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961.
T Vanden Driessche 《Chronobiology international》1984,1(2):113-120
In order to support the hypothesis that circadian rhythms are implicated in cap formation, experiments were undertaken on the possible time-dependency of the effects of (a) a competitive inhibitor of auxins, morphactin and (b) of auxin (IAA). It was found that: (i) the inhibitory effect of morphactin varies dramatically with the time at which the several weeks' treatment was first begun; (ii) the maximum inhibition varies with development and decreases with time; (iii) IAA accelerates cap formation when the algae are submitted to IAA during the exponential growth phase; the effect is time dependent and decreases with time; (iv) IAA first applied on smaller algae has a transient inhibitory effect which is time dependent; (v) anucleate fragments also respond differentially to an IAA treatment begun at several times in the 24-hr cycle, most clearly when newly formed mRNA have been accumulated and (vi) the effect of iAA is not cumulative with that of a LD shift; that of morphactin is not, or only slightly, improved by a LD shift. 相似文献
962.
Protonemata of the moss Funaria hygrometrica Sibth. (L.) show a strong pH dependence for auxin accumulation. IAA uptake is enhanced when the pH of the incubation medium is lowered from 7.6 to 4. In low light intensity grown protonemata (0.56 W m−2 ) a component of IAA uptake could be saturated by IAA; efflux of IAA could be inhibited by 2,3,5-triiodobenzoic acid. This is explained by the presence of influx and efflux carriers for IAA. In protonemata grown at high light intensity (2.00-2.30 W m−2 ) these carriers could not be shown to be present. These results are discussed with regard to the different physiological behavior of moss protonemata grown under different light conditions. 相似文献
963.
964.
Mitsuru Haniu Kerry T. Yasunobu Irwin C. Gunsalus 《Biochemical and biophysical research communications》1982,107(3):1075-1081
The Pseudomonas putida cytochrome P-450 was alkylated with the SH-reagent, 2-bromoacetamido-4-nitrophenol. One out of eight cysteine residues present in the enzyme reacted rapidly while another 3 ~ 4 cysteine residues were gradually alkylated at longer reaction times. The derivative in which the most reactive cysteine residue was labeled with this reagent was hydrolyzed with trypsin and a tryptic peptide isolated. From the amino acid composition and end group analysis of the peptide, the rapidly reacting cysteine residue was shown to be Cys 355. This cysteine residue is probably exposed on the surface and is involved in the dimerization of the enzyme. The amino acid sequence about cysteine 355 shows sequence homology with residues 429–445 of the rat liver cytochrome P-450-LM-2. 相似文献
965.
Two DNA fragments which contain the Escherichia coli tryptophan promoter-operator region but lack the attenuator have been used in the construction of a series of pAT153 based plasmids suitable for the regulated expression of foreign genes in E. coli. The first, a 139-bp HhaI fragment includes 59 bp of the trp leader sequence, ending within the “attenuator peptide” coding sequence, eleven codons from the N-terminus. A fusion-type expression plasmid incorporating this fragment has been constructed. The second, a 99-bp HaeIII-TaqI fragment contains no coding sequence but includes the “attenuator peptide” SD site situated 4 bp upstream of the TaqI site. This fragment has been incorporated in expression vectors which result in the direct expression of cloned gene sequences. To further maximise expression, plasmids with directly repeating trp promoter HaeIII-TaqI units have been constructed. 相似文献
966.
W. M. Zhou K. Yoshida Y. Shintaku G. Takeda 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1991,82(5):657-661
Summary Flowering hybrid plants were obtained from reciprocal crosses between N. tabacum L. (2n=48) and N. repanda Willd. (2n = 48), in which cross incompatibility and hybrid inviability were manifested. Stylar pollination and ovule culture were used to overcome the cross incompatibility of stylar barriers and ovular death. It was shown that application of 2 mg/l indole-3-acetic acid (IAA) during the growth period, from the fiveto six-leaf stage to the flowering stage, is a useful and easy method to overcome hybrid inviability. 相似文献
967.
《Bioorganic & medicinal chemistry letters》2020,30(2):126809
As the most abundant heat shock protein (HSP), Hsp90 is actively involved in tumor cell growth and various responses to anti-carcinogenic stress. Hsp90 has thus emerged as a potential drug target. A structure-based drug design approach was applied to develop novel resorcinolyltriazole derivatives as Hsp90 inhibitors. Structure-activity relationships (SARs) and molecular docking were investigated to provide a rationale for binding affinity and paralog selectivity. Click chemistry between iodoethynylresorcinol and an azido derivative was used to synthesize a new family of 2-((4-resorcinolyl)-5-aryl-1,2,3-triazol-1-yl) acetates that exhibited Hsp90 binding affinities of 40–100 nM (IC50). Among the synthesized molecules, the triazole alkyl acetates displayed the highest Hsp90 binding affinities. Their potency against Hsp90 was over 100-fold stronger than against TRAP1 and 1–3-fold stronger than against Grp94. In particular, compounds 18, 19, and 30 had Hsp90 inhibitory activities of ~45 nM (IC50) and they displayed over 350-fold selectivity for Hsp90 over TRAP1. 相似文献
968.
Polydnaviruses (PDVs) are a group of insect DNA viruses, which exhibit a mutual symbiotic relationship with their specific host wasps. Moreover, most encapsidated genes identified so far in PDVs share homologies with insect‐originated genes, but not with virus‐originated genes. In the meantime, PDVs associated with 2 wasp genera Cotesia and Glytapanteles encode some genes presumably originated from other viruses. Cotesia plutellae bracovirus (CpBV) encodes 4 genes homologous to baculoviral p94: CpBV‐E94k1, CpBV‐E94k2, CpBV‐E94k3, and CpBV‐E94k4. This study was conducted to predict the origin of CpBV‐E94ks by comparing their sequences with those of baculoviral orthologs and to determine the physiological functions by their transient expressions in nonparasitized larvae and subsequent specific RNA interference. Our phylogenetic analysis indicated that CpBV‐E94ks were clustered with other E94ks originated from different PDVs and shared high similarity with betabaculoviral p94s. These 4 CpBV genes were expressed during most developmental stages of the larvae of Plutella xylostella parasitized by C. plutellae. Expression of these 4 E94ks was mainly detected in hemocytes and fat body. Subsequent functional analysis by in vivo transient expression showed that all 4 viral genes significantly inhibited both host immune and developmental processes. These results suggest that CpBV‐E94ks share an origin with betabaculoviral p94s and play parasitic roles in suppressing host immune and developmental processes. 相似文献
969.
Stereoselectivity and affinity in molecular pharmacology. III. Structural aspects in the mode of action of natural and synthetic auxins 总被引:3,自引:0,他引:3
P A Lehmann F 《Chemico-biological interactions》1978,20(2):239-249
Analysis of available potency estimates for 35 pairs of enantiomeric arylcarboxylic acids with auxin activity (flax-root-growth inhibition test) revealed extensive correlations between the activity of the more potent and less potent isomers, as well as between the log of the ratio of potencies and the log potency of the more active isomer when structurally similar analogs are compared. 5 structural subgroups were discernible (n, eudismic-affinity quotient (EAQ), r2); (1) arylpropionic acids (6, -0.36, 0.66); (2) 2-naphthoxy-carboxylic acids (6, +1.07, 0.99); (3) 1-naphthoxycarboxylic acids (3, +1.56, 0.96); (4) ortho-substituted phenoxycarboxylic acids (10, +0.97, 0.96) and (5) ortho-unsubstituted phenoxycarboxylic acids (10, +0.56, 0.70). For achiral lower homologs such as auxin itself 3-indolyl-acetic acid (IAA), phenoxyacetic acid and 1-naphthoxyacetic acid, extrapolated potencies were found to agree well with experimental values. On the basis of these observations an auxin receptor is postulated and binding arrangements are described which explain most of the experimental data available. A 3-point attachment when allowed is the only binding mode compatible with the reported data. 相似文献
970.