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151.
Some participants will get HIV‐infected in HIV prevention trials, despite risk reduction measures. The subsequent treatment responsibilities of sponsor‐investigators have been widely debated, especially where access to antiretroviral therapy (ART) is not available. In this paper, we explore two accounts of beneficence to establish whether they can shed light on sponsor‐investigator responsibilities. We find the notion of general beneficence helpful insofar as it clarifies that some beneficent actions will be obligatory where they can be dispensed without scuppering the trial. We find the notion of specific beneficence helpful insofar as it directs investigators to attend to the needs of trial participants; however the range of interventions that could be provided remains unhelpfully broad. We then examine accounts of the investigator‐participant relationship to narrow the range of interventions that investigators should provide, concluding that health‐care, and HIV infection, are appropriate foci. We conclude that when investigators are able to meet the ART needs of their participants (e.g. referral, assisted referral or direct provision) without sacrificing trial quality, they must do so. However, there is little of this explicit direction to be found in the account of specific beneficence itself, but rather it is found in accounts of the relationship that are compatible with beneficence. 相似文献
152.
A flexible method is proposed for group sequentially performed clinical trials which allows for an adaptive, data‐driven sample size reassessment at each stage. By also adaptively assigning different weights to the several stages the total number of study parts can be steered to an intended early or late end of the trial in dependence on all information available prior to a stage. Although at each stage the null hypothesis is tested on rejection, the full level‐α‐test is preserved at the end of the study. The proposed method is not restricted to normally distributed responses. The discussed adaptive designing is a useful tool provided that a priori information about parameters involved in the trial are not available or subject to uncertainty. The presented learning algorithm enables the complete self‐designing of a study. 相似文献
153.
《Journal of lipid research》2017,58(9):1756-1764
154.
In this paper, we consider the case of efficient estimation of the risk difference in a multicenter study allowing for baseline heterogeneity. We consider the optimally weighted estimator for the common risk difference and show that this estimator has considerable bias when the true weights (which are inversely proportional to the variances of the center-specific risk difference estimates) are replaced by their sample estimates. In addition, we propose a new estimator for this situation of the Mantel-Haenszel type that is unbiased and, in addition, has a smaller variance for small sample sizes within the study centers. Simulations illustrate these findings. 相似文献
155.
Dodier N 《Culture, medicine and psychiatry》2005,29(3):285-307
This article looks at the AIDS-related controversy surrounding the experiments on and the availability of medicines in southern
countries. It situates these debates in a longer-term history of transnational medicine. It highlights the rise of
international therapeutic modernity at the beginning of the 1990s, based on the strict regulation of clinical trials and on the formalization of the international
ethical rules governing experiments. This rise helped to change radically the reception of experiments conducted in southern
countries around AIDS. With regard to this new ethics applied to clinical trials in southern countries, this article goes
on to demonstrate the confrontation at the end of the 1990s between two different approaches to the universalization of healthcare.
Finally, it shows how new laws on international trade have reinitiated this confrontation. Through this story, the article
suggests in what sense the study of the political transformations of transnational medicine could offer a new field of investigation
for the social sciences. 相似文献
156.
Alan G. Glaros 《Applied psychophysiology and biofeedback》2001,26(1):61-65
The paper by La Vaque and Rossiter recommends that placebo-controlled trials only be conducted when best proven treatments are not available. In this comment, I review evidence suggesting that identifying best proven treatments is a complex task involving many variables and that making such a decision entails many real-world difficulties. 相似文献
157.
BiTEs(bispecificTcellengagers)是一种以T细胞作为效应细胞的双特异性单链抗体 ,它具有两个抗原结合臂 ,可以同时和T细胞及靶细胞结合 ,并激活细胞毒性T细胞杀伤病变细胞。和其它双特异性抗体相比 ,BiTEs的分子柔韧性更好 ,能更好地促进CD3复合体和肿瘤靶标的连接 ,并且它不受T细胞受体和靶细胞上MHCⅠ类分子的约束 ,不需要共刺激分子的参与 ,是一种极具应用潜力的抗体形式。就BiTEs的结构、作用机理及其在肿瘤临床上的应用前景几个方面做一综述。 相似文献
158.
Menadione sodium bisulphite (MSB) increased the growth of tomato plants and alfalfa callus and stimulated rooting of mungbean cuttings. Investigations into its effect on auxin metabolism resulted in decreased activities of the enzymes involved in IAA oxidation in tomato plants. The levels of IAA were increased by about 3 to 4 fold following application of MSB to tomato, cucumber, corn and capsicum plants.NCL Communication No. 3358. 相似文献
159.
L. Gusmão 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1985,71(2):314-319
Summary Based on theoretical demonstrations and illustrated with a numerical example from triticale yield trials in Portugal, the Completely Randomized Design is proposed as the one suited for Regression Analysis. When trials are designed in Complete Randomized Blocks the regression of plot production on block mean instead of the regression of cultivar mean on the overall mean of the trial is proposed as the correct procedure for regression analysis. These proposed procedures, in addition to providing a better agreement with the assumptions for regression and the philosophy of the method, induce narrower confidence intervals and attenuation of the hyperbolic effect. The increase in precision is brought about by both a decrease in the t Student values by an increased number of degrees of freedom, and by a decrease in standard error by a non proportional increase of residual variance and non proportional increase of the sum of squares of the assumed independent variable. The new procedures seem to be promising for a better understanding of the mechanism of specific instability. 相似文献
160.
《Microbes and infection / Institut Pasteur》2021,23(8):104841
SARS-CoV-2 has infected more than 167 million individuals globally. Highly effective and safe vaccines are required to accelerate the development of herd immunity to end the pandemic. This review focuses on vaccines that are being developed at unprecedented speed globally and are completing late phase clinical trials to meet this urgent need. 相似文献