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121.
M. P. Fuggetta E. Alvino R. Pepponi R. de Filippi S. Marini E. Bonmassar 《Cell proliferation》1993,26(4):305-316
There is general agreement that several distinct subpopulations of lymphocytes, including major histocompatibility complex (MHC)-restricted T lymphocytes and non-restricted natural killer, or lymphokine-activated killer (LAK), cells are active in lysing neoplastic cells. In this study experiments were designed to compare the inhibitory effects of LAK cells and allosensitized cytotoxic T lymphocytes (CTL) on in vitro growth of an Epstein–Barr virus-transformed B-cell line (BSM) and of a HTLV-I producer T-cell line (MT-2). It was found that allosensitized CTL are more efficient at inducing BSM, or MT-2, cell growth inhibition than LAK cells. These results are consistent with the hypothesis that MHC-restricted T effector cells could mediate higher tumour suppressive effects than non-MHC restricted LAK cells. 相似文献
122.
The traditional view regarding the pathogenesis of cervical lymphadenitis in guinea pigs is that Lancefield Group C Streptococcus gains access to cervical lymph nodes via an abraded oral mucosa. In this study, it is established that inoculation of intact nasal and conjunctival mucous membranes with Streptococcus zooepidemicus (Lancefield Group C) also can produce the disease. Weanling (SPF) guinea pigs (Cavia porcellus) were divided into two experimental groups of 10 and two control groups of four each. Guinea pigs from each group were individually housed in separate cubicles. Group I was inoculated with 0.05 ml of culture containing 2.8 x 10(7) CFU/ml of S. zooepidemicus into the conjunctiva of the left eye. Group II received a similar inoculum into the left nares. Control groups received 0.05 ml of TSB broth in the same sites. Five of ten guinea pigs in Group II died four to nine days postinoculation. Surviving guinea pigs were euthanatized at intervals between days 4-13 postinoculation. All guinea pigs were necropsied, cultured and examined for evidence of infection. S. zooepidemicus was recovered from 30/50 and 39/46 sites cultured from Groups I and II, respectively. Lymphadenitis was found in cervical lymph nodes from 8/10 guinea pigs in Group I and 10/10 in Group II. The conjunctival and nasal mucosa, therefore, represent potential sites of entry resulting in cervical lymphadenitis in guinea pigs. 相似文献
123.
The uvsC gene of Aspergillus nidulans is a homolog of the RAD51 gene of Saccharomyces cerevisiae. However, with respect to its effects on UV mutagenesis, it differs from the yeast gene, since it seems to be required for
UV mutagenesis; however, this conclusion is based only on data from resting conidia. To further clarify the functional role
of the uvsC gene, we tested the UV mutability of strains bearing a uvsC mutation in resting as well as in germinating conidia, by the p-fluoro-phenyl-alanine resistance test. We also evaluated the mutability of the uvsE mutant which belongs to the same epistatic group. Our results show that the uvsC and uvsE genes do not have a significant role in the mutagenic UV-repair pathway.
Received: 20 January 1998 / Accepted: 22 April 1998 相似文献
124.
David L. Lentz Maria Luisa Reyna de Aguilar Raul Villacorta Helen Marini 《Economic botany》1996,50(1):108-114
Paleoethnobotanical studies in the Zapotitdn Valley of north-central El Salvador revealed that a species of grass,Trachypogon plumosus, was in common use as a thatch material at the Ceren site, a small mesoamerican farming community inundated by volcanic ash circaa.d. 590. Although the grass must have been common in Precolumbian times, repeated attempts to collect fresh specimens from the modern valley were unsuccessful. A survey of the major herbaria with collections from El Salvador likewise demonstrated a lack of modern specimens from the Zapotitdn Valley. The elimination of theT. plumosus from this area and its characteristic savanna habitat probably occurred as a result of the introduction of competing Old World grasses and excessive herbivory. This finding demonstrates why conservationists working in the tropics should be concerned not only with the extinction of rain forest habitats, but with the elimination of other habitats as well. 相似文献
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128.
A. M. Berghella Patrizia Pellegrini Tiziana Del Beato Matteo Marini Ennio Tomei Domenico Adorno Carlo Umberto Casciani 《Cancer immunology, immunotherapy : CII》1997,45(5):241-249
Current research has still not clarified the biological role of soluble interleukin(IL)-2 receptor (sIL-2R) and the significance
of its increase in the serum of colon cancer patients compared to healthy subjects. To address these questions at the immunological
level in a group of patients and healthy subjects, we determined the sIL-2R level in the serum and its release from peripheral
blood mononuclear cells (PBMC) as a function of tumour necrosis factor (TNF) α, IL-1α, IL-1β, IL-2, interferon (IFN) γ, IL-4,
IL-6 and IL-10 levels in the serum and PBMC production; and PBMC proliferative responses to IL-2, IL-4 and anti-CD3 monoclonal
antibody (CD3), variously combined. The level of sIL-2R in patients’ serum was higher than in healthy subjects and correlated
with the stage of advancement. Moreover, while in healthy subjects the serum level of sIL-2R was not significantly correlated
with other parameters, in patients it was positively related to IL-4, IL-6 and IL-10 serum levels, PBMC IL-4 production and
to the PBMC proliferative response to CD3 and CD3+IL-2; it was negatively correlated to IL-2 serum level and IL-1β PBMC release.
A negative connection between IFNγ serum level and the PBMC production of sIL-2R was also found. This suggests that the increase
of sIL-2R in the serum of patients, compared to healthy subjects, is involved in the inappropriate expansion of the T helper
(TH2) suppressive immune response, which we previously reported. The multivariate statistical method supported the above suggestions
and we also found that, in healthy subjects, the up- and down-regulation of sIL-2R in the serum within the physiological ranges
seems to have a regulating role in the relationships between TNFα, IFNγ and IL-4, IL-6, contributing to the operation of the
cytokine network between TH1 and TH2 cells. However, in patients compared to healthy subjects the increased sIL-2R serum level
seems to direct the immune response towards a suppressive type, which may be due to an alteration in the above-mentioned physiological
regulating role.
Received: 12 April 1997 / Accepted: 4 September 1997 相似文献
129.
Marini Mario Bongiorno Lucilla Urbani Alessandra Trani Eugenia Roda L. Giorgio 《Neurochemical research》1997,22(12):1415-1423
Leu-enkephalin hydrolysis kinetics were measured in the presence of soluble supernatants obtained from cultures of the K562(S) leukaemic cell line. Under these conditions, the substrate is degraded with formation of two distinct patterns of the hydrolysis by-products: in one pattern, similar amounts of Tyr and Tyr-Gly are formed; in the other, only Tyr-Gly can be measured. Kinetic data suggest that soluble proteolyses are released by these cells, and that either dipeptidylaminopeptidases alone, or both aminopeptidases and dipeptidylaminopeptidases are involved in substrate hydrolysis. This alternation of hydrolysis patterns appears consistent with existing data on the heterogeneity of K562 cells. In contrast with these results, chromatographic separation of the soluble enzymes indicates the release of all three classes of proteolyses known to hydrolyze enkephalins: aminopeptidases, dipeptidylaminopeptidases and dipeptidylcarboxypeptidases. In cells induced to differentiate by treatment with butyric acid, substrate hydrolysis is increased, and the pattern of the enzymes released is modified. In these cells, variations in both total proteolytic activity, and ratio between the three enzyme classes mentioned above are only minor, while the ratio between the different enzyme species within each class is greatly modified. Data obtained suggest that the expression of soluble enzymes is modified by differentiation. These data may also be interpreted as stressing the role of competition in controlling substrate hydrolysis by the multiple enzymes co-released by K562(S) cells. 相似文献
130.
Fragmented and scrambled mitochondrial ribosomal RNA coding regions among green algae: a model for their origin and evolution 总被引:4,自引:1,他引:3
Mitochondrial ribosomal RNA coding regions in the only three green algal
taxa investigated to date are fundamentally different in that they are
continuous in Prototheca wickerhamii, but highly fragmented and scrambled
in Chlamydomonas reinhardtii and Chlamydomonas eugametos. To gain more
insight into the mode of evolution of fragmented and scrambled
mitochondrial ribosomal RNA (rRNA) genes within the green algal group, this
work (1) provides additional information on fragmentation patterns of
mitochondrial small- and large-subunit (SSU and LSU) rRNAs that strongly
supports the concept of a gradual increase in the extent of discontinuity
of mitochondrial rRNAs among chlorophycean green algae and (2) reports the
first example of fragmented and scrambled mitochondrial LSU rRNA coding
regions in a green algal taxon outside the Chlamydomonas group. The present
study (1) suggests that the scrambling of the mitochondrial rRNA coding
regions may have occurred early in the evolution of fragmented and
scrambled mitochondrial rRNA genes within the chlorophycean green algal
group, most likely in parallel with the fragmentation events, (2) proposes
recombination as a possible mechanism involved in the evolution of these
mitochondrial rRNA genes, and (3) presents a hypothetical pathway for
converting continuous mitochondrial rRNA genes into the highly fragmented
and scrambled rRNA coding regions of Chlamydomonas through a series of
recombinatorial events between short repeated sequences.
相似文献