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991.
Selective changes in gangliosides of human milk during lactation: a molecular indicator for the period of lactation 总被引:2,自引:0,他引:2
Gangliosides of human milk from women at various periods of lactation were analyzed. GD3 in colostrum, particularly in the early period of lactation, was the major ganglioside, and the molar ratio of GM3 to GD3 was 0.2-0.3 in the milk at 2-6 days postpartum. In contrast, milk from women at 60-390 days postpartum contained GM3 as the major ganglioside and the molar ratio of GM3 to GD3 was more than 3. Milk at 8-40 days postpartum represented an intermediate stage in terms of the ratio of GM3 to GD3. The selective change in the molar ratio of gangliosides was observed as a phenomenon common to all human milk from different individuals at different periods of lactation, indicating that the periods of lactation can be defined on the basis of the ratio. Since glycolipids in human milk are preferentially localized in the milk fat globule membrane, which is derived from the plasma membrane of epithelial cells in the mammary gland, the changes in the ganglioside composition reported in this communication may reflect a qualitative change of the cells in the mammary gland. 相似文献
992.
Diethylenetriaminepentaacetic acid (DTPA), a strong chelating agent, was covalently linked to murine monoclonal anti-HLA IgG1 antibody (H-1) with the use of poly(L-lysine) (Mr 14,000) as a multivalent, intermediary carrier, via thiol-disulfide exchange reaction. The conjugates contained up to 42.5 mol DTPA per mol antibody, and retained over 90% of their antibody activity in vitro. The conjugates incorporated gadolinium (Gd) through an exchange reaction with Gd-EDTA, used to prevent colloid formation and nonspecific binding of the free metal. The IgG-poly(L-lysine)-DTPA-Gd had a greater effect per mol on proton relaxation rates than DTPA-Gd itself. Use of poly(L-lysine) as an intermediary carrier for attachment of chelating agents to IgG thus offers great potential for achieving high-specific-activity conjugates, particularly for use as biologically specific contrast agents in nuclear magnetic resonance imaging. 相似文献
993.
Histopathological examinations on nephlocalcinosis of the Fischer 344 (F344) rats were carried out. As the results of comparison on its appearance among F344, Wistar and SD strains of rats, F344 female rats showed the most severe nephrocalcinosis. Nephrocalcinosis developed between 4 weeks and 8 weeks and was likely to keep its appearance through 108 weeks of the survival period of the rats. Histologically, mineral deposit was always observed at cortico-medullary junction. It seemed to locate at the outer portion of the basement membrane of the tubular epithelium, adjacent to the capillary wall in the connective tissue. Four weeks after ovariectomy at 4 weeks of age, the rats showed a decrease in degree of nephrocalcinosis. In contrary, the rats treated with estorone following ovariectomy revealed an increase in degree of nephrocalcinosis. It was suggested that the oestrogen-type sex hormone appeared to give a role in nephlocalcinosis. 相似文献
994.
A comparison of the inhibitory effects of somatostatin-14, -25, and -28 on motility of the guinea pig ileum 总被引:2,自引:0,他引:2
C H McIntosh V Bakich Y N Kwok J C Brown 《Canadian journal of physiology and pharmacology》1986,64(3):303-306
A number of studies have suggested that somatostatin-14 (SS-14) and somatostatin-28 (SS-28) exhibit a similar spectrum of biological activities but have different potencies. In the present study the effects of SS-14, SS-28, and somatostatin-25 on electrically induced contractions of the guinea pig ileum have been compared. All three peptides exhibited equipotent inhibitory effects. Inhibition was obtained at a threshold concentration less than 10(-10) M, with maximal inhibition at 10(-7) M and IC50 values of 6.0-6.5 X 10(-10) M. The N-terminal 14 amino acid fragment of SS-28 had no effect either on motility, when added alone, or on the actions of SS-28, suggesting that this region of the molecule is not critical for biological activity. 相似文献
995.
The expression for the sedimentation rate in inclined tubes given by Nakamura et al (Nakamura, H. and Kuroda, K. Keijo J. Med. 8, 256-296, 1937) is improved to be applicable to the problem that the falling velocity of a particle from the top wall of the tube v' differs from the one from the interface between the particle free layer and the suspended layer v. The effects of the shape at the bottom of the tube and the increase in height of the layer closely packed with particles are taken into account. 相似文献
996.
Multiplication of Legionella pneumophila Philadelphia-1 in cultured peritoneal macrophages and its correlation to susceptibility of animals 总被引:13,自引:0,他引:13
Intracellular growth of Legionella pneumophila Philadelphia-1 strain in peritoneal macrophages (PMP) from various rodents was measured and its correlation to the level of susceptibility of the animal was examined. In guinea pig PMP, the organism grew well and the guinea pig was very susceptible to it (50% lethal dose, LD50 = 7.6 X 10(4)). On the other hand, the bacteria hardly multiplied in mouse PMP and the animal was resistant to infection (LD50 = 6.7 X 10(7)). Intracellular growth rate correlated well with susceptibility in these animals. In golden hamsters, a discrepancy between intracellular growth and susceptibility was found. The organism grew intracellularly as rapid as in guinea pig PMP, but the golden hamster was very resistant to infection (LD50 = 2.2 X 10(8)). In rat PMP, the organism did not grow intracellularly during a 24-h period of infection, but started to grow after that and the growth rate thereafter was as rapid as in guinea pig PMP. WKA rats were resistant and the LD50 in the animal was 1.9 X 10(7). In vivo natural resistance of rats and golden hamsters to the organism was considered to be a result of other factors than macrophages. 相似文献
997.
Y Deshaies 《Canadian journal of physiology and pharmacology》1986,64(7):885-891
The present study was undertaken to compare plasma lipoprotein lipid composition, as well as white adipose tissue lipoprotein lipase activity, in rats fed purified diets high in either sucrose or corn oil. The experimental diets (65% of calories as sucrose or corn oil, 15% as the opposite nutrient, and 20% as casein) were given ad libitum for 4 weeks. An additional group was fed a nonpurified diet as a reference diet. Both sucrose and oil diets were spontaneously consumed in isocaloric amounts by the animals. Despite energy intakes that were 35% lower than that of the reference group, the sucrose and oil groups exhibited final body weights that were only 6 and 9% lower, respectively, than that of the reference group, and accumulated more fat in the epididymal depots. Postprandial as well as fasting total cholesterol levels were similar in the sucrose and oil groups, while the high-density lipoprotein to total cholesterol ratio was highest in the animals fed corn oil. In both the fasted and fed states, plasma total triglyceride levels were 73% higher in the sucrose group than in the corn oil group. The largest triglyceride differences due to diet were observed in the chylomicron + very-low-density lipoprotein fraction. The oil-fed rats accumulated large amounts of triglycerides in their livers. Postprandial lipoprotein lipase activity in epididymal adipose tissue was almost twice as high in the sucrose group as in the oil group.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
998.
Secretion of a suppressor cell inducing factor by an interleukin-3 dependent cell line with natural cytotoxic activity 总被引:2,自引:0,他引:2
This report describes the morphology, surface markers, growth requirements, and functional activity of the M1-A5 cell line, which was established by the limiting dilution of spleen cells from a mouse bearing a large methylcholanthrene-induced fibrosarcoma. The M1-A5 cells share many of the morphological features of large granular lymphocytes and, in addition, express asialo GM1 and Ly-5 surface markers which are commonly found on natural killer cells (NK) cells. There is no expression of T-cell differentiation antigens, surface immunoglobulin, or the granulocyte/macrophage marker, MAC-1. M1-A5 cells are dependent on exogenous growth factor(s) for survival and will proliferate if cultured in interleukin 3 (IL-3), but not in interleukin 1 (IL-1), interleukin 2 (IL-2), or granulocyte/macrophage colony stimulating factor (GM-CSF). In addition, the M1-A5 cells do not absorb IL-2. Despite their morphology and surface characteristics, the M1-A5 cells do not lyse NK targets such as YAC-1 and RLM1 in 4- or 18-hr cytotoxic assays but do lyse the natural cytotoxic (NC) susceptible target, WEHI-164, and to a very small extent, the M-1 fibrosarcoma cells, in an 18-hr assay. Thus they exhibit NC-like cytotoxic activity. In addition, the M1-A5 cells secrete a small molecular weight factor which activates suppressor cells capable of inhibiting antibody synthesis by cocultured syngeneic spleen cells. 相似文献
999.
Chromosome condensation activity in the cytoplasm of anucleate and nucleate fragments of mouse oocytes 总被引:3,自引:0,他引:3
The activity of maturation promoting factor (MPF) which causes chromosome condensation and subsequent oocyte maturation was investigated in mouse oocytes using polyethylene-glycol-mediated cell fusion technique. Fully grown oocytes were bisected at germinal vesicle (GV) stage or shortly after germinal vesicle breakdown (GVBD) into anucleate and nucleate fragments. After 2-3 or 15-17 hr of culture these fragments were fused with interphase blastomeres from two-cell embryos. It was found that almost all the anucleate oocyte fragments cultured for a short term (2-3 hr), regardless of whether they were produced at GV stage or after GVBD, induced premature chromosome condensation in the blastomere nuclei, whereas only about 20% of those cultured for a long term (15-17 hr) could do so. On the other hand, the nucleate fragments always retain the cytoplasmic activity to induce chromosome condensation. Thus we suggested that the MPF initially could appear in mouse oocytes independently of the GV, that the mixing of GV material with the oocyte cytoplasm following GVBD had no effect on the activity of MPF in anucleate fragments, and that oocyte chromosomes or some components associated with them could play a significant role in maintaining the MPF activity. 相似文献
1000.
Progestin (P) target cells were identified in the pituitary gland of gonadectomized female rats which had been primed with estrogen (E). P staining was localized using the immunohistochemical avidin-biotin-peroxidase (ABP) complex method. Dark brown precipitates were primarily found over the cytoplasm of cells in the pars distalis, but not in the pars intermedia nor in the pars nervosa. The majority of P-sensitive cells in the pars distalis were identical with luteotrophs, a few being lactotrophs. These observations suggest a role of P in the regulation of production and secretion of gonadotrophins in the pituitary glands of female rats. 相似文献