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21.
曾子申;胡峻;利容千 《武汉植物学研究》1985,3(4):439-442
本文对我国栽培辣椒Capsicum annuum L.的四个品种即汉川椒、华椒一号、牛角椒和二金条进行了核型分析,其染色体数目均为2n=2x=24,核型公式均为2n=24=20m+2sm+2st,但汉川椒和华椒一号具一对随体,牛角椒和二金条具两对随体。本文还对它们的进化关系进行了讨论。 相似文献
22.
通过过聚乙二醇6000-磷酸钾缓冲液双相分离、Sephadex G-100凝胶过滤、DEAE-Sephadex A-50离子交换层析、羟基磷灰石层析及SephadexG-100凝胶过滤等提纯步骤,从海枣曲霉(Aspergillus phoenicis)麦麸培养物抽提液中提纯得到凝胶电泳均一的β-半乳糖苷酶。该酶的最适pH为3.5—4.0,最适温度为60℃(反应15分钟),在pH5.0—8.5之间及60℃以下稳定。在65℃和70℃保温时失活50%的时间分别为27和2分钟。用SDS凝胶电泳法和梯度凝胶电泳法分别测得该酶的分子量为115,000和118,000。薄层凝胶等电聚焦法测得其等电点为pH4.6。 相似文献
23.
Yan Yongshan 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1986,72(5):700-705
Summary The coculture of mouse PG19 cells with human MGC cells can significantly suppress nucleolar organizer region (NORs) activity of both PG19 and MGC cells. 5-bormodeoxyuridine (BrdU) can also significantly suppress the NOR activity of rat RC cells, human MGC and Hela cells, and mouse PG19 cells: i.e. the average number of Ag-NORs and the number of chromosomes bearing Ag-NORs per cell decrease significantly. The degree of the suppression increases with increase in both BrdU concentration in the culture medium and BrdU treatment time. The suppressed NOR activity of the PG19 cells can gradually be restored when the BrdU-treated cells are transferred into BrdU-free medium for 50 h. In PG19 cells deoxycytidine (dC) can reverse the suppression of NOR activity caused by BrdU. Coculture plus BrdU treatment suppress the NOR activity of PG19 cells more severely than BrdU treatment alone. In coculture medium containing 30 g BrdU/ml, dC can also reverse the suppression of the NOR activity of PG19 cells but not that of the MGC cells. The degree of the reversion in the coculture plus BrdU treatment is significantly lower than that found with BrdU-treatment alone. 相似文献
24.
The effect of 1-β-d-arabinofuranosyl-cytosine on the expression of the common fragile site at 3p14 总被引:1,自引:0,他引:1
Summary The effect of the G2-treatment of 1--d-arabino-furanosyl-cytosine (araC) on the expression of the common fragile site at 3p14 (FRA3B) was studied. A significantly increased frequency of FRA3B induced by G2 treatment of araC was found in the lymphocytes grown in folate-deficient medium (positive rate 100%). A relatively low frequency of FRA3B was also induced in the cultures with folate in four of the seven subjects. These is a synergistic effect between araC and growth in folate-deficient medium on the induction of FRA3B. The results suggest that the DNA lesions related to the expression of FRA3B induce the long-patch repair and that the low DNA polymerase activity and inefficient repair process during G2 phase is involved in the expression of FRA3B. 相似文献
25.
B. Dahhou I. Queinnec F. Y. Zeng J. B. Pourciel G. Goma 《Bioprocess and biosystems engineering》1991,7(4):157-163
The paper presents an Intelligent CAD system for Fermentation Process Control (FPC-ICAD) based on a hierarchical architecture possessing three levels: real-time supervision level, CAD level and learning level. The aims of the learning are mainly composed of the aspects fermentation process modelling, determination of appropriate control and estimation methods, determination of the corresponding parameters and fermentation monitoring through measurement and software management. Three independent, but interactive software packages allow user to organize his system for different purposes: on-line control system (with only supervision), off-line CAD as a teaching software, off-line intelligent CAD (CAD+learning package), and on-line intelligent CAD. 相似文献
26.
C F Yang Z C Zeng S C Chou F X Yu J D Taylor T T Tchen 《Pigment cell research / sponsored by the European Society for Pigment Cell Research and the International Pigment Cell Society》1989,2(5):408-413
We have previously shown that the dispersion and aggregation of carotenoid droplets in goldfish xanthophores are regulated, respectively, by phosphorylation and dephosphorylation of a carotenoid droplet protein p57. There is a basal level of p57 phosphorylation of p57 in unstimulated cells, which is greatly stimulated by adrenocorticotropic hormone (ACTH) or cyclic adenosine monophosphate (cAMP) acting via cAMP-dependent protein kinase. We have also observed that, in permeabilized xanthophores, pigment dispersion can be induced when cAMP is replaced by fluoride. Since p57 has multiple phosphorylation sites, there is the question of whether all p57 phosphorylation is by cAMP-dependent protein kinase or whether phosphorylation by cAMP-independent protein kinase coupled with inhibition of phosphatase activity by fluoride can replace cAMP-dependent protein kinase and that the ability of fluoride to replace cAMP for pigment dispersion in permeabilized cells is probably due to activation of adenylcyclase. We also show that ACTH causes an approximately threefold increase in the level of cAMP in these cells. 相似文献
27.
Three major questions regarding the post-translational modification of amino acid side chains in proteins are briefly considered: (1) What are the biological functions of the reactions, (2) what is the specificity of the processing reactions in selecting only a few or sometimes even only one residue for modification, and (3) how do we solve the uniqueness of the processing steps in the production of recombinant proteins? The answers to these questions are not obvious at this time. 相似文献
28.
T Uchiyama T Tadakuma K Imanishi M Araake S Saito X J Yan H Fujikawa H Igarashi N Yamaura 《Journal of immunology (Baltimore, Md. : 1950)》1989,143(10):3175-3182
Toxic shock syndrome toxin-1 (TSST-1)-binding structures present on murine lymphoid tissues were investigated by using 125I-TSST-1. T-depleted C57BL/6 spleen cells incubated with TSST-1 for 3 h at 0 degree C were mitogenic to splenic T cells, indicating that the former cells bind and present TSST-1 to T cells. TSST-1-binding activity was observed in C57BL/6 splenic B cells and L cells transfected with I-Ab genes, but not in splenic T cells and control L cells. Scatchard plot analysis showed that these B cells and transfectants bound TSST-1 with similar binding affinity. SDS-PAGE analysis showed that lysates of C57BL/6 spleen cells and the I-Ab-positive transfectants contain a single band which bound TSST-1 and comigrated with I-Ab heterodimers. TSST-1-binding activity observed clearly in C57BL/6. BALB/c, and C3H/HeN spleen cells and L cells transfected with I-Ab or I-Ak genes was not reduced by paraformaldehyde fixation. Binding of 125I-TSST-1 to the three spleen cells was markedly reduced by anti-I-A antibodies, but not by anti-I-E antibodies. C57BL/6, C3H/HeN, and (C3H/HeN x C57BL/6) F1 T cells were activated by TSST-1 to proliferate and produce IL-2 in the presence of FT6.2 cells, LT1-30-3 cells and either of them, respectively, but not in the presence of control L cells. These results indicate that I-A molecules function as the structures via that accessory cells directly bind TSST-1 on the cell surface and present a triggering signal of TSST-1 to T cells. 相似文献
29.
Amplification of multicistronic plasmids in the human 293 cell line and secretion of correctly processed recombinant human protein C 总被引:2,自引:0,他引:2
We have constructed multicistronic vectors containing the cDNAs for murine dihydrofolate reductase (DHFR), hygromycin phosphotransferase (HyPR), and human protein C (HPC), an antithrombotic factor. Using a sequential selection protocol with hygromycin (Hy) and methotrexate (MTX), we demonstrate the selective amplification of the murine dhfr cDNA in the adenovirus-transformed human kidney cell line 293, and the coamplification of the cDNA for HPC. Such recombinant 293 cell lines secreted HPC at levels as high as 25 micrograms/10(6) cells/day. In addition, we found that the complex vitamin K-dependent posttranslational modification of gamma-carboxylation of glutamate was not limiting at these high secretion levels, although the proteolytic processing of the protein was slightly reduced. Further, the HPC secreted from the gene-amplified cell lines had full anticoagulant activity when compared to plasma-derived HPC. 相似文献
30.