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71.
Induction of G protein-coupled peptide receptor EBI 1 by human herpesvirus 6 and 7 infection in CD4+ T cells. 总被引:5,自引:3,他引:2 下载免费PDF全文
EBI 1, a putative lymphocyte-specific G protein-coupled peptide receptor, was induced by human herpesvirus 6 or 7 infection in CD4+ T cells, and its expression increased early after infection and reached a plateau at 48 h. The induction of the EBI 1 gene by human herpesvirus 6 or 7 infection was not mediated by soluble factors but by the virus itself. Deduced from comparisons of the amino acid sequences among members of the G protein-coupled receptor superfamily, these findings suggest that EBI 1 may be a member of the leukocyte chemotactic peptide receptor family. 相似文献
72.
Evolution of HCN from both rice ( Oryza sativa ) and cocklebur ( Xanthium pennsylvanicum ) seeds increased during a pre-germination period and preceded the evolution of (C2 H4 ). These two species were adopted as the representatives of starchy and fatty seeds, respectively. Ethylene promotes seed germination of many species. However, HCN evolution declined abruptly when the radicles emerged and before the peak in C2 H4 evolution. More-over, both rice and soybean ( Glycine max ) seeds showed some activity of β-cyanoalanine synthase (CAS, EC 4.4.1.9) even in the unimbibed dry state. The activities of CAS in the lower seed of cocklebur and in soybean seeds increased rapidly after emergence of the radicle. However, the CAS of rice seeds, with high activity in the dry state, exhibited a bimodal change, gradually decreasing until radicle emergence had occurred, but then increaing. It is thus likly that HCN evolution during initial imbibition may be derived from cyanogenic reserves and controlled by both pre-existing and subsequently-developing CAS. The exogenous application of C2 H4 stimulated the activities of CAS in both rice and upper cocklebur seeds and reduced their cyanogen contents. Therefore, the decline of HCN evolution after germination seems to be due to the increased activities of CAS by endogenously produced C2 H4 . 相似文献
73.
74.
Kazuo Ohtsuka Katsuhiko Hasegawa Kazunari Sato Katsumitsu Arai Hisami Watanabe Hitoshi Asakura Toru Abo 《Microbiology and immunology》1994,38(8):677-683
Two major populations of extrathymically differentiated T cells exist in the liver and intestine. Such T cells in the liver have TCR of intermediate intensity (i.e., intermediate TCR cells) and constitutively express IL-2 receptor β-chain (IL-2Rβ), whereas those in the intestine, especially intraepithelial lymphocytes, have TCR of bright intensity, consisting of a mixture of IL-2Rβ+ and IL-2Rβ–. All mature thymocytes and thymus-derived T cells seen in the peripheral immune organs are TCR-bright+IL-2Rβ– under resting conditions. When the expression pattern of adhesion molecules, including CD44, L-selectin, LFA-1 and ICAM-1, was compared among these T-cell populations, they displayed quite unique patterns of expression. All extrathymic T cells in the liver, intestine, and even other organs were CD44+L-selectin– LFA-1++ICAM-1+, whereas thymocytes and thymus-derived T cells were CD44– L-selectin+LFA-1+ICAM-1–. This inverted expression of adhesion molecules between extrathymic T cells and thymus-derived T cells might be associated with their unique tissue-localization. 相似文献
75.
Phylogenetic place of guinea pigs: no support of the rodent-polyphyly hypothesis from maximum-likelihood analyses of multiple protein sequences 总被引:3,自引:2,他引:1
Graur et al.'s (1991) hypothesis that the guinea pig-like rodents have an
evolutionary origin within mammals that is separate from that of other
rodents (the rodent-polyphyly hypothesis) was reexamined by the
maximum-likelihood method for protein phylogeny, as well as by the
maximum-parsimony and neighbor-joining methods. The overall evidence does
not support Graur et al.'s hypothesis, which radically contradicts the
traditional view of rodent monophyly. This work demonstrates that we must
be careful in choosing a proper method for phylogenetic inference and that
an argument based on a small data set (with respect to the length of the
sequence and especially the number of species) may be unstable.
相似文献
76.
Jianyu Zheng Kohei Irifune Kouji Hirai Masashi Nakata Ryuso Tanaka Hiromichi Morikawa 《Journal of plant research》1994,107(4):365-369
In situ hybridization with a biotin-labeled rice ribosomal DNA (rDNA) probe to the somatic metaphase chromosomes of six species ofPhaseolus andVigna (P. angularis, P. calcaratus, P. coccineus, P. vulgaris, V. sesquipedalis andV. sinensis) was done to determine the sites of rDNA. Hybridization signals were present in the terminal and subterminal chromosome regions
of each of the six species. The number of rDNA sites was two inP. angularis andP. calcaratus, four inP. coccineus andP. vulgaris, and six inV. sesquipedalis andV. sinensis. 相似文献
77.
78.
Tetsuo Hashimoto Eiko Otaka Jun Adachi Keiko Mizuta Masami Hasegawa 《Journal of molecular evolution》1993,36(3):282-289
Summary Using - and -hemoglobin sequences, we made a maximum likelihood inference as to the phylogenetic relationship among carnivores, including the two pandas, giant and lesser. Molecular phylogenetic studies up to 1985 had consistently indicated that the giant panda is more closely related to the bear than to the lesser panda. In 1986, however, a contradictory tree was constructed, using hemoglobins and so on, in which the two pandas link together (Tagle et al. 1986). In contrast to that tree, our conclusion supports the close relationship between bear and giant panda. The surface impression of a close relationship between the two pandas drawn from pairwise amino acid differences is explained by a rapid rate of hemoglobin evolution in the bear compared to that in the two pandas.Offprint requests to: T. Hashimoto 相似文献
79.
Noriyuki Suka Yoshinobu Shinohara Yasushi Saitoh Hisato Saitoh Kohei Ohtomo Masahiko Harata Edward Shpigelman Shigeki Mizuno 《Genetica》1993,88(2-3):93-105
About 65% of DNA in the chicken W chromosome has been shown to consist ofXhoI andEcoRI family repetitive sequences. These sequences showed remarkable delay in the electrophoretic mobility at low temperature
on a polyacrylamide gel. Three dimensional structures of the 0.7-kbXhoI and the 1.2-kbEcoRI family repeating units were estimated to be irregular solenoids using a computer program based on wedge angles of all the
16 dinucleotide steps. Fluorescencein situ hybridization demonstrated that these two family sequences were localized in a major heterochromatic body in an interphase
nucleus. Incorporation of bromodeoxyuridine into the W chromosome in the synchronous culture of MSB-1 cells occurred about
1 h later than the peak of S phase. The chromatin structure formed alongXhoI andEcoRI family sequences was suggested to be different from the total chromatin or chromatin containing the β-actin gene sequence
in that the linker DNA lengths of the former were significantly longer. Fractionation of theHaeIII-digested MSB-1 nuclei yielded a chromatin fraction in whichXhoI family sequences were partially enriched. Several DNA-binding proteins showing higher affinity for theXhoI family sequence were present in this fraction. 相似文献
80.
Laboratory experiments were conducted to test the hypothesis that widelyforaging generalist lizard,Eumeces okadae, visually discriminates palatable queen ants from unpalatable worker ants. The workers ofCamponotus japonicus andLasius niger were rejected on sight, while the queens of both species were eaten with little prior chemical examination by tongue flicks
or licks. Comparison of the lizards' responses towards the workers and wingless queens of similar size indicated that neither
body size nor presence or absence of wings accounted for difference in responses toward the 2 ant castes. The lizards probably
discriminated different ant castes by body proportions. 相似文献