全文获取类型
收费全文 | 269篇 |
免费 | 5篇 |
专业分类
274篇 |
出版年
2023年 | 4篇 |
2022年 | 8篇 |
2021年 | 7篇 |
2020年 | 8篇 |
2019年 | 7篇 |
2018年 | 9篇 |
2017年 | 5篇 |
2016年 | 15篇 |
2015年 | 11篇 |
2014年 | 17篇 |
2013年 | 17篇 |
2012年 | 20篇 |
2011年 | 20篇 |
2010年 | 15篇 |
2009年 | 5篇 |
2008年 | 7篇 |
2007年 | 8篇 |
2006年 | 13篇 |
2005年 | 7篇 |
2004年 | 11篇 |
2003年 | 3篇 |
2002年 | 5篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1971年 | 3篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1964年 | 3篇 |
1963年 | 1篇 |
排序方式: 共有274条查询结果,搜索用时 15 毫秒
141.
142.
Upadhyay SK Saurabh S Singh R Rai P Dubey NK Chandrashekar K Negi KS Tuli R Singh PK 《The protein journal》2011,30(6):374-383
A lectin was purified from the leaves of Allium altaicum and corresponding gene was cloned. The lectin namely Allium altaicum agglutinin (AAA) was ~24 kDa homodimeric protein and similar to a typical garlic leaf lectin. It was synthesized as 177 amino
acid residues pre-proprotein, which consisted of 28 and 43 amino acid long N and C-terminal signal peptides, respectively.
The plant expressed this protein more in scapes and flowers in comparison to the bulbs and leaves. Hemagglutination activity
(with rabbit erythrocytes) was 1,428 fold higher as compared to Allium sativum leaf agglutinin (ASAL) although, the insecticidal activity against cotton aphid (Aphis gossypii) was relatively low. Glycan array revealed that AAA had higher affinity towards GlcAb1-3Galb as compared to ASAL. Homology
analysis showed 57–94% similarity with other Allium lectins. The mature protein was expressed in E. coli as a fusion with SUMO peptide in soluble and biologically active form. Recombinant protein retained high hemagglutination activity. 相似文献
143.
Adaptive theory predicts that mothers would be advantaged by adjusting the sex ratio of their offspring in relation to their offspring's future reproductive success. In the present study, we tested the effect of housing mice under crowded condition on the sex ratio and whether the fat content of the diet has any influence on the outcome of pregnancies. Three-week-old mice were placed on the control diet (NFD) for 3 weeks. Thereafter the mice were allotted randomly to two groups of 7 cages each with 4, 6, 8, 10, 12, 14, and 16 mice in every cage to create increasing crowding gradient and fed either NFD or high fat diet (HFD). After 4 weeks, dams were bred and outcomes of pregnancy were analyzed. The average dam body weight (DBW) at conception, litter size (LS) and SR were significantly higher in HFD fed dams. Further, male biased litters declined with increasing crowding in NFD group but not in HFD. The LS and SR in NFD declined significantly with increasing crowding, whereas only LS was reduced in HFD group. We conclude that female mice housed under overcrowding conditions shift offspring SR in favor of daughters in consistent with the TW hypothesis and high fat diet reduces this influence of overcrowding. 相似文献
144.
The present study presents the development of a standard protocol for detection and screening of nanoparticle(s) for their antimicrobial activity with particular reference to organophilic montmorillonite (Ommt). For this purpose, Ommt nanoparticles have been synthesized through cation exchange of commercial montmorillonite (K10) with a cetyl pyridinium bromide. The formation of Ommt has been ascertained through UV-visible, Fourier transform infrared spectroscopy, X-ray diffraction spectra, and transmission electron microscopy. Subsequently, "zone of inhibition" and "bacterial killing" assays were performed by incubating the four Gram-negative test bacteria with Ommt, to determine antimicrobial activity and reduction in colony forming unit per mL (confirmative test), respectively. The developed assay will provide an easy approach over conventional disc diffusion antibiotic sensitivity test, to study the impact of different nanoparticles against different bacterial species. 相似文献
145.
Kaur S Singh HP Batish DR Negi A Mahajan P Rana S Kohli RK 《Biological trace element research》2012,146(3):360-368
The present study investigated the effect of Arsenic (As; 5, 10, 50 μM) on protein and sugar metabolism vis-à-vis oxidative
damage during early germination process and radicle emergence (at 12, 24 and 48 h stage) in Phaseolus aureus. As-exposure (50 μM) significantly enhanced protein content (by 40–60%), whereas carbohydrate content declined (by 31–44%)
over that in the control. It was associated with a decline in the activities of proteases (47–53%), and increase in the activities
of α- and β-amylases, starch phosphorylases, and acid invertases by 3.0, 2.6, 4.8, and 1.7 times after 48 h exposure to 50 μM
As. The alteration in protein and carbohydrate metabolic machinery was also accompanied by As-induced reactive oxygen species
(ROS)-mediated oxidative damage. As treatment enhanced malondialdehyde and hydrogen peroxide content by 46–252% and 23–216%,
and hydroxyl and superoxide ion generation by 15–104% and 17–278%, respectively. As-induced lipid peroxidation and membrane
disruption was confirmed by enhanced electrolyte leakage (by 49%) and reduced cell viability (by 43%). Furthermore, in response
to 50 μM As, the activities of superoxide dismutases, catalases, ascorbate peroxidases, guaiacol peroxidases, and glutathione
reductases increased by 77%, 70%, 116%, 43% and 120%, respectively, in radicles at 48 h stage over that in the control. The
study concludes that As inhibits radicle emergence and elongation in germinating P. aureus seeds by altering biochemical processes related to sugar metabolism and inducing an ROS-mediated oxidative damage. 相似文献
146.
147.
148.
The OTAN treatment, which is the only histochemical method available at present for the simultaneous localization of hydrophobic and hydrophilic unsaturated lipids in tissue sections, requires unduly long exposure to O3O4 and use of free-floating sections, which makes handling the sections difficult and often results in their loss or damage. Simple modifications using O3O4 treatment at 37 C and slide-mounted sections eliminate the practical drawbacks of the existing method and provide as good or better localization in less than one-eighth of the time. The modified method is applicable to fixed as well as fresh frozen tissues. 相似文献
149.
150.
A. Singh M. S. Negi V. K. Moses B. Venkateswarlu P. S. Srivastava M. Lakshmikumaran 《In vitro cellular & developmental biology. Plant》2002,38(5):519-524
Summary The importance of neem (Azadirachta indica A. Juss.) as a medicinal tree species has been acknowledged worldwide. Superior trees with desired traits such as high azadirachtin
content have been identified and micropropagated. Somaclonal variants that may arise in vitro, however, pose limitations to large-scale micropropagation. It is, therefore, imperative to establish genetic uniformity
of such plantlets by ensuring strict quality checks at various stages of in vitro culture. This is the first study that evaluates the applicability of amplified fragment length polymorphism (AFLP) markers
in establishing clonal fidelity of tissue culture(TC)-raised neem plants. Seven AFLP primer combinations generated a total
of 334 amplified fragments across the mother plant, TC progenies, and other neem accessions that were included as controls.
Two hundred and thirty-nine amplified fragments were monomorphic across the mother tree and its TC progenies. No extra band
was detected in the TC plantlets that was absent in the mother tree, indicating that the TC plantlets regenerated through
nodal explants are indeed true-to-type. Ninety-five AFLP fragments were detected in the controls, which allowed their discrimination
from the elite mother tree and its TC progenies. Similarity matrix based on Jaccard's coefficient revealed that the pair-wise
value between the mother tree and its TC plantlets was ‘1’, indicating perfect similarity. Phenetic dendrogram based on UPGMA
(unweighted pair group method of arithmetic averages) analysis further confirmed the true-to-type nature of TC progenies,
since a tie was observed between the mother tree and its TC plantlets. On the contrary, the control neem accessions were distinct
from the mother and its TC progenies. AFLP markers proved to be an ideal tool for routine analysis and certification of genetic
fidelity of micropropagated plants prior to commercialization, especially in tree species because of their long generation
time. 相似文献