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141.
Development of a shaker culture of Buffalo green monkey kidney cells: potential use for detection of enteroviruses. 下载免费PDF全文
Buffalo green monkey kidney cells were adapted to grow as shaker cultures. Replication of environmental and clinical isolates of poliovirus, coxsackievirus, and echovirus in these cultures was analyzed by plaque assay and compared with replication in Buffalo green monkey kidney cell monolayers and HEp-2 cell shaker cultures. Dose-response tests with various concentrations of Mahoney type 1 poliovirus indicated that Buffalo green monkey kidney cell shaker cultures could detect as little as 1 PFU in an inoculum of 0.2 ml. These data suggest that Buffalo green monkey kidney cell shaker cultures can be effectively used for the detection of small quantities of enteroviruses from environmental sources. 相似文献
142.
The effective enzyme activity decay can be decreased by diffusion limitation in the immobilized pellet. Thiele modulus changes and/or poisoning of various enzyme forms are two phenomena which are influenced by diffusion limitation. This article considers these effects on enzyme decay as applied to glucose isomerase. 相似文献
143.
Characterization of blood mononuclear cells reacting with K 562 cells after yellow fever vaccination
At various times after yellow fever (17 D) vaccination mononuclear blood cells were tested for cytotoxic potential in conjugate with K 562. They were characterized with monoclonal reagents Leu2a, Leu4, and OKM1, using indirect immunofluorescent technique. The cytotoxicity against K 562 increased after vaccination with a peak on Days 8–12 when the [3H]thymidine uptake was also maximal. The majority of cells in conjugates with K 562 were then T cells. Later the conjugates contained more OKM1-positive cells. OKM1 reagent was found to react with K 562 and thereby cause a coagglutination between this target cell and the OKM1-positive monocytic cells. The surface moiety reacting with OKM1 reagent might be of lipid nature. 相似文献
144.
Surface antigen changes occurring in short-term cultures of activated human T lymphocytes: analysis by flow cytometry 总被引:4,自引:0,他引:4
Surface antigens of activated and cultured human T cells were studied using peripheral blood lymphocytes activated with conditioned medium from phytohemagglutinin-activated leukocytes and maintained in liquid culture for 2 weeks with conditioned medium containing Interleukin 2. The ensuing cell population was tested for kinetic changes in cell size and for the expression of surface antigens by immunofluorescence staining with a panel of monoclonal antibodies and analysis by flow cytometry. Upon activation, the cell population progressively increased in size to large blasts, with the rapid appearance on all of the large dividing cells of the antigen recognized by OKT9, the transferrin receptor. Cells within the population continued to express the common peripheral T-cell antigens bound by OKT3 and UCHT1, and also the antigen bound by 3A1, but never the antigen bound by OKT6, a thymic cell marker. From the time of activation an increasing proportion of the T cells, up to 80%, expressed the antigen detected with OKIa and FMC4, which recognise nonpolymorphic Ia determinants. This sequence of events was followed by a general decrease in size of the cell population, a process accompanied by further phenotypic changes. The percentage of cells expressing Ia antigens decreased, but most striking was the rapid change in the OKT4:OKT8 ratio of cells within the population, from 60:40 to 40:60. Thereafter the proportions of OKT4+ to OKT8+ cells within the cultures remained relatively stable and it is suggested that these data provide evidence for a possible change in phenotype of cultured human T lymphoblasts, from OKT4 to OKT8. 相似文献
145.
J.A. Goldstein P. Linko J.N. Huckins D.L. Stalling 《Chemico-biological interactions》1982,41(2):131-139
Hexachlorobenzene (HCB) produced increases in ethoxyresorufin (ERR) O-deethylase, aryl hydrocarbon hydroxylase (AHH) and aminopyrine N-demethylase activities in rat liver microsomes which were intermediate between those produced by phenobarbital and 3,4-benzpyrene (BP). α-Naphthoflavone (ANF) selectively inhibited ERR activity in BP and HCB-induced microsomes (94% and 88%). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of liver microsomes indicated that HCB did not produce a detectable increase in a polypeptide with electrophoretic properties similar to those of purified cytochrome P-448 (Mr = 56 000). However, HCB did induce a polypeptide with Mr = 53 000 corresponding to one of two polypeptide bands induced by BP. This polypeptide may represent a second form of cytochrome P-448. Purification of HCB to remove possible dibenzo-p-dioxin impurities did not alter the ‘mixed-type’ induction produced by HCB. In contrast to HCB, all other chlorinated benzenes tested resembled phenobarbital as inducers. 相似文献
146.
39-kDa protein modulates binding of ligands to low density lipoprotein receptor-related protein/alpha 2-macroglobulin receptor. 总被引:41,自引:0,他引:41
J Herz J L Goldstein D K Strickland Y K Ho M S Brown 《The Journal of biological chemistry》1991,266(31):21232-21238
A 39-kDa protein of unknown function has previously been reported to copurify with the low density lipoprotein receptor-related protein (LRP)/alpha 2-macroglobulin receptor. In this study we demonstrate that a recombinant 39-kDa fusion protein can reversibly bind to the 515-kDa subunit of the LRP/alpha 2-macroglobulin receptor. This interaction inhibits the binding and uptake of the receptor's two known ligands: 1) beta-migrating very low density lipoproteins activated by enrichment with apoprotein E and 2) alpha 2-macroglobulin activated by incubation with plasma proteases or methylamine. A potential in vivo role of the 39-kDa protein is to modulate the uptake of apoE-enriched lipoproteins and activated alpha 2-macroglobulin in hepatic and extrahepatic tissues. 相似文献
147.
A M Irani S M Goldstein B U Wintroub T Bradford L B Schwartz 《Journal of immunology (Baltimore, Md. : 1950)》1991,147(1):247-253
Two murine mAb were prepared against human mast cell carboxypeptidase (HMC-CP) purified from human skin, and were termed CP1 and CP2, respectively. Double immunohistochemical labeling of Carnoy's-fixed sections of human skin, lung, and gastrointestinal tissue with CP1 and CP2, respectively, and with a murine monoclonal antitryptase antibody demonstrated that HMC-CP was selectively present in a subset of human mast cells. Double labeling experiments with CP1 and CP2, respectively, and a murine anti-chymase mAb demonstrated the presence of HMC-CP in the tryptase-positive, chymase-positive mast cell type (MCTC) only. Immunohistochemical labeling of peripheral blood leukocytes resulted in staining of monocytes with CP2 but not with CP1. In addition to chymase and a cathepsin-G like proteinase, HMC-CP is another neutral protease that is selectively present in the MCTC tryptase-positive, chymase-positive mast cells type of mast cell, thus extending the biochemical definition of human mast cell heterogeneity. 相似文献
148.
1. Chloramine was previously shown to inhibit glutamine uptake by human lymphoblast tumour cells. In the present study, the effect of monochloramine on the glutamine and glucose transport systems in HeLa cells and rat mesenteric lymphocytes was investigated. 2. Initial exposure to monochloramine slightly inhibited both the glutamine and glucose transport systems in HeLa cells. However, pre-exposing the cells to monochloramine increased its inhibitory action. 3. Similar results were obtained using rat mesenteric lymphocytes, which suggests that monochloramine's effects are not cell specific. 4. Only the Na(+)-independent (system L) component of glutamine transport activity in HeLa cells was inhibited by monochloramine. 5. Dithiothreitol protected both the glucose and glutamine transport carriers in HeLa cells against monochloramine inhibition. 6. Monochloramine did not inhibit HeLa cell metabolism, nor enhance cell lysis, which, in conjunction with other experimental data, suggests that monochloramine inhibits cellular transport activity by binding to thiol groups present on the membrane. 相似文献
149.
The direct and indirect methods for assaying the superoxide dismutase activity of a compound are compared. With the use of a direct method. the mechanism of the catalysis of O2-dismutation by the tested compound can be determined. while with the indirect method it cannot. and this may lead to misinterpretation of the results. Assuming that the catalysis occurs via the 'ping-pong' mechanism, both the direct and indirect methods are limited to the determination of values of kcat ≥ 105M-1s-1 and kcat ≥ 3 × 106M-1s-1. respectively. Moreover, many side reactions may occur with the indirect method which may interfere with the measurements. Nevertheless. the indirect method approximates better the in vivo conditions than the direct method, and a tested compound that has high SOD activity using a direct method and low SOD activity using an indirect method. will most probably be a poor SOD mimic in vivo. 相似文献
150.
Naum I. Goldstein Roman N. Goldstein Mark N. Merzlyak 《International journal of biometeorology》1992,36(2):118-122
The physico-chemical characteristics and possible formation mechanisms of negative air ions are considered. It was found that the products of oxygen and nitrogen negative ionization reduce ferricytochromec and nitroblue tetrazolium, and that these reactions were inhibited by superoxide dismutase. The interaction of negatively ionized oxygen with water led to hydrogen peroxide accumulation, which was inhibited by tetranitromethane or catalase. Nitrogen ionization under these conditions caused the formation of the hydrated electron e
aq
—
and the superoxide anion O
2
—
. The data obtained indicate that the biological activity of negative air ions may be dependent on superoxide. The generation of reactive oxygen ions in the gas phase and also at a gas/water interface is described. A scheme for superoxide production under oxygen and nitrogen ionization is proposed. 相似文献