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41.
L. C. Maxwell M. R. Moody C. S. Enwemeka 《Anatomical record (Hoboken, N.J. : 2007)》1992,233(3):376-386
We studied soleus (SOL), plantaris (PLN), and gastrocnemius (GST) muscles to determine whether early cast removal minimizes muscle atrophy or permits recovery from atrophy after tendon repair. After right tendocalcaneus (Achilles tendon) was transected and repaired, rabbit right hindlimbs were immobilized with the ankle plantar flexed and the knee flexed to 90°, Rabbits were maintained in the cast and sacrificed at 5, 15, or 21 days postoperatively or the cast was removed on day 5 and the animals sacrificed at day 15 or 21. SOL, PLN, and GST muscles of both limbs were removed and weights, mean fiber cross-sectional area, and percentage of Type I fibers and increased the percentage of Type IIc fibers. Ten days after cast removal (i. e., postoperative day 15), SOL muscle atrophy and fiber composition did not differ significantly from continuously immobilized controls. However, 16 days after cast removal (i. e., postoperative day 21), SOL muscle fiber cross-sectional area and fiber composition were near normal, differing significantly from continuously casted controls. At each of the time intervals studied, PLN (containing many glycolytic fibers) did not atrophy as much as SOL (containing mainly oxidative fibers). Our results indicate that (1) early cast removal prevents atrophy of PLN glycolytic fibers, but not oxidative fibers in either PLN or SOL, and (2) early cast removal promotes recovery from atrophy of both oxidative and glycolytic fibers. In spite of the many differences between rabbits and humans, these findings suggest that, although early cast removal may not prevent oxidative muscle fiber atrophy after postoperative immobilization, it may facilitate recovery from atrophy. © 1992 Wiley-Liss, Inc. 相似文献
42.
Ian A. Maxwell Edwin M. F. J. Verdurmen Anton L. German 《Macromolecular chemistry and physics.》1992,193(10):2677-2695
The four important factors that determine the rate of emulsion polymerization are the propagation rate coefficient, the latex-particle concentration, the monomer concentration in the latex particles, and the free-radical concentration in the latex particles. Both theoretical considerations and experimental evidence suggest that the important factors that may reduce the rate of emulsion polymerization at high conversion are the propagation rate coefficient and the monomer concentration in the latex particles, and not the free-radical concentration in the latex particle, if the initiator is not depleted. Various approaches for increasing the rate of emulsion polymerization at high conversion are suggested. 相似文献
43.
Fiber type distribution and mean fiber area were determined for seven sites in diaphragm muscles of premature (140 days gestation), full-term (180 days gestation), and adult baboons. Within a group, data did not differ significantly amongst the seven sites. The diaphragm of premature animals had a large proportion [56(+/- 2)%] of type IIc fibers, smaller proportions of type I, IIo, and IIh fibers [16(+/- 2), 21(+/- 1), and 7(+/- 2)%, respectively], and no type IIg fibers. Full-term animals had fewer type IIc [2(+/- 1)%] fibers, greater proportions of type I [46(+/- 2)%], IIh [23(+/- 1)%], and IIg [11(+/- 1)%] fibers, and a similar proportion of type IIo fibers [17(+/- 1)%]. Diaphragm from adult baboons had similar proportions of type IIh, IIg, and IIc fibers in females [39(+/- 4), 20(+/- 2), 1(+/- 1), 41(+/- 5), and 1(+/- 1)%] and males [48(+/- 2), 16 (+/- 1), 0(+/- 0), 36(+/- 2), and 3(+/- 2)%]. Fiber area for premature [143(+/- 9), 210(+/- 15), 231(+/- 15), and 156(+/- 16) microns2 for type I, IIo, IIh, and IIc fibers], newborn [317(+/- 32), 374(+/- 36), 468(+/- 42), 498(+/- 43), and 322(+/- 37) microns2 for type I, IIo, IIh, IIg, and IIc fibers], and for type I, IIo, IIg, and IIc fibers from adult female [1,759(+/- 130), 2,365(+/- 284), 5,026(+/- 742), and 1,843(+/- 111) microns2] and adult male [2,513(+/- 221), 3,987(+/- 267), 6,102(+/- 376), and 2,833(+/- 151) microns2] baboons indicated growth which correlated with body weight. Our results also show that metabolic and contractile enzymes develop normally, but growth of respiratory muscle fibers is arrested, during 10 days following premature birth. 相似文献
44.
Shirley L. Buchanan Richard H. Thompson Brian L. Maxwell D. A. Powell 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1994,100(3):469-483
The different cytoarchitectonic regions of the medial prefrontal cortex (mPFC) have recently been shown to play divergent
roles in associative learning in rabbits. To determine if these subareas of the mPFC, including areas 24 (anterior cingulate
cortex), 25 (infralimbic cortex), and 32 (prelimbic cortex) have differential efferent connections with other cortical and
subcortical areas in the rabbit, anterograde and retrograde tracing experiments were performed using thePhaseolus vulgaris leukoagglutinin (PHA-L), and horseradish peroxidase (HRP) techniques. All three areas showed local dorsal-ventral projections
into each of the other areas, and a contralateral projection to the homologous area on the other side of the brain. All three
also revealed a trajectory through the striatum, resulting in heavy innervation of the caudate nucleus, the claustrum, and
a lighter projection to the agranular insular cortex. The thalamic projections of areas 24 and 32 were similar, but not identical,
with projections to the mediodorsal nucleus (MD) and all of the midline nuclei. However, the primary thalamic projections
from area 25 were to the intralaminar and midline nuclei. All three areas also projected to the ventromedial and to a lesser
extent to the ventral posterior thalamic nuclei. Projections were also observed in the lateral hypothalamus, in an area just
lateral to the descending limb of the fornix. Amygdala projections from areas 32 and 24 were primarily to the lateral, basolateral
and basomedial nuclei, but area 25 also projected to the central nucleus. All three areas also showed projections to the midbrain
periaqueductal central gray, median raphe nucleus, ventral tegmental area, substantia nigra, locus coeruleus and pontine nuclei.
However, only areas 24 and the more dorsal portions of area 32 projected to the superior colliculus. Area 25 and the ventral
portions of area 32 also showed a bilateral projection to the parabrachial nuclei and dorsal and ventral medulla. The dorsal
portions of area 32, and all of area 24 were, however, devoid of these projections. It is suggested that these differential
projections are responsible for the diverse roles that the cytoarchitectonic subfields of the mPFC have been demonstrated
to play in associative learning. 相似文献
45.
Cruz I Napier SS van der Waal I Snijders PJ Walboomers JM Lamey PJ Cowan CG Gregg TA Maxwell P Meijer CJ 《Journal of clinical pathology》2002,55(2):98-104
AIMS: No good predictive marker for the malignant transformation of potentially malignant oral lesions (PMOLs) is currently available. This study re-evaluated the value of p53 immunoexpression to predict malignant transformation of PMOLs after discounting possible confounding factors. METHODS: PMOLs from 18 patients who showed progression to carcinoma, 16 of the respective carcinomas, and PMOLs from 18 matched controls were evaluated by immunohistochemistry (IHC) for p53 expression. A mouse monoclonal antibody that detects wild-type and mutant forms of human p53 was used. The p53 immunostaining pattern was also correlated with the degree of dysplasia. RESULTS: Suprabasal p53 staining was significantly associated with high grades of dysplasia (p < 0.01). The specificity and positive predictive value (PPV) for malignant transformation of suprabasal p53 staining were superior to the assessment of dysplasia, but sensitivity was inferior. All carcinomas derived from PMOLs with suprabasal p53 showed strong p53 immunostaining. However, the absence of suprabasal p53 staining and/or dysplastic changes did not preclude malignant transformation in a considerable proportion of PMOLs. CONCLUSIONS: This study confirms and extends previous findings that suprabasal p53 immunoexpression has a high PPV for malignant transformation of PMOLs and can be used as a specific marker for lesions that are at high risk for malignant transformation. The absence of suprabasal p53 staining (that is, absence of, or basal, p53 staining) is non-informative for prognostic purposes. Because of its limited sensitivity, p53 IHC is not a substitute for the assessment of dysplasia in the evaluation of PMOLs. Instead, p53 IHC emerges as a clinically useful supplement of histopathological assessment in the prognosis of PMOLs. 相似文献
46.
Holger Hoehn Maria L. Rodriguez Thomas H. Norwood Clare L. Maxwell Uta Francke 《American journal of medical genetics. Part A》1978,2(3):253-266
The last decade has witnessed increasing application of human cytogenetic technology to prenatal chromosome analysis. However, unlike the rather uniform peripheral blood T-lymphocyte system which has provided most of our experience in human cytogenetics, long-term amniotic-fluid cell cultures display extreme cellular heterogeneity and disproportionate growth of certain cell types as a consequence of clonal amplification. When they enter cell culture, many of these cells are approching the terminal stages of their respective life spans and may have accumulated chromosomal aberrations. Concern about the possibility of true fetal mosaicism seems warranted chiefly in situations were multiple colonies display potentially viable aberrations. Clonal analysis, preferable of multiple clonal types, and attention to details of clonal morphology are likely to minimize diagnostic errors and undue apprehension resulting from mosaicism in amniotic-fluid cell cultures. 相似文献
47.
48.
Maxwell DJ Kerr R Rashid S Anderson E 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2003,149(1):114-124
Serotonin 5-HT3 receptors are abundant in the superficial dorsal horn and are likely to have an involvement in processing of nociceptive
information. It has been shown previously that 5-HT3 receptors are present on primary afferent terminals and some dorsal horn cells. The primary aim of the present study was
to determine what classes of primary afferent possess 5-HT3A receptor subunits. We performed a series of double- and triple-labelling immunofluorescence experiments. Subunits were labelled
with an anti-peptide antibody and primary afferent axons were identified by the presence of calcitonin gene-related peptide
(CGRP) and binding of the lectin IB4. Quantitative confocal microscopic analysis revealed that approximately 10% of axons
displaying 5-HT3A immunoreactivity were also labelled for CGRP but that only 3% of these fibres bind IB4. We also investigated the relationship
between immunoreactivity for the subunit and descending serotoninergic systems, axons originating from inhibitory neurons
that contain glutamic acid decarboxylase, and axons of a subpopulation of excitatory neurons that contain neurotensin. None
of these types of axon was associated with immunoreactivity for receptor subunits. Ultrastructural studies confirmed that
punctate immunoreactive structures observed with the light microscope were axon terminals. These terminals invariably formed
asymmetric synaptic junctions with dendritic profiles and often contained a mixture of granular and agranular vesicles. Some
terminals formed glomerular-like arrangements. Immunoreactive cells were also examined and were found to contain intense patches
of reaction product within the cytoplasm. We conclude that the majority (about 87%) of dorsal horn axons that are immunoreactive
for 5-HT3A receptor subunits do not originate from the subtypes of primary afferent fibres that bind IB4 or contain CGRP. It is likely
that most of these axons have an excitatory action and they may originate from dorsal horn interneurons and/or fine myelinated
primary afferent fibres.
Electronic Publication 相似文献
49.
Catt SL; Sakkas D; Bizzaro D; Bianchi PG; Maxwell WM; Evans G 《Molecular human reproduction》1997,3(9):821-825
Controlling the sex of offspring by the separation of X and Y
chromosome-bearing spermatozoa using flow cytometry has been reported as a
clinical technique aiding prevention of X-linked diseases. Although this
technique has resulted in several hundred normal births in animals and at
least one human birth, there is still concern over its genetic safety due
to the involvement of two potentially mutagenic agents: UV light and the
fluorochrome dye, Hoechst 33342 (H33342). Human spermatozoa, particularly
those considered abnormal, may be more likely to suffer DNA damage
following exposure to mutagenic agents, compared with other mammalian
species. The stability of normal fresh and decondensed human spermatozoa
were examined after exposure to a range of levels of UV and H33342
staining, using an assay that detects endogenous nicks in the DNA of
spermatozoa. The stability of abnormal and normal, fresh and frozen-thawed
human spermatozoa was examined following UV laser, H33342 staining and flow
cytometry treatments utilizing the same assay. There was an increase in the
presence of endogenous nicks when spermatozoa were decondensed compared
with fresh spermatozoa. There was no increase in the incidence of nicks in
any group of spermatozoa after UV and fluorochrome exposure compared with
controls without exposure.
相似文献
50.
Brass DM Savov JD Whitehead GS Maxwell AB Schwartz DA 《The Journal of allergy and clinical immunology》2004,114(3):586-592
BACKGROUND: Inhaled endotoxin is a risk factor for asthma exacerbation, and endotoxin inhalation by itself recapitulates many of the classical features of asthma in mice, including reversible airflow obstruction and inflammation, airways hyperresponsiveness, and airway remodeling. OBJECTIVE: Our objective was to determine the importance of LPS binding protein (LBP) in the response to inhaled LPS. METHODS: We challenged LBP-deficient mice (C57BL/6(LBP-/-)) and C57BL/6 mice with inhaled endotoxin for 4 hours, 5 days, or 4 weeks, followed by 3 days of recovery. RESULTS: LBP in the lung was significantly increased in LPS-exposed C57BL/6 mice from all 3 groups. Only LPS-exposed C57BL/6 mice had significantly enhanced airway responsiveness to inhaled methacholine. Total lavage cells in LPS-exposed C57BL/6(LBP-/-) mice were significantly reduced compared with those seen in LPS-exposed C57BL/6 mice; however, the percentage of PMNs was similarly increased in both the C57BL/6 and C57BL/6(LBP-/-) mice. TNF-alpha, IL-1 beta, and IL-6 protein concentrations in whole-lung lavage fluid from C57BL/6(LBP-/-) mice were also significantly reduced when compared with those seen in C57BL/6 mice. In C57BL/6(LBP-/-) mice submucosal cell proliferation was significantly reduced in the 1-week group when compared with that seen in similarly exposed C57BL/6 mice. The 4-week exposed C57BL/6 mice had significantly thickened airway submucosa and significantly increased lavaged TGF-beta(1) protein compared with that seen in C57BL/6(LBP-/-) mice. CONCLUSIONS: These findings indicate that LBP is one of the critical molecules regulating the acute and chronic airway response to inhaled LPS. 相似文献