全文获取类型
收费全文 | 15958篇 |
免费 | 1402篇 |
国内免费 | 1619篇 |
专业分类
18979篇 |
出版年
2024年 | 38篇 |
2023年 | 228篇 |
2022年 | 590篇 |
2021年 | 876篇 |
2020年 | 661篇 |
2019年 | 756篇 |
2018年 | 724篇 |
2017年 | 529篇 |
2016年 | 689篇 |
2015年 | 1007篇 |
2014年 | 1178篇 |
2013年 | 1295篇 |
2012年 | 1550篇 |
2011年 | 1298篇 |
2010年 | 797篇 |
2009年 | 765篇 |
2008年 | 827篇 |
2007年 | 703篇 |
2006年 | 613篇 |
2005年 | 556篇 |
2004年 | 403篇 |
2003年 | 401篇 |
2002年 | 358篇 |
2001年 | 245篇 |
2000年 | 209篇 |
1999年 | 240篇 |
1998年 | 134篇 |
1997年 | 145篇 |
1996年 | 139篇 |
1995年 | 121篇 |
1994年 | 117篇 |
1993年 | 88篇 |
1992年 | 96篇 |
1991年 | 75篇 |
1990年 | 82篇 |
1989年 | 61篇 |
1988年 | 58篇 |
1987年 | 44篇 |
1986年 | 50篇 |
1985年 | 50篇 |
1984年 | 33篇 |
1983年 | 21篇 |
1982年 | 22篇 |
1981年 | 11篇 |
1980年 | 10篇 |
1979年 | 16篇 |
1978年 | 6篇 |
1977年 | 12篇 |
1976年 | 9篇 |
1973年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Formation of bacterial biofilms at solid–liquid interfaces creates numerous problems in biomedical sciences. Conventional sterilization and decontamination methods are not suitable for new and more sophisticated biomaterials. In this paper, the efficiency and effectiveness of gas discharges in the inactivation and removal of biofilms on biomaterials were studied. It was found that although discharge oxygen, nitrogen and argon all demonstrated excellent antibacterial and antibiofilm activity, gases with distinct chemical/physical properties underwent different mechanisms of action. Discharge oxygen- and nitrogen-mediated decontamination was associated with strong etching effects, which can cause live bacteria to relocate thus spreading contamination. On the contrary, although discharge argon at low powers maintained excellent antibacterial ability, it had negligible etching effects. Based on these results, an effective decontamination approach using discharge argon was established in which bacteria and biofilms were killed in situ and then removed from the contaminated biomaterials. This novel procedure is applicable for a wide range of biomaterials and biomedical devices in an in vivo and clinical setting. 相似文献
92.
93.
94.
Kun Liang Dong‐Jin Lee Robert J. Elias Helje Pärnaste Mari‐Ann Mõtus 《Palaeontology》2013,56(4):867-891
Protoheliolites is an early heliolitine coral characterized by closely spaced corallites separated in places by sparse coenenchyme. Growth characteristics in the type species, P. norvegicus, are revealed by detailed analysis based on serial peels and thin sections of coralla from the uppermost Katian of north‐western Estonia. Colonies of this species had a strong ability to recover from damage and partial mortality, resulting in various forms of rejuvenation, regeneration, fusion and reorganization of corallites; in some cases, this involved relatively large areas of undifferentiated soft parts. The shells of commensal cornulitids became enclosed in host coralla during colony growth. Coralla of P. norvegicus exhibit distinctive growth cycles due to responses to seasonal changes. The production of new corallites by coenenchymal increase usually occurred in low‐density bands, in which corallites generally display round to subrounded transverse outlines. In high‐density bands, the corallites became crenulated, their wall thickness increased, septal development was more pronounced, and the amount of coenenchyme increased. In addition to these cyclomorphic changes, there were significant astogenetic changes during growth. Compared with the early stage of colony development, distinctive characteristics in the late astogenetic stage include a decrease in the growth rate of the colony, better coordination among corallites, maximum development of corallite crenulations and septa in high‐density bands, more numerous coenenchymal tubules and a greater proportion of corallum area occupied by coenenchyme. In general, the role of polyps in determining morphological characteristics of individual corallites, such as tabularium area, corallite crenulations and wall thickness, was subordinate to the astogeny of the colony. Growth characteristics including colony‐wide coordination of polyp behaviour and subjugation of individuals to restore the colony following damage suggest a strong astogenetic control and high level of colony integration. Protoheliolites probably arose from a heliolitine genus rather than from a nonheliolitine group as some authors have proposed. 相似文献
95.
Minglong Liang Zongmei Wang Chuanjian Wu Sidong Xiong Ling Zhao Chunsheng Dong 《中国病毒学》2022,37(3):455-458
Highlights:
1. A replication-competent recombinant VSV with RABV-G protein replacement was generated.
2. Single dose of VSV-RABVG immunization induce potent antigen-specific humoral immune response, especially the virus neutralizing antibodies.
3. Mice intranasally immunized with single dose of VSV-RABVG were 100% protected upon RABV challenge. 相似文献
1. A replication-competent recombinant VSV with RABV-G protein replacement was generated.
2. Single dose of VSV-RABVG immunization induce potent antigen-specific humoral immune response, especially the virus neutralizing antibodies.
3. Mice intranasally immunized with single dose of VSV-RABVG were 100% protected upon RABV challenge. 相似文献
96.
97.
TRAIL(TNF-related apoptosis-inducing ligand)是一种能识别和选择性杀伤肿瘤细胞的蛋白质因子,但研究发现胰腺癌对TRAIL的敏感程度远远不及其他肿瘤,其抵抗机制主要集中于胞内水平的调节,如c-FLIPS、BCL-2/BCL-xL、XIAP表达上调等,且针对性的逆转策略也进行了深入的研究.本文就TRAIL途径在胰腺癌中的研究进展作一概要的介绍. 相似文献
98.
SIRT1 expression is refractory to hypoxia and inflammatory cytokines in nucleus pulposus cells: Novel regulation by HIF‐1α and NF‐κB signaling 下载免费PDF全文
99.
100.
Functional Characterization of 14 Pht1 Family Genes in Yeast and Their Expressions in Response to Nutrient Starvation in Soybean 总被引:1,自引:0,他引:1
Lu Qin Yongxiang Guo Liyu Chen Ruikang Liang Mian Gu Guohua Xu Jing Zhao Thomas Walk Hong Liao 《PloS one》2012,7(10)