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121.
122.
With regards to pollination there exist several mutualistic relationships between Hadena -species and Caryophyllaceae. As mutualists have both negative and positive effects on their partners, mutualism is often betoken as reciprocative exploitation which may shift to parasitism if the exploitation of one partner becomes prevalent.
Several Silene - and Saponaria -species are considered to be larval host plants of Hadena bicruris . Although Silene latifolia ssp. alba and S. dioica are frequently cited as hosts of the seed eating larvae, field and laboratory observations at Ulm were suggestive for only S. latifolia ssp. alba being a suitable host. Records of the oviposition behavior of H. bicruris made it evident that in fact a considerable number of eggs could be found in planted stands of both species. On the other hand, phenological data of the flowering periods and of the oviposition behavior of H. bicruris showed that S. latifolia ssp. alba is clearly preferred for oviposition if host selection is possible due to contemporaneous flowering of individuals of both plant species growing at close range. In addition, the flowering periods of S. latifolia ssp. alba and the periods of moth activity overlap to a large extent. This is not the case in S. dioica . Feeding experiences first indicated that the caterpillars may not prefer one of the species to the other, but comparison of the pupal weight of the animals reared on fruits of exclusively one of the species showed that the seeds of S. latifolia ssp. alba were more profitable for nutrition than those of S. dioica ; the pupal weight of animals reared on seeds of the former species significantly exceeded that of animals reared on seeds of the latter one. The question arises if the symbiosis of H. bicruris and its hosts constitutes a stable situation or if an evolutionary shift to mutualism or parasitism will take place. 相似文献
Several Silene - and Saponaria -species are considered to be larval host plants of Hadena bicruris . Although Silene latifolia ssp. alba and S. dioica are frequently cited as hosts of the seed eating larvae, field and laboratory observations at Ulm were suggestive for only S. latifolia ssp. alba being a suitable host. Records of the oviposition behavior of H. bicruris made it evident that in fact a considerable number of eggs could be found in planted stands of both species. On the other hand, phenological data of the flowering periods and of the oviposition behavior of H. bicruris showed that S. latifolia ssp. alba is clearly preferred for oviposition if host selection is possible due to contemporaneous flowering of individuals of both plant species growing at close range. In addition, the flowering periods of S. latifolia ssp. alba and the periods of moth activity overlap to a large extent. This is not the case in S. dioica . Feeding experiences first indicated that the caterpillars may not prefer one of the species to the other, but comparison of the pupal weight of the animals reared on fruits of exclusively one of the species showed that the seeds of S. latifolia ssp. alba were more profitable for nutrition than those of S. dioica ; the pupal weight of animals reared on seeds of the former species significantly exceeded that of animals reared on seeds of the latter one. The question arises if the symbiosis of H. bicruris and its hosts constitutes a stable situation or if an evolutionary shift to mutualism or parasitism will take place. 相似文献
123.
124.
Gerhard Kopperschlger Jürgen Kirchberger 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1996,684(1-2)
Lactate dehydrogenase (LDH), an ubiquitous enzyme among vertebrates, invertebrates, plants and microbes was discovered in the early period of enzymology. The enzyme has been dissolved in several distinguishable molecular forms. In mammals, three types of subunits encoded by the genes Ldh-A, Ldh-B and Ldh-C give rise to a selected number of tetrametric isoenzymes. LDH-A4, LDH-B4 and the mixed hybrid forms of the A- and B-subunits are present in many tissues but with certain distribution patterns. LDH-C4 is confined in mammals to testes and sperm. Numerous techniques have been employed to purify, characterize and separate the different forms of the enzyme. This report deals with the main protocols and procedures of purification of LDH and its isoenzymes including chromatographic and electrophoretic methods, partitioning in aqueous two-phase systems and precipitation approaches. In particular, affinity separation techniques based on natural and pseudo-biospecific ligands are described in detail. In addition, basic physico-chemical and kinetic properties of the enzyme from different sources are summarized. In a second part, the clinical significance of the determination of LDH in diverse body fluids in respect to the total activity and the isoenzyme distribution in different organs is discussed. 相似文献
125.
Rémy Kachadourian Alia Dellagi Jacqueline Laurent Laurent Bricard Gerhard Kunesch Dominique Expert 《Biometals》1996,9(2):143-150
Iron deprivation of Erwinia amylovora CFBP1430, a species causing fire blight on Pomoïdeae, was shown to induce the production of siderophores of the desferrioxamine (dfo) family and two outer membrane polypeptides with apparent molecular weight of about 70 and 80 kDa, respectively. Cyclic dfo E was characterized as the major metabolite. Phage MudIIpR13 insertional mutagenesis and screening on CAS-agar medium yielded three dfo non-producing and one overproducing clones. These clones failed to grow in the presence of the Fe(III) chelator EDDHA and were determined further as dfo and ferrioxamine transport negative mutants, respectively. The transport mutant which appeared to lack the 70 kDa polypeptide in the outer membrane allowed the purification of dfo E. Growth under iron limitation of dfo negative mutants was stimulated with ferrioxamine E and B but not with other ferrisiderophores tested. The host DNA sequence flanking the left terminal part of the MudIIpR13 prophage responsible for the transport mutation was cloned and used to probe a parental gene library by DNA-DNA hybridization. Two recombinant cosmids restoring the transport mutation to normal were identified. Both cosmids also conferred the ability to utilize ferrioxamine B and E as iron sources on a FhuE1 mutant of Escherichia coli. This correlated with the production of an additional polypeptide of 70 kDa in the outer membrane of E. coli transconjugants, thus confirming that this protein serves the ferrioxamine receptor function (FoxR) in E. amylovora.R. Kachadourian and A. Dellagi have contributed equally to this work. 相似文献
126.
Holger Hackstein Gerhard Jahn Holger Kirchner Gregor Bein 《Histochemistry and cell biology》1996,106(2):229-234
Radioactive in situ hybridization techniques or enzymatic detection procedures of hapten-modified human cytomegalovirus (HCMV)
probes have been widely used for studying the infection of peripheral blood leukocytes with HCMV. This report describes significant
improvements in terms of signal resolution which can be obtained by applying a highly sensitive fluorescence in situ hybridization
(FISH) technique in conjunction with a large subgenomic HCMV DNA probe. Three cosmid clones spanning 119.1 kb of the HCMV
genome (230 kb) were used to construct the digoxigenin-11-dUTP-labeled probe which was found to be superior to a total HCMV
probe representing the entire genome. Crucial hybridization parameters were analyzed systematically in order to ensure optimal
resolution power and sensitivity. The protocol was successfully applied to HCMV-infected fibroblasts and peripheral blood
leukocytes of 12 transplant patients and unambiguously facilitated the precise intracellular localization of HCMV genomes
in infected cells. Because of its excellent resolution properties, accompanied by the virtual absence by any background staining,
we recommend the use of this protocol as a sensitive approach for further virological analyses of the interactions between
HCMV and peripheral blood leukocytes at the single-cell level.
Accepted: 16 February 1996 相似文献
127.
Using electron microscopy we demonstrate that degenerating neurons and cellular debris resulting from neuronal reorganization
are phagocytosed by glial cells in the brain and nerve cord of the fruitfly Drosophila melanogaster during the first few hours following pupariation. At this stage several classes of glial cells appear to be engaged in intense
phagocytosis. In the cell body rind, neuronal cell bodies are engulfed and phagocytosed by the same glial cells that enwrap
healthy neurons in this region. In the neuropil, cellular debris in tracts and synaptic centres resulting from metamorphic
re-differentiation of larval neurons is phagocytosed by neuropil-associated glial cells. Phagocytic glial cells are hypertrophied,
produce large amounts of lysosome-like bodies and contain a large number of mitochondria, condensed chromatin bodies, membranes
and other remains from neuronal degeneration in phagosomes.
Received: 23 January 1996 / Accepted in revised form: 21 May 1996 相似文献
128.
Bettina Schmidt Thomas Tradler Jens-U. Rahfeld Birgit Ludwig Bunty Jain Karlheinz Mann K. Peter Rücknagel Bernhard Janowski Angelika Schierhorn Gerhard Küllertz Jörg Hacker Gunter Fischer 《Molecular microbiology》1996,21(6):1147-1160
Legionella pneumophila is the causative agent of a severe form of pneumonia in humans (Legionnaires’disease). A major virulence factor, the Mip protein (FK506-binding protein, FKBP25mem), belongs to the enzyme family of peptidyl-prolyl cis/trans isomerases (PPIases). Here we show that L. pneumophila Philadelphia I possesses an additional cytoplasmic PPiase at a level of enzyme activity comparable to that of FKBP25mem. The N-terminal amino acid sequence of the purified protein was obtained by Edman degradation and showed that the protein is a member of the cyclophilin family of PPIases. The Icy gene (Legionella cycophn) was cloned and sequenced. It encodes a putative 164-amino-acid protein with a molecular mass of 17 968 Da called L. pneumophila cyclophilin 18 (L. p. Cyp18). Amino acid sequence comparison displays considerable similarity to the cytoplasmic and the periplasmic cyclophilins of Escherichia coll with 60.5% and 51.5% identity, respectively. The substrate specificity and inhibition by cyclosporin A revealed a pattern that is typically found for other bacterial cyclophilins. An L. pneumophila Cyp18 derivative with a 19-amino-acid polypeptide extension including a 6-histi-dine tag and an enterokinase cleavage site exhibits 相似文献
129.
It was our goal to determine the location of the intermediate chain within the complex of cytoplasmic dynein by immunoelectron microscopy. To do so we generated two monoclonal antibodies (m74-1 and m74-2) specific for the intermediate chain. Both antibodies recognised the intermediate chain by sodium dodecyl sulphate–polyacrylamide gel electrophoresis immunoblot and ELISA assays of native and denatured proteins. When sucrose density gradient-purified cytoplasmic dynein from bovine brain was incubated with the gold-conjugated monoclonal antibodies, m74-1 and m74-2, and examined by negative staining, the gold label was found opposite the globular heads at the base of the V-shaped stalk of the motor complex. The labelling of the intermediate chain is the first mapping of a component within cytoplasmic dynein. The identification of the intermediate chain at the base of the complex supports a possible docking function of the intermediate chain. 相似文献
130.
A cell-free system capable of converting [14C]geranylgeranyl diphosphate to ent-[14C]kaurene and to an unidentified acid-hydrolysable compound was obtained from the basal portions of 5-d-old shoots of wheat seedlings (Triticum aestivum L.). By means of marker enzyme activities, the synthesis of ent-kaurene and the unknown compound could be quantitatively assigned to a plastid fraction obtained by Percoll-gradient centrifugation of the homogenate. The enzyme activities were located within the plastids, probably in the stroma, because they withstood trypsin treatment of the intact plastids, and the plastids had to be broken to release the activity, which was then obtained in soluble form. Plastid membranes had no activity. Plastid stroma preparations obtained from pea (Pisum sativum L.) shoot tips and pumpkin (Cucurbita maxima L.) endosperm also yielded ent-kaurene synthetase activity, but did not form the unknown compound. The exact nature of the active plastids was not ascertained, but the use of methods for proplastid isolation was essential for full activity, and the active tissues are all known to contain high proportions of proplastids, developing chloroplasts or leucoplasts. We therefore believe that ent-kaurene synthesis may be limited to these categories. Mature chloroplasts from the wheat leaves did not contain ent-kaurene synthetase activity and did not yield the unknown component. Incorporation of [14C]geranylgeranyl diphosphate into ent-[14C]kaurene and the unknown component was assayed by high-performance liquid chromatography with on-line radiocounting. ent-[14C]Kaurene was identified by Kovats retention index and full mass spectra obtained by combined gas chromatography-mass spectrometry. The unknown component was first believed to be copalyl diphosphate, because it yielded a compound on acid hydrolysis, which migrated like copalol on high-performance liquid chromatography and gave a mass spectrum very similar to that of authentic copalol. However, differences in the mass spectrum and in retention time on capillary gas chromatography excluded identity with copalol. Furthermore, the unhydrolysed compound was not converted to ent-kaurene by a cell-free system from C. maxima endosperm as copalyl diphosphate would have been.Abbreviations ADH
alcohol dehydrogenase
- AMO 1618
2isopropyl-4-(trimethylammoniumchloride)-5-methylphenyl piperi-dine-1-carboxylate
- BSA
bovine serum albumin
- DTT
dithioth-reitol
- GAn
gibberellin An
- GAPDH
NADP+-glyceraldehyde 3-phosphate dehydrogenase
- GC-MS
combined gas chromatography-mass spectrometry
- GGPP
all trans-isomer of geranyl-geranyl diphosphate
- KS
ent-kaurene synthetase
- MDH
malate dehydrogenase
- MAA
mevalonate activating activity
- SOR
shikimate oxidoreductase
We thank Mrs. Gudrun Bodtke and Mrs. Dorothee Dasbach for able technical assistance, Prof. L.N. Mander (Australian National University, Canberra, Australia) for ent-[2H2]kaurene and Dr. Yuji Kamiya (RIKEN, Saitama, Japan) for geranylgeraniol and copalol. The work was supported by the Deutsche Forschungsgemeinschaft. 相似文献