全文获取类型
收费全文 | 397篇 |
免费 | 18篇 |
国内免费 | 2篇 |
出版年
2022年 | 3篇 |
2021年 | 4篇 |
2019年 | 10篇 |
2018年 | 7篇 |
2017年 | 6篇 |
2016年 | 10篇 |
2015年 | 14篇 |
2014年 | 22篇 |
2013年 | 18篇 |
2012年 | 36篇 |
2011年 | 26篇 |
2010年 | 22篇 |
2009年 | 22篇 |
2008年 | 25篇 |
2007年 | 22篇 |
2006年 | 40篇 |
2005年 | 14篇 |
2004年 | 18篇 |
2003年 | 15篇 |
2002年 | 15篇 |
2001年 | 13篇 |
2000年 | 14篇 |
1999年 | 9篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1992年 | 7篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1982年 | 2篇 |
1968年 | 1篇 |
排序方式: 共有417条查询结果,搜索用时 78 毫秒
81.
Physiological effects of Na2SO4 and NaCl on callus cultures of Brassica campestris (Chinese cabbage)
Hypocotyl-derived callus cultures of Brassica campestris L. ssp. pekinensis cv. Kim-jung (Chinese cabbage) were grown on Murashige and Skoog medium containing no additional salt, NaCl or Na2 SO4 . Na2 SO4 was more than twice as inhibitory in comparison to the same concentration of NaCl when growth and fresh:dry weight ratios of established callus were measured. Levels of protein, starch, sucrose and α-amino nitrogen were not significantly altered in salt-grown callus. Concentrations of reducing sugars and chlorophyll were 2–3 times greater in callus grown on either salt. Proline concentration increased 15–20 fold on the highest levels of salt. Final concentrations (reached in 20–24 days) were closely correlated to the initial Na+ concentration of the medium, regardless of salt type. The osmotic potential in callus transferred to NaCl or Na2 SO4 reached a maximum negative value after 16 days. For both salts, subsequent increases were correlated to increases in fresh:dry weight and growth. On both salts, turgor remained relatively constant (0. 6–0.75 MPa). Changes in Na+ , K+ , Mg2+ and Ca2+ content were correlated to initial Na+ concentration in the medium, not salt type. Accumulation of Na+ was accompanied by loss of K+ and Mg2+ . Six to seven times less sulfate was measured in callus grown on Na2 SO4 than chloride in callus grown on similar concentrations of NaCl. 相似文献
82.
Activation of PPARδ attenuates neurotoxicity by inhibiting lipopolysaccharide‐triggered glutamate release in BV‐2 microglial cells
下载免费PDF全文
![点击此处可从《Journal of cellular biochemistry》网站下载免费的PDF全文](/ch/ext_images/free.gif)
83.
Jong-Du Lee Kim-Cuong Le Young-Ki Park Hosakatte Niranjana Murthy Kee-Yoeup Paek So-Young Park 《Plant Cell, Tissue and Organ Culture》2018,132(2):295-302
Panax ginseng and Panax quinquefolius of Panax genus are valuable as health foods as well as pharmaceuticals for the treatment of cancer, diabetes and ageing as these plants possess saponins. In the current study, Cell and adventitious root cultures of P. ginseng and P. quinquefolius were investigated for the biomass, cell division, saponin content and ginsenosides profile from four lines namely P. quinquefolius (AM), P. ginseng mountain (Mt.) Baekdu line, P. ginseng Cheong-sol line (CS) and P. ginseng CBN line (CBN) with the objective of comparing cell and adventitious root systems to check their efficacy for the production of ginseng saponins. Additionally, genes related to ginsenoside biosynthesis were also analyzed concerning to cell and adventitious root lines. The results indicated that various cell lines were better in multiplication and growth compared to adventitious root lines. However, adventitious root lines showed higher accumulation of dry biomass (1.5–2 fold) than that of cell lines. CS adventitious root line showed higher saponin content and ginsenoside productivity (10.48 mg·g?1 DW, 12.88 mg·L?1, respectively) than that of CS cell line (9.50 mg·g?1 DW, 2.39 mg·L?1, respectively). Especially, Rd ginsenoside productivity of CS adventitious root line recorded fourfold higher than CS cell line. Genes which are related to ginsenoside biosynthesis such as P. ginseng squalene synthase (PgSS2), P. ginseng squalene epoxidase (PgSE2), P. ginseng protopanaxadial synthase (PgPPDS) and P. ginseng protopanaxatriol synthase (PgPPTS) were analyzed by real time quantitative polymerase chain reaction to support ginsenoside production. The adventitious root culture system described in this study is useful system for biomass and ginsenoside production. 相似文献
84.
Ho Thanh-Tam Lee Jong-Du Jeong Cheol-Seung Paek Kee-Yoeup Park So-Young 《Applied microbiology and biotechnology》2018,102(1):199-209
Applied Microbiology and Biotechnology - We examined the effects of abiotic (methyl jasmonate [MeJA] and salicylic acid [SA]) and biotic (yeast extract and chitosan) elicitors for improvement of... 相似文献
85.
A procedure for the regeneration of fertile transgenic Chinese cabbage (Brassica campestris ssp. pekinensis cv. Spring Flavor) is presented in this report. The protocol is based on infection of cotyledon explants of 5-d-old seedlings with an Agrobacterium tumefaciens strain LBA4404 carrying a disarmed binary vector pTOK/BKS-1. The T-DNA region of this binary vector contains the nopaline synthase/neomycin phosphotransferase II (nptII) chimeric gene for kanamycin resistance and the cauliflower mosaic virus 35S/coat protein gene of tobacco mosaic virus L (TMV-L) chimeric gene. After co-cultivation for 48 h, the cotyledonary petioles were placed on shoot induction media containing 15 mg/L kanamycin sulfate. Shoot induction was continued for 3–4 weeks, then subcultured once and after 2 weeks the shoots were transferred to root induction medium. After 1 week 8 putatively transformed plantlets from 200 cotyledon explants were obtained and transferred to greenhouse. Six of them grew to maturity, produced normal flowers and set seeds. Polymerase chain reaction and Southern blot hybridization analyses confirmed the introduction of the T-DNA into the Chinese cabbage genome. Further, Western blot analysis using polyclonal TMV antiserum showed most of the regenerants (5 out of 6) expressed TMV coat protein gene. Stable inheritance of the inserted clone was investigated in the next generation. 相似文献
86.
Zusammenfassung In histochemischen Untersuchungen an der Mamma von Ratten soll die Beeinflussung der Enzymaktivität durch Östrogene und Progesteron demonstriert werden. Die Untersuchungen wurden an 40 weiblichen juvenilen und kastrierten Albinoratten durchgeführt, von denen die 1. Gruppe Follikelhormon (Progynon, 5 /d), die 2. Gruppe Corpus luteum-Hormon (Proluton, 1 mg/d) erhielten. Neben Kontrolltieren gleichen Alters wurden die Brustdrüsen unbehandelter infantiler Tiere untersucht. Am 3., 5., 10. und 20. Tag nach Injektionsbeginn wurden die Tiere getötet und die Brustdrüsen histologisch sowie enzymhistochemisch durch den Nachweis von alkalischer Phosphatase (Azofarbstoff und Schwermetallsimultanmethode), Glukose-6-Phosphatase, Adenosintriphosphatase, 5-Nukleotidase, Glukose-6-Phosphat-Dehydrogenase, Succinodehydrogenase und Laktatdehydrogenase aufgearbeitet.Es wurde festgestellt, daß unter dem Einfluß der Behandlung mit Geschlechtshormonen ein Anstieg der Enzymaktivität einsetzt, wobei Östrogen eine dominierende Bedeutung hat. Diese zeigt sich vor allem in den ersten 5 Tagen, während danach eine gewisse Gleichförmigkeit in der Intensität dieser Reaktion eintritt. Die Ergebnisse lassen sich dem Wandel der Zellstruktur unter gleichartigen hormonalen Einflüssen zuordnen und sind damit Ausdruck hormonal induzierter Stoffwechselleistungen.
Herrn Prof. Dr. Karl-Heinz Bässler, Physiolog.-chem. Institut der Universität Mainz, sei für sachkundige Beratung in biochemischen Fragen vielmals gedankt. 相似文献
Histochemical enzymepattern of the mammary gland during the experimental influence of sex hormones
Summary The influence of estrogene und progesterone on the activity of enzymes is to be demonstrated by histochemical examinations of the mammary gland of rats. The examinations were made with 40 female juvenile and castrated albino rats of which the 1st group was given follicle-hormone (progynon, 5 /d), the 2nd group corpus-luteum-hormone (proluton, 1 mg/d). Besides control animals of the same age the mammary glands of untreated infantile animals were examined. On the 3rd, 5th, 10th, and 20th day after the beginning of the injections the animals were killed and the mammary glands were treated histologically as well as enzymehistochemically by examining their reaction to alcaline phosphatase, glucose-6-phosphatase, adenosine triphosphatase, 5-nucleotidase, glucose-6-phosphatase-dehydrogenase, succinic dehydrogenase, and lactic dehydrogenase.We found that under the influence of sex hormones the activity of enzymes increased and that estrogene had a dominating importance. This importance could be demonstrated during the first five days, while later these reactions showed a certain balance in their intensity. The results correspond to the change of the cellstructure under similar hormonal influences and thus are results of hormonally induced changes of metabolism.
Herrn Prof. Dr. Karl-Heinz Bässler, Physiolog.-chem. Institut der Universität Mainz, sei für sachkundige Beratung in biochemischen Fragen vielmals gedankt. 相似文献
87.
The effects of 1-naphthaleneacetic acid and N6-benzyladenine on the growth of Cymbidium forrestii rhizomes in vitro 总被引:2,自引:0,他引:2
An Asiatic orchid, Cymbidium forrestii, was clonally propagated using seed-derived rhizomes as explants. The rhizomes were cultured and proliferated on Murashige and Skoog medium supplemented with various growth substances. Auxins stimulated rhizome growth by increasing branching and fresh weight of the explant, with 1-naphthaleneacetic acid (NAA) being the most effective auxin. All auxins tested suppressed normal shoot formation. The apical meristem of the rhizome reacted to exogenously applied auxin by reducing the cytoplasmic zone of the apical meristem and causing meristem derivatives to rapidly differentiate into vacuolated parenchyma cells. Leaf formation and development was retarded in the presence of auxin. Cytokinins generally reduced rhizome growth and the number of branches, but benzyladenine (BA) can induce shoot formation in vitro. BA induced the cytoplasmic zone of the apical meristem to enlarge and enhanced leaf development. A 5% (w/v) sucrose concentration was most effective in shoot induction when combined with 5 mg1-1 BA. Activated charcoal promoted rhizome growth; however, shoot formation was inhibited. 相似文献
88.
Kee Yoeup Paek Stephen F. Chandler Trevor A. Thorpe 《Plant Cell, Tissue and Organ Culture》1987,9(2):159-165
Shoot cultures were established from seedling shoot tips of Raphanus sativus var. longipinnatus Bailey cv. Gungjung, (Japanese radish) cultured on a Murashige-Skoog medium supplemented with ca. 4.5–135 M kinetin or N6-benzyladenine. The latter cytokinin supported overall better growth, and 22.2 M was adopted for maintenance of established cultures. The nitrate: ammonium levels in the medium proved optimal for growth and shoot proliferation and both these parameters were significantly increased by addition of adenine sulfate or sodium phosphate. Rooting of excised shoots was achieved on auxin containing medium. Indole-3-butyric acid (ca. 5 or 10 M) also enhanced shoot growth. Plants were easily established in soil, appeared morphologically normal, and flowered. 相似文献
89.
We have investigated the complex formation between an immobilized monoclonal antibody and antigens that differ in size about 50-fold. As a model system, we used an iodinated progesterone derivative and a progesterone-horseradish peroxidase conjugate as tracer and a monoclonal antibody as binding protein. The antibody was immobilized by four different methods: physical adsorption, chemical binding, and binding via protein G in the absence or presence of a protective protein (gelatin). These investigations have shown that the performance of competitive immunoassays is determined by a combination of factors: (a) the relative size of the analyte and the tracer, (b) the antibody density on the solid matrix, (c) the method of immobilization of the antibody, and (d) the binding constants between antibody-analyte and antibody-tracer. All of these interactions have to be considered in designing an optimal immunoassay. The smaller antigen can form a 3- to 35-fold higher maximal complex density than the larger antigen. Dose-response curves are less affected by the size of the tracer than by the binding constant with the antibody. A large enzyme tracer with a relatively low binding constant can, therefore, provide a more sensitive assay. On the other hand, the increase in complex density achieved with a smaller tracer yields a higher signal that in turn can provide a better signal-to-noise ratio in highly sensitive competitive solid-phase immunoassays. We have suggested a model for antibody immobilization that accounts for the interdependence of tracer size, complex formation, and antibody density. The methods described can be used to design and optimize immunoassays of predefined performance characteristics. The results are particularly useful for converting radioimmunoassays to enzyme immunoassays. 相似文献
90.