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71.
Basic fibroblast growth factor prolongs the proliferation of rat cortical progenitor cells in vitro without altering their cell cycle parameters 总被引:12,自引:0,他引:12
Cavanagh JF; Mione MC; Pappas IS; Parnavelas JG 《Cerebral cortex (New York, N.Y. : 1991)》1997,7(4):293-302
Basic fibroblast growth factor (bFGF) has been shown to influence the
survival, proliferation and differentiation of a variety of cell types in
the nervous system. In this investigation we have examined the action of
bFGF on: (i) the rate of proliferation; (ii) cell cycle parameters; (iii)
the maintenance of cell division; (iv) the recruitment of quiescent cells;
and (v) the degree of differentiation of cortical progenitor cells in
cultures prepared from E16 rat embryos. The proliferation rate (labelling
index) of cortical progenitor cells doubled in the presence of bFGF over 48
h. However, the lengths of the cell cycle phases were unchanged. Clones
marked with a recombinant retrovirus on the first day in vitro (DIV) grew
significantly larger in the presence of bFGF. Furthermore, many of the
clones examined in control cultures had ceased to divide after a maximum of
four cell cycles, whereas almost all clonally related cells were still
dividing in the presence of bFGF 4 days later, i.e. for at least six cell
cycles. Basic FGF also stimulated the division of quiescent progenitor
cells, which otherwise would have differentiated or undergone cell death.
The degree of neuronal and glial differentiation was studied after 5 DIV
using MAP-2 and GFAP immunocytochemistry. In the presence of bFGF, the
percentage of MAP-2-labelled cells was less than half that of control
cultures, whereas the number of cells immunoreactive for nestin (a marker
of progenitor cells) remained very high. Cells immunoreactive for GFAP were
present in bFGF-treated cultures, yet were extremely rare in control
conditions. These experiments show that bFGF, a potent mitogen for cortical
progenitor cells, has no effects on the parameters of their cell cycle but
extends their proliferative capability, promotes their survival and delays
their differentiation into neurons.
相似文献
72.
RJ Reyes FRCS S Zicchi H Hamed FRCS MA Chaudary FRCS IS FentiMan FRCS ICRF 《International journal of clinical practice》1995,49(4):177-179
SUMMARY Gynaecomastia is a common and well-recognised side-effect of anabolic steroid abuse in athletes. A staging system is proposed and a technique of excision under local anaesthetic described. Careful selection of cases and the use of meticulous technique can achieve good cosmetic results, without risk of recurrence of gynaecomastia. 相似文献
73.
Gene therapy of human T-lymphocyte disorders, including acquired immunodeficiency syndrome (AIDS), would be greatly facilitated by the development of an in vivo system in which transduced human hematopoietic stem cells can be used to reconstitute the T-lymphoid compartment. Here we use the SCID-hu mouse as a recipient for human CD34+ hematopoietic progenitor cells transduced in vitro with a retroviral vector carrying the neomycin resistance gene (neoR). The transduced cells engraft and reconstitute the lymphoid compartments of the human thymus implant with as few as 5 x 10(4) CD34+ cells. The neoR gene was expressed at low levels in human thymocytes and there was no apparent effect on thymocyte differentiation as a result of vector transduction. Thus, this SCID-hu mouse system is the first in vivo model showing human thymopoiesis after transduction of exogenous vectors, and should allow preclinical testing of gene therapeutic reagents designed to function in human cells of the T-lymphoid lineage. Because human immunodeficiency virus type 1 infection induces depletion of human thymocytes in SCID-hu mice, this system may be particularly valuable in evaluating efficacy of gene therapies to combat AIDS. 相似文献
74.
A deletion in the proximal untranslated pX region of human T-cell leukemia virus type II decreases viral replication but not infectivity in vivo 总被引:2,自引:1,他引:2
The function of untranslated (UT) nucleotide sequences in the proximal portion of the pX region of the human T-cell leukemia virus (HTLV) family of retroviruses remains enigmatic. Previous studies have shown that these sequences are not necessary for the expression of viral proteins or for the induction, transmission, or maintenance of the transformed cell type in vitro. To determine the effect of the UT region in vivo, separate groups of rabbits were inoculated with lethally irradiated, stable clones of the human B-lymphoblastoid cell line, 729, transfected with either a full-length wild-type HTLV-II clone (pH6neo) or a mutant clone containing a 324-bp deletion in the proximal UT portion of pX (pH6neo delta UT[6661-6984]), or nontransfected 729 cells. All rabbits inoculated with either wild-type or pX-deleted HTLV-II developed a similar profile and titer of serum antibodies against HTLV-II antigens, as determined by Western immunoblots, by 4 weeks postinoculation (PI). Antibody titers, as determined by enzyme immunoassay, were similar between the two groups of rabbits and increased over the 18-week period of study. All rabbits were killed at 18 weeks PI, and spleen, peripheral blood lymphocytes (PBMC), bone marrow, and mesenteric lymph node were assayed for HTLV-II tax/rex sequences by quantitative polymerase chain reaction. Virus was detected in all tissues tested from all rabbits inoculated with 729pH6neo cells containing wild-type HTLV-II, which contained between 1.4 and 0.3 mean copies of provirus per cell. In contrast, the distribution and number of provirus copies were more limited in rabbits inoculated with 729pH6neo delta UT(6661-6984) cells containing UT- deleted HTLV-II; in most tissues, there was a fivefold to sevenfold reduction in mean provirus copies per cell as compared with rabbits inoculated with wild-type HTLV-II. All rabbits inoculated with control 729 cells remained negative for HTLV-II infection, as determined by the same techniques. It was concluded that UT sequences in the proximal portion of HTLV-II are not necessary for infection but confer increased replicative capacity in vivo. 相似文献
75.
We have determined the nucleotide sequence of the 2,360-bp long EcoRI fragment from four chromosomes; this fragment is located 3' to the A gamma globin gene and is considered to contain the enhancer element identified by Bodine and Ley. The chromosomes were from an Arabian sickle cell anemia patient with high Hb F and a homozygosity for haplotype No 31 and from a black sickle cell anemia patient with low Hb F and a homozygosity for haplotype No 19. A third chromosome carried the determinant for a nondeletional hereditary persistence of fetal hemoglobin seen in a Chinese subject, and the fourth was a normal chromosome from a Yugoslavian subject. Twenty-one differences were observed when a comparison was made with the published sequence; no differences were seen between the sequences of the four different samples except for an additional mutation in the Chinese. These data make it unlikely that specific mutations within this sequence are associated with increases in G gamma and A gamma production. 相似文献
76.
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79.
Vigabatrin as Initial Therapy for Infantile Spasms: A European Retrospective Survey 总被引:14,自引:11,他引:3
J. Aicardi Sabril IS Investigator Peer Review Groups J. P. Mumford† C. Dumas‡ S. Wood§ 《Epilepsia》1996,37(7):638-642
Purpose: The efficacy and tolerability of vigabatrin (VGB) as an add-on therapy in the treatment of infantile spasm (IS) prompted physicians to explore its use as the first drug in this seizure type. Methods: Our retrospective study included 250 infants diagnosed with IS; the data obtained were subjected to peer-group review. Of this infant population, 192 infants were considered to have classic IS and had received VGB as their first treatment for the spasms. There was a slight preponderance of boys (57%) in this population. Mean age of IS onset was 5.8 months; 60% had typical hypsarrhythmia. Results: Initial suppression of spasms was obtained in 68% of infants with a median time to response of 4 days at an average VGB dose of 99 mg/kg/day. The best response was seen in those infants with tuberous sclerosis (96% response) and in those younger than 3 months at onset of spasms (90% response). Of these infants, 43 (22%) of 192 subsequently had other types of seizures, and a recurrence of infantile spasms occurred in 28 (21%) of 131 responders. At the end of this study, 96 of 192 infants who could be evaluated were seizure free with VGB monotherapy. Treatment appeared to be well tolerated, with only 33 (13%) infants with adverse events, of which the most common were somnolence (15 patients) and hyper-kinesia (eight patients). In only two cases did adverse events require VGB withdrawal. Conclusion: This study supports the opinion that VGB may be considered an initial treatment for IS regardless of cause. 相似文献
80.
De Simone DN; Kundel HL; Arenson RL; Seshadri SB; Brikman IS; Khalsa SS; Davey MJ; Brisbon NE 《Radiology》1988,169(1):41-44
This study examined the effect of a medical image management network on the behavior of physicians working in a medial intensive care unit (MICU). For 1 year, 8-week periods during which chest radiographs were digitized and made available to MICU physicians on a digital display console were alternated with 8-week periods during which only film images were available. Clinical efficacy during the periods was compared by measuring the time between completion of imaging examinations and initiation of specific clinical actions such as placement and positioning of tubes. Results indicate that the time required to take some clinical actions decreased with the immediate availability of images on the digital display console. Established procedures for obtaining radiologic information were altered by the digital imaging network. The time at which physicians viewed images changed, and consultations between MICU staff and radiologists decreased. These results indicate that behavior patterns are altered when a new technology replaces an existing one. Optimal use of this technology may require changes in the logistics of clinical practice. 相似文献