全文获取类型
收费全文 | 1358篇 |
免费 | 88篇 |
国内免费 | 2篇 |
专业分类
1448篇 |
出版年
2023年 | 4篇 |
2022年 | 19篇 |
2021年 | 22篇 |
2020年 | 11篇 |
2019年 | 24篇 |
2018年 | 28篇 |
2017年 | 19篇 |
2016年 | 33篇 |
2015年 | 54篇 |
2014年 | 58篇 |
2013年 | 79篇 |
2012年 | 104篇 |
2011年 | 109篇 |
2010年 | 82篇 |
2009年 | 75篇 |
2008年 | 70篇 |
2007年 | 90篇 |
2006年 | 77篇 |
2005年 | 79篇 |
2004年 | 80篇 |
2003年 | 80篇 |
2002年 | 60篇 |
2001年 | 13篇 |
2000年 | 10篇 |
1999年 | 15篇 |
1998年 | 23篇 |
1997年 | 19篇 |
1996年 | 11篇 |
1995年 | 18篇 |
1994年 | 5篇 |
1993年 | 8篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1979年 | 6篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1965年 | 2篇 |
1935年 | 1篇 |
排序方式: 共有1448条查询结果,搜索用时 0 毫秒
11.
12.
Peter Ort Igor A. Zalunin Victor S. Gasparov Galina G. Chestukhina Valentin M. Stepanov 《Journal of Protein Chemistry》1995,14(4):241-249
Denaturation ofBacillus thuringiensis CryIIIA-endotoxin—an insecticidal protein, active againstColeoptera larvae—in concentrated guanidine hydrochloride solutions was pursued by fluorescence and circular dichroism spectroscopy and limited proteolysis. It was found that the protein consists of two fragments that differ by their stability to denaturation by guanidine hydrochloride atpH 3. The less stable fragment corresponds to the N-terminal-helical domain limited by Leu-279; the more stable one starts with Ile-280, contains about 330 amino acid residues, and corresponds to the molecule C-terminal moiety that consist of its two-structural domains forming a superdomain.Abbreviations BT
Bacillus thuringiensis
- Gdn-HCl
guanidine hydrochloride
- PAGE
electrophoresis in polyacrylamide gel
- SDS
sodium dodecylsulfate
- CD
circular dichroism 相似文献
13.
Detection of signs of estrus in the charolais cow and its Brahman cross under continuous observation
In order to study the characteristic signs of an induced estrus in beef cattle maintained in the tropics, 31 animals, 16 pure Charolais and 15 Charolais/Brahman cross, were continuously observed during the first 100 hours following prostaglandin injection. The animals were pastured in a field of approximately 3 hectares. A highly significant relationship (P < 0.01) seemed to exist between behavioural tendencies and the interval following the onset of estrus. Behaviour included butting, attempts to mount, smelling of genitalia (active) and allowing to be mounted and have genitalia smelled (passive). No consistant pattern of sexual activity could be established since some animals were more active than others. Mounts were observed to occur between 6 and 9 in the morning (33%), 9 and 12 at night (16%) and midnight and three in the morning (13%). Differences existed between the Charolais and the Brahman cross with respect to the number of mounts (P < 0.05) and in the response to an induced estrus (P < 0.05). No correlation was found between grazing habits and sexual activity, the former expressed as the number of animals standing up during each hour. 相似文献
14.
Rat liver chromatin activated by partial hepatectomy is more susceptible to the action of DNAse I than control chromatin isolated from intact liver. The study on the transfer of chromatin material to the acid-soluble fraction reveals a higher rate of activated chromatin degradation. Activated chromatin shows also an increased capacity for ethidium bromide (EB) binding as estimated from the isotherms of adsorption. The difference in EB binding between activated and control chromatin is abolished after DNAse I treatment. Conditions of mild digestion with DNAse I have been found under which the number of binding sites for EB per nucleotide decreases to almost the same level in activated and non-activated chromatin. The results suggest a preferential degradation of those DNA sequences in activated chromatin that are responsible for the increase in the ligand binding. 相似文献
15.
Pupae of Drosophila melanogaster were heat-shocked under conditions required to induce phenocopies in more than 90% of the flies that subsequently emerge. The effects of these treatments on protein synthesis in two tissues (thoracic epithelium and brain) were followed for several hours after the heat treatments. Results from pulse-labeling and protein separations on sodium dodecylsulfate (SDS) acrylamide gels showed a virtually complete cessation of protein synthesis immediately after the shock, followed by a noncoordinate resumption of the starting pattern. Similar experiments following double heat shocks demonstrated a more rapid resumption of synthesis of heat shock proteins after two successive heat treatments than after a single one. 相似文献
16.
Herschel K. Mitchell Galina Moller Nancy S. Petersen Loveriza Lipps-Sarmiento 《Genesis (New York, N.Y. : 2000)》1979,1(2):181-192
Mild heat treatments applied to whole animals or cell cultures of Drosophila prior to lethal heat shocks result in increased survival and protection against phenocopy induction. The optimal condition for the preliminary mild heat treatment is that which induces the synthesis of heat-shock proteins but does not turn off the protein synthesis that is in progress. Recovery of protein synthesis but not RNA synthesis following a drastic heat shock is much enhanced by the pretreatments. The results suggest that the protection for survival and against phenocopy induction is due to storage of messenger RNA. 相似文献
17.
Ashwani Kumar Galina Aglyamova Yun
Young Yim Aaron O Bailey Haley
M Lynch Reid
T Powell Nghi
D Nguyen Zachary Rosenthal Wen-Ning Zhao Yi Li Jianping Chen Shanghua Fan Hubert Lee William
K Russell Clifford Stephan Alfred
J Robison Stephen
J Haggarty Eric
J Nestler Jia Zhou Mischa Machius Gabby Rudenko 《Nucleic acids research》2022,50(16):9548
18.
Valeri B. Kozhemyako Galina N. Veremeichik Yuri N. Shkryl Svetlana N. Kovalchuk Vladimir B. Krasokhin Valeri A. Rasskazov Yuri N. Zhuravlev Victor P. Bulgakov Yuri N. Kulchin 《Marine biotechnology (New York, N.Y.)》2010,12(4):403-409
Silicatein genes are known to be involved in siliceous spicule formation in marine sponges. Proteins encoded by these genes,
silicateins, were recently proposed for nanobiotechnological applications. We studied silicatein genes of marine sponges Latrunculia oparinae collected in the west Pacific region, shelf of Kuril Islands. Five silicatein genes, LoSilA1, LoSilA1a, LoSilA2, and LoSilA3 (silicatein-α group), LoSilB (silicatein-β group), and one cathepsin gene, LoCath, were isolated from the sponge L. oparinae for the first time. The deduced amino acid sequence of L. oparinae silicateins showed high-sequence identity with silicateins described previously. LoCath contains the catalytic triad of amino acid residues Cys-His-Asn characteristic for cathepsins as well as motifs typical for
silicateins. A phylogenetic analysis places LoCath between sponge silicateins-β and L-cathepsins suggesting that the LoCath gene represents an intermediate form between silicatein and cathepsin genes. Additionally, we identified, for the first time,
silicatein genes (AcSilA and AcSilB) in nonspicule-forming marine sponge, Acаnthodendrilla sp. The results suggest that silicateins could participate also in the function(s) unrelated to spiculogenesis. 相似文献
19.
Occurrence and diversity of mesophilic Shewanella strains isolated from the North-West Pacific Ocean 总被引:1,自引:0,他引:1
Ivanova EP Sawabe T Zhukova NV Gorshkova NM Nedashkovskaya OI Hayashi K Frolova GM Sergeev AF Pavel KG Mikhailov VV Nicolau DV 《Systematic and applied microbiology》2003,26(2):293-301
Although bacteria of the genus Shewanella belong to one of the readily cultivable groups of "Gammaproteobacteria", little is known about the occurrence and abundance of these microorganisms in the marine ecosystem. Studies revealed that of 654 isolates obtained from marine invertebrates (ophiuroid Amphiopholis kochii, sipuncula Phascolosoma japonicum, and holothurian Apostichopus japonicus, Cucumaria japonica), seawater and sediments of the North-West Pacific Ocean (i.e. the Sea of Japan and Iturup Is, Kurile Islands), 10.7% belonged to the genus Shewanella. The proportion of viable Shewanella species varied from 4% to 20% depending on the source of isolation. From the isolation study, representative strains of different phenotypes (from seventy presumptive Shewanella strains) were selected for detailed characterization using phenotypic, chemotaxonomic, and phylogenetic testing. 16S rDNA sequence-based phylogenetic analysis confirmed the results of tentative identification and placed the majority of these strains within only a few species of the genus Shewanella with 98-99% of 16S rDNA sequences identity mainly with S. japonica and S. colwelliana, suggesting that the strains studied might belong to these species. Numerically dominant strains of S. japonica were metabolically active and produced proteinases (gelatinases, caseinases), lipases, amylases, agarases, and alginases. Shewanella strains studied demonstrated weak antimicrobial and antifungal activities that might be an indication of their passive role in the colonization on living and non-living surfaces. 相似文献
20.
We tested the pathogenicity of 18 Metarhizium anisopliae (Metschn.) Sorokin isolates and 22 Beauveria bassiana (Balsamo) Vuillemin isolates against Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) larvae and adults. The efficacy of the most virulent isolate—M. anisopliae K—was evaluated in containers with a concrete bottom covered with wood shavings, under simulated poultry house conditions.
Application of conidia of this isolate to the shavings or directly to the concrete bottom reduced the yield of larvae in 8–15
time compared with the control. In another test, the mortality of mature larvae placed on previously inoculated shavings or
bottom reached 80–90% within 14 days, compared with 14% in the control. The residual activity of conidia kept at 28°C retained
its initial level during 14 days post-inoculation, but declined after three weeks. Based on our data M. anisopliae has considerable potential for the control of A. diaperinus.
相似文献
Michael SamishEmail: Email: |