全文获取类型
收费全文 | 19677篇 |
免费 | 797篇 |
专业分类
各国政治 | 694篇 |
工人农民 | 791篇 |
世界政治 | 1368篇 |
外交国际关系 | 607篇 |
法律 | 12764篇 |
中国共产党 | 35篇 |
中国政治 | 175篇 |
政治理论 | 3870篇 |
综合类 | 170篇 |
出版年
2021年 | 118篇 |
2020年 | 325篇 |
2019年 | 340篇 |
2018年 | 415篇 |
2017年 | 512篇 |
2016年 | 545篇 |
2015年 | 450篇 |
2014年 | 473篇 |
2013年 | 1768篇 |
2012年 | 456篇 |
2011年 | 547篇 |
2010年 | 465篇 |
2009年 | 548篇 |
2008年 | 582篇 |
2007年 | 569篇 |
2006年 | 573篇 |
2005年 | 530篇 |
2004年 | 512篇 |
2003年 | 452篇 |
2002年 | 455篇 |
2001年 | 752篇 |
2000年 | 689篇 |
1999年 | 516篇 |
1998年 | 320篇 |
1997年 | 252篇 |
1996年 | 255篇 |
1995年 | 227篇 |
1994年 | 267篇 |
1993年 | 244篇 |
1992年 | 371篇 |
1991年 | 436篇 |
1990年 | 383篇 |
1989年 | 378篇 |
1988年 | 403篇 |
1987年 | 373篇 |
1986年 | 417篇 |
1985年 | 386篇 |
1984年 | 310篇 |
1983年 | 316篇 |
1982年 | 212篇 |
1981年 | 233篇 |
1980年 | 181篇 |
1979年 | 221篇 |
1978年 | 159篇 |
1977年 | 145篇 |
1976年 | 128篇 |
1975年 | 102篇 |
1974年 | 130篇 |
1973年 | 139篇 |
1972年 | 105篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The purpose of the present investigation was to test the accuracy of a new scoring system in recording tooth wear for age estimation. The material consisted of dental stone casts of 383 volunteers who had sound premolars and molars with normal occlusion. The degree of occlusal wear for all premolar and molar teeth was scored with the new system. The high intra- and inter-examiner concordances showed that the new score system was very reliable. The degree of tooth wear showed a significant positive correlation with age in each and every examined tooth of both males and females. Tooth wear scores of males were higher than those of females. Calculating tables for age estimation were designed and the accuracy of age estimation was obtained with the General Linear Models procedures. Our system could provide estimation of an individual's age within +/-3 years in 42.4% of males and 49.4% of females, within +/-5 years in 61.8% of males and 63.3% of females. When the subjects were divided into two age groups and data were re-treated, the accuracy of age estimation was increased. Collectively, it was shown that our new system for scoring tooth wear is a reliable and accurate method for age estimation. 相似文献
992.
Phillips SA Lowe A Marshall M Hubbard P Burmeister SG Williams DR 《Journal of forensic sciences》2000,45(2):324-332
Recent criminal acts in the United Kingdom, United States and other countries have demonstrated the dangers to public safety from the criminal use of improvised explosives on a large scale. Four sets of trials were carried out over four years, partly in collaboration with the United States Federal Bureau of Investigation, involving the firing of large bombs, mostly fertilizer based. The principal objectives of the firings were to measure the physical effects of the explosions upon objects representative of those that would be found at a real bomb scene and to recover any chemical traces deposited on these objects. The results are intended for use as an aid in determining the approximate size and type of an explosive employed in a terrorist attack. This paper describes the background behind the trials, the procedures for preparation of witness materials and charges, and the collection and analysis of physical and chemical evidence. 相似文献
993.
Corte-Real F Andrade L Anjos MJ Carvalho M Vieira DN Carracedo A Vide MC 《Journal of forensic sciences》2000,45(2):432-435
The Short Tandem Repeats (STRs) D3S1358, HUMvWA31/A, HUMFIBRA/FGA, D8S 1179, D2S11, D18S51, D5S818, D13S317, and D7S820 were studied in two Brazilian populations (from Amazonia and S. Paulo) using the "AmpF1 STR Profiler Plus PCR Amplification Kit." The nine loci showed a combined discrimination power greater than 0.9999999999 and a chance of exclusion of 0.9999. 相似文献
994.
Our laboratory was asked to help with the rehydration of mummified human fingertips that had been removed from a recently deceased, unidentified female. Using a solution that was found in the archeological literature, we were able to successfully rehydrate dermal tissues to the extent that fingerprints could be taken. We believe that this solution, which until now has not been described in the forensic literature, is effective, affordable, and relatively easy to produce and use. 相似文献
995.
In recent years the forensic scientist has been afforded great advances in technology both in the detection of latent bloodstains and in acquiring reliable DNA typing results from very small pieces of physical evidence. Scientists are now able to detect minute quantities of latent bloodstains by utilizing the luminol reagent, oftentimes indicating that an attempt has been made to conceal any evidence of bloodshed. With the introduction of PCR based technology to the forensic arena, scientists are now routinely able to obtain DNA typing results from previously insufficient amounts of biological material, items as small as a single hair, saliva on a cigarette butt, or a bloodstain the size of a pin head. We present here a merging of these two advances coupled with a new collection medium for post luminol treated latent bloodstains. The forensic scientist is now able to routinely isolate and recover an adequate amount of DNA suitable for PCR typing at all of the Promega GenePrint PowerPlex 1.1 loci. In this study, several dilutions of latent bloodstains were prepared in an effort to simulate transferred bloodstains that are routinely encountered in a crime scene setting. The latent bloodstains were treated with luminol and subsequently collected using conventional cotton tipped swabs as well as a Puritan sponge tipped swab. PCR typing at the Promega GenePrint PowerPlex 1.1 loci was then attempted upon all dilutions of the latent bloodstains for both collection mediums. The results clearly indicate that it is now routinely possible to recover adequate amounts of DNA suitable for PCR typing upon post luminol treated bloodstains. 相似文献
996.
Tahir MA Balraj E Luke L Gilbert T Hamby JE Amjad M 《Journal of forensic sciences》2000,45(4):902-907
A body was exhumed from the ground after 27 years. Samples of femur bone, tooth, and a fingernail were collected and successfully subjected to DNA extraction, quantitation, amplification, and subsequently typed for DQA1, polymarker, and nine STR loci. All three types of samples were typed for D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S17, D7S820, and amelogenin using ABI Prism 377 DNA sequencer. 相似文献
997.
Sturner WQ Herrmann MA Boden C Scarritt TP Sherman RE Harmon TS Woods KB 《Journal of forensic sciences》2000,45(4):908-910
State Supreme Courts require a minimum threshold of reliability and acceptance in the scientific community for all medical and similar evidence to be admitted at trial. In Florida and some other states, the courts adhere to what is known as the Frye standard, whereas in most states and in Federal Courts, it is the so-called Daubert standard. The jurisdiction of the present case is Hillsborough County (Tampa), Florida. Forensic pathologists seldom, if ever, are requested to participate in such hearings, unlike their toxicological and basic science colleagues who are more involved in research methodology and technical procedures. The burden is on the proponent of the evidence to prove the general acceptance of both the underlying scientific principle of the test and procedures used to apply that principle to the facts of the case at hand. The trial judge has the sole discretion to determine this question and general acceptance must be established by a preponderance of the evidence. The authors describe in detail a hearing in a case in which they were all involved. One author (WQS) had researched and documented the original scientific methodology in the literature. The situation involved a car and tractor trailer crash with the two occupants of the car dying of multiple trauma, whereas the truck driver was not injured. Autopsy of the auto driver revealed multiple injuries with exsanguination, and only vitreous humor and liver tissue, but not blood, were tested for ethyl alcohol. The estate of the driver of the automobile brought suit against the owner of the trucking company for wrongful death. The plaintiff requested a Frye hearing to question the reliability of testing other body specimens to translate to probable blood alcohol level. The testimony, submitted documents, and eventual decision by the judge are discussed. 相似文献
998.
Mauricio-da-Silva L Silva RS Dellalibera E Donadi EA 《Journal of forensic sciences》2000,45(3):684-686
One hundred thirty-four unrelated Northeast Brazilian individuals were typed for the HPRTB, F13B, and LPL short tandem repeats (STRs). DNA was amplified by specific primers and identified by silver staining of polyacrylamide gels. The allelic frequencies of these loci were in agreement with Hardy-Weinberg proportions. The most frequent alleles were HPRTB*13, F13B*10, LPL*10. The combined probability of paternity and the discrimination power of these 3 STRs were high, permitting their utilization for forensic science purposes. 相似文献
999.
1000.
An accurate and simple method was developed to determine the level of toluene in urine and blood quantitatively by using the gas chromatography/mass spectrometry (GC/MS) with headspace--solid phase microextraction (HS-SPME) technique. An assembly of SPME with a replaceable extraction fiber, coated with 100 microm polydimethylsiloxane, was used. The detection limit of toluene in blood and urine with HS-SPME technique was 10 times higher than that with headspace (HS) technique. To compare the HS-SPME with HS technique for the determination of toluene in biological fluids, blood and urine samples from glue sniffers were analyzed by both methods. The level of toluene by the two techniques was highly correlated: the correlation coefficient (r2) between the two sets of values were 0.98 and 0.96 in urine and blood, respectively. 相似文献