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71.
Christina Brahe Isabella Velonà Gerrit van der Steege Stefania Zappata Anneke Y. van de Veen Jan Osinga Carli M. J. Tops Riccardo Fodde P. Meera Khan Charles H. C. M. Buys Giovanni Neri 《Human genetics》1994,93(5):494-501
The locus responsible for the childhood-onset proximal spinal muscular atrophies (SMA) has recently been mapped to an area of 2–3 Mb in the region q12–13.3 of chromosome 5. We have used a series of radiation hybrids (RHs) containing distinct parts of the SMA region as defined by reference markers. A cosmid library was constructed from one RH. Thirteen clones were isolated and five of these were mapped within the SMA region. Both RH mapping and fluorescence in situ hybridization analysis showed that two clones map in the region between loci D5S125 and D5S351. One of the cosmids contains expressed sequences. Polymorphic dinucleotide repeats were identified in both clones and used for segregation analysis of key recombinant SMA families. One recombination between the SMA locus and the new marker 9Ic (D5S685) indicates that 9Ic is probably the closest distal marker. The absence of recombination between the SMA locus and marker Fc (D5S684) suggests that Fc is located close to the disease gene. These new loci should refine linkage analysis in SMA family studies and may facilitate the isolation of the disease gene. 相似文献
72.
The effect of an acute increase in temperature, exhaustive exercise and hypoxia on the haematology of the benthic Antarctic teleost, Trematomus bernacchii was investigated. High temperature and hypoxia caused the biggest changes to the blood, with increases in haematocrit, haemoglobin concentrations and plasma chloride levels. The spleen decreased in mass. Exercise produced the smallest changes. Changes were substantially less than reported for the more active cryopelagic species Pagothenia borchgrevinki. The magnitude of the haematocrit increase is discussed in relation to life-style of fish living in the Antarctic. 相似文献
73.
Summary A cDNA clone encoding an ADP-ribosylation factor from potato (Solanum tuberosum L.) was isolated. The nucleotide and deduced amino acid sequences show high homology to known ADP-ribosylation factor sequences from Arabidopsis, yeast, cow and man. In northern blot experiments, all tissues analysed showed expression of the corresponding mRNA. Strongest expression was found, however, in potato tubers.Abbreviations ARF, ADP
ribosylation factor
- BSA
bovine serum albumin
- EDTA
ethylenediaminetetraacetic acid
- SDS
sodium dodecyl sulfate
- SSC
sodium saline citrate 相似文献
74.
Plasma membrane phosphatidic acid phosphohydrolase (PAPH) plays an important role in signal transduction by converting phosphatidic acid to diacylglycerol. PAPH-2, a Mg2+-independent, detergent-dependent enzyme involved in cellular signal transduction, is reportedly absent from the plasma membranes of neutrophilic leukocytes, a cell that responds to metabolic stimulation with abundant phospholipase
-dependent diacylglycerol generation. The present study was designed to resolve this discrepancy, focusing on the influence of cellular disruption techniques, detergenta availability and cation sensitivity on the apparent distribution of PAPH in neutrophil sub-cellular fractions. The results clearly indicate the presence of two distinct types of PAPH within the particulate and cytosolic fractions of disrupted cells. Unlike the cytosolic enzyme, the particulate enzyme was not potentiated by magnesium and was strongly detergent-dependent. The soluble and particulate enzymes displayed dissimilar pH profiles. Separation of neutrophil particulate material into fractions rich in plasma membranes, specific granules and azurophilic granules by high speed discontinuous density gradient centrifugation revealed that the majority of the particulate activity was confined to plasma membranes. This activity was not inhibited by pretreatment with n-ethyl-maleimide in concentrations as high as 25 mM. PAPH activity recovered in the cytosolic fraction of disrupted neutrophils was almost completely inhibited by 5.0 mM n-ethylmaleimide. We conclude that resting neutrophils possess n-ethylmaleimide-resistant PAPH (type 2) within their plasma membranes. This enzyme may markedly influence the kinetics of cell activation by metabolizing second messengers generated as a result of activation of plasma membrane phospholipase D. 相似文献
75.
76.
Jacek Najda Jan Gmiński Marian Dróżdż Franciszek Zych 《Biological trace element research》1993,37(2-3):101-106
The influence of silicon-treatment on the levels of TSH and thyroid hormones was studied in rats. Concentrations of thyrotropin
(TSH), triiodothyronine (T3), and thyroxine (T4) were estimated in sera of rats receiving per os a soluble silicon compound—sodium metasilicate nonahydrate (Na2SiO3·9H2O), dissolved in the animals' drinking water. An increase in the TSH level in the tested group was observed, without statistically
significant differences in T3 and T4 concentrations between the two groups of animals. The results provide evidence for the influence of silicon on the endocrine
balance. They could also prove that this chemical element is capable of modifying the rate of some hormones' synthesis. 相似文献
77.
78.
Arlette Pesty Brigitte Lefvre Jacek Kubiak Grard Graud Jan Tesarik Bernard Maro 《Molecular reproduction and development》1994,38(2):187-199
The incubation of mechanically denuded mouse oocytes in medium containing LiCl delayed both germinal vesicle breakdown (GVBD) and polar body extrusion in a dose-dependent and reversible manner. When myo-inositol alone was added to the culture medium, we observed that it accelerated GVBD and increased the rate of polar body extrusion, whereas, when combined with LiCl, the normal timing of GVBD was recovered. In the same way, when inositol trisphosphate (InsP3) was microinjected into the ooplasma, we observed an important improvement of the rate of GVBD, as compared to control oocytes, and prevention of lithium inhibition. However, neither myo-inositol nor InsP3 were able to rescue totally the oocytes from the negative effect of lithium on polar body extrusion. Moreover, lithium induced some important changes in microtubule and chromosome organizations. Before extrusion of the first polar body, the reduction of the spindle size or the appearance of short individualized chromosomes dispersed around a large aster of microtubules were often observed, whereas, after polar body extrusion, the spindle appeared smaller and chromosomes were often trapped in the midbody. Thus lithium affects mouse oocyte maturation at two different levels: GVBD and polar body extrusion. Whereas the former seems to be affected via polyphosphoinositide turnover, the latter is InsP3-independent and seems to be influenced negatively via underdevelopment of microtubular structures. © 1994 Wiley-Liss, Inc. 相似文献
79.
Jan Jeník 《Folia Geobotanica》1994,29(2):291-306
Bulkiness, longevity and solidity of the body in woody plants enable the successive development of accessory shoots and adventitious roots in (1) both proximal and distal positions on organs, (2) both the above-ground and below-ground space, (3) both the aerial and soil environments. In monocotyledons, woody rhizomes play an essential role in the basic growth habit and architectural models. In dicotyledonous and a few gymnospermous trees, attached and successively disconnected ramets play a multilateral role in the pertinent life strategies. The majority of sprouts, coppice shoots and root suckers behave as opportunistic organs (a) serving as means of vegetative reproduction, (b) securing colonization of unoccupied ground, (c) increasing competitive power of the species within the community, (d) increasing survival rate of the stressed/disturbed genet in marginal habitats, (e) forming replacement for ageing or damaged organs, and (f) enabling reiteration of the genet's entire architectural model. 相似文献
80.
Marc Vandermeeren‡ Marc Mercken‡ Eugeen Vanmechelen‡ Jan Six‡ ré Van de Voorde‡Jean-Jacques Martin† Patrick Cras 《Journal of neurochemistry》1993,61(5):1828-1834
Abstract— Alzheimer's disease is a progressive degenerative dementia characterized by the abundant presence of neurofibrillary tangles in neurons. This study was designed to test whether the microtubule-associated protein, a major component of neurofibrillary tangles, could be detected in CSF. Additionally, we investigated whether CSF levels were abnormal in Alzheimer's disease as compared with a large group of control patients. We developed a sensitive sandwich enzyme-linked immunosorbent assay using AT120, a monoclonal antibody directed to human, as a capturing antibody. With this technique, the detection limit for was less than 5 pg/ml of CSF. Using ATS, which recognizes abnormally phosphorylated ser-ines 199–202 in, the detection limit was below 20 pg/ml of CSF. However, with AT8, we found no immunoreactiv-ity in CSF, suggesting that only a small fraction of CSF contains the abnormally phosphorylated AT8 epitope. Our results indicate that CSF levels are significantly increased in Alzheimer's disease. Also, CSF levels in a large group of patients with a diversity of neurological diseases showed overlap with CSF levels in Alzheimer's disease. 相似文献