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71.
William R. Tolbert Joseph Peder Richard C. Kimes 《In vitro cellular & developmental biology. Plant》1981,17(10):885-890
Summary A system has been developed for growth and maintenance of mammalian cells in suspension culture at high density. In principle,
the maintenance of constant levels of required nutrients coupled with the removal of toxic cell byproducts can support much
higher suspension cell densities than may be obtained in conventional spinners. The system consisted of 4- or 40-liter reaction
vessels equipped with a vertically supported rotating cylindrical filter. Agitation was provided by the magnetically driven,
rotating filter. Fresh medium was supplied at a rate of 10 to 20 ml/h per 109 cells and the expended medium free of cells was withdrawn through the rotating filter. Both pH and dissolved O2 and CO2 were monitored and regulated. Walker 256 carcinosarcoma cells have been grown in these reactors to densities 10-to 30-fold
greater than that obtained in Bellco spinners. In addition to high cell densities, the yield of cells per liter of medium
used was 2- to 3-fold that obtained in the conventional systems. Both 4-and 40-liter versions of this reactor have been operated
without the use of antibiotics. The 40-liter reactor also has been modified for chemostat operation. In a single run, for
example, the Walker cell density was maintained between 6 and 10×106 cells/ml with a total yield of 8.7×1011 cells from 360 liters of medium. 相似文献
72.
Summary To optimize culture conditions and gain a more reliable culturing system for studies of metabolic properties of neuronal cells,
a simplified perfusion chamber was developed. It consists of two parts: a perfusion block and a standard plastic culture dish.
To confirm the suitability of this chamber for continuous culturing of anchorage-dependent cells, the growth and morphology
of the four neuronal cell lines glioma C6 and glioma 138MG, neuroblastoma C1300, clones N1E115 and N18 were followed for 4
d using both traditional and perfusion techniques. A marked increase in growth and a decrease in the degree of morphological
differentiation were obtained with the latter technique compared to the former.
This work was supported by grants from the National Swedish Board for Technical Development (Grant 81-5009), the Swedish Work
Environmental Foundation (Grant 76-53), and Ollie and Elof Ericssons Foundation for Scientific Research. 相似文献
73.
The functional effect of neurotensin on the kinetics of dopamine (DA) release in the substantia nigra of the freely moving rat was investigated. After guide tubes for push-pull perfusion were implanted stereotaxically just above the substantia nigra, endogenous stores of DA in this structure were labelled by micro-injection of 0.02–0.05 μCi of [14C]-DA. Then an artificial cerebrospinal fluid (CSF) was perfused within the site at a rate of 20 μl/min at successive 5 min intervals. Neurotensin added to the CSF perfusate in concentrations of 0.05–0.1 μg/μl evoked an immediate, Ca++ dependent release of DA from sites directly within the substantia nigra or a delayed efflux when the peptide was perfused at the edge of this structure. Neurotensin failed to affect the pattern of release of this monoamine at sites which were not within the substantia nigra. Further, the body temperature of the rat also was not altered by neurotensin at any of the sites of perfusions. A relatively inactive analogue of the peptide, [D-Arg]9 neurotensin, was essentially without effect on DA activity. In double isotope experiments in which the substantia nigra of the rat was labelled with both [3H]-5-HT and [14C]-DA, the perfusion with neurotensin failed to affect 5-HT efflux while the release of DA was enhanced. Chromatographic analysis of the metabolites of DA in samples of push-pull perfusates revealed that neurotensin enhanced significantly the level of DOPAC and HVA. Overall, these results demonstrate that in the unrestrained rat neurotensin acts selectively within the substantia nigra to alter the presynaptic, Ca++ dependent release of DA. It is suggested that the mechanism by which the tri-decapeptide functions within this brainstem structure is through its modulation of nigral dopaminergic neurons. 相似文献
74.
The efficiency of lgM production by hybridoma cells (1) cultured in suspension; (2) entrapped in alginate beads; or (3) packed in hollowfiber cartridge bioreactors, were compared in long-term perfusion cultures. The results showed that steady-state cell concentration and antibody production, per liter of perfused medium per day, were similar when cells were either entrapped in alginate beads of maintained in suspension. These values were also similar whether cells were maintained at high density in a hollowfiber cartridge bioreactro, or at low density in suspension. This work points out that cell behavior and antibody yield are comparable overall in the various perfusion systems currently used. However, a significant reduction of antibody production appeared whenever a part of the viable cells was lost in the filtrate. The reduction was due both to a decrease of viable cell yield and a decline of lgM productivity on a percell basis. This result is well in agreement with the previously presented model of "grow or die" cell cycle system of hybridoma, which proposes that the ratio of arrested to proliferating cells in perfusion cultures, should be increased in proportion to cell retention in the bioreactor, with a concomitant increase of lgM productivity. 相似文献
75.
I Dormehl F Redelinghuys N Hugo D Oliver W Pilloy 《Journal of medical primatology》1992,21(5):270-274
Single photon emission computed tomography of the brain can be useful in animal experimentation directed toward cerebral conditions. A well established and understood baboon model, necessarily under anesthesia, could be especially valuable in such investigations. Six normal baboons were studied under various anesthetic agents and their combinations: ketamine, thiopentone, pentobarbitone, and halothane. Cerebral blood flow (CBF) studies were performed with 99mTc-HMPAO. CBF effects from various anesthesia were detected, requiring careful choice of the anesthesia for cerebral investigations. 相似文献
76.
Hybridomas lend themselves particularly well to large scale cultivation techniques since they grow as single cells in suspension without requiring attachment to a substrate. Furthermore, many cell strains have been adapted to grow in serum-free (SF) media to a similar cell density and antibody production as in serum containing media. This review will concern itself mainly with the cultivation of hybridomas in SF-media in bioreactors of various types with the ultimate goal of producing large quantities of monoclonal antibodies (mAb). 相似文献
77.
Julien Deschênes Jean-Paul Valet Normand Marceau 《In vitro cellular & developmental biology. Plant》1980,16(8):722-729
Summary The two-step collagenase perfusion method originally developed for the high yield isolation of parenchymal cells from adult
rat livers has been adapted to rats of 1 day, 1 week, and 3 weeks of age. The use of this method to isolate hepatocytes from
five or six rats of the respective ages demonstrated its reliability in terms of cell yield, percentage of single cells, and
cell viability. In all cases, hepatocytes attach with high efficiency to fibronectin precoated dishes using serum-free culture
medium. The dynamics of spreading is faster for newborn hepatocytes than adult ones. The functional integrity of these parenchymal
liver cells was assessed by their capacity to secrete albumin and α-fetoprotein in serum-free medium and to express lactate
dehydrogenase activity over a 24-hr period in primary culture.
Part of this work was presented at the 30th Annual Meeting of the Tissue Culture Association, Seattle, June, 1979. 相似文献
78.
Differentiation between the somatostatin inhibition and the post-somatostatin rebound observed on growth hormone secretion in vitro 总被引:1,自引:0,他引:1
A rebound in growth hormone secretion following somatostatin treatment has been shown in several systems where somatostatin suppresses secretion of the hormone. We have developed an in vitro system in which isolated and cultured pituitary cells were perfused after mild trypsinization. After washing, these cells retained their sensitivity and secreted growth hormone (GH) in response to physiological activators (norepinephrine, dopamine, serotonin) or inhibitors (somatostatin) as well as pharmacological activators (PGE2). The variation in GH secretion occurred within a minute after commencement of the infusion and was as rapidly reversible and repeatable minutes later. During somatostatin infusion the GH secretion was not totally suppressed (residual secretion (mean +/- S.D.) 34 +/- 7%). After the infusion a rapid rebound in GH secretion occurred, reaching levels in excess of the pretreatment value of 138 +/- 13%. This rebound effect occurred at doses higher than (10(-10)M) but not at lower doses, even when significant inhibition was observed. The inhibitory effect is of greater magnitude than the rebound effect (rebound = inhibition X 57 +/- 7% (mean +/- S.D.)). Furthermore, rebound was not enhanced by prolongation of somatostatin infusion. These latter results indicate that the rebound in secretion cannot be explained on the sole basis of storage of intracellular GH during somatostatin infusion and in fact suggest the involvement of a process of GH degradation and/or an inhibition of GH synthesis. 相似文献
79.
H. Stam H. Jansen W.C. Hülsmann 《Biochemical and biophysical research communications》1980,96(2):899-906
Chylomicron degradation by hearts from fed and fasted rats was studied using a perfusion technique, which allows the separate collection of coronary (Qrv) and interstitial effluent (Qi). Upon perfusion with [3H]-cholesterol-containing chylomicrons the tissue recovery of label was highest in the fasted state, while label recovered in Qi was highest in the fed state. Density gradient centrifugation of Qi indicated that the label was recovered in lipoproteins with higher densities: low density lipoproteins (1.019<d<1.050), high density lipoproteins (1.050<d<1.21) and a fraction of d>1.21. These particles probably represent chylomicron degradation products (remnants and “surface fragments”). Our results indicate that tissue cholesterol uptake during chylomicron degradation may be inhibited in the fed state. Furthermore, the role of the myocyte (or interstitial) lipoprotein lipase in chylomicron degradation is discussed. 相似文献
80.
Brian A. Laishes Gary M. Williams 《In vitro cellular & developmental biology. Plant》1976,12(7):521-532
Summary The conditions for obtaining representative, primary adult rat hepatocyte cultures were explored. The methods applied included
enzymatic liver perfusion which was nondestructive to hepatocytes, the prevention of aggregation of dissociated cells and
the selective attachment of viable cells. These procedures yielded a recovery of 50% of the liver cells which gave rise to
cultures representing 14% of the total liver cells. The cultures were composed of homogeneous epithelial-like cells cytologically
similar to hepatocytes and possessed a number of liver-specific enzymes. There was virtually no cell division initially and
most cells died between 24 and 48 hr. Insulin enhanced the attachment of the liver cells, altered their morphology, but did
not prolong cell survival.
This study was supported by grant no. BC 133 from the American Cancer Society. 相似文献