208篇 |
2022年 | 174篇 |
2021年 | 938篇 |
2020年 | 652篇 |
2019年 | 864篇 |
2018年 | 1228篇 |
2017年 | 962篇 |
2016年 | 1672篇 |
2015年 | 2689篇 |
2014年 | 2999篇 |
2013年 | 3500篇 |
2012年 | 4522篇 |
2011年 | 4321篇 |
2010年 | 2729篇 |
2009年 | 2405篇 |
2008年 | 3425篇 |
2007年 | 3170篇 |
2006年 | 2885篇 |
2005年 | 2592篇 |
2004年 | 2552篇 |
2003年 | 2254篇 |
2002年 | 1919篇 |
2001年 | 1659篇 |
2000年 | 1565篇 |
1999年 | 1223篇 |
1998年 | 514篇 |
1997年 | 454篇 |
1996年 | 383篇 |
1995年 | 414篇 |
1994年 | 317篇 |
1993年 | 305篇 |
1992年 | 651篇 |
1991年 | 523篇 |
1990年 | 484篇 |
1989年 | 491篇 |
1988年 | 409篇 |
1987年 | 397篇 |
1986年 | 322篇 |
1985年 | 333篇 |
1984年 | 275篇 |
1983年 | 229篇 |
1982年 | 189篇 |
1981年 | 163篇 |
1980年 | 161篇 |
1979年 | 221篇 |
1978年 | 197篇 |
1977年 | 180篇 |
1976年 | 170篇 |
1974年 | 197篇 |
1972年 | 157篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
11.
12.
13.
Amanda L. McGuire Sophia C. Bennett Sally M. Lansley Natalia D. Popowicz Julius F. Varano della Vergiliana Daniel Wong Y. C. Gary Lee Aron Chakera 《PloS one》2015,10(3)
A major complication of peritoneal dialysis is the development of peritonitis, which is associated with reduced technique and patient survival. The inflammatory response elicited by infection results in a fibrin and debris-rich environment within the peritoneal cavity, which may reduce the effectiveness of antimicrobial agents and predispose to recurrence or relapse of infection. Strategies to enhance responses to antimicrobial agents therefore have the potential to improve patient outcomes. This study presents pre-clinical data describing the compatibility of tPA and DNase in combination with antimicrobial agents used for the treatment of PD peritonitis. tPA and DNase were stable in standard dialysate solution and in the presence of antimicrobial agents, and were safe when given intraperitoneally in a mouse model with no evidence of local or systemic toxicity. Adjunctive tPA and DNase may have a role in the management of patients presenting with PD peritonitis. 相似文献
14.
Transient Receptor Potential, Melastatin-related, member 4 (TRPM4) channels are Ca2+-activated Ca2+-impermeable cation channels. These channels are expressed in various types of mammalian tissues including the brain and are implicated in many diverse physiological and pathophysiological conditions. In the past several years, the trafficking processes and regulatory mechanism of these channels and their interacting proteins have been uncovered. Here in this minireview, we summarize the current understanding of the trafficking mechanism of TRPM4 channels on the plasma membrane as well as heteromeric complex formation via protein interactions. We also describe physiological implications of protein-TRPM4 interactions and suggest TRPM4 channels as therapeutic targets in many related diseases. [BMB Reports 2015; 48(1): 1-5] 相似文献
15.
Kelsey R. Downum Lee A. Swain Lavina J. Faleiro 《Archives of insect biochemistry and physiology》1991,17(4):201-211
Plant phototoxins are broad-spectrum biocides which adversely affect an array of potential plant enemies, including among others disease-causing pathogens, nematodes, insect herbivores, and competing plant species. Thus far, plants which contain these broad-spectrum allelochemicals have been found to occur in open habitats (i.e., in full sunlight) where a defensive mechanism mediated by light would seem to operate most effectively. The levels of available light in shaded environments, although considerably lower than full sun (1–10% of full sun), are equivalent to the intensities of light used to kill phototoxin-treated insects in laboratory studies. This suggests that phototoxic reactions might mediate important organismal interactions in shaded environments as well. In this study, more than 230 Costa Rican rainforest plants were bioassayed for phototoxic metabolites in an effort to ascertain their prevalence among plants growing in moderate to extreme shade. Microbial bioassays, employing Bacillus cereus (a gram positive bacterium), Escherichia coli (a gram negative bacterium), and Saccharomyces cerevisiae (a yeast) were used to rapidly and sensitively indicate phototoxic action and potential for insecticidal action. Tissue extracts from 12 plant families tested positive for phototoxins. This is the first report of phototoxins occurring in eight of those families (Acanthaceae, Campanulaceae, Gesnariaceae, Loganiaceae, Malpigaceae, Phytolaccaceae, Piperaceae, and Sapotaceae). The presence of phototoxins in rainforest plants suggests that phototoxic plant allelochemicals may function as important defenses in low-light, as well as high-light, environments. 相似文献
16.
M G Lee 《Molecular and cellular biology》1996,16(3):1220-1230
17.
18.
19.
E Lang G I Szendrei I Elekes V M Lee L Otvos 《Biochemical and biophysical research communications》1992,182(1):63-69
Serine416 of human tau protein is believed to be phosphorylated in Alzheimer neurofibrillary tangles. We synthesized a fragment of tau, consisting of amino acids 408-421 in both non-phosphorylated and serine416-phosphorylated forms. Circular dichroism in a trifluoroethanol-water mixture indicated a beta-turn----beta-pleated sheet conformational transition upon phosphorylation. The beta-structure formation is intermolecular and can be inhibited by addition of Ca2+ ions or a phosphorylated tripeptide, but not with its non-phosphorylated analog. The presence of the phosphorylated tau peptide did not facilitate the formation of beta-pleated sheets of a phosphorylated neurofilament fragment. Multivalent cations induced a conformational transition of this phosphorylated neurofilament peptide, but the effect was less specific than the transition induced in the tau fragment, and it could also be reversed with the competing phosphorylated tripeptide. 相似文献
20.