全文获取类型
收费全文 | 4880篇 |
免费 | 41篇 |
专业分类
各国政治 | 170篇 |
工人农民 | 54篇 |
世界政治 | 753篇 |
外交国际关系 | 481篇 |
法律 | 2643篇 |
中国共产党 | 112篇 |
中国政治 | 290篇 |
政治理论 | 333篇 |
综合类 | 85篇 |
出版年
2021年 | 27篇 |
2018年 | 22篇 |
2016年 | 17篇 |
2015年 | 23篇 |
2014年 | 120篇 |
2013年 | 35篇 |
2012年 | 328篇 |
2011年 | 291篇 |
2010年 | 139篇 |
2009年 | 106篇 |
2008年 | 259篇 |
2007年 | 358篇 |
2006年 | 346篇 |
2005年 | 300篇 |
2004年 | 261篇 |
2003年 | 255篇 |
2002年 | 252篇 |
2001年 | 188篇 |
2000年 | 196篇 |
1999年 | 99篇 |
1998年 | 55篇 |
1997年 | 40篇 |
1996年 | 37篇 |
1995年 | 33篇 |
1994年 | 71篇 |
1993年 | 41篇 |
1992年 | 54篇 |
1991年 | 46篇 |
1990年 | 32篇 |
1989年 | 29篇 |
1988年 | 121篇 |
1987年 | 33篇 |
1986年 | 34篇 |
1985年 | 34篇 |
1984年 | 42篇 |
1983年 | 35篇 |
1982年 | 27篇 |
1981年 | 40篇 |
1980年 | 45篇 |
1979年 | 39篇 |
1978年 | 20篇 |
1977年 | 55篇 |
1976年 | 36篇 |
1973年 | 16篇 |
1964年 | 27篇 |
1963年 | 25篇 |
1962年 | 41篇 |
1961年 | 19篇 |
1960年 | 22篇 |
1959年 | 32篇 |
排序方式: 共有4921条查询结果,搜索用时 15 毫秒
261.
Individual health insurance markets differ from state to state, and as a result approaches to individual market reforms need to be different. In evaluating approaches, policy makers need to remember that since the decision to purchase health insurance coverage is voluntary, the potential for adverse selection exists. In addition, rather than putting the focus of individual market reforms almost exclusively on access to health insurance for a small number of persons with high-cost health conditions, more attention needs to be put on how to decrease the number of uninsured persons. This includes making the premiums paid for individual health insurance 100 percent tax deductible, similar to those of employer-based health insurance. Finally, market reforms need to treat all types of coverage issued in the individual market the same, whether they are purchased direct for the insurer or through an out-of-state association. 相似文献
262.
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
263.
Analysis of eight STR loci in two Hungarian populations 总被引:1,自引:0,他引:1
Egyed B Füredi S Angyal M Boutrand L Vandenberghe A Woller J Pádár Z 《Forensic science international》2000,113(1-3):25-27
A collection of eight STR loci (D3S1358, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820) was used to generate allele frequency databases for two Hungarian population samples, Caucasians from the Budapest area and Romanies from Baranya county. During the analysis two intermediate sized alleles and a sequence variant allele were observed at the D7S820 locus. All three types of allelic variants were found to have modification (deletion, insertion, transversion) in the same block of a (T)(9) stretch located within the 3' flanking region of each allele, which may indicate a possible higher mutation rate of this (T)(9) block. For the loci D3S1358 and D7S820 the Romany population database showed departures from Hardy-Weinberg equilibrium. The forensic efficiency values for the Romany population were slightly different from those found in the Hungarian Caucasian population. Comparing the allele frequency values by G-statistic, calculating the F(st) indices and with the pairwise comparisons of inter-population variance, the two Hungarian populations could be distinguished using data of the eight STR loci. 相似文献
264.
Chattopadhyay PK Cleef S Duelmer M Henke L Henke J 《Forensic science international》2000,113(1-3):29-32
This study provides Jat Sikhs population data in North India for nine short tandem repeat (STR) loci. 相似文献
265.
To improve the possibilities to delimit the time of death after longer laytime it was examined if this is possible by immunohistochemical detection of thyroglobulin. The results show that in our examination material the colloid and the follicular cells of the thyroid glands of up to 5-day-old corpses produce a positive immunoreaction towards thyroglobulin in all cases whereas none of the corpses older than 13 days show such a reaction. This means that in case of a negative immunoreaction the time of death can be assumed to lie more than 6 days before the autopsy. The fact that a negative immunoreaction occurs consistently after 13 days leads to the conclusion that when thyroglobulin has been stained in a specimen, the death of the respective person must lie a maximum of 12 days earlier, whereby these time-limits may change in considerably different surrounding conditions. 相似文献
266.
To develop a method of detecting methadone in the human brain by immunohistochemistry, brain tissue of frontal cortex, cerebellum, hippocampus, basal ganglions and brain stem from victims of a lethal methadone overdose was examined. The staining was performed with a monoclonal anti-methadone antibody from the mouse, originally developed for immunochemichal purposes (ELISA). With the help of the DAKO((R)) Catalyzed Signal Amplification (CSA) System, a specific positive immunoreaction was obtained in the neurons of the frontal cortex and hippocampus, as compared with specimen from deaths without exposition to methadone. Thus, along with metamphetamine, phenobarbital, morphine and insulin, immunohistochemical detection is also possible for methadone and the intake of this medicament can now be proven morphologically. 相似文献
267.
Golden J 《Journal of health politics, policy and law》2000,25(3):473-498
This article examines the portrayal of pregnancy and alcohol in thirty-six national network evening news broadcasts (ABC, CBS, NBC). Early coverage focused on white, middle-class women, as scientific authorities and government officials warned against drinking during pregnancy. After 1987, however, women who drank during pregnancy were depicted as members of minority groups and as a danger to society. The thematic transition began before warning labels appeared on alcoholic beverages and gained strength from official government efforts to prevent fetal alcohol syndrome. The greatest impetus for the revised discourse, however, was the eruption of a "moral panic" over crack cocaine use. By linking fetal harm to substance abuse, the panic suggested it was in the public's interest to control the behavior of pregnant women. 相似文献
268.
By means of the new method of Streifenlichttopometrie (SLT) it is possible to record the complete body surface of casualties in a practically photorealistic fashion, i.e. three-dimensionally and in colour. In comparison with the classic method of Photogrammetry Streifenlichttopometrie (SLT) is remarkably faster (10,000 points/s instead of 1 point/s) and in addition the colour of every point measured upon the corpse's surface is instantly recorded. Taking into consideration the resolution required and the qualities of the camera system the body surface is recorded in 'patches', i.e., areas of a defined extension (in the present case 500 mmx500 mmx200 mm) which are marked with a body fixed reference frame to grant the exact matching of the data after the recording process. Length, perimeter, square and volume of the body segments and injuries can be determined. Furthermore the natural colour of the wounds can be used for an immediate classification according to the intensity of the impact forces. In addition the 3-D coordinates of the body surface including the wounds can be transferred into an animated computer simulation for the reconstruction of the traumatic events. 相似文献
269.
Pontocerebellar hypoplasia (PCH) is a very rare congenital (autosomal recessive) condition with fetal onset. Only a few cases have been published on the basis of both clinical data (symptoms/neuroradiological imaging) and autopsy results. This paper reports on such a case involving a 1.5-year-old male infant. The child suffered from severe psychomotor delay, extrapyramidal dyskinesia and epileptic seizures, but did not exhibit signs of spinal muscular atrophy as related to PCH type 1. Magnetic resonance imaging (MRI) at the age of 6 months demonstrated olivo-pontine and bilateral cerebellar hypoplasia. The boy was unexpectedly found dead. Autopsy disclosed a severe aspiration of gastric contents as the final cause of death. The neuropathological examination confirmed PCH type 2 (according to Barth [Brain Dev., 15 (1993) 411-422]) with marked microcephaly and olivopontocerebellar hypoplasia. Histologically, decreased density of olivo-pontine neurons, reduction of granular and Purkinje's cell layers of the cerebellum, slight astroglial proliferation and fragmented appearance of the dentate nuclei were observed. The immunohistochemical expression pattern was determined using antibodies against glial fibrillary acidic protein, synaptophysin and neurofilament protein. Summarizing, typical features of PCH type 2 were present and proved by clinical course, MRI and autopsy. Despite severe symptoms due to a natural disease this rare neurogenetic entity can become of forensic interest, when sudden unexpected death occurs. 相似文献
270.
Wulf J Bednarz J Junge M Engelmann K Püschel K 《Forensic science international》2000,113(1-3):495-496
Between 1997 and 1999 a steady increase in cornea donations was achieved, but the number of transplantations remained stable because many grafts did not pass quality control. Intermediate organ culture of entire bulbi was examined as a possible solution to reduce post-mortem times and increase suitability for transplantation. 相似文献