全文获取类型
收费全文 | 4705篇 |
免费 | 285篇 |
国内免费 | 1篇 |
专业分类
各国政治 | 355篇 |
工人农民 | 12篇 |
世界政治 | 640篇 |
外交国际关系 | 766篇 |
法律 | 1796篇 |
中国共产党 | 299篇 |
中国政治 | 558篇 |
政治理论 | 212篇 |
综合类 | 353篇 |
出版年
2023年 | 28篇 |
2022年 | 30篇 |
2021年 | 19篇 |
2020年 | 30篇 |
2019年 | 40篇 |
2018年 | 51篇 |
2016年 | 32篇 |
2015年 | 35篇 |
2014年 | 161篇 |
2013年 | 112篇 |
2012年 | 298篇 |
2011年 | 306篇 |
2010年 | 189篇 |
2009年 | 156篇 |
2008年 | 214篇 |
2007年 | 228篇 |
2006年 | 241篇 |
2005年 | 200篇 |
2004年 | 190篇 |
2003年 | 204篇 |
2002年 | 199篇 |
2001年 | 142篇 |
2000年 | 137篇 |
1999年 | 99篇 |
1998年 | 78篇 |
1997年 | 73篇 |
1996年 | 69篇 |
1995年 | 82篇 |
1994年 | 79篇 |
1993年 | 50篇 |
1992年 | 54篇 |
1991年 | 56篇 |
1990年 | 52篇 |
1989年 | 64篇 |
1988年 | 101篇 |
1987年 | 80篇 |
1986年 | 82篇 |
1985年 | 90篇 |
1984年 | 87篇 |
1983年 | 88篇 |
1982年 | 59篇 |
1981年 | 59篇 |
1980年 | 80篇 |
1979年 | 39篇 |
1964年 | 21篇 |
1962年 | 17篇 |
1961年 | 14篇 |
1959年 | 17篇 |
1957年 | 15篇 |
1956年 | 13篇 |
排序方式: 共有4991条查询结果,搜索用时 15 毫秒
271.
Inayama Y Udaka N Amano T Watanuki Y Odagiri S Kawano N Nakatani Y 《Journal of forensic sciences》2000,45(2):478-482
We report a fatal case of death due to unusual aspiration of sardine fry in an elderly Japanese man with lung cancer. The cause of death was sudden respiratory arrest while eating. Autopsy revealed peculiar materials with cell nests and pigmented particles, together with striated muscle and skin, in the ectatic bronchioles of the left lower lobe. Serial histologic sections suggested that the structures observed were the eyeballs of small animals that appeared to have been inhaled. The patient had habitually eaten sardine fry and rice gruel, which were also detected in the gastric contents. Therefore, the eyes were considered to be those of the fry, which is a popular food item in Japan. This was confirmed by histologic examination of fry that were obtained commercially. 相似文献
272.
A high-density aqueous salt solution for the preparation of density gradients is presented. It has been used successfully by the authors in forensic soil analysis. It has a density range that allows for the separation of a soil specimen's heavy mineral components. It has no odor or toxic fumes, which eliminates the need to use a hood during preparation, and is far superior to the organic liquids normally used to prepare density gradients. This liquid should cause many forensic scientists to reexamine their attitudes towards using density gradients in forensic soil casework. 相似文献
273.
Lemmens T 《McGill law journal. Revue de droit de McGill》2000,45(2):347-412
This article discusses the desirability of legislation focusing on genetic discrimination, in particular in the context of insurance. Many American states and some European countries as well as the Council of Europe have introduced protective measures against discrimination on the basis of genetic susceptibility. The author questions their effectiveness and queries whether they may be inequitable, because they fail to address more fundamental underlying issues related to the nature of insurance, access to health care, and unequal distribution of wealth. There is also a problem of definition in these statutes. They fail to capture what constitutes genetic information. Nonetheless, the author argues it is important to consider the social consequences of genetic testing. Michael Walzer's theory of justice is used to examine the role of insurance and health care. Using this approach, the author finds the American system of distribution for health care to be problematic. This is then used to inform the author's discussion of the future of health care in Canada. Anti-discrimination provisions could be used in a way that is consistent with Walzer's theory of justice. They would encompass both genetic and non-genetic health factors. These can be modelled on current anti-discrimination statutes in Canada. The author then proposes administrative committee structures to regulate the use of genetic data in Canada. 相似文献
274.
Steadman HJ Silver E Monahan J Appelbaum PS Robbins PC Mulvey EP Grisso T Roth LH Banks S 《Law and human behavior》2000,24(1):83-100
Since the 1970s, a wide body of research has suggested that the accuracy of clinical risk assessments of violence might be increased if clinicians used actuarial tools. Despite considerable progress in recent years in the development of such tools for violence risk assessment, they remain primarily research instruments, largely ignored in daily clinical practice. We argue that because most existing actuarial tools are based on a main effects regression approach, they do not adequately reflect the contingent nature of the clinical assessment processes. To enhance the use of actuarial violence risk assessment tools, we propose a classification tree rather than a main effects regression approach. In addition, we suggest that by employing two decision thresholds for identifying high- and low-risk cases--instead of the standard single threshold--the use of actuarial tools to make dichotomous risk classification decisions may be further enhanced. These claims are supported with empirical data from the MacArthur Violence Risk Assessment Study. 相似文献
275.
Statistical examination of hair color as a potential biasing factor in hair analysis 总被引:3,自引:0,他引:3
We review eight different data sets in this paper for the purposes of assessing the possibility that reported color of hair can produce a systematic bias in the interpretation of hair assays. We review studies or data sets that include heroin and its metabolites, cocaine and its metabolites, MDMA and its analogs, and amphetamine and methamphetamine. The studies have utilized a variety of different degrees of color categorization, ranging from the simple dichotomy of brown and black, to a high of 12 categories. The mean number of categories reported approaches 6 (mean = 5.875). There are a total of 2791 data points in this analysis. We utilize two major statistical techniques for assessing significance; one-way analysis of variance, and Tukey's Honestly Significant Difference procedure. In circumstances were only dichotomous contrasts are possible, one-way analysis of variance is used. In contrasts involving three or more categorical groups, Tukey's procedure is used. In circumstances where the homogeneity of group variances is not sustained by the Levene statistic, we use the Tamahane procedure, allowing an assessment that assumes unequal variances. The analysis of this data fails to discern a significant color effect. We speculate that it may be that variance is large in many domains affecting analyte recovery from hair. In large groups these variations tend to regress towards a typical or mean value. Thus the data here show that while there are group or aggregate differences in these 'typical' values, they are not great when considered in relation to the within-group variations which exist for those values. It is our view that color may play a role in the accumulation of drugs in hair, however it is likely to account for only a very small part of the complex process of drug accumulation. 相似文献
276.
A biomechanical study of the human vertebral artery with implications for fatal arterial injury 总被引:8,自引:0,他引:8
We studied the biomechanical behaviour of ring and strip specimens from along the length of 18 vertebral arteries taken from 16 subjects aged 28-90 years, in order to consider some of the factors which may play a role in vertebral artery rupture. The method was chosen to allow a comparison between circumferential distension (ring samples) and longitudinal extension, (strip samples). The samples were extended between the jaws of a tensile testing apparatus until the specimen broke and a number of biomechanical parameters were derived. These were the percentage extension to break, the tensile strength, Young's modulus and the peak load. There were a number of important findings. The vertebral artery was shown to be susceptible to longitudinal stretching with a number of strip samples breaking when extended by as little as 16-20%. The tensile strength and load at peak of the strip specimens were correspondingly lower than for the ring samples. Marked intersubject variations were shown for all these parameters and prominent changes in behaviour occurred along the vertebral artery. This study indicates that the artery may be susceptible to head and neck movements which cause the vessel to stretch, and intersubject variations in behaviour may be one important explanation for the marked differences in outcome which appear to exist in subjects who suffer broadly similar head and neck insults. 相似文献
277.
The estimation of the age of skin bruises is of importance in forensic medicine, especially in child abuse cases. Time-dependent changes in bruise colour and/or associated histological features have been used with a limited degree of success. An increased rate of apoptosis in the injured tissue has been considered as a novel time-dependent marker of cell death, by injury inflicted in a rat model. The object of the present study was to apply the TUNEL method of DNA end labelling to identify and enumerate apoptotic cells in bruised and normal skin in order to study the relationship of apoptotic cell density with the age of the bruise. A commercially available DNA end labelling kit, TUNEL method, was standardised, validated and used for this purpose. Twenty unselected post-mortem cases with bruises due to a variety of causes were studied. The apoptotic cells stained with TUNEL reaction were counted in 10 high power fields in the epidermis, as well as in the dermis of formaldehyde-fixed paraffin-embedded skin specimens. The mean positive cell densities (+/- 1 S.E.) were compared with respect to the age of the bruise. In the epidermis, the mean apoptotic cell count was statistically significantly greater in the bruised skin compared to normal skin in 2- to 6-day-old bruises; whilst in the dermis the same was true in 3- to 8-day-old bruises. The overall findings suggest that there is a quiescent period prior to the increase in the apoptotic cell activity that is seen following skin bruising. This is so provided the post-mortem skin samples were collected within a lapse of 6 days or less between the time of death and formalin fixation and paraffin embedding to avoid the bias made by the difference of length of post-mortem interval. 相似文献
278.
The paper extends on the traditional methodology used to quantify DNA evidence in paternity or identification cases. By extending we imply that there are more than two alternatives to choose between. In a standard paternity case the two competing explanations H(1): "John Doe is the father of the child and H(2): "A random man is the father of the child, are typically considered. A paternity index of 100000 implies that the data is 100000 more likely assuming hypothesis H(1) rather than H(2). If H(2) is replaced by "A brother of John Doe is the father", the LR may change dramatically. The main topic of this paper is to determine the most probable pedigree given a certain set of data including DNA profiles. In the previous example this corresponds to determining the most likely relation between John Doe and the child. Based on DNA obtained from victims of a fire, bodies found in an ancient grave or from individuals seeking to confirm their anticipated family relations, we would like to determine the most probable pedigree. The approach we present provides the possibility to combine non-DNA evidence, say age of individuals, and DNA profiles. The program familias, obtainable as shareware from http://www.nr.no/familias, delivers the probabilities for the various family constellations. More precisely, the information (if any) prior to DNA is combined with the DNA-profiles in a Bayesian manner to deliver the posterior probabilities. We exemplify using the well published Romanov data where the accepted solution emerges among 4536 possibilities considered. Various other applications based on forensic case work are discussed. In addition we have simulated data to resemble an incest case. Since the true family relation is known in this case, we may evaluate the method. 相似文献
279.
Mitchell E Krous HF Donald T Byard RW 《The American journal of forensic medicine and pathology》2000,21(4):395-400
Retrospective analysis of autopsy findings in 60 infants who had been found unexpectedly dead in their cribs or beds in South Australia from 1994 to 1998 was undertaken to determine the diagnostic usefulness of individual stages in the postmortem investigation. Positive findings occurred in 2 of 43 scene examinations (3%), 2 of 60 external examinations (3%), 2 of 11 radiologic examinations (18%), 8 of 60 internal examinations (13%), 7 of 60 histologic examinations (12%), and 3 of 58 microbiologic examinations (5%). No positive findings were detected on toxicologic screening. Not every case underwent each diagnostic step. This gave alternative diagnoses to sudden infant death syndrome (SIDS) in 15 cases (25%). This study demonstrates an increase in the percentage of cases of unexpected infant death due to causes other than SIDS; it also shows the diagnostic yield of individual stages in the postmortem evaluation of such cases. Negative findings were important in giving validity to the diagnosis in the 45 cases that were ultimately designated as SIDS. 相似文献
280.