全文获取类型
收费全文 | 256篇 |
免费 | 27篇 |
国内免费 | 2篇 |
专业分类
285篇 |
出版年
2021年 | 5篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 2篇 |
2017年 | 7篇 |
2016年 | 6篇 |
2015年 | 3篇 |
2014年 | 12篇 |
2013年 | 13篇 |
2012年 | 15篇 |
2011年 | 18篇 |
2010年 | 9篇 |
2009年 | 9篇 |
2008年 | 9篇 |
2007年 | 6篇 |
2006年 | 13篇 |
2005年 | 9篇 |
2004年 | 7篇 |
2003年 | 3篇 |
2002年 | 8篇 |
2001年 | 8篇 |
2000年 | 9篇 |
1999年 | 6篇 |
1998年 | 9篇 |
1997年 | 2篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 9篇 |
1989年 | 6篇 |
1988年 | 7篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 10篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1974年 | 7篇 |
1973年 | 4篇 |
1972年 | 1篇 |
1971年 | 4篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 2篇 |
1938年 | 1篇 |
1925年 | 1篇 |
排序方式: 共有285条查询结果,搜索用时 8 毫秒
1.
A simple dispenser using a 2-ml disposable syringe is described. The range of operation is 0.02–1.5 ml and an unusual accuracy is obtained by employing a new principle for dispensers: the dispensed volume is only a fraction of total tidal flow of fluid in the dispenser. 相似文献
2.
Dr. H. H. Boer L. P. C. Schot H. W. M. Steinbusch Cora Montagne Dagmar Reichelt 《Cell and tissue research》1984,238(2):411-412
Summary Consecutive sections of certain neurons in the central ganglia of the pond snail Lymnaea stagnalis appear to be immunoreactive to anti-dopamine and anti-serotonin. The Cerebral Giant Neurons stain in addition with antivasotocin. The observations indicate the presence of two biogenic amines within the same neuron and in addition their co-existence with a biologically active peptide. 相似文献
3.
Øyvind Skraastad Karl L. Reichelt 《Virchows Archiv. B, Cell pathology including molecular pathology》1988,56(1):321-325
Previous work indicates that the colonic epithelial cell proliferation in mice is reversibly inhibited by the tripeptide pGlu-His-GlyOH
found in aqueous extracts of the intestine. In the present study we examined the possible tissue specificity of the colon
mitosis inhibitor. The mitotic rate in the small intestine, epidermis and forestomach in mice was registered after a single
i.p. injection of the tripeptide. A significantly reduced rate of cell renewal was found at 18 h in the epidermis whereas
no inhibition was observed in the forestomach or ileal epithelium. To investigate whether the amino acid sequence of the tripeptide
is essential for the inhibitory effect, three structurally related bioactive peptides were tested and compared to the effect
of CMI. CMI showed a bell-shaped dose-response relationship as previously shown, whereas the mitotic rate was not reduced
in the colonie epithelium after treatment with either an epidermal mitosis inhibitory pentapeptide, or the dipeptide pGlu-GlyOH,
or an analogue of luteinizing hormone-releasing hormone. The efficacy of the tripeptide was dependent on the basal rate of
cell renewal in the colonie epithelium. When the tripeptide was given at the circadian nadir of cell proliferation a delayed
reduction of the proliferative activity was observed at 6 h after treatment, whereas treatment when the rate of cell proliferation
was at its circadian zenith gave an immediate mitotic inhibition. 相似文献
4.
The morphological life-forms, that is to say, physiognomic-structural attributes, of two coral reef communities were used in a numerical analysis to determine the power of these attributes in recovering the underlying community structure. We used 17 attributes from the benthic communities at 6 reef slope sites on each of a midshelf and off-shore reef of the central Great Barrier Reef. These reefs had been previously well studied by traditional species-level means for several major taxonomic groups such as corals, fish and soft corals. Our multivariate analyses were able to recover broad patterns of between-reef affinity and discrete within-reef zonation patterns similar to those found in earlier studies, and in broad accord with the prevailing model of reef community structure, but with far greater efficacy. But perhaps more importantly, by placing all the benthos within the same context for the first time, our analyses were able to recover new patterns of community structure independent of the ones described earlier. This suggests that single-model explantations for the complex phenomena of coral reefs are likely to be inadequate. 相似文献
5.
Prof. Dr. H. H. Boer L. P. C. Schot Dagmar Reichelt H. Brand A. ter Maat 《Cell and tissue research》1984,238(1):197-201
Summary Three neuronal systems of the pond snail Lymnaea stagnalis were immunocytochemically investigated at the ultrastructural level with the unlabeled peroxidase-antiperoxidase technique. Preliminary electrophysiological and cell-filling investigations have shown that a cluster of neurons which reacts positively with an antiserum against the molluscan cardio-active peptide FMRFamide, sends axons to the penis retractor muscle. In this muscle anti-FMRF-amide (aFM) positive axons form neuro-muscular synapses with (smooth) muscle fibers. The morphological observations suggest the aFM immunoreactive system to be involved in peptidergic neurotransmission. In the right parietal ganglion a large neuron (LYAC) is penetrated by aFM positive axons which form synapse-like structures (SLS) with the LYAC. The assumption that the SLS represent the morphological basis for peptidergic transmission is sustained by the observation that iontophoretical application of synthetic FMRFamide depolarizes the LYAC. The axons of a group of pedal anti-vasopressin (aVP) positive cells run in close vicinity to the cerebral ovulation (neuro-)-hormone producing cell system (CDC system) Synapses or SLS between the two systems were not observed. The fact that (bath) application of arg-vasopressin induces bursting in the CDC, may indicate that the vasopressin-like substance of the aVP cells is released non-synaptically. 相似文献
6.
DNA-DNA homology among twenty-nine isolates having the phenotypic properties ofVibrio cholerae was studied using the S1 endonuclease method. Ten strains ofV. cholerae O1 isolated from patients and from the environment in Australia showed greater than 88% homology with the neotype strain ofV. cholerae NCTC 8021. Strains of the non-O1 serotype isolated from a variety of clinical and environmental sources also showed a high level of relatedness, including four luminescent strains and a reference strain of the biotypealbensis. A group of sucrose-negative strains showed a low level of homology (40 to 43%) withV. cholerae, but 75% and 82% homology within the group. 相似文献
7.
Reichelt J 《European journal of cell biology》2007,86(11-12):807-816
The epidermis, like many other tissues, reacts to mechanical stress by increasing cell proliferation. Mechanically stressed skin regions often develop thicker skin and hyperkeratosis. Interestingly, a large number of skin diseases are accompanied by epidermal proliferation and hyperkeratosis even under normal mechanical stress conditions. Although, some of the molecular pathways of mechanical signaling involving integrins, the epidermal growth factor receptor and mitogen-activated protein kinases are known it is still unclear, how mechanical force is sensed and transformed into the molecular signals that induce cell proliferation. This review focuses on the molecules and pathways known to play a role in mechanotransduction in epidermal keratinocytes and discusses the pathways identified in other well-studied cell types. 相似文献
8.
A rapid benthic line-transect survey method for use by non-specialist observers is described. At both Davies Reef (mid-continental shelf) and Myrmidon Reef (outer-continental shelf) in the central Great Barrier Reef a set of 6 sites of varying depths on the reef flat, crest and slope were sampled using this method. At least 10 contiguous 10 m transects were made at each site. Benthic organisms were recorded as life forms with categories based on both high level taxa and morphologies, and including scleractinian corals, alcyonarians, sponges, algae and others. Percentage cover data for 19 benthic categories are presented for all sites. Coral cover on both reefs is high on the crest and slope but low on the reef flat. At all sites the cover of soft corals and sponges is much less than cover of hard corals and algae. Abundances of soft corals and sponges increase with depth. Analysis of gaps between hard corals show that many colonies grow close to each other (<1 cm)even when total coral cover is low. 相似文献
9.
10.
Martin Schäfer Christoph Brütting Klaus Gase Michael Reichelt Ian Baldwin Stefan Meldau 《The Plant journal : for cell and molecular biology》2013,76(3):506-518
Field experiments with transgenic plants often reveal the functional significance of genetic traits that are important for the performance of the plants in their natural environments. Until now, only constitutive overexpression, ectopic expression and gene silencing methods have been used to analyze gene‐related phenotypes in natural habitats. These methods do not allow sufficient control over gene expression for the study of ecological interactions in real time, of genetic traits that play essential roles in development, or of dose‐dependent effects. We applied the sensitive dexamethasone (DEX)‐inducible pOp6/LhGR expression system to the ecological model plant Nicotiana attenuata and established a lanolin‐based DEX application method to facilitate ectopic gene expression and RNA interference‐mediated gene silencing in the field and under challenging conditions (e.g. high temperature, wind and UV radiation). Fully established field‐grown plants were used to silence phytoene desaturase and thereby cause photobleaching only in specific plant sectors, and to activate expression of the cytokinin (CK) biosynthesis gene isopentenyl transferase (ipt). We used ipt expression to analyze the role of CKs in both the glasshouse and the field to understand resistance to the native herbivore Tupiocoris notatus, which attacks plants at small spatial scales. By spatially restricting ipt expression and elevating CK levels in single leaves, damage by T. notatus increased, demonstrating the role of CKs in this plant–herbivore interaction at a small scale. As the arena of most ecological interactions is highly constrained in time and space, these tools will advance the genetic analysis of dynamic traits that matter for plant performance in nature. 相似文献