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131.
Membrane-associated inhibitor of DNA synthesis in senescent human diploid fibroblasts: characterization and comparison to quiescent cell inhibitor. 总被引:4,自引:3,他引:4 下载免费PDF全文
G H Stein L Atkins 《Proceedings of the National Academy of Sciences of the United States of America》1986,83(23):9030-9034
Cell membranes prepared from senescent human diploid fibroblasts (HDF) inhibited entry into S phase by 35% when added to the medium of replicating young HDF. This membrane-associated inhibitory activity was (i) sensitive to trypsin, heat, and periodate, which suggests that the inhibitor is a glycoprotein, and (ii) not able to inhibit DNA synthesis in simian virus 40-transformed HDF, which indicates that not all types of cells are sensitive to this inhibitor. Quiescent young HDF also have a surface membrane-associated inhibitor of DNA synthesis. A comparison of the senescent HDF and quiescent HDF inhibitor activities indicates that they may have the same chemical and physical nature and the same specific activity, but their regulation is different. The inhibitory activity of quiescent young HDF is abolished within 20 hr after refeeding with fresh serum-containing medium, whereas that of senescent HDF remains unchanged. Quiescent old HDF (two or three population doublings remaining) exhibit an intermediate response to serum with approximately two-thirds of the inhibitory activity abolished. The fraction of cells in S phase at 20-24 hr post-stimulation (37% in young HDF, 24% in old HDF, and 0% in senescent HDF) is inversely proportional to inhibitor levels. This suggests that inability to neutralize the inhibitory activity in response to serum stimulation could be involved in the inability of senescent HDF to enter S phase. Disappearance of the inhibitory activity from quiescent young HDF occurs late in G1 phase. Thus, the inhibitor may play a role in determining the length of the G0 to S phase transition in these cells. 相似文献
132.
Technetium stannous pyrophosphate myocardial scintigrams in patients with chest pain of varying etiology. 总被引:5,自引:0,他引:5
J T Willerson R W Parkey F J Bonte S L Meyer J M Atkins E M Stokley 《Circulation》1975,51(6):1046-1052
Technetium-99m stannous pyrophosphate was utilized for myocardial imaging in 202 patients admitted to the hospital with chest pain of uncertain etiology. One hundred and one patients had clinical and evolved electrocardiographic and enzymatic evidence of acute myocardial infarction. Ninety-six of these 101 patients had increased myocardial uptake of the technetium stannous pyrophosphate and positive myocardial scintigrams; there was nearly precise correlation between the ECG and myocardial imaging localization of the area of infarction for acute transmural myocardial infarctions. In the five patients with negative myocardial images the scintigrams were obtained after seven or more days had elapsed following the myocardial infarction. In the remaining 101 patients no clinical, ECG, or enzymatic evidence of infarction developed; 92 of these patients had negative myocardial scintigrams. Seven of the remaining nine patients were admitted with "unstable angina pectoris", and despite the absence of diagnostic ECG and enzyme evolution each of these patients had faintly and diffusely positive myocardial scintigrams. The remaining two patients had positive myocardial scintigrams but no definite ECG or enzymatic evidence of acute myocardial infarction. Thus the technetium pyrophosphate imaging technique appears safe, inexpensive and to correlate well with ECG and enzyme identification of the presence of infarction and with ECG localization of myocardial infarction. In addition the positive myocardial scintigrams in some patients with "unstable angina" suggest that there may be limited myocardial necrosis that is ordinarily undetected by ECG and enzymes in these patients. The incidence of false positive and false negative scintigrams appears to be small. 相似文献
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M P Dolan W R Roberts W E Penk R Robinowitz H G Atkins 《Journal of clinical psychology》1983,39(5):807-813
Used MMPI Content Scale scores (Wiggins, 1966) to assess personality differences among black, white, and Hispanic-American heroin addicts. Ss were 423 male veterans who volunteered for the first time for treatment between 1972 and 1979 to an inpatient Drug Dependence Treatment Program (DDTP) of a Veterans Administration Medical Center. Two hypotheses were tested: First, that minority group heroin addicts (blacks and Hispanics) will show better adjustment than majority group (white) heroin addicts; second, that Hispanic-American heroin addicts will evidence personality characteristics unlike those of either whites or blacks. Both hypotheses were confirmed. Results were interpreted as supporting cultural theories of substance abuse and providing implications for diagnosis and treatment of substance abuse disorders among minority ethnic groups. 相似文献
138.
Arianne C Lim Kitty WM Bloemenkamp Kees Boer Johannes J Duvekot Jan Jaap HM Erwich Tom HM Hasaart Pieter Hummel Ben WJ Mol Jos PM Offermans Charlotte M van Oirschot Job G Santema Hubertina CJ Scheepers Willem A Schöls Frank PHA Vandenbussche Maurice GAJ Wouters Hein W Bruinse 《BMC pregnancy and childbirth》2007,7(1):1-6
Background
Adequate vitamin D concentrations during pregnancy are necessary to neonatal calcium homeostasis, bone maturation and mineralization. The aim of study is to evaluate serum vitamin D concentrations in mothers and their newborns and effect of vitamin D deficiency on pregnancy outcomes.Methods
552 pregnant women were recruited from Tehran University educating hospitals in the winter of 2002. Maternal and cord blood samples were taken at delivery. The serum was assayed for 25-hydroxyvitamin D3, calcium, phosphorus and parathyroid hormone.Results
The prevalence of vitamin D deficiency in maternal and cord blood samples were 66.8% and 93.3%, respectively (<35 nmol/l). There was significant correlation between maternal and cord blood serum concentrations of vitamin D. In mothers with vitamin D deficiency, cord blood vitamin D concentrations was lower than those from normal mothers (P = .001). Also, a significant direct correlation was seen between maternal vitamin D intake and weight gain during pregnancy.Conclusion
Consideration to adequate calcium and vitamin D intake during pregnancy is essential. Furthermore, we think it is necessary to reconsider the recommendation for vitamin D supplementation for women during pregnancy. 相似文献140.
Atkins BZ Onaitis MW Hutcheson KA Kaye K Petersen RP Wolfe WG 《American journal of surgery》2011,202(5):565-567