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981.
P M Martin C Cochet P H Rolland E M Chambaz 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1977,284(14):1305-1307
Evidence is presented demonstrating the presence of a high affinity (Ka10(8)M-1), limited capacity (3-4 pmoles/mg protein) estradiol binder in the soluble fraction of the Bovine, Rat and Human adrenal cortex. The binding appears specific to the estrogen structure whereas C19 and C21 steroids do not bind. Upon sucrose density gradient centrifugation, the estradiol binder sedimented at 9 S at low ionic strength and was shifted to 4.5 S in the presence of 0.5 M KCl. This demonstration of a receptor-like moiety for estradiol in the adrenal cortex lends biochemical support to previous observations suggesting that adrenal cortex functions may be modulated by a direct effect of gonadal steroid hormones. 相似文献
982.
983.
984.
985.
F Declo?tre J Chauveau A Benoit M Martin 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1975,280(8):1027-1030
The organophosphorus insecticide ethyl-parathion was transformed by rat liver microsomes into metabolites which were bound to calf thymus DNA, in large amount. When the rats were treated by phenobarbital or 3-methylcholanthrene, the metabolite binding to DNA was increased two-fold. By contrast, in the same conditions, the organochlorine insecticides, aldrin, dieldrin and gamma hexachlorocyclohexane (lindane), did not yield metabolites able to bind to DNA and to proteins. 相似文献
986.
987.
It no longer seems likely that DNA molecules in situ have a uniform conformation, represented by the classical B-form helix. For example, recent structural studies have shown that in certain conditions DNA can have a left-handed (so-called Z-form) helix, and have revealed extensive sequence-dependent variations of B-DNA helical parameters. Such sequence-dependent variations in DNA structure can be investigated in solution with reagents that bind to DNA in a conformation-dependent manner, and cut one or both strands of the double-helix at the site of binding, as, for example, has been shown for the endonuclease DNase I3. We describe here a simple way to endow a DNA-binding ligand with the ability to cleave DNA--labelling with 125I. The radiochemical damage associated with 125I decay induces a double-stranded DNA break. Using this technique we have shown that a sequence of four consecutive A X T base pairs is a necessary, but not sufficient, condition for strong binding to DNA of the bis-benzamide Hoechst 33258--presumably the other important factor is the conformation of the double-helix at the site of the (A/T)4 sequence. We suggest 125I-Hoechst 33258 may be a useful new probe of DNA structure. 相似文献
988.
Allogeneic reactions are the major limitation to organ transplantation. These are manifested as rejection of the grafted tissue, and also, in the case of bone marrow transplantation (BMT), graft-versus-host disease (GVHD). Recent methods of avoiding GVHD, by depleting T cells from donor marrow, have led to an increased incidence of marrow graft rejection. Current recipient conditioning protocols involving drugs or irradiation cannot safely be increased, so alternatives must be found. Monoclonal antibodies can be used to control immune responses in vivo, and would be useful in this context if we could define and deplete the cells responsible for marrow rejection. We show here that elimination of residual L3T4+ and Lyt-2+ cells from mice receiving fully mismatched bone marrow abrogates rejection and promotes tolerance to donor-type skin grafts, even in sub-lethally irradiated recipients. 相似文献
989.
A. H. Martin 《Cellular and molecular life sciences : CMLS》1968,24(5):476-477
Résumé Des études autoradiographiques effectuées sur les stades du cycle cellulaire dans les cellules neuroépithéliales de poulet de 2 jours, ont donné les résultats suivants: G2=1,5 h; M=1,0 h; S=6,5–6,8 h; G1=1,0–1,5 h et le temps de génération=10,0–10,8 h. On a également constaté que la thymidine H3 administrée à l'embryon comme dans l'expérience ci-dessus mit au moins 2 h à être incorporée. 相似文献
990.
Autosomal recessive lissencephaly with cerebellar hypoplasia is associated with human RELN mutations 总被引:20,自引:0,他引:20
Hong SE Shugart YY Huang DT Shahwan SA Grant PE Hourihane JO Martin ND Walsh CA 《Nature genetics》2000,26(1):93-96
Normal development of the cerebral cortex requires long-range migration of cortical neurons from proliferative regions deep in the brain. Lissencephaly ("smooth brain," from "lissos," meaning smooth, and "encephalos," meaning brain) is a severe developmental disorder in which neuronal migration is impaired, leading to a thickened cerebral cortex whose normally folded contour is simplified and smooth. Two identified lissencephaly genes do not account for all known cases, and additional lissencephaly syndromes have been described. An autosomal recessive form of lissencephaly (LCH) associated with severe abnormalities of the cerebellum, hippocampus and brainstem maps to chromosome 7q22, and is associated with two independent mutations in the human gene encoding reelin (RELN). The mutations disrupt splicing of RELN cDNA, resulting in low or undetectable amounts of reelin protein. LCH parallels the reeler mouse mutant (Reln(rl)), in which Reln mutations cause cerebellar hypoplasia, abnormal cerebral cortical neuronal migration and abnormal axonal connectivity. RELN encodes a large (388 kD) secreted protein that acts on migrating cortical neurons by binding to the very low density lipoprotein receptor (VLDLR), the apolipoprotein E receptor 2 (ApoER2; refs 9-11 ), alpha3beta1 integrin and protocadherins. Although reelin was previously thought to function exclusively in brain, some humans with RELN mutations show abnormal neuromuscular connectivity and congenital lymphoedema, suggesting previously unsuspected functions for reelin in and outside of the brain. 相似文献