首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   12334篇
  免费   420篇
各国政治   791篇
工人农民   485篇
世界政治   999篇
外交国际关系   680篇
法律   6679篇
中国政治   87篇
政治理论   2926篇
综合类   107篇
  2021年   69篇
  2020年   154篇
  2019年   197篇
  2018年   309篇
  2017年   332篇
  2016年   392篇
  2015年   240篇
  2014年   289篇
  2013年   1612篇
  2012年   320篇
  2011年   322篇
  2010年   289篇
  2009年   296篇
  2008年   370篇
  2007年   418篇
  2006年   393篇
  2005年   334篇
  2004年   332篇
  2003年   318篇
  2002年   288篇
  2001年   374篇
  2000年   327篇
  1999年   330篇
  1998年   176篇
  1997年   162篇
  1996年   141篇
  1995年   127篇
  1994年   141篇
  1993年   141篇
  1992年   187篇
  1991年   218篇
  1990年   213篇
  1989年   192篇
  1988年   207篇
  1987年   203篇
  1986年   206篇
  1985年   184篇
  1984年   168篇
  1983年   147篇
  1982年   108篇
  1981年   120篇
  1980年   86篇
  1979年   145篇
  1978年   104篇
  1977年   88篇
  1976年   69篇
  1975年   94篇
  1974年   109篇
  1973年   91篇
  1971年   62篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
In a strict and conservative society like Malaysia, the number of cases of infanticide has continued to occur. The authors present two typical cases of infanticide in Malaysia. Case 1 concerned a body of a fully mature newborn fetus disposed in a rubbish bin. The head was traumatically amputated by the rubbish truck's compactor. The umbilical cord was still attached to the body, with no reddening around the insertion. The severed neck showed features consistent with post-mortem amputation. The significant finding was expanded crepitant lungs, which floated in water. The histology of the lungs showed expanded alveoli. It was concluded that the baby had been born alive, but no cause of death could be elicited. Case 2 concerned a decomposed mature newborn found in a scrub forest. The internal organs showed advanced putrefaction, the lungs being collapsed, congested, and hemorrhagic, typical of decomposed lungs. No conclusion could be made about the state of birth or the cause of death because of the putrefied state of the body. The two cases illustrate the typical cases and problems faced by pathologists locally and probably elsewhere in the world. Most of the bodies are found in a putrefied state. Pathologists have to ascertain not only maturity and live birth but also the cause of death, which may be very subtle or masked by putrefaction. The problems of diagnosis of live birth are discussed.  相似文献   
942.
Three modeling methods were used to estimate the time for laying of Lucilia sericata eggs (Diptera, Calliphoridae) after measurements of hatching times at several constant temperatures. These models were tested first under controlled conditions with 19 profiles of fluctuating temperatures, and on the other hand under field conditions on mice. All three models were allowed to determine the time of laying within a period of about 2h, and consequently this determines the time of death, as this species lays immediately after death under favorable conditions. Rearing of eggs sampled on a corpse may therefore contribute to the determination of a short post-mortem interval (PMI).  相似文献   
943.
Bite mark identification is based on the individuality of a dentition, which is used to match a bite mark to a suspected perpetrator. This matching is based on a tooth-by-tooth and arch-to-arch comparison utilising parameters of size, shape and alignment. The most common method used to analyse bite mark are carried out in 2D space. That means that the 3D information is preserved only two dimensionally with distortions. This paper presents a new 3D documentation, analysis and visualisation approach based on forensic 3D/CAD supported photogrammetry (FPHG) and the use of a 3D surface scanner. Our photogrammetric approach and the used visualisation method is, to the best to our knowledge, the first 3D approach for bite mark analysis in an actual case. The documentation has no distortion artifacts as can be found with standard photography. All the data are documented with a metric 3D measurement, orientation and subsequent analysis in 3D space. Beside the metrical analysis between bite mark and cast, it is possible using our method to utilise the topographical 3D feature of each individual tooth. This means that the 3D features of the biting surfaces and edges of each teeth are respected which is--as shown in our case--very important especially in the front teeth which have the first contact to the skin. Based upon the 3D detailed representation of the cast with the 3D topographic characteristics of the teeth, the interaction with the 3D documented skin can be visualised and analysed on the computer screen.  相似文献   
944.
The aim of the study was to test the hypothesis that polymerase slippage correlates to the length of repeat stretches consisting of uniform repeats against the alternative hypothesis that the total number of repeats is most relevant. Two short tetrameric short tandem repeats (STRs) with different repeat structures were investigated: D3S1545 containing only homogeneous (GATA)n repeat stretches and D7S1517 with compound repeat arrays of GAAA and CAAA repeats. Additionally two different polymerases (Herculase and AmpliTaq Gold) were used which gave comparable results. No correlation was found for the hypothesis "total repeat number against percent of stutter"; in contrast, the other hypothesis that the number of uniform repeats is relevant for the degree of stutter gave a strong positive correlation (0.82 for selected D7S1517 alleles) which confirmed the hypothesis that polymerase slippage correlates to the length of repeat stretches consisting of uniform repeats.  相似文献   
945.
Fibronectin, MRP8, MRP14 and defensin were detected immunohistochemically in 46 surgically treated, fresh (hours old) human wounds and in wounds of 13 individuals who died immediately from fatal trauma (airplane crashes or train rollovers). In immediate fatal trauma, it was not possible to detect fibronectin outside of bleeding areas nor could inflammatory cells be visualized in the interstitium using MRP8, MRP14, or defensin antibodies. Fibronectin staining could be regularly demonstrated in wounds at least 20 min-old. Granulocytic infiltrates limited to the perivasal space could be detected 20-30 min after infliction of the wound expressing MRP8, MRP14 and defensin. It was also possible to detect fibronectin networks and MRP8-, MRP14-, and defensin-positive granulocytes and macrophages in particular wounds up to 30 days-old. No differences between the expression of MRP8 and MRP14 could be demonstrated in the wounds, the majority of which were only several hours old. As wound age increased, the number of defensin-positive granulocytes detected decreased. The immunohistochemical detection of fibronectin is a useful way to demonstrate vitality in fresh wounds, beginning about 20-30 min post-trauma. However, detection of MRP8, MRP14 and defensin provides no advantage over the routine histological detection of granulocytes and macrophages in wounds under 1-2 days old.  相似文献   
946.
Among the few cases of suicidal self-incineration primary or secondary complex suicides are a rarity. Accordingly the number of reports on this subject in the forensic literature is small. In a retrospective analysis of the Freiburg and Berlin autopsy material, four cases were found within an observation period of 11 years. These are described together with seven other cases reported in the literature. Altogether most of these suicides are primary combinations, especially with falls from a height. Other combinations include hanging or the infliction of stabs, cuts or gunshot injuries. The sex and age distribution is similar to that found for suicide by self-incineration alone.  相似文献   
947.
Detection and correct classification of gasoline is important for both arson and fuel spill investigation. Principal component analysis (PCA) was used to classify premium and regular gasolines from gas chromatography-mass spectrometry (GC-MS) spectral data obtained from gasoline sold in Canada over one calendar year. Depending upon the dataset used for training and tests, around 80-93% of the samples were correctly classified as either premium or regular gasoline using the Mahalanobis distances calculated from the principal components scores. Only 48-62% of the samples were correctly classified when the premium and regular gasoline samples were divided further into their winter/summer sub-groups. Artificial neural networks (ANNs) were trained to recognise premium and regular gasolines from the same GC-MS data. The best-performing ANN correctly identified all samples as either a premium or regular grade. Approximately 97% of the premium and regular samples were correctly classified according to their winter or summer sub-group.  相似文献   
948.
Blowfly larvae found on human corpses are important for the estimation of the postmortem interval (PMI) and other questions of forensic relevance. Some of these species are difficult to differentiate morphologically, therefore a molecular method was elaborated for species identification. Specific fragments of the COI and COII region of the mitochondrial DNA (mtDNA) were amplified followed by digestion with different restriction enzymes. Using a 1.3 kb fragment, identification of Lucilia sericata, Calliphora vicina and Calliphora vomitoria was possible by digestion with only one restriction enzyme using either DraI or HinfI. Furthermore, we sequenced 349 bp (a part of the COI and COII regions) from the same three species and found 34 nucleotide distinctions between C. vicina and L. sericata, 30 between C. vomitoria and L. sericata and 15 between the two Calliphora species. These results aid in quick identification of species used for estimation of PMI.  相似文献   
949.
The past decade provides a useful window through which to examine whether states are likely to provide health care leadership. During this era, states were given increased discretion to set health care policy, they had the financial resources to encourage innovation, and their administrative capacity was at its strongest ever. Despite the favorable conditions, however, states were reluctant to spend their own funds on programs for the uninsured, their efforts to make private insurance more affordable for the small business community were disappointing, and their efforts to regulate the managed care industry fell short. At the same time, though, the most promising innovations over the past decade were in programs financed primarily with federal dollars, administered primarily by state officials, and advanced by an intergovernmental partnership in which administrators at different levels of government prod each other to try and do more. This sort of intergovernmental partnership provides the best model for innovative health policy leadership.  相似文献   
950.
Nineteen Y-chromosomal short tandem repeats (STRs), DYS19, DYS389-I, DYS389-II, DYS390, DYS391, DYS392, DYS393, DYS385, DYS388, DYS434, DYS435, DYS436, DYS437, DYS438, DYS439, DYS460, DYS461 and DYS462 were typed in Inuit (n=70) and Danish (n=62) population samples.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号