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51.
Norepinephrine constricts the canine coronary bed via postsynaptic alpha 2-adrenoceptors 总被引:3,自引:0,他引:3
The effect of alpha 2-blockade (0.3 mg/kg i.v. rauwolscine) and alpha 1-blockade (1.2 mg/kg i.v. prazosin) on coronary constrictions induced by intracoronary injections of azepexole (B-HT 933, alpha 2-agonist, 0.1-10 microgram/kg), phenylephrine (0.3-3 microgram/kg) and norepinephrine (0.001-0.1 microgram/kg) were studied in dog hearts perfused in situ under beta-blockade. Constrictions by azepexole (antagonized by rauwolscine, yet resistant to prazosin and methysergide) demonstrated coronary alpha 2-adrenoceptors. Norepinephrine-induced constrictions were more attenuated (22-fold) by alpha 2-blockade than by alpha 1-blockade (2.6-fold) and thus were mediated mainly by activation of postsynaptic alpha 2-receptors. 相似文献
52.
Dr. med. R. Sörensen U. Holtz D. Banzer M. Khalil A. Hirner 《Cardiovascular and interventional radiology》1978,1(3):179-185
Twenty-two cases with communication of an artery and the portal vein or one of its tributaries are discussed. Four conditions
in which relatively significant arterio-portal shunts may exist can be differentiated: (1) angiodysplasias or arteriovenous
malformations, (3) traumatic and postoperative lesions, and (4) benign and malignant tumors. The significance of the portal
vein's early opacification during arteriographic examinations of the abdominal organs is discussed, and the findings are compared
to those reported in the literature. 相似文献
53.
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55.
Skenders G Fry AM Prokopovica I Greckoseja S Broka L Metchock B Holtz TH Wells CD Leimane V 《Emerging infectious diseases》2005,11(9):1461-1463
To improve multidrug-resistant tuberculosis (MDR-TB) detection, we successfully introduced the rpoB gene mutation line probe assay into the national laboratory in Latvia, a country with epidemic MDR-TB. The assay detected rifampin resistance with 91% sensitivity and 96% specificity within 1 to 5 days (vs. 12-47 days for BACTEC). 相似文献
56.
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58.
Membrane–bound and secreted neuregulin isoforms induce
growth, survival and differentiation by activating erbB tyrosine kinase receptors.
In cultured cardiomyocytes, erbB2 and erbB4 receptors regulate apoptosis
by controlling bcl–x splicing, and conditional elimination of erbB2
induces dilative cardiomyopathy in vivo. Therefore, we analyzed expression
and activation of erbB receptors in left ventricular myocardium from 32 heart
failure patients, from 10 organ donors, and from 15 heart failure patients
prior to and following unloading by ventricular assist devices. ErbB receptors,
expressed in cardiomyocytes and noncardiomyocytes, are downregulated
in failing myocardium as mRNA (which is renormalized by hemodynamic
unloading) and as protein (erbB2: –25%; erbB4: –70%), their phosphorylation
is reduced and bcl–x splicing is shifted towards 6.7–fold augmentation
of proapoptotic Bcl–xS, compatible with attenuated erbB signaling.
However, secreted and membrane–anchored neuregulin–1 isoforms, preferentially
expressed in microvascular endothelium, are induced and not lowered
with heart failure, while expression of erbB–inhibitory neuregulin isoforms
or of autoinhibitory soluble erbB isoforms could not be demonstrated
as potential causes of erbB receptor inhibition. We conclude that erbB receptor
inactivation by unknown mechanisms results in altered splicing of bcl–x
towards enhanced formation of proapoptotic Bcl–xS, thereby contributing to
enhanced apoptotic susceptibility of failing human myocardium. 相似文献
59.
Background
South African households are severely affected by human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) but health and economic impacts have not been quantified in controlled cohort studies. 相似文献60.
Lehner AF Almeida P Jacobs J Harkins JD Karpiesiuk W Woods WE Dirikolu L Bosken JM Carter WG Boyles J Holtz C Heller T Nattrass C Fisher M Tobin T 《Journal of analytical toxicology》2000,24(5):309-315
Remifentanil (4-methoxycarbonyl-4-[(1-oxopropyl)phenylamino]-1-piperidinepropionic acid methyl ester) is a mu-opioid receptor agonist with considerable abuse potential in racing horses. The identification of its major equine urinary metabolite, 4-methoxycarbonyl-4-[(1-oxopropyl)phenylamino]-1-piperidinepropionic+ ++ acid, an ester hydrolysis product of remifentanil is reported. Administration of remifentanil HCl (5 mg, intravenous) produced clear-cut locomotor responses, establishing the clinical efficacy of this dose. ELISA analysis of postadministration urine samples readily detected fentanyl equivalents in these samples. Mass spectrometric analysis, using solid-phase extraction and trimethylsilyl (TMS) derivatization, showed the urine samples contained parent remifentanil in low concentrations, peaking at 1 h. More significantly, a major peak was identified as representing 4-methoxycarbonyl-4-[(1-oxopropyl)phenylamino]-1-piperidinepropionic+ ++ acid, arising from ester hydrolysis of remifentanil. This metabolite reached its maximal urinary concentrations at 1 h and was present at up to 10-fold greater concentrations than parent remifentanil. Base hydrolysis of remifentanil yielded a carboxylic acid with the same mass spectral characteristics as those of the equine metabolite. In summary, these data indicate that remifentanil administration results in the appearance of readily detectable amounts of 4-methoxycarbonyl-4-[(1-oxopropyl)phenylamino]-1-piperidinepropionic+ ++ acid in urine. On this basis, screening and confirmation tests for this equine urinary metabolite should be optimized for forensic control of remifentanil. 相似文献