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991.
With the use of monoclonal antibodies that inhibit the ristocetin- induced binding of von Willebrand factor (VWF) to platelets and the binding to collagen, we have previously identified two distinct tryptic fragments. To prove that these fragments contain the platelet binding or the collagen binding domain, we investigated the direct binding of tryptic fragments of 125I-VWF to platelets in the presence of ristocetin and to collagen fibrils. During the course of the tryptic digestion, there was a rapid and parallel decrease in binding to platelets and collagen. In the first ten minutes, binding decreased greater than 50%; a further decrease to 19% and 29%, respectively, was noted at 90 minutes, but no further decrease was observed thereafter. The bound fragments were eluted from platelets and collagen and analyzed on polyacrylamide gradient gels. The fragments bound to the platelets appeared to be reduced, probably by endogenous reducing substances from the platelets. This was prevented by addition of N- ethylmaleimide during the incubation. After 24 hours of digestion, platelets predominantly bound fragments of 116 kd and collagen bound a single fragment of 48 kd. These fragments are similar to those previously identified with the monoclonal antibodies. 相似文献
992.
Sisto SA; Tapp WN; LaManca JJ; Ling W; Korn LR; Nelson AJ; Natelson BH 《QJM : monthly journal of the Association of Physicians》1998,91(7):465-473
We measured physical activity after strenuous exercise in 20 women with
chronic fatigue syndrome (CFS), compared to 20 sedentary healthy volunteers
who exercised no more than once per week. Activity was measured for 2 weeks
using a portable waist-worn vertical accelerometer. After the first week of
activity monitoring, all participants returned for a maximal treadmill
test, followed by continued activity monitoring for the second week. Five
activity measures were derived from the data: (i) average activity; (ii)
total activity; (iii) duration of waking day; (iv) duration; and (v) number
of daily rests. A repeated measures ANCOVA was used to determine post-
treadmill group differences accounting for pre-treadmill differences. There
was a significant reduction in overall average activity after the treadmill
test, with the greatest decrease on days 12 through 14. This reduction was
accompanied by a significant increase in the duration of the waking day and
number of daily rests. Thus, marked exertion does produce changes in
activity, but later than self-report would suggest, and are apparently not
so severe that CFS patients cannot compensate.
相似文献
993.
994.
AM Herzenberg JJ Telford LG De Luca JK Holden AB Magil 《American journal of kidney diseases》1998,31(3):521-526
Cryoglobulinemic membranoproliferative glomerulonephritis (MPGN) and increased incidence of vascular thromboses are complications of hepatitis C virus (HCV) infection. This report describes the clinical, laboratory, and renal biopsy findings in two HCV-positive patients with cryoglobulinemic MPGN and thrombotic microangiopathy (TMA). Testing for circulating antiphospholipid antibodies, which are detected in a significant proportion of patients with HCV, was negative in the one case in which it was done. This article discusses the possible cause of the TMA in these two cases. 相似文献
995.
Analysis of N-ras gene mutation and p53 gene expression in human hepatocellular carcinomas 总被引:16,自引:2,他引:14
AnalysisofNrasgenemutationandp53geneexpressioninhumanhepatocelularcarcinomasLUODan1,LIUQiFu1,CGove2,NVNaomov2,SUJianJia1a... 相似文献
996.
997.
998.
999.
Correlation between fibrinogen binding to human platelets and platelet aggregability 总被引:39,自引:0,他引:39
Fibrinogen is essential for aggregating platelets with adenosine diphosphate (ADP) and was recently shown to bind to platelets stimulated with ADP. The present work confirms the specific and saturable nature of the platelet-fibrinogen interaction. Binding of 125iodine-labeled fibrinogen to human gel-filtered platelts was maximal at 1 min, and the receptors were saturated when the fibrinogen concentration in the suspending medium approached 0.8 mg/ml. Assuming that one fibrinogen molecule interacts with a single receptor, experiments with 9 normal donors revealed the presence of 12,896 +/- 2456 receptors per platelet. Much of the bound material dissociated from platelets after incubation with apyrase or EDTA. Binding was markedly inhibited at pH 6.5, in the presence of EDTA, and with platelets from 3 thrombasthenic patients but not with those from a patient with the Bernard-Soulier syndrome. Fibrinogen binding was also virtually absent with platelets that had been incubated with EDTA for 8 min at 37 degrees C and pH 7.8. These platelets could not aggregate when mixed with ADP and adequate CaCl2 and fibrinogen, although they could still change their shape. Thus, ADP-induced binding of fibrinogen correlates with platelet aggregability. 相似文献
1000.
Mutations causing achondroplasia and thanatophoric dysplasia alter bFGF- induced calcium signals in human diploid fibroblasts 总被引:1,自引:1,他引:0
Mutations in the fibroblast growth factor receptor (FGFR) gene family
recently have been shown to underlie several hereditary disorders of bone
development, with specific FGFR3 mutations causing achondroplasia (Ach) and
thanatophoric dysplasia (TD). However, for none of these mutations has the
defect in receptor function been demonstrated directly and, therefore, for
none has the pathophysiological mechanism of the disease been defined.
Using our established techniques for single-cell ratiometric real-time
calcium image analysis, we defined the nature of the basic fibroblast
growth factor (bFGF)-induced calcium signal in human diploid fibroblasts,
and, in blinded studies, have analyzed the bFGF-induced signals from 18
independent fibroblast cell lines, including multiple lines from patients
with known mutant alleles of FGFR3 and syndromes of Ach or TD. Control
cells responded with transient increases in intracellular calcium, with
many cells showing oscillatory calcium waves. Homozygous Ach cell lines
failed to signal, whereas heterozygous Ach lines responded nearly normally.
We observed heterogeneous signals in TD heterozygotes: the unresponsive
lines all turned out to carry TD1 alleles, whereas all responsive lines had
TD2 alleles. Since FGFR1, 2 and 3 receptors are known to be expressed in
fibroblasts, our results suggest that specific mutant FGFR3 alleles can
function in a dosage-dependent dominant-negative fashion to inactivate FGFR
signaling.
相似文献