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41.
G R Newton P J Hansen F W Bazer M V Leslie D C Stephenson B G Low 《Biology of reproduction》1989,40(2):417-424
Allantoic and amniotic fluids were collected on Days 60 (n = 3), 100 (n = 4), and 140 (n = 3) of pregnancy. The presence of uterine milk proteins (UTM-proteins) in these samples was evaluated by Ouchterlony immunodiffusion and enzyme-linked immunoabsorbant assay (ELISA). Eight of ten samples of allantoic fluid and three of ten samples of amniotic fluid produced one or two immunoprecipitin bands against antiserum to UTM-proteins. Each band fused with immunoprecipitin bands from UTM-proteins purified from uterine fluid. Data from a semi-quantitative ELISA indicated that allantoic fluid from all ewes and amniotic fluid from six of ten ewes contained immunoreactive UTM-proteins. Concentrations of UTM-proteins in these fluids were not statistically affected by day of gestation (p greater than 0.10), but tended to decline as gestation advanced. Greater concentrations of UTM-proteins were detected in allantoic fluid than in amniotic fluid (p less than 0.05). The physical characteristics of the immunoreactive material in allantoic and amniotic fluids were examined by polyacrylamide gel electrophoresis and Western blotting. The immunoreactive material was found to possess pIs and molecular weights identical to UTM-proteins. These results indicate that fetal fluids contain material that reacts with antiserum to UTM-proteins and has physical properties similar to UTM-proteins. It is likely, therefore, that the UTM-proteins are transported across the placenta during gestation, perhaps to serve some function in the fetal compartment. 相似文献
42.
Autonomous replication sequences in an extrachromosomal element of a pathogenic Entamoeba histolytica. 总被引:2,自引:1,他引:1
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Entamoeba histolytica possesses a 24.5 kilobase plasmid-like molecule which encodes for the organism's ribosomal RNAs. Sequence analysis of this extrachromosomal element revealed the presence of AT rich sequences which show homology to the origin of replication of other lower eucaryotes. An 802 bp fragment containing these sequences was cloned into a yeast shuttle vector lacking the origin of replication and the construct tested for its ability to replicate autonomously in yeast. Mitotic stability tests as well as evidence for plasmid maintenance indicate that the transformed cells contained self-replicating episomes and not stably integrated molecules. The nucleotide sequence of this ARS-containing fragment is presented. 相似文献
43.
Common expression of a tumor necrosis factor resistance mechanism among gynecological malignancies 总被引:2,自引:0,他引:2
C. Bethan Powell David G. Mutch L. Stewart Massad Ming-Shian Kao John Leslie Collins 《Cancer immunology, immunotherapy : CII》1990,32(2):131-136
Summary The efficacy of tumor necrosis factor (TNF) as an anticancer agent is limited. This limitation might be related to the expression of a protein-synthesis-dependent resistance mechanism that prevents the lysis of tumor cells by TNF. To test this possibility eight randomly selected human cell lines, three derived from ovarian carcinomas and five derived from cervical carcinomas, were tested for their in vitro sensitivity to TNF-mediated lysis. The results of this analysis showed that all eight cell lines are normally resistant to lysis by TNF. However, in the presence of inhibitors of protein synthesis, seven of them showed a significant increase in TNF-mediated lysis. Measurement of protein synthesis showed that there is a linear correlation between the level of inhibition of protein synthesis and the level of TNF-mediated lysis. The fact that seven of eight randomly selected cell lines are resistant to TNF because they express a protein-synthesis-dependent resistance mechanism suggests that this mechanism of resistance may be common among gynecological cancers. The results also suggest that a therapy involving TNF and inhibitors of protein synthesis might be useful for the treatment of gynecological malignancies. 相似文献
44.
Guinea-pig hepatocytes whose plasma membranes were rendered permeable by treatment with saponin, accumulated 45calcium in the presence of potassium oxalate and ATP. The uptake was linear with time for up to one hour when high-capacity EGTA buffers were used (5mM). In the presence of a supra-maximal concentration of inositol 1,4,5-trisphosphate, under conditions minimising metabolism of this calcium-mobilising messenger, 45calcium accumulation was inhibited by about 40% for a period of one hour. Electron microscopic examination of the cells, revealed the presence of electron dense precipitates. Electron microprobe analysis of the precipitates indicated that they constituted the majority of the oxalate-dependent calcium uptake. The precipitates were located throughout the non-nuclear regions of the cells. Cells treated with inositol 1,4,5-trisphosphate contained fewer precipitates, but high cell-to-cell variability prevented conclusions as to the precise location of the pool sensitive to inositol 1,4,5-trisphosphate. These results support the previous contention that a fraction of endoplasmic reticulum is completely emptied of calcium by maximal concentrations of inositol 1,4,5-trisphosphate, while another fraction is insensitive to this action. In addition, these findings indicate that the pool of intracellular calcium on which inositol 1,4,5-trisphosphate acts is oxalate-permeable, and that the calcium-releasing action of inositol 1,4,5-trisphosphate does not desensitise within one hour. 相似文献
45.
Judith R. Turnlund Leslie Wada Janet C. King William R. Keyes Lorra L. Acord 《Biological trace element research》1988,17(1):31-41
Copper absorption was measured at two levels of dietary zinc in six healthy young men who were confined to a metabolic unit
for a 75 d study of zinc utilization. A diet of conventional foods was fed, providing either 16.5 or 5.5 mg zinc and 1.3 mg
copper daily. Copper absorption was determined by feeding65Cu, a stable isotope of copper, once during the 16.5 mg Zn diet and near the beginning and end of the 5.5 mg Zn diet. Apparent
copper absorption averaged 48.1% when the 16.5 mg Zn diet was fed. This was significantly higher than the averages of 37.2
and 38.5% when the 5.5 mg Zn diet was fed. Absorption also differed significantly among subjects. Fecal copper did not differ
between diets or among subjects. All subjects were in positive copper balance at both levels of dietary zinc. These results
suggest that a dietary zinc intake slightly above the Recommended Dietary Allowance of 15 mg/d does not increase fecal copper
loss and does not interfere with copper absorption. 相似文献
46.
Leslie S. Indrasith Takuji Sasaki Toshinobu Yaginuma Okitsugu Yamashita 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1988,158(1):1-7
Summary Analysis of yolk proteins of the silkworm,Bombyx mori, by SDS-polyacrylamide gel electrophoresis and immunoblotting showed that there was a developmental change in subunit composition of egg-specific protein; egg-specific protein consisting of 72 kDa subunits alone (premature form) was found in vitellogenic follicles, whereas the protein in mature eggs was composed of 72 kDa and 64 kDa subunits (mature form). The premature form of egg-specific protein was purified from young ovaries to homogeneity using a high performance liquid chromatography system. The purified protein had an apparent molecular mass of 225 kDa which could not be distinguished from that of the mature form. By circular dichroism analysis, both egg-specific proteins were estimated to have about 30% -helix and 20% -sheet, but the mature form showed a relatively rigid conformation in the aromatic region. The premature egg-specific protein purified from vitellogenic ovaries, consisted of three 72 kDa subunits, whereas mature egg-specific protein was composed of two 72 kDa subunits and one 64 kDa subunit. All of these subunits showed the same immunoreactivity towards antiserum raised against the mature form. An identical NH2-terminal amino acid sequence was found in both 72 kDa polypeptides and 64 kDa polypeptide for the initial 10 amino acids.Abbreviations
SDS
sodium dodecyl sulfate
-
PMSF
phenylmethylsulfonyl fluoride
-
PAGE
polyacrylamide gel electrophoresis
-
HPLC
high performance liquid chromatography
-
ESP
egg-specific protein
-
Vtn
vitellin 相似文献
47.
Allison A. Welder Tina Machu Steven W. Leslie Richard E. Wilcox June Bradlaw Daniel Acosta 《In vitro cellular & developmental biology. Plant》1988,24(8):771-777
Summary Primary mycolardial cell cultures and freshly isolated cardiac cells in suspension resprensent two isolated, whole cell models
for investigating cellular transsarcolemmal45Ca++ exchange in response to a receptor-coupled stimulus. Studies were performed to characterize beta-adrenergic receptor binding,
beta-adrenergic receptor mediated cellular calcium (45Ca++) exchange, and viability in purified primary myocardial cell cultures and freshly isolated cardiac cells in suspension obtained
from 3-to 3-d-old Sprague-Dawley rats. In addition, beta-adrenergic receptor binding was characterized in whole-heart crude
membrane preparations. All three preparations had saturable beta-adrenergic binding sites with the antagonist [125I]iodopindolol ([125I]IPIN). The suspensions had a significantly lower B
max
(42±6 fmol/mg protein) than the membranes and cultures (77±8 and 95±10 fmol/mg protein, respectively). The K
D
of the cultures (218±2.0 pM) was significantly higher than that for the suspensions (107 ±1.3 pM) and membranes (93±1.3 pM). Viability was significantly lower in the suspensions (57%) when compared to 94% viability in myocardial cell cultures after
3 h of incubation in Kreb's Henseleit buffer. Incubation of the cultures with 5.0×10−7
M isoproterenol resulted in a significant increase in45Ca++ exchange as early as 15 s. In contrast,45Ca++ exchange into the suspensions was not increased. Although both primary cell cultures and cardiac cells in suspension possess
saturable beta-adrenergic receptors, only the monolayer cultures exhibited functional beta-adrenergic receptor-mediated45Ca++ exchange. Of the two intact cell models investigated, these data suggest that primary myocardial cell cultures are more suitable
than cell suspensions for investigating beta-adrenergic receptor binding and functions in the postnatal rat heart.
This research was supported by The University of Texas Research Institute, a grant from the Texas Advanced Research Technology
Program awarded to S. W. Leslie and R. E. Wilcox, and contract 223-86-2109 from the Food and Drug Administration. 相似文献
48.
Aino Laatikainen Leslie Schultz-Suhonen Rauno Mäntyjärvi 《Cancer immunology, immunotherapy : CII》1992,35(3):205-210
Summary The effect of interferon (IFN) on the immunogenicity and immunosensitivity of mouse cell lines transformed by bovine papillomavirus type 1 (BPV1) DNA was examined in a syngeneic mouse model. The overnight incubation of BPV1-transformed cell lines with 100 IU/ml IFN did not affect their ability to induce the generation of cytotoxic effector cells but it clearly increased their sensitivity to lysis by interleukin-2-induced lymphokine-activated killer (LAK) cells and by nonspecific LAK-type effector cells induced by BPV-1-transformed cell lines. The treatment of two allogeneic lymphoid tumour cell lines, P815X2 and YAC-1, with IFN either decreased or had no effect on their sensitivity to LAK-cell-mediated lysis. 相似文献
49.
Pathogenesis-related protein 4 is structurally homologous to the carboxy-terminal domains of hevein, Win-1 and Win-2 总被引:5,自引:0,他引:5
Leslie Friedrich Mary Moyer Eric Ward John Ryals 《Molecular & general genetics : MGG》1991,230(1-2):113-119
Summary The extracellular, acidic pathogenesis-related protein, PR-4, was purified to homogeneity from leaves of Nicotiana tabacum infected with tobacco mosaic virus (TMV) and characterized by partial amino acid sequencing. Complementary DNA clones encoding PR-4 were isolated using an oligonucleotide probe based on the sequence of one of the peptides. The deduced PR-4 protein sequence was found to be related to a family of proteins including hevein and Win-1, which have an amino-terminal lectin domain and a carboxy-terminal domain of unknown function. PR-4 is homologous to the carboxy-terminus of these proteins but does not contain the lectin domain. Thus, the organization of the PR-4 family of proteins is similar to that of the plant chitinase family, in that both contain structural subclasses characterized by the presence or absence of an amino-terminal lectin domain. This observation is consistent with the proposal that the DNA encoding the lectin domain may be capable of transposing to form new genes encoding proteins of more complex, multi-domain structure. The expression of PR-4 mRNA was found to increase dramatically in response to TMV infection and the time course of RNA accumulation was similar to that of other PR proteins. 相似文献
50.
Calicotyle urolophi n. sp. is proposed for calicotylines found in the cloaca of three stingaree species, Urolophus cruciatus, U. bucculentus and U. paucimaculatus, collected off the southeastern coast of Tasmania. Variations in the soft body parts were observed between specimens taken from U. cruciatus and U. bucculentus but were not considered sufficient for separation into two species. C. urolophi is differentiated from other Calicotyle spp. found in the South Pacific by the configuration of the tubular male copulatory organ, the structure of the intestinal caeca and the arrangement of the vaginae. Amended diagnoses for the subfamily Calicotylinae and the genus Calicotyle are provided. 相似文献