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991.
Selective-Differential Medium for Isolation and Differentiation of Pectinatus from Other Brewery Microorganisms 总被引:2,自引:2,他引:0 下载免费PDF全文
An agar medium, LL-agar (lactate-lead acetate) was designed to selectively differentiate members of the genus Pectinatus (S. Y. Lee, M. S. Mabee, and N. O. Jangaard, Int. J. Syst. Bacteriol. 28:582-594, 1978; S. Y. Lee, M. S. Mabee, N. O. Jangaard, and E. K. Horiuchi, J. Inst. Brew. 86:28-30, 1980) from other brewery microorganisms. Selectivity was achieved by the use of sodium lactate as the sole source of carbon and phenylethyl alcohol as an inhibitor for aerobic gram-negative bacteria and yeast. Differentiation was established by the introduction of lead acetate into the medium, which reacted with the H2S liberated by Pectinatus and resulted in a blackening of the Pectinatus colonies while the other brewery organisms, when present, remained white. In combination with the Lee tube (J. E. Ogg, S. Y. Lee, and B. J. Ogg, Can. J. Microbiol. 25:987-990, 1979) and this medium, isolation of Pectinatus organisms from beer samples was accomplished with convenience and simplicity. 相似文献
992.
Michael G. Gabridge Edward P. Dougherty Martha F. Gladd Rose A. Meccoli 《In vitro cellular & developmental biology. Plant》1982,18(12):1023-1032
Summary Tracheal explants were used to evaluate the relative ciliostatic and cytotoxic potential of heavy metal salts (cadmium chloride,
chromium chloride, nickel chloride, and copper sulfate). Explants from hamster, rat, and guinea pig were all sensitive to
the metals, though guinea pig explants showed the greatest difference between the untreated and metal treated tissues. Dosage
levels were 50, 100, and 500μM, for 24 to 148 h. Cadmium caused the greatest degree of ciliostasis and cell necrosis. Copper was less toxic, and nickel
and chromium caused marginal damage when tested at 100μM or lower. In each instance, damage became detectable at approximately 24 to 48 h and was nearly stabilized by 72 h. A significant
loss of ciliary motion was always accompanied by a decrease in metabolic activity (dehydrogenase activity and ATP content).
Transmission and scanning electron microscopy revealed a severely necrotic epithelium after exposure to cadmium, with only
subtle morphological alterations after exposure to other metals. With all of the treatments there was no overt structural
damage to cilia and little alteration in membranes of cells remaining in the epithelium. Some coagulation or vacuolization
was noted in cadmium and copper treated explants but most cellular organelles did not display obvious damage. The most significant
changes in the tracheal epithelium exposed to heavy metal salts in vitro were a loss of ciliary motion and a decrease in total
ATP content.
This study was supported in part by Grant HL 26880 from the National Heart, Lung and Blood Institute, Bethesda, MD. 相似文献
993.
Michael G. Gabridge Marlene J. Bright Helen R. Richards 《In vitro cellular & developmental biology. Plant》1982,18(1):55-62
Summary Cell monolayer cultures were prepared from hamster tracheal explants by a collagenase exposure and subsequent incubation in
Waymouth’s MAB 87/3 medium. The epithelial outgrowth occurred on glass cover slips. Cilia on the monolayers continued to beat
normally after the “parent” explant was removed. Monolayer cultures infected withMycoplasma pneumoniae had significant amounts of attachment. A morphological analysis of the attachment was conducted with scanning electron microscopy.
Clusters, cocci, and filaments ofM. pneumoniae all attached to the epithelial cells, but the filaments were especially common. Mycoplasmas were seen in association with
both ciliated and nonciliated cell membranes. On ciliated cells, mycoplasmas were on the ciliary strands and on the cell membrane.
When located immediately adjacent to or in between cilia, mycoplasmas were oriented vertically with the constricted attachment
tip oriented down toward the host cell membrane. When located more than a micron away from the ciliary fibers, mycoplasmas
lay horizontally along the epithelial cell membrane. The photographic data suggest that clusters or “sperules” of mycoplasmas
may liberate individual mycoplasmas that attach to the cell membrane. It appears that the receptor sites forM. pneumoniae are rather uniformly distributed along the ciliated cell membrane, and are not restricted to the interciliary areas.
Electron microscopy was done with the cooperation of Dr. R. Macleod and the staff of the Center for Electron Microscopy at
the University of Illinois. Critical editorial review was provided by C. Dayton.
This investigation was supported in part by grants to M. G. G. from the National Institute of Allergy and Infectious Diseases
(AI 12559) and the National Heart, Lung, and Blood Institute (HL 23806), Bethesda, Maryland. 相似文献
994.
Lynn J. Romrell Michael G. O'Rand Pamela R. Sandow James P. Porter 《Molecular reproduction and development》1982,5(1):35-48
Autoantigens that appear during spermatogenesis in the rabbit were identified using immunoadsorbent chromatography and SDS-PAGE. To identify cell-surface proteins, samples of freshly isolated, staged cells were labeled by the lactoperoxidase or Iodo-Gen iodination procedure and run on SDS-PAGE. Autoradiograms of the stained, dried gels were prepared. By correlating the band patterns in the SDS gels of immunocolumn and surface-labeled samples with the band patterns in the autoradiograms, it was possible to show when the autoantigenic proteins appeared on the cell surface. To further support the identification of membrane autoantigens, surface-labeled, staged cell samples were lysed in Triton X-100 and immunoprecipitated with antitestis cell autoantisera. Three types of autoantigens have been identified: (1) late class antigens that are present only on late spermatids and epididymal spermatozoa, but are intracellular in early stages, (2) early class antigens which occur on the surface of pachytene spermatocytes and are present throughout subsequent stages of development, and (3) early class, transient antigens, which appear on spermatogenic cells but are not present on epididymal spermatozoa. 相似文献
995.
996.
997.
Barry W. Festoff Michael R. Patterson Karl Romstedt 《Journal of cellular physiology》1982,110(2):190-195
Clonal mouse skeletal muscle cells which differentiate in culture and from synpases with neuronal cells were found to secrete high levels of protease activity as measured with an 125I-fibrin assay. The secreted proteolytic activity was more than 90% dependent upon the presence of plasminogen in the medium, and had a pH optimum at 7 to 8. This activity was not inhibited by n-ethylmaleimide, pepstatin, EDTA, or EGTA. At millimolar concentrations, greater than 90% inhibition was obtained with either soybean typsin inhibitor, epsilon aminocaproic acid, Trasylol, or leupeptin. Almost complete inhibition occured with 1 mM diisopropylfluorophosphate suggesting the presence of a serine residue at the catalytic site. In contrast to the high levels of secreted activity, a lower steady-state level of cell-associated protease activity was detected in cell lysates. The high level of plasminogen activator secreted into the medium of cultured muscle cells suggests a role for such extracellular protease activity in myogenesis during development and remodeling following muscle injury. Such information may be useful in understanding the initial degeneration of neuromusclar contacts in experimental and pathologic denervation. 相似文献
998.
Carlo M. Ignoffo Clemente Garcia Michael J. Kroha 《Journal of invertebrate pathology》1982,39(2):198-202
The LD50 for larvae of Trichoplusia ni injected with blastospores of Nomuraea rileyi was 4.30 ± 1.16 hyphal bodies/larva; the LD50 for injected conidia was ca. 25,000 conidia/larva. The dose-mortality regression line for blastospores was Y = 4.6504 + 0.5487 X. Larval mortalities of Anticarsia gemmatalis and T. ni at 100 blastospores/larva were 0.4 ± 0.5% and 96.7 ± 1.9%, respectively. At a dosage of 25,000 conidia/larva, larval mortalities for A. gemmatalis and T. ni were 0.4 ± 0.5% and 43.1 ± 8.7%, respectively. Thus, larvae of A. gemmatalis were > 100 times and >200 times more resistant to injected conidia and blastospores, respectively, than were larvae of T. ni. Resistance of A. gemmatalis to N. rileyi may not be solely at the integumental barrier, as is often believed, but may also be a function of an internal physiological response. 相似文献
999.
Anthony V. Capuco Pamela A. Feldhoff R.Michael Akers James L. Wittliff H.Allen Tucker 《Steroids》1982,40(5):503-517
Binding of [3H]R5020 (17,21-dimethyl-19-nor-4,9-pregnadiene-3, 20-dione) to bovine mammary cytosol indicated the presence of progestin binding sites of high-affinity and low-capacity in tissue from prepartum, nonlactating and from postpartum, lactating cows. To prevent binding of [3H]R5020 to glucocorticoid binding sites, a 200-fold molar excess of nonradioactive cortisol was included during all incubations, thus specific binding was limited to progestin binding sites. Nonradioactive R5020 and progesterone effectively inhibited [3H]R5020 binding to progestin binding sites, while estradiol-17β, dihydrotestosterone (17β-hydroxy-5α-androstan-3-one), dexamethasone (9-fluoro-11β, 17, 21-trihydroxy-16α-methyl-1,4-pregnadiene-3,20-dione) or additional cortisol were ineffective. Dissociation constants for specifically bound [3H]R5020 in cytosol from mammary tissue of nonlactating and lactating cows were nearly identical, averaging 1.9 ( ± 0.3) and 0.8( ± 0.2) × 10?9M, respectively. However, binding capacities (fmol/mg cytosolic protein) were greater in cytosol from prepartum, nonlactating (179 ± 53) than postpartum, lactating (41 ± 15) cows. Specific binding components in cytosol from lactating cows sedimented in the 6-7S region on linear sucrose density gradients. When subjected to isoelectric focusing, specific binders with isoelectric points (pI) of approximately 6.1, 7.9 and 8.3 were resolved. The decrease in number of binding sites during lactation was due to the virtual absence of the anionic binding species, suggesting that their presence is necessary for progesterone to inhibit milk secretion. 相似文献
1000.
Aleurone tissue from undried immature developing wheat grains (Triticum aestivum L. cv. Sappo), normally insensitive to gibberellic acid, can be made to respond to the hormone by a series of temperature treatments. Incubation of the de-embryoed grains at temperatures above 27° C for at least 8 h causes the tissue to become sensitive. Prolonged incubation at temperatures below 27° C does not effect a change in sensitivity. In addition to the requirement for exposure to an elevated temperature for a period of several hours the tissue must also subsequently be subjected to a period at a lower temperature for just a few seconds for the response to be observed. Once sensitized, the tissue remains responsive to gibberellic acid for substantial periods of time. Exposure of the tissue to temperatures which induce sensitivity to gibberellic acid also results in an increased leakage of amino acids. It is suggested that the increase in sensitivity to gibberellin requires two separate processes to take place. One could be a homeoviscous adaptation of the cell membranes in response to elevated temperature, the other a subsequent, permanent change in conformation of membrane components. 相似文献