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51.
Many physiological markers vary similarly during training and overtraining. This is the case for the blood lactate concentration
([La−]b), since a right shift of the lactate curve is to be expected in both conditions. We examined the possibility of separating
the changes in training from those of overtraining by dividing [La−]b by the rating of perceived exertion ([La−]b/RPE) or by converting [La−]b into a percentage of the peak blood lactate concentration ([La−]b,peak). Ten experienced endurance athletes increased their usual amount of training by 100% within 4 weeks. An incremental test
and a time trial were performed before (baseline) and after this period of overtraining, and after 2 weeks of recovery (REC).
The [La−]b and RPE were measured during the recovery of each stage of the incremental test. We diagnosed overtraining in seven athletes,
using both physiological and psychological criteria. We found a decrease in mean [La−]b,peak from baseline to REC [9.64 (SD 1.17), 8.16 (SD 1.31) and 7.69 (SD 1.84) mmol · l−1, for the three tests, respectively; P < 0.05] and a right shift of the lactate curve. Above 90% of maximal aerobic speed (MAS) there was a decrease of mean [La−]b/RPE from baseline to REC [at 100% of MAS of 105.41 (SD 17.48), 84.61 (SD 12.56) and 81.03 (SD 22.64) arbitrary units, in
the three tests, respectively; P < 0.05), but no difference in RPE, its variability accounting for less than 25% of the variability of [La−]b/RPE (r=0.49). Consequently, [La−]b/RPE provides little additional information compared to [La−]b alone. Expressing [La−]b as a %[La−]b,peak resulted in a suppression of the right shift of the lactate curve, suggesting it was primarily the consequence of a decreased
production of lactate by the muscle. Since the right shift of the curve induced by optimal training is a result of improved
lactate utilization, the main difference between the two conditions is the decrease of [La−]b,peak during overtraining. We propose retaining it as a marker of overtraining for long duration events, and repeating its measurement
after a sufficient period of rest to make the distinction with overreaching.
Accepted: 26 September 2000 相似文献
52.
Anja Kimpe Annemie Decostere Margo Baele Luc A Devriese Freddy Haesebrouck 《Avian pathology》2004,33(3):310-313
Faecal samples from 50 pigeons all originating from different lofts were screened for the presence of macrolide and lincosamide (ML)-resistant isolates of Streptococcus gallolyticus and Enterococcus columbae by plating the samples onto selective media. Sixty-eight ML-resistant E. columbae strains were recovered from the faecal samples of 29 animals. Two of these samples also harboured ML-resistant S. gallolyticus strains. The erm(B) gene was detected in 58 E. columbae and in five S. gallolyticus isolates. Four of these E. columbae isolates also carried the mef(A) gene. Five E. columbae strains possessed the mef(A) gene in the absence of erm(B). On the basis of the sequence of the complete erm(B) gene, 10 E. columbae isolates clustered together in six groups. In two of these isolates, the erm(B) gene sequence was identical to that of S. gallolyticus strains, indicating that exchange of resistance genes might occur between pathogenic and non-pathogenic bacterial species belonging to the pigeon's intestinal flora. 相似文献
53.
Honey K Benlagha K Beers C Forbush K Teyton L Kleijmeer MJ Rudensky AY Bendelac A 《Nature immunology》2002,3(11):1069-1074
CD1d antigen presentation to natural killer T (NKT) cells expressing the semi-invariant T cell receptor V(alpha)14J(alpha)18 requires CD1d trafficking through endosomal compartments; however, the endosomal events remain undefined. We show that mice lacking the endosomal protease cathepsin L (catL) have greatly reduced numbers of V(alpha)14(+)NK1.1(+) T cells. In addition, catL expression in thymocytes is critical not only for selection of these cells in vivo but also for stimulation of V(alpha)14(+)NK1.1(+) T cells in vitro. CD1d cell-surface expression and intracellular localization appear normal in catL-deficient thymocytes, as does the lysosomal morphology; this implies a specific role for catL in regulating presentation of natural CD1d ligands mediating V(alpha)14(+)NK1.1(+) T cell selection. These data implicate lysosomal proteases as key regulators of not only classical major histocompatibility complex class II antigen presentation but also nonclassical CD1d presentation. 相似文献
54.
Trisomy 7 mosaicism, maternal uniparental heterodisomy 7 and Hirschsprung's disease in a child with Silver-Russell syndrome 总被引:1,自引:0,他引:1
Flori E Girodon E Samama B Becmeur F Viville B Girard-Lemaire F Doray B Schluth C Marcellin L Boehm N Goossens M Pingault V 《European journal of human genetics : EJHG》2005,13(9):1013-1018
Prenatal trisomy 7 is usually a cell culture artifact in amniocytes with normal diploid karyotype at birth and normal fetal outcome. In the same way, true prenatal trisomy 7 mosaicism usually results in a normal child except when trisomic cells persist after birth or when trisomy rescue leads to maternal uniparental disomy, which is responsible for 5.5-7% of patients with Silver-Russell syndrome (SRS). We report here on the unusual association of SRS and Hirschsprung's disease (HSCR) in a patient with maternal uniparental heterodisomy 7 and trisomy 7 mosaicism in intestine and skin fibroblasts. HSCR may be fortuitous given its frequency, multifactorial inheritance and genetic heterogeneity. However, the presence of the trisomy 7 mosaicism in intestine as well as in skin fibroblasts suggests that SRS and HSCR might possibly be related. Such an association might result from either an increased dosage of a nonimprinted gene due to trisomy 7 mosaicism in skin fibroblasts (leading to SRS) and in intestine (leading to HSCR), or from an overexpression, through genomic imprinting, of maternally expressed imprinted allele(s) in skin fibroblasts and intestine or from a combination of trisomy 7 mosaicism and genomic imprinting. This report suggests that the SRS phenotype observed in maternal uniparental disomy 7 (mUPD(7)) patients might also result from an undetected low level of trisomy 7 mosaicism. In order to validate this hypothesis, we propose to perform a conventional and molecular cytogenetic analysis in different tissues every time mUPD7 is displayed. 相似文献
55.
56.
57.
Tartour Eric; de la Salle Henri; de la Salle Corinne; Teillaud Christophe; Camoin Luc; Galinha Annie; Latour Sylvain; Hanau Daniel; Fridman Wolf H.; Sautes Catherine 《International immunology》1993,5(8):859-868
Low affinity FcR are a heterogeneous group of glycoproteinswhich exist in transmembrane (TM) as well as in soluble forms.Two membrane isoforms of the murine type II FcR, FcRilb1 andFc;Rilb2, have been described. They result from the translationof alternatively spliced premRNA, FcRilb2 lacking sequencesof the first intracytoplasmic domain (IC1). Soluble forms ofFcR (sFcR) have previously been shown to result from proteolysisof membrane receptors. We report here the identification, inmacrophages, of a mRNA derived from the FCRll gene by splicingexons encoding the TM and IC1 domains, i.e. corresponding toa TM-deleted FcRllb2 mRNA. A soluble protein possibly encodedby this mRNA was identified in macrophage supernatants. In accordancewith FcR nomenclature, we propose to name this new FcRll IsoformFcRllb3. It is the most abundant 8FcR present in serum, as comparedwith 8FcR resulting from cleavage of membrane FcR. 相似文献
58.
Van Kaer L 《Immunologic research》2004,30(2):139-153
Natural killer T (NKT) cells are a unique subset of T lymphocytes that share receptor structures and properties with conventional
T lymphocytes and natural killer (NK) cells. NKT cells are specific for glycolipid antigens such as the marine sponge-derived
agent α-galactosylceramide (α-GalCer) presented by the major histocompatibility complex (MHC) class I-like molcule CD1d. My
laboratory has evaluated the function of NKT cells by generating and analyzing CD1d-deficient mice. These studies showed that
CD1d expression is required for NKT cell development, but not absolutely necessary for the generation of polarized T helper
(Th) cell responses. Further, we have studied the in vivo response of NKT cells toα-GalCer stimulation and the capacity of
α-GalCer to modulate innate and adaptive immune responses. Our results revealed that, quickly following administration of
α-GalCer, NKT cells expand and produce cytokines, trans-activate a variety of innate and adaptive immune cells, and promote Th2 responses that are capable of suppressing Th1-dominant
autoimmunity. Our findings indicate that NKT cells play a regulatory role in the immune response and that specific activation
of these cells may be exploited for therapeutic purposes. 相似文献
59.
Tacchini-Cottier F Allenbach C Otten LA Radtke F 《European journal of immunology》2004,34(6):1588-1596
Notch1 proteins are involved in binary cell fate decisions. To determine the role of Notch1 in the differentiation of CD4(+) Th1 versus Th2 cells, we have compared T helper polarization in vitro in naive CD4(+) T cells isolated from mice in which the N1 gene is specifically inactivated in all mature T cells. Following activation, Notch1-deficient CD4(+) T cells transcribed and secreted IFN-gamma under Th1 conditions and IL-4 under Th2 conditions at levels similar to that of control CD4(+) T cells. These results show that Notch1 is dispensable for the development of Th1 and Th2 phenotypes in vitro. The requirement for Notch1 in Th1 differentiation in vivo was analyzed following inoculation of Leishmania major in mice with a T cell-specific inactivation of the Notch1 gene. Following infection, these mice controlled parasite growth at the site of infection and healed their lesions. The mice developed a protective Th1 immune response characterized by high levels of IFN-gamma mRNA and protein and low levels of IL-4 mRNA with no IL-4 protein in their lymph node cells. Taken together, these results indicate that Notch1 is not critically involved in CD4(+) T helper 1 differentiation and in resolution of lesions following infection with L. major. 相似文献
60.
Jean-Pierre Monthard Marcel Camps Ahmed Belfkira Michel Chatzopoulos Robert Granger Luc Jorat Grard Noyel 《Macromolecular chemistry and physics.》1985,186(7):1519-1532
The relations between structure and isothermal, dielectric properties of poly(α-acetoxystyrene)s substituted in para position by ? OCOCH3 ( 1a ), ? OCOCH2CH3 ( 1b ), ? OCOCH2CH2CH3 ( 1c ), ? OCOC6H5 ( 1d ), ? OCOCH2CH2Cl ( 1f ) and ? OCOOCH3 ( 1g ) were studied. The dielectric constants, at 105 Hz and 20 ± 2°C, were found to be: 3,79 ( 1a ), 3,36 ( 1b ), 3,18 ( 1c ), 3,51 ( 1d ), 3,36 ( 1e ), 3,65 ( 1f ) and 3,07 ( 1g ). The polymers 1a – 1g do not show any α- or β-transition. Increasing bulkiness of the para substituent gives rise to a decreasing dielectric constant due to an increase of the degree of syndiotacticity, as determined from 1H and 13C NMR spectra. 相似文献