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991.
Effect of Ethylene and its Antagonist 1-MCP on the Senescence of Detached Leaves of Arabidopsis thaliana 总被引:2,自引:1,他引:1
V.S. Alexieva I.G. Sergiev D.A. Todorova E.N. Karanov A.R. Smith M.A. Hall 《Biologia Plantarum》2004,48(4):593-595
1-Methylcyclopropene (1-MCP) applied alone did not influence significantly the chlorophyll and carotenoid content of the older leaves of Arabidopsis thaliana (L.) Heynh., but retarded the senescence of the younger ones (6th and 7th leaf nodes). However, 1-MCP effectively blocks the ethylene induced senescence of excised rosette leaves. The preliminary application of 1-MCP (3 h in advance to the treatment by Ethrel) almost totally eliminated the ethylene action. Similar trend was also observed after simultaneous application of Ethrel and 1-MCP, and the effects of both treatments on the chlorophyll and carotenoid destruction are comparable. 相似文献
992.
Dayue Chen Raymond Nims Sandra Dusing Pamela Miller Wen Luo Michelle Quertinmont Bhavin Parekh Josh Poorbaugh Jeri Ann Boose E. Morrey Atkinson 《Biologicals》2008,36(6):393
An adventitious agent contamination occurred during a routine 9 CFR bovine viral screening test at BioReliance for an Eli Lilly Chinese Hamster Ovary (CHO) cell-derived Master Cell Bank (MCB) intended for biological production. Scientists from the sponsor (Eli Lilly and Company) and the testing service company (BioReliance) jointly conducted a systematic investigation in an attempt to determine the root cause of the contamination. Our investigation resulted in the identification of the viral nature of the contaminant. Subsequent experiments indicated that the viral contaminant was a non-enveloped and non-hemadsorbing virus. Transmission electron microscopy (TEM) revealed that the viral contaminant was 25–30 nm in size and morphologically resembled viruses of the family Picornaviridae. The contaminant virus was readily inactivated when exposed to acidic pH, suggesting that the viral contaminant was a member of rhinoviruses. Although incapable of infecting CHO cells, the viral contaminant replicated efficiently in Vero cell with a life cycle of 16 h. Our investigation provided compelling data demonstrating that the viral contaminant did not originate from the MCB. Instead, it was introduced into the process during cell passaging and a possible entry point was proposed. We identified the viral contaminant as an equine rhinitis A virus using molecular cloning and DNA sequencing. Finally, our investigation led us to conclude that the source of the viral contaminant was the equine serum added to the cell growth medium in the 9 CFR bovine virus test. 相似文献
993.
Appraisal of green fluorescent protein as a model substrate for seryl-histidine dipeptide cleaving agent 总被引:1,自引:0,他引:1
Du Hailian Wang Yating Yang Lifeng Luo Wenxin Xia Ningshao Zhaoh Yufen 《International journal of peptide research and therapeutics》2002,9(1):5-10
Summary We have investigated the action of seryl-histidine dipeptide (SH) on Green Fluorescent Protein (GFPxm) by SDS-PAGE and fluorescence
techniques. It was found that 1 mmol SH showed a 75 units protease K (PK)-like cleavage effect at 50°C, pH 6.5–7.5. Compared
with the results of SH cleavage on BSA, SDS-PAGE experiments showed no obvious fragments resulting from SH cleavage of GFPxm.
SH quenched the GFPxm fluorescence greatly prior to cleavage. When the SH concentration reached 150 mM, the fluorescence quenching
phenomena stopped. Compared cleavage. When the SH concentration reached 150 mM, the fluorescence quenching phenomena stopped.
Compared with seryl-histidine dipeptide, the individual amino acids Ser and His, and these two amino acids mixed together,
showed no effects on the spectral characteristics of GFPxm nor cleavage of GFPxm. Further study of the SH protein cleavage
mechanism might provide insight for protease mechanisms and biomacromolecule evolution. 相似文献
994.
David T Briese 《Australian Journal of Entomology》2004,43(3):304-317
Abstract Exotic weeds pose a problem of considerable economic and environmental importance to Australia. As a consequence, Australia has developed into a leading centre of research on weed biological control, with over 60 weeds the targets of past and current projects. Using primarily entomological examples, this review highlights the contributions made by Australian scientists to the development of theory and the improvement of practice in weed biological control. It also shows how biological control practitioners have made use of, and contributed to, broader theory and knowledge of plant-herbivore relationships. Finally, it concludes with some reflections on the future direction of biological control in Australia. 相似文献
995.
Ichiro Satoh 《Cluster computing》2004,7(1):73-83
This paper presents a framework for building and deploying protocols for migrating mobile agents over the Internet. The framework enables network protocols for agent migration to be naturally implemented within mobile agents and then dynamically deployed at remote hosts by migrating the agents that perform the protocols. It is built on a hierarchical mobile agent system, called MobileSpaces, and several protocols for migrating agents for managing cluster computing systems have been designed and implemented based on the framework. This paper describes the framework and its prototype implementation, which uses Java as both the implementation language and the protocol development language. 相似文献
996.
Reactive oxygen species (ROS) are natural products inevitably generated along cellular metabolism. Due to their highly reactive nature, which can damage DNA, proteins and lipids, cells utilize antioxidative or defense systems to balance these toxic products to keep the cells in a state of redox homeostasis. However, under the situation of imbalance in redox status, depending on the magnitude of ROS encountered, high levels of ROS can induce apoptosis, whereas chronic low levels of ROS promote vascular diseases such as arteriosclerosis. Although ROS seem to be catastrophic to life, accumulating evidence points to the beneficial roles of ROS by virtue of the ability as chemotherapeutic agents to cure human diseases. Many anti-cancer drugs have been developed in this way which can generate ROS and cause oxidative stress-induced apoptosis in cancer cells. The effects of ROS are paradoxical because they can act as both disease culprits and chemotherapeutic agents. In this review, the current knowledge of ROS and the potential applications of ROS in cancer therapeutic will be discussed. 相似文献
997.
In an in vitro experiment, aluminosilicates (Atox® and Novasil™ Plus) and a yeast cell wall derivate (Mycosorb®) were used as sequestering agents (SAs) to verify their capacity for binding aflatoxin B1 (AFB1) in vitro. SAs were individually mixed at three different ratios with AFB1 (1:5000, 1:50,000 and 1:500,000, w/w) in water (CTR), rumen fluid from a lactating cow with a low rumen pH (LRS) or rumen fluid from a dry cow with a high rumen pH (HRS), and then used in a 3 × 3 × 3 factorial arrangement of a completely randomized design. At the 1:500,000 AF:SA ratio Atox® and Novasil™ Plus sequestered over 0.87 and 0.98 of the AFB1 in the CTR and rumen solutions (LRS and HRS), respectively. This efficacy decreased when the amount of clays was reduced, with higher values (P<0.001) for Atox® compared with Novasil™ Plus (0.50 vs. 0.28 in CTR; 0.58 vs. 0.16 in LRS and 0.44 vs. 0.27 in HRS). Mycosorb® had a lower sequestering efficacy (P<0.001) in all of tested experimental conditions, with 0.34 being the maximum value obtained in the CTR solution. 相似文献
998.
Mitochondrial voltage-dependent anion channels (VDACs) as novel pharmacological targets for anti-cancer agents 总被引:1,自引:0,他引:1
Recently, it was demonstrated that some anti-cancer agents used mitochondrial voltage-dependent anion channels (VDAC1–3 isoforms)
as their pharmacological target. VDACs are expressed more highly in cancer cells than normal cells; thus the VDAC-dependent
cytotoxic agents can have cancer-selectivity. Furanonaphthoquinones (FNQs) induced caspase-dependent apoptosis via the production
of NADH-dependent reactive oxygen species (ROS) by VDAC1. The ROS production and the anti-cancer activity of FNQs were increased
by VDAC1 overexpression. Meanwhile, erastin induced RAS-RAF-MEK-dependent non-apoptotic cell death via VDAC2. On the other
hand, VDACs were needed for transporting ATP to hexokinase (HK), which was highly expressed in cancer cells. We hypothesized
that the high glycolysis might induce up-regulation of VDAC. In this review, we propose that VDACs are novel candidates for
effective pharmacological targets of anti-cancer drugs. 相似文献
999.
The resolutions of (9-anthryl)methoxyacetic acid (9AMAA) and (9-anthryl)hydroxyacetic acid (9AHAA) were performed by capillary electrophoresis using hydroxypropyl-beta-cyclodextrin (HP-beta-CD) as a chiral selector. Various factors affecting migration time and resolutions of these compounds were investigated with a run voltage of 20 kV, column temperature 20 degrees C and 20 mM Tris-H(3)PO(4) buffer (pH 6.5) containing 5 mM HP-beta-CD for 9AMAA, or 10 mM HP-beta-CD for 9AHAA, (+/-)-9AMAA and (+/-)-9AHAA were successfully separated at Rs 3.27 and 1.92, respectively. 相似文献
1000.
Norio Nagao Keiko Watanabe Shinichiro Osa Tatsushi Matsuyama Norio Kurosawa Tatsuki Toda 《World journal of microbiology & biotechnology》2008,24(8):1417-1424
Long term fed-batch composting experiments were conducted for 200 days using two types of bulking agents; woodchip and PET
flake, with periodic compost withdrawal through a washing process. The bacterial communities of composting materials in the
two different bulking agents were also investigated by 16S rRNA gene clone analysis. The decomposition rate in both composting
reactors was 86.1% and 88.2% of the total organic load, respectively. The control experiment of dead-end operation without
compost withdrawal by washing process could not be maintained for more than 102 days because of its low performance. The reactor
with compost withdrawal, however, improved the decomposition rate in the composting process, and could be applied in the long
run. There was a significant difference in the bacterial community between the FBC reactor with woodchip and another with
PET flake as the bulking agent though the decomposition rates were similar. The reactor with woodchip as the bulking agent
consisted of 95% Bacillales while the PET flake reactor contained 54% of total bacteria count. In addition, Lactobacillales was dominant at 38% in the PET flake reactor and the bacterial community in general significantly differed from the woodchip
reactor. Furthermore, there was a difference in the species composition in the Bacillales and the bacterial community showed a significant difference at the species level between the two reactors. Although bacterial
community differed, the decomposition rates between the two reactors were similar and PET flake showed greater viability than
woodchip as a bulking agent due to its high abrasion resistance and non-biodegradability. 相似文献