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21.
Because the acrosome of human sperm is too small to be directly visualized by phase-contrast microscopy, acrosome reactions (that is loss of the acrosome) are generally not evaluated in studies of human sperm capacitation and fertilization. Nevertheless, it would be useful in such studies to have a technique for easily identifying and quantitating acrosome-reacted sperm. In this paper, we describe a method for labeling the human sperm acrosome with fluorescein-conjugated Ricinus communis agglutinin-60 (FITC-RCA); we show that in sperm without acrosomal caps, FITC-RCA labeling occurs either not at all or only in the equatorial segment of the acrosome. To determine if the absence of FITC-RCA labeling in the acrosomal cap region gives a reliable estimate of acrosome reactions, washed sperm or sperm incubated in a capacitating medium (BWW) were divided into two groups, which were then fixed for FITC-RCA labeling or transmission electron microscopy. Counts of acrosome reactions made by each method were similar, and we observed an increase in the percentage of reactions following incubation in BWW. We conclude that the FITC-TCA labeling technique is a reliable method for accurately scoring the percentage of acrosome-reacted human sperm. 相似文献
22.
L. Marklund M. Johansson U. Gustafsson L. Andersson A. K. Winterö M. Fredholm P. D. Thomsen 《Animal genetics》1993,24(5):333-338
Restriction fragment length polymorphisms (RFLPs) were described for the porcine loci for β-glucosidase (GBA) and the β-polypeptide 1 of the Na+, K+-transporting ATPase (ATP1B1). Linkage analyses using a three-generation pedigree provided evidence for the assignment of ATP1B1, GBA and two microsatellite loci (S0001 and S0067) to a previously described linkage group comprising the loci for blood group L (EAL) and an anonymous microsatellite (S0097). The linear order of the six markers was determined with confidence by multipoint analyses and the length of the linkage group was estimated at 88 CM. This linkage group was assigned to pig chromosome 4 on the basis of a previous physical localization of the ATP1B1 gene. In situ hybridization data for S0001 presented in this study were consistent with a localization on chromosome 4 and suggested a regional localization to 4pl2-pl3. The present study reveals conflicting data concerning the genetic localization of the K88 loci controlling the expression of the receptors for the E. coli pilus antigens. One group has reported data suggesting a loose linkage between K88 and EAL, now mapped to chromosome 4, whereas two other groups have found linkage between K88 and the transferrin locus (TF), mapped to chromosome 13 by in situ hybridization. 相似文献
23.
Natural antibodies to interferon-gamma 总被引:3,自引:0,他引:3
Natural antibodies to interferon (IFN)-γ were detected in the serum of virus-infected patients and also, at a low titre, in
the serum of healthy subjects. The increased titre of antibodies to IFN-γ in the sera of virus-infected patients, and its
decrease with clinical resolution, indicate that these antibodies are related to viral infection and probably reflect IFN-γ
production as a result of antigenic stimulationin vivo. Natural antibodies to IFN-γ were affinity purified and studied for their capability to interferein vitro with the multiple activities of the lymphokine. Data obtained show that these human anti-IFN-γ antibodies have no inhibitory
effect on the antiviral and antiproliferative activity of IFN-γ and do not interfere with the binding of the lymphokine to
its specific cell receptor. Instead, they can inhibit the expression of HLA-DR antigens induced by IFN-γ on U937 cells and
interfere, in mixed lymphocyte culture, with the proliferation of lymphocytes and the generation of cytotoxic lymphocytes.
Experiments in animal models suggest that natural antibodies to IFN-γ may have a role in the immunoregulatory process limiting
the intensity and/or duration of immune response. As they can interfere only with the immunomodulating activities of IFN-γ,
these antibodies might open up new therapeutic approaches to diseases with evidence of activated cell-mediated immunity. 相似文献
24.
Abstract. Anopheles stephensi mosquitoes which had fed upon mice infected with Plasmodium yoelii nigeriensis malaria parasites produced significantly fewer eggs than mosquitoes fed on an uninfected mouse. Fecundity reduction was more pronounced when the bloodmeal contained malaria gametocytes and the mosquitoes developed oocysts. Egg production and haematin excretion were correlated for uninfected bloodfed mosquitoes; the presence of P.y. nigeriensis in the blood affected this relationship. Reduced fecundity was associated with a significant reduction of bloodmeal size (measured by haematin excretion) in mosquitoes which ingested gametocytaemic blood. The bloodmeal size in mosquitoes fed on parasitaemic blood without gametocytes was not significantly reduced. The use of haematin assays for determination of bloodmeal size in mosquitoes is discussed. 相似文献
25.
26.
David A. Smith John L. Glover Laurace E. Townsend Diane E. Maupin 《In vitro cellular & developmental biology. Animal》1991,27(12):914-920
Summary Myocardial cell culture methods are now well established for animal and fetal human tissue. We present here a method for harvesting
and culturing adult human atrial myocardiocytes. Cells are obtained from fresh atrial tissue normally discarded after being
removed to cannulate the right atrium during open heart surgery. The atrial tissue is minced and then digested using collagenase.
The single cell suspension is initially cultured in serum-containing growth medium, then transferred to defined medium, selective
for myocardial cell growth. The cells are characterized by immunoperoxidase stains and transmission electron microscopy. The
cultured cells stain positive for myoglobin, whereas control cultured fibroblasts and endothelial cells do not. Electron microscopy
shows the presence of numerous myofibrils, Z-bodies, pleomorphic mitochondria, and secretory granules. The chronological age
of the donor was an important factor in culturing the adult tissue, the younger tissue correlated with a higher success rate.
This method provides a means for in vitro study of human adult myocardial cells and provides guidelines for appropriate atrial
tissue to use. 相似文献
27.
The development of a sensitive and specific enzyme immunoassay for GA3 is reported. This method was based on the use of peroxidase labelled GA3 and immobilized antibodies. In order to obtain a rapid immunoassay, several steps of purification were analyzed to show their necessity. Barley seed extracts were assayed at different steps of purification to exhibit the effect of extract components on the assay. It was demonstrated that HPLC had to be performed when a selective quantitation of GA3 was required. This assay allowed GA3 to be measured with reproducibility as its unmethylated form and the quantitation of GA3 in barley seeds with this enzyme immunoassay was correlated to a GC-MS method.Abbreviations GA3
gibberellin A3
- EIA
enzyme immunoassay
- DMF
dimethylformamide
- TEA
tri(n)ethylamine
- BSA
bovine serum albumin
- OVA
ovalbumine
- ECF
ethylchloroformate
- PB
phosphate buffer 相似文献
28.
Synthesis and in vitro bioactivity of C-terminal deleted analogs of human growth hormone-releasing factor 总被引:4,自引:0,他引:4
N Ling A Baird W B Wehrenberg N Ueno T Munegumi P Brazeau 《Biochemical and biophysical research communications》1984,123(2):854-861
A series of C-terminal deleted analogs of human growth hormone-releasing factor (hGRF) with either an amidated or a free carboxylic acid C-terminus were synthesized by solid phase methodology. Their capacity to release growth hormone was tested on rat anterior pituitary cells in monolayer culture. A gradual decrease of bioactivity down to 23% relative to hGRF was noted when the C-terminal amino acids were deleted to hGRF (1-34)OH. Further deletions, however, did not decrease the bioactivity because the potencies of the fragments, hGRF(1-31)NH2, (1-30)NH2 and (1-29)NH2 remained at about 50% of that of hGRF. Continual deletion of residues to hGRF(1-23)NH2, (1-22)NH2 and (1-21)NH2 still yielded bioactive fragments with full intrinsic activity despite very low potency. Only with the deletion down to hGRF(1-19)NH2 did the bioactivity completely disappear. Thus, together with the data published in a previous paper (1), the minimal biologically active core of hGRF with full intrinsic activity comprises the fragment (3-21). 相似文献
29.
The measurement of the ATP content of fresh semen is as accurate as the estimation of sperm motility by conventional methods in discriminating between semen of fertile versus subfertile men. The ATP content of frozen thawed donor semen is correlated with the probability of conception per cycle of insemination. Exact quantification of cytotoxic sperm antibodies in serum is possible with the adenosine-triphosphate-release-cytotoxicity test, since measurement is free of the bias of microscopic examination. The procedure has been simplified by testing only one serum dilution and calculating the ‘sperm toxicity index’. 相似文献
30.
MariáL. Tomaro Rosalìa B. Frydman Abraham Gutnisky Adriana Sburlati 《Biochimica et Biophysica Acta (BBA)/General Subjects》1981,676(1):31-42
Porphobilinogen is the substrate of two enzymes: porphobilinogen deaminase and porphobilinogen-oxygenase. The first one transforms it into the metabolic precursors of heme and the second diverts it from this metabolic pathway by oxidizing porphobilinogen to 5-oxopyrrolinones. Rat blood is devoid of porphobilinogen-oxygenase under normal conditions while it carries porphobilinogen-deaminase activity. When the rats were submitted to hypoxia (pO2 = 0.42 atm) for 18 days, the activity of porphobilinogen-oxygenase appeared at the tenth day of hypoxia and reached the maximum at the 14–16th day. It decreased to a half after 2 days (half-life of the enzyme) and disappeared after 4 days of return to normal oxygen pressure. Porphobilinogen-deaminase activity increased after the first day of hypoxia, reached a maximum at the 14–16th day and did not decrease to normal values until the 15th day after return to normal oxygen pressure. The activities of both prophobilinogen-oxygenase and porphobilinogen-deaminase were induced by administration of erythropoietin. When rats were made anaemic with phenylhydrazine, porphobilinogen-oxygenase activity also appeared in the blood cells. Although the reticulocyte concentration was higher when compared to that obtained under hypoxia, the activities of the oxygenase obtained under both conditions were comparable. Porphobilinogen-deaminase activity was always closely related to the reticulocyte content. The appearance of porphobilinogen-oxygenase under the described erythropoietic conditions was due to a de novo induction of the enzyme, as shown by its inhibition with actinomycin D and cycloheximide. Porphobilinogen-oxygenase as well as porphobilinogen-deaminase were present in the rat bone marrow under normal conditions. Their activities increased in phenylhydrazine treated rats. The properties and kinetics of porphobilinogen-oxygenase from the rat blood and bone marrow were determined and found to differ in several aspects. 相似文献