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821.
Massimo De Felici 《Molecular reproduction and development》1984,10(4):423-432
Fluorescent lectins were used to study the chemical nature of carbohydrate moieties present on the surface of female and male germ cells isolated from mouse gonads during fetal and early posnatal development. Concanavalin A (ConA), lens culinaris agglutinin (LCA), ricinus communis agglutinin (RCAI) and wheat germ agglutinin (WGA) bound intensely to the germ cell plasma membrane at all stages studied. Other lectins such as ulex europaeus agglutinin (UEAI) and agglutinin (SBA) did not bind or bound moderately (SBA to female germ cells only). Distinct developmental-related changes were observed when female germ cells were labeled with fluorescein-conjugated peanut agglutinin (PNA) or dolichos biflorus agglutinin (DBA). DBA and PNA binding was absent or weak in fetal female and male germ cells, but became intensely positive in oocytes in the immediate postnatal period. The percentage of oocytes stained with DBA increased during the first three days after birth, and from day 3–4 onwards all oocytes were strongly labeled. I suggest that these changes in lectin binding reflect changes in biochemical structure of the oocyte surface related to differentiative events occurring in the mouse ovary immediately after birth. 相似文献
822.
Lynn R. Trusal Albert W. Guzman Carol J. Baker 《In vitro cellular & developmental biology. Plant》1984,20(4):353-364
Summary The pathophysiology of endothelial cells is important to a variety of vascular conditions including coagulation and hemostasis
resulting from clinical frostbite. Use of an in vitro model system demonstrated that when bovine endothelial cells were frozen
at 1°C or 20°C/min and thawed immediately (20°C/min), a variety of ultrastructural alterations occurred. Membraneous structures
were most extensively damaged, with mitochondria the most sensitive organelle. Low amplitude mitochondrial swelling, first
evident at 0°C, progressed to high amplitude swelling by −10°C (frozen). In addition, the rough endoplasmic reticulum was
dilated and formed large vesicles with a homogeneous matrix. Nuclear changes first occurred at −15°C. These included separation
and distortion of the nuclear membrane, changes in chromatin distribution, and disruption of the nucleolus. Scanning electron
microscopy revealed perforated plasma membranes in some cells at −10°C (frozen) and in most cells by −20°C. Cultures frozen
at 20°C/min revealed mostly the same ultrastructural damage noted at 1°C/min except a higher percentage of cells exhibited
alterations. Data from the recovery index and lactic dehydrogenase (LDH) release correlated well with observed ultrastructural
changes. Early swelling of mitochondria and dilation of rough endoplasmic reticulum was not lethal in the absence of freezing.
Increased swelling in cytoplasmic organelles coupled with nuclear alterations at −15°C resulted in a decreased survival rate
and release of significant quantities of LDH by −20°C. No unique morphological changes were temperature specific, but the
total number of cells that displayed alterations increased as temperature decreased.
The views, opinions or findings, or both, contained in this report are those of the authros and should not be construed as
indicative of an official Department of the Army position, policy, or decision unless so designated by other official documentation. 相似文献
823.
Michael Ma Shuenn-Jue Wu Maureen Howard Alexej B. Borkovec 《In vitro cellular & developmental biology. Plant》1984,20(9):739-742
Summary We report here that the use of murine thymoma cell EL-4 conditioned medium enhances hybridoma yield in a low-antigen dose
in vitro immunization protocol. This improved protocol allowed the production of a panel of monoclonal antibodies toDrosophila yolk proteins using less than 1 nanomole of antigen. We believe this refinement will be valuable for the application of hybridoma
technology to biologically active materials that are hard to isolate and purify due to their low concentration in the biological
fluids.
This research was supported by the College of Agriculture and Life Sciences, University of Maryland, USDA-University of Maryland
Cooperative
Editor's Statement This observation should simplify in vitro immunization approaches and shed new light on the factors required
for the in vitro immune response. Wallace L. McKeehan 相似文献
824.
George E. Milo G. Adolph Ackerman Ronald L. Sanders 《In vitro cellular & developmental biology. Plant》1984,20(12):899-911
Summary Human lung epithelial cells have been isolated and maintained in pure culture and characterized during their time in culture.
Any residual fibroblasts were removed by selective trypsinization within the first 48 h in culture and the residual epithelial
cells from the primary culture grew to confluent density. The epithelial cells at Passage 2 or greater were serially subpassaged
when cultures reached ca. 80% confluency. This procedure permitted us to conduct biochemical and structural studies of starting
materials and subsequent population doublings.
Electron microscope evaluation of both initial monolayers and cell suspensions showed cultures to be composed of a single
cell type. These cells had microvilli on their free or apical surface. Subsequent population doubling level 1 up to 5 exhibited
the same structures. They contained lamellar inclusions, which are typical of Type II alveolar epithelial cells. Fetal lung
(age 18 to 20 wk) cell suspensions processed for electron microscopy before culturing showed cells to be undifferentiated,
epithelial-like with small microvilli along cell borders, and with desmosomes at cell junctions. Lamellar inclusions were
not observed in these cells. Ultrastructural studies of the cultured epithelial cells demonstrated that the lamellar inclusions
had a slightly positive reaction when tested for acid phosphatase. Phospholipid analysis of these lung epithelial cells showed
a phospholipid composition consistent with that found in surfactant-containing Type II cells. Cultured epithelial cells stained
with phosphine 3-R demonstrated a green fluorescent cytoplasm and nucleus with brightly fluorescent yellow-orange perinuclear
particles. The preceding characterization of these cells leads us to conclude that they exhibit structural and biochemical
features commensurate with Type II epithelial cells from human lung. Moreover, these selection techniques applied to the isolation
of human lung Type II cells from the tissue permit us to study the differentiative function of these cells routinely under
conditions of growth in vitro.
This work was supported in part by grants from EPA, R 806638-01 and 131-640-1599A1 相似文献
825.
Shu’a Yagev Michael Heller Arié Pinson 《In vitro cellular & developmental biology. Plant》1984,20(12):893-898
Summary Postnatal rat heart cells in culture enriched with respect to muscle cells were obtained by either high density seeding or
by the replating technique. [3H]Thymidine incorporation to DNA and the enzymatic pattern of cytoplasmic and lysosomal enzymes have been studied as a function
of the culture’s age, of seeding density, and replating. It was shown that (a) replating maintains predominance of myocyte
population for at least 2 wk in culture; (b) heavy seeding density allows homogeneous myocyte population for the 1st wk in
culture; and (c) the enzyme profile of the culture may serve as an indicator for the type of cell population in culture and
its state of differentiation.
This study was done as partial fulfilment of the M.Sc. thesis in Biochemistry (SY). Supported by grants from The Chief Scientist,
Ministry of Health, State of Israel; The Ministry of Education and Sciences, State of Niedersachssen (FRG); and The Foundation
for Heart Research from Mr. and Mrs. D. Vidal-Madjar, Paris, France. 相似文献
826.
K. Norrby S. Bergström P. Druvefors 《In vitro cellular & developmental biology. Plant》1984,20(8):607-614
Summary The intact membranous rat mesentery was cultured in Eagle's minimum essential medium containing no serum or only low concentrations
of serum. The procedure is in some important respects superior to previous organ culture techniques. To estimate the extent
of disturbance of homeostasis of the tissue in culture, the spontaneous mast-cell histamine release was quantitated after
preculture preparation of the specimens and after different intervals in culture. Also, the proliferation of fibroblasts and
mesothelial cells that predominate in the mesentery was assessed at 48 h by cytofluorometric quantitation of DNA in single-tissue
cells.
Spontaneous histamine release was time dependent during cultivation, amounting to ca. 50% at 48 h, and was affected by the
medium used for moistening the tissue before cultivation. Culturing also brought about great spontaneous increase in the proliferation
of fibroblasts and mesothelial cells, the rate being related to the concentration of serum. Addition of the mast-cell secretagogues
48/80 or polymyxin B at 1 h caused rapid release of 50 to 60% of the histamine and was followed by augmented proliferation
in the serum-containing media.
The spontaneous increase of cell proliferation in tissue culture may be causally related to mast-cell secretion. Further studies
are needed to define factors influencing the spontaneous mast-cell secretion and the mast-cell-dependent mitogenesis in normal
tissue cells
Supported by grants from the Swedish Medical Research Council (Project 5942) and State Board for Animal Experiments. 相似文献
827.
James S. Clegg 《Cell biochemistry and biophysics》1984,6(3):153-169
Cysts of the crustaceanArtemia are a useful model for studies on intracellular water because they are capable of essentially complete and reversible desiccation.
We have used a variety of techniques on this system, the present work being an attempt to estimate the density of intracellular
water (ρw). The density of individual cysts was evaluated from sedimentation velocity. Heptane displacement methods were used to determine
the volume of a known mass of cysts, from which the density was calculated. The two methods produce comparable results. It
was shown that the densities and water contents of large masses of cysts accurately reflect those of individual cysts. Cyst
densities (ρc) were determined over the entire range of water content from 0 to 0.63 weight fraction of water (W
f), and temperature dependence was measured for 0.61W
f over 2–41°C. The following refer to 25°C. No marked change was detected in ρc until the water content exceeded 0.15W
f, at which ρc decreased as a linear function of Wf to maximum water content. However, the cyst does not behave ideally in the sense that
the densities of the nonaqueous components and added water are not additive as a function ofW
f. The partial specific volume of water in cysts at maximum hydration was estimated to be 3% larger than that of pure water.
These observations are compared with density measurements on other systems, and with previous findings on the physical properties
of water in this system. 相似文献
828.
4,4′-Diisothiocyano-1,2-diphenylethane-2,2′-disulfonic acid (H2DIDS) known as an irreversible inhibitor of the anion transport in red blood cells (Cabantchik, Z.I. and Rothstein, A. (1972) J. Membrane Biol. 10, 311–330) blocks also the uptake of bile acids and of some foreign substrates in isolated hepatocytes (Petzinger, E. and Frimmer, M. (1980) Arch. Toxicol. 44, 127–135). [3H]H2DIDS was used for labeling of membrane proteins probably involved in anion transport of rat liver cells. The membrane proteins modified in vitro by [3H]H2DIDS were compared with those labeled by brominated taurodehydrocholic acid. The latter is one of a series of suitable taurocholate derivatives, all able to bind to defined membrane proteins of hepatocytes and also known to block the uptake of bile acids as well as of phallotoxins and of cholecystographic agents (Ziegler, K., Frimmer, M., Möller, W. and Fasold, H. (1982) Naunyn-Schmiedeberg's Arch. Pharmacol. 319, 254–261). The radiolabeled proteins were compared after SDS-electrophoresis with and without reducing agent present, solubilization by detergents, two-dimensional electrophoresis and after separation of integral and peripheral proteins. Our results suggest that the anion transport system of liver cells cannot distinguish between bile acids and the anionic stilbene derivative (DIDS). The labeling pattern for both kinds of affinity labels was very similar. Various combinations of separation techniques gave evidence that the radiolabeled membrane proteins are not subunits of a single native channel protein. 相似文献
829.
(1) Krebs II ascites cells were taken as a model of the neoplastic cells to investigate the transverse distribution of phospholipids in the plasma membrane. The experimental procedure was based on non-lytic degradation of phospholipids in the intact cell by Naja naja phospholipase A2 and Staphylococcus aureus sphingomyelinase C and on phopholipid analysis of purified plasma membranes. It was shown that the three major phospholipids, i.e., phosphatidylcholine, phosphatidylethanolamine and sphingomyelin, are randomly distributed between the two halves of the membranes, whereas phosphatidylserine remains located in the inner leaflet. (2) The membrane localization of phosphatidylcholine and phosphatidylethanolamine subclasses (diacyl, alkylacyl and alkenylacyl) was also examined, using a new procedure of ether-phospholipid determination. The method involves a selective removal of diacyl species by guinea pig pancreas phospholipase A1 and of alkenylacyl species by acidolysis. This analysis revealed a 50% increase of ether phospholipids in the plasma membrane as compared to the whole cell (36.5 and 23.1% of total phospholipid, respectively). Furthermore, a strong membrane asymmetry was demonstrated for the three phosphatidylcholine subclasses, since 1-alkyl-2-acyl-sn-glycerol-3-phosphocholine (alkylacyl-GPC) was entirely found in the inner leaflet, whereas both diacyl- and alkenylacyl-GPC displayed an external localization. The same pattern was observed for phosphatidylethanolamine subclasses, except for 1-alkenyl-2-acyl-sn-glycero-3-phosphoethanolamine, which was found randomly distributed. These results are discussed in relation to the process of cell malignant transformation and to the biosynthesis of platelet-activating factor (PAF-acether or 1-alkyl-2-acetyl-GPC). 相似文献
830.
Taenia taeniaeformis: characterization of larval metabolic products and growth of host gastric cells in vitro 总被引:1,自引:0,他引:1
Development of larvae of the cestode parasite Taenia taeniaeformis in the liver of rats induces gross hyperplasia of the gastric mucosa and excessive mucus production in the stomach without any direct contact with the stomach. Because the taeniid larvae are known to elaborate excretory-secretory (E-S) product in vivo and in vitro, the product was analyzed further, and its effects on cultured rat and dog stomach cells were investigated. In vitro E-S product contained less negatively charged glycosaminoglycan than either heparin or chondroitin sulfate, and proteins of various molecular weights. It stimulated the growth of both rat and dog stomach cells at concentrations of 3-9 micrograms protein/ml culture medium. At a concentration of 30 micrograms protein/ml culture medium, it stimulated hexosamine production in the cells up to 20 times, and multiple intracytoplasmic granules were found in both rat and dog cultured cells by light and electron microscopy. These results suggest that larval E-S product may be involved in the induction of gastric hyperplasia and hypermucus secretion. 相似文献