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941.
942.
Maruyama Akiko; Ishizawa Kimiharu; Takagi Takashi; Esashi Yohji 《Plant & cell physiology》1998,39(7):671-680
The activity of rß-cyanoalanine synthase (CAS, EC4.4.1.9
[EC]
) in cotyledons of cocklebur seeds (Xanthium penn-sylvanicumWallr.) was detected both in the soluble and particulate fractions.The CAS activity of the soluble fraction (cytosolic CAS activity)was 10 times higher than that of the particulate fraction. TheCAS activity of the particulate fraction was confirmed to belocalized in the mitochondria. Both enzymatic activities wereclearly separated by non-denaturing PAGE. The enzyme with cytosolicCAS activity has been extensively purified and separated intothree different forms designated as cyt-1, cyt-2, and cyt-3.According to the SDS-PAGE analysis, the three enzymes are estimatedto be a homodimer composed of 35-kDa sub-units. The purifiedenzymes showed CS activity. Partial amino acid sequences ofcyt-1 were determined and had a high homology with cysteinesynthases (CS, EC 4.2.99.8
[EC]
) from other plant sources. The catalyticaction of the purified CSs in converting cyanide and cysteineinto H2S and rß-cyanoalanine was confirmed by thedetection of significant 14CN incorporation into rß-cyanoalanine.These results indicated that cytosolic CAS activity is due tocytosolic CS and suggested that the CAS activity of CS is likelyto be involved in cyanide metabolism in plant tissues. (Received January 7, 1998; Accepted March 16, 1998) 相似文献
943.
Takashi Fujita Hitoshi Hatamoto Mari Miyamoto Taisuke Iwasaki Shin-ichi Takafuji 《Biotechnology letters》1998,20(11):1057-1061
Cell suspensions derived from Acer nikoense callus, not containing (S)-rhododendrol, converted 4-(p-hydroxyphenyl)-2- butanone into (R)-, (S)-rhododendrol and their glycosides. (R)- and (S)-rhododendrol formed was only detected in the culture medium and their glycosides only in the cells. The former compound disappeared within a short time and the latter one also tended to decrease during prolonged culture. Quantitative analysis of rhododendrol glycosides in the callus showed that most of them were (S)-rhododendrol 2-O--D-glucopyranoside and its content was much lower than that of the original plants. © Rapid Science Ltd. 1998 相似文献
944.
Takashi Araki Yasushi Kobayashi Hidetaka Kaya Masaki Iwabuchi 《Journal of plant research》1998,111(2):277-281
Transition from vegetative to reproductive development (flowering) is one of the most important decisions during the post-embryonic
development of flowering plants. More than twenty loci are known to regulate this process inArabidopsis. Some of these flowering-time genes may act at the shoot apical meristem to regulate its competence to respond to floral
inductive signals and floral evocation. Genetic and phenotypic analyses of mutants suggest that the late-flowering geneFT may be a good candidate for such genes. To test this, we have cloned theFT gene using aFT-deficiency line associated with a T-DNA insertion. Cloned genes and loss-of-function mutants in hand, it is now possible
to analyse the role ofFT and other genes in flowering at the biochemical and cellular levels as well as at the genetic level. The deduced FT protein
has homology with TFL1 and CEN proteins believed to be involved in regulation of inflorescence meristem identity. Phylogenetic
analysis suggests that theFT group and theTFL1/CEN group of genes diverged before the diversification of major angiosperm clades. This raises the interesting question of the
evolutionary relationship between the regulation of vegetative/reproductive switching in the shoot apical meristem and the
regulation of inflorescence architecture in angiosperms.
The extended abstract of a paper presented at the 13th International Symposium in Conjugation with Award of the International
Prize for Biology “Fronitier of Plant Biology” 相似文献
945.
Yasunori Machida Marina Nakashima Kayoko Morikiyo Hiroharu Banno Masaki Ishikawa Takashi Soyano Ryuichi Nishihama 《Journal of plant research》1998,111(2):243-246
The tobaccoNPK1 gene encodes a homolog of mitogenactivated protein kinase kinase kinases. We have recently identified tobacco kinesin-like
proteins (NACK1/2) as activators for NPK1. Immunochemical analyses of NPK1 and NACK1 proteins suggest that NPK1 is involved
in the regulation of some process in the M phase of the plant cell cycle.
The extended abstract of a paper presented at the 13th International Symposium in Conjugation with Award of the International
Prize for Biology “Frontier of Plant Biology” 相似文献
946.
Yosuke Andoh Takashi Kuramoto Norihide Yokoi Toshiro Maihara Kazuhiro Kitada Tadao Serikawa 《Mammalian genome》1998,9(4):287-293
To correlate rat genetic linkage maps with cytogenetic maps, we localized 25 new cosmid-derived simple sequence length polymorphism
(SSLP) markers and 14 existing genetic markers on cytogenetic bands of chromosomes, using fluorescence in situ hybridization
(FISH). Next, a total of 58 anchor loci, consisting of the 39 new and 19 previously reported ones, were integrated into the
genetic linkage maps. Since most of the new anchor loci were developed to be localized near the terminals of the genetic or
cytogenetic maps for each chromosome, the orientation and coverage of the whole genetic linkage maps were determined or confirmed
with respect to the cytogenetic maps. Thus, we provide here a new base for rat genetic maps.
Received: 9 September 1997 / Accepted: 11 November 1997 相似文献
947.
Toshikazu Ushijima Tomoko Nomoto Takashi Sugimura David E. Housman Minako Nagao 《Mammalian genome》1998,9(12):1008-1012
Mapping of genetic suppressors, modifiers, and quantitative trait loci (QTLs) requires genetic markers that can be efficiently
and inexpensively genotyped for a large number of individuals. To isolate rat genetic markers suitable for this purpose, representational
difference analysis (RDA) was performed with amplicons prepared by PCR with the B1 repetitive sequence used as the primer
(B1-amplicons). In total, 48 polymorphic DNA fragments were isolated by five series of RDA, subtracting the B1-amplicons prepared
from an ACI/N (ACI) rat from those prepared from BUF/Nac (BUF), and vice versa. All the polymorphic fragments detected ``presence-or-absence'
polymorphisms with B1-amplicons prepared from ACI, BUF, and their F2 progeny, and each fragment was linkage mapped. Dot-blotting amplicons onto filters at a high density and hybridization of
the filters with these B1-RDA markers made it possible to genotype a large number of rats simultaneously for multiple loci.
These B1-RDA markers were polymorphic between two given inbred strains of rat at frequencies between 30% and 70%. This is
the first report on the isolation of B1-RDA markers among inbred strains of rats.
Received: 15 July 1998 / Accepted: 18 August 1998 相似文献
948.
IL-12 and Viral Infections 总被引:2,自引:0,他引:2
Takashi Komastu Derek D. C. Ireland Carol Shoshkes Reiss 《Cytokine & growth factor reviews》1998,9(3-4):277-285
Interleukin-12 activates natural killer cells and promotes the differentiation of Th1 CD4+ cells; it is a critical factor in viral immunity. IL-12 is secreted by antigen presenting cells including dendritic cells, macrophages and astrocytes, both in tissues and in secondary lymphoid organs. Experimental studies have shown that administration of the cytokine rapidly activates both innate and specific immune responses; this results in enhanced host cellular responses and generally, promotes clearance of virus and host recovery from infection. The observations of many laboratories, studying viral immunity to both RNA and DNA based pathogens, are summarized. 相似文献
949.
Yasuyuki Ishibashi Takashi Saitoh Syuiti Abe Michihiro C. Yoshida 《Population Ecology》1998,40(1):51-59
Kinship amongClethrionomys rufocanus was investigated during the winter of 1992/93 in a 3-ha enclosure using both molecular and catch-mark-release techniques.
Forty-six adult voles (22 males and 24 females) having high heterozygosities, which were collected from several natural populations,
were released into the enclosure on 29 September 1992. Most fall-born individuals of both sexes stayed in their natal site
during the non-breeding period (December–March), although reproductively active females dispersed during the fall breeding
season (October–November). These philopatric individuals aggregated and formed an maternal family in the winter. Several females
which failed to reproduce were solitary during this season. Some individuals which were derived from several families also
aggregated into a mixed lineage group. Survival rate of fall-born voles from earlier litters was higher than that from later
ones. Maternal families broke up soon after the onset of spring reproduction. Most females established a territory near the
wintering site and made a kincluster, in which close relatives neighbored each other. Maternal families in winter bring about
female kin-clusters in spring, which may influence reproductive output in the breeding season. 相似文献
950.
Yasuyuki Ishida Hiroaki Yokoi Shinichi Isomura Hajime Ohtani Shin Tsuge Tatsuki Sekino Masami Nakanishi Takashi Kimoto 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1998,716(1-2)
Pyrolysis–gas chromatography (Py–GC) combined with on-line methylation was applied to a correlation analysis between the distributions of fatty acid components in the lipids of zooplankter individuals and those of ingested algae using principal component analysis (PCA). Py–GC in the presence of organic alkali, tetramethylammonium hydroxide (TMAH), was used to estimate the apparent distributions of fatty acid components contained in a single individual zooplankter weighing several tens of micrograms and a small sample size of ingested algae samples in the order of 10 μg. The observed fatty acid compositions were used as a database for the PCA in order to discriminate the zooplankton and ingested algae samples. The result obtained indicated that the fatty acid compositions of zooplankton individuals used in this work were significantly reflected in those of their ingested food in spite of some contribution from isomerization and/or elongation of fatty acid components during digestion of the ingested algae phytoplankton in living zooplankters. 相似文献