全文获取类型
收费全文 | 3450篇 |
免费 | 95篇 |
专业分类
各国政治 | 328篇 |
工人农民 | 75篇 |
世界政治 | 367篇 |
外交国际关系 | 261篇 |
法律 | 1272篇 |
中国共产党 | 1篇 |
中国政治 | 23篇 |
政治理论 | 1179篇 |
综合类 | 39篇 |
出版年
2023年 | 10篇 |
2022年 | 14篇 |
2021年 | 33篇 |
2020年 | 61篇 |
2019年 | 59篇 |
2018年 | 100篇 |
2017年 | 118篇 |
2016年 | 119篇 |
2015年 | 78篇 |
2014年 | 94篇 |
2013年 | 606篇 |
2012年 | 87篇 |
2011年 | 103篇 |
2010年 | 86篇 |
2009年 | 124篇 |
2008年 | 152篇 |
2007年 | 140篇 |
2006年 | 102篇 |
2005年 | 109篇 |
2004年 | 106篇 |
2003年 | 86篇 |
2002年 | 95篇 |
2001年 | 71篇 |
2000年 | 64篇 |
1999年 | 68篇 |
1998年 | 61篇 |
1997年 | 55篇 |
1996年 | 46篇 |
1995年 | 57篇 |
1994年 | 47篇 |
1993年 | 45篇 |
1992年 | 29篇 |
1991年 | 50篇 |
1990年 | 26篇 |
1989年 | 41篇 |
1988年 | 32篇 |
1987年 | 36篇 |
1986年 | 51篇 |
1985年 | 15篇 |
1984年 | 25篇 |
1983年 | 31篇 |
1982年 | 34篇 |
1981年 | 21篇 |
1980年 | 27篇 |
1979年 | 17篇 |
1978年 | 22篇 |
1977年 | 16篇 |
1976年 | 16篇 |
1974年 | 20篇 |
1973年 | 8篇 |
排序方式: 共有3545条查询结果,搜索用时 15 毫秒
221.
Padosch SA Schmidt PH Schyma C Hirsch RD Kröner LU Dettmeyer RB Madea B 《Archiv für Kriminologie》2004,214(5-6):149-162
The second part of the paper on suicides by gunshots to the head in the presence of witnesses focuses on relevant morphological autopsy findings such as entrance site, signs of close range or contact shots, bullet path etc. and also discusses selected aspects of ascertaining gunshot residues. For the identification of the shooter an integral medicolegal assessment of all the facts including the investigation results and the autopsy findings is essential. However, the morphological findings alone do not allow safe diagnosis, as for example in a homicide the temporal region, which was affected in all our cases, may have been deliberately chosen by the perpetrator as a localization typical of suicide. Thus methods to ascertain gunshot residues on the firing hand (by means of adhesive films and the polyvinyl-alcohol collection method--PVAL) are of great practical importance. In seven cases adhesive films and/or the polyvinyl-alcohol collection method were used. In one case the gunshot residues (GSR) were analysed by means of tape lifts and subsequent scanning electron microscopy (SEM). It was found that especially the combined application of topographical (adhesive tape/PVAL) and cumulative (SEM) methods allowed for the doubtless identification of the shooter, thus usually confirming the suicide. By the example of one case it is demonstrated that without the immediate collection of evidence at the scene objective reconstruction of the event becomes impossible. On the basis of the reported cases recommendations are finally given for a differentiated approach in the medicolegal evaluation of alleged witnessed suicide by gunshot (to the head). 相似文献
222.
223.
In this paper, we describe the development of a device for fuming fingerprints with cyanoacrylate (Super Glue) to enable police tactical units to obtain fingerprint evidence from suspicious packages using a remote-controlled robot. Through a series of initial experiments and preliminary designs, we show that effective cyanoacylate fuming requires sufficient heat, humidity, and airflow. This work led to the development of a final working prototype, called robot accessory for fuming fingerprint evidence (RAFFE), which is currently being field tested by the Calgary Police Service. 相似文献
224.
An HPLC-APCI-MS(/MS) method for the (trace) analysis of the most commonly encountered peroxide explosives, hexamethylenetriperoxidediamine (HMTD) and triacetonetriperoxide (TATP), has been developed. With this method, HMTD and TATP have been analyzed in the same run. (Pseudo-)molecular ions of these peroxides have been obtained as base peak under the same condition. A series of product ions was produced from these pseudo-molecular ions ([HMTD - 1]+ and [TATP + NH4]+) in the MS/MS analysis. We also pioneered in showing that a TATP molecular ion [TATP + H]+ can be observed with HPLC-MS/MS. The limit of detection for HMTD and TATP was 0.26 and 3.3 ng, respectively, on column by HPLC-MS in the Full Scan mode and 0.08 and 0.8, respectively, by HPLC-APCI-MS/MS in Selected Reaction Monitoring (single mass unit) mode. The method presented has been applied successfully for the identification of peroxides in the bulk solid state (powder sample), as well as in post-blast extracts originating from a forensic case. For the post-blast extracts, the use of tandem MS has been shown clearly to be of crucial importance for the identification and detection of the peroxide explosives. 相似文献
225.
Since 1995 the Forensic Science Service (FSS) has carried out DNA profiling of reference samples for the UK National DNA Database and in forensic casework using two multiplex STR profiling systems. During this period, profiles with anomalous banding patterns, although comparatively rare, have been encountered regularly. The FSS has collected instances of triallelic patterns and aberrant diallelic patterns. A systematic examination of these patterns has provided insight into their underlying genetic cause. The triallelic patterns could be classified into two types based on the relative intensities of their component alleles. In the Type 1 pattern the alleles were of uneven intensity, whereas in the Type 2 pattern, all three alleles were of even intensity. Evidence is presented that the more frequent Type 1 pattern is the result of somatic mutation at a heterozygous locus, and the Type 2 pattern is the result of a localized chromosomal rearrangement at a heterozygous locus. Directly from the Type 1 pattern, it was possible to deduce the size difference between the progenitor and mutated allele. All mutational changes were found to be multiples of four nucleotides, suggesting the loss or addition of one or more tetrameric repeat units. Aberrant diallelic patterns were identified by analysts due to an unexpectedly large difference in intensity between alleles at a heterozygous locus. While some of these diallelic patterns are likely caused by the same genetic phenomena described above occurring at a homozygous locus, others are demonstrated to be caused by a mutation in the primer binding sequence, leading to a reduction in amplification efficiency of one allele. It is concluded that based on a visual inspection of a profile, it is possible to infer a likely genetic basis directly from the triallelic pattern. By contrast, the aberrant diallelic patterns can be due to any one of a number of possible genetic effects. 相似文献
226.
Multiplex analysis of genetic markers has become increasingly important in a number of fields, including DNA diagnostics and human identity testing. Two methods for examination of single nucleotide polymorphisms (SNPs) with a potential for a high degree of multiplex analysis of markers are primer extension with fluorescence detection, and allele-specific hybridization using flow cytometry. In this paper, we examined 50 different SNPs on the Y-chromosome using three primer extension multiplexes and five hybridization multiplex assays. For certain loci, the allele-specific hybridization method exhibited sizable background signal from the absent alternate allele. However, 100% concordance (>2000 alleles) was observed in ten markers that were typed using both methods. A total of 18 unique haplogroups out of a possible 45 were observed in a group of 229 U.S. African American and Caucasian males with the majority of samples being assigned into 2 of the 18 haplogroups. 相似文献
227.
228.
A simple method for analyzing nitrite in urine has been developed to confirm and quantify the amount of nitrite in potentially adulterated urine samples. The method involved separation of nitrite by capillary electrophoresis and direct UV detection at 214 nm. Separation was performed using a bare fused silica capillary and a 25 mM phosphate run buffer at a pH of 7.5. Sample preparation consisted of diluting the urine samples 1:20 with run buffer and internal standard, and centrifuging for 5 min at 2500 rpm. The sample was hydrodynamically injected, then separated using -25 kV with the column maintained at 35 degrees C. The method had upper and lower limits of linearity of 1500 and 80 microg/mL nitrite, respectively, and a limit of detection of 20 microg/mL. The method was evaluated using the National Committee for Clinical Laboratory Standards (NCCLS) protocol (Document EP10-A2), and validated using controls, standards, and authentic urine samples. Ten anions, ClO-, CrO4(-2), NO3-, HCO3-, I-, CH3COO-, F-, SO4-, S2O8(-2), and Cl-, were tested for potential interference with the assay. Interferences with quantitation were noted for only CrO4(-2) and S2O8(-2). High concentrations of Cl- interfered with the chromatography. The method had acceptable accuracy, precision, and specificity. 相似文献
229.
230.
Szentmariay IF Laszik A Sotonyi P 《The American journal of forensic medicine and pathology》2004,25(4):324-326
A 70-year-old male patient with a 23-year-old history of right lower lung lobectomy for primary pulmonary adenocarcinoma (T1 N0 M0) presented with recurrent bronchopneumonia and purulent sputum. Pleural callus, lung abscess, bronchopleural fistula, and stitch granulomas were confirmed by chest x-ray, computed tomography scan, and bronchoscopy in the background of his complaints. An attempt to remove the bronchial purulent discharge and tissue sampling was made by using a flexible bronchoscope. The area of the lower trachea suddenly became clogged during bronchoscopic removal of the suspected piece of tissue (which later turned out to be organizing surgical gauze). The resuscitation following ventricular fibrillation failed to save the patient's life. The forensic postmortem examination confirmed the position of the foreign body extending from the abscess cavity, crossing the midline at carina and obstructing the lower trachea. This foreign body was a remnant of the surgical gauze left behind during a thoracic surgery 23 years ago. 相似文献