全文获取类型
收费全文 | 15313篇 |
免费 | 1332篇 |
国内免费 | 4篇 |
专业分类
各国政治 | 487篇 |
工人农民 | 448篇 |
世界政治 | 906篇 |
外交国际关系 | 623篇 |
法律 | 10039篇 |
中国共产党 | 330篇 |
中国政治 | 845篇 |
政治理论 | 1992篇 |
综合类 | 979篇 |
出版年
2022年 | 59篇 |
2021年 | 95篇 |
2020年 | 402篇 |
2019年 | 364篇 |
2018年 | 400篇 |
2017年 | 484篇 |
2016年 | 480篇 |
2015年 | 491篇 |
2014年 | 517篇 |
2013年 | 1304篇 |
2012年 | 426篇 |
2011年 | 645篇 |
2010年 | 878篇 |
2009年 | 858篇 |
2008年 | 609篇 |
2007年 | 654篇 |
2006年 | 744篇 |
2005年 | 553篇 |
2004年 | 327篇 |
2003年 | 326篇 |
2002年 | 341篇 |
2001年 | 562篇 |
2000年 | 380篇 |
1999年 | 313篇 |
1998年 | 155篇 |
1997年 | 139篇 |
1996年 | 110篇 |
1995年 | 139篇 |
1994年 | 148篇 |
1993年 | 126篇 |
1992年 | 224篇 |
1991年 | 244篇 |
1990年 | 223篇 |
1989年 | 237篇 |
1988年 | 216篇 |
1987年 | 184篇 |
1986年 | 209篇 |
1985年 | 231篇 |
1984年 | 221篇 |
1983年 | 188篇 |
1982年 | 147篇 |
1981年 | 133篇 |
1980年 | 129篇 |
1979年 | 150篇 |
1978年 | 92篇 |
1977年 | 79篇 |
1976年 | 67篇 |
1975年 | 71篇 |
1974年 | 77篇 |
1973年 | 64篇 |
排序方式: 共有10000条查询结果,搜索用时 410 毫秒
801.
Oliver WR Baker AM Powell JD Cotone CM Meeker J 《The American journal of forensic medicine and pathology》2002,23(3):252-256
An ordnance-disposal expert was killed while disposing of a cache of explosives. The likely position of the body was reconstructed by modeling the explosion as an omnidirectional emission of particles from a model of the explosion site and noting the distribution of particles on a model of a human. The applications and limitations of this method in reconstructing the events and correlation with the injuries noted at autopsy are discussed. 相似文献
802.
Childhood sporting deaths 总被引:1,自引:0,他引:1
Byard RW James RA Gilbert JD 《The American journal of forensic medicine and pathology》2002,23(4):364-367
803.
Cohle SD Suarez-Mier MP Aguilera B 《The American journal of forensic medicine and pathology》2002,23(1):83-89
Sudden unexpected deaths in young persons with noncontributory histories, autopsy results, and drug screen results are a common problem in forensic pathology. As part of the evaluation of such cases, the cardiac conduction system (CCS) should be studied. To determine the type and incidence of lethal CCS lesions, the authors reviewed their files of sudden unexpected cardiac deaths with particular attention to cases with causes of death in the conduction system. Cases of sudden cardiac death in patients aged < or=40 years during a 10-year period (Michigan) and a 4 year-period (Spain) were selected from the files. From this group, cases were identified in which the cause of death was a lethal change in the CCS. The portions of the heart containing the CCS were excised, and at least one hematoxylin and eosin slide and at least one trichrome or elastic trichrome slide per block were studied. In the two centers, 381 cases of sudden cardiac death were identified. The most common causes of sudden cardiac death were arteriosclerotic narrowing of the coronary arteries, cardiomyopathy, and myocarditis. In 82 cases, there was no identifiable cause of death even after complete gross and microscopic autopsy was performed, a medical history was obtained, and a drug screen was performed. In 11 cases, the CCS contained lesions that were considered lethal: narrowing of the atrioventricular node artery by fibromuscular hyperplasia (7 cases) and atrioventricular node tumors (4 cases). The 11 cases accounted for 2.9% of the 381 cases of sudden cardiac death and 11.8% of the indeterminable cases. It was concluded that examination of the CCS in deaths in which the gross and microscopic autopsy, history, and drug screen fail to provide a cause of death can yield a cause of death in a significant percentage of cases. If heart block was not documented during life and no explanatory lesions were found during routine cardiac examination, examination of the CCS can yield valuable information. 相似文献
804.
805.
FN-Ⅲcs在皮肤切创中的表达与损伤时间关系 总被引:3,自引:1,他引:2
目的研究纤维连接蛋白可变剪接片段Ⅲcs在不同损伤时间皮肤中的表达,为早期损伤时间的判定指标提供实验依据.方法DIG标记反意RNA探针,以原位杂交的方法检测大鼠和人体皮肤在损伤早期FNⅢcs表达的变化.结果(1)人体及大鼠皮肤损伤后30min皮肤网状层的毛囊、皮脂腺、血管内皮层中表达FNⅢcs的阳性细胞数开始增多,至伤后6h达到高峰,以后又逐渐减少.(2)人体皮肤FNⅢcs表达的部位与大鼠有明显的差异.结论FNⅢcs的原位检测可望成为判断早期损伤时间的有用指标;为FNⅢcs在创伤修复中的合成方式、部位和作用的研究提供了实验基础. 相似文献
806.
The use of ortho- and para-phenylenediamine (OPD & PPD respectively) for the enhancement of fingerprints in blood has been investigated. Optimal pH conditions and H2O2 concentrations have been determined using UV/Vis spectroscopy. Both OPD and PPD are effective and less hazardous alternatives to the presently used 3,3'-diaminobenzidine (DAB) for the development of blood fingerprints, especially on porous surfaces. The orange color of OPD and the purple color of PPD offer alternative colors to the brown color of DAB and the light green color of ABTS for standing out against particular backgrounds. Both OPD and PPD can be used after ninhydrin treatment, but the reverse is not the case. 相似文献
807.
808.
The concentrations of ten elements in 209 unrelated glass specimens received as evidence were used to assess the frequencies of errors of false association (Type II errors) using several comparison criteria at specified significance levels (Type I errors). Pairwise comparisons of the samples using either the equal-variance t-test or Welch's modification (unequal variances) result in a small number of errors of false association, even when adjusting the significance level (Bonferroni correction) for multivariate comparisons. At the 95% confidence level (overall Type I error of 0.05, or individual element comparison error of 0.005), only two Type II errors are made in 21736 comparisons (0.009%) when using the equal-variance t-test for comparison of sample means. In this study, the range overlap test using three replicate measurements per specimen results in no errors of false association. Most specimen pairs in this data set are readily discriminated either by differences in the concentrations of several elements or by an extremely large difference in the concentrations of one or more element. 相似文献
809.
Tumescent liposuction is a common cosmetic procedure that is performed as an outpatient service in physician's offices and is largely believed to be safe. The protuberant areas of the body containing the undesirable fat deposits are injected with normal saline containing lidocaine and epinephrine for pain control and hemostasis, and the waterlogged cells are suctioned out via cannula through a small incision. We recently encountered three cases in which deaths were attributed to this procedure. Two showed fat embolization in the lung and one died from fluid overload. The osmium tetroxide post-fixed lung sections showed fat emboli in the interstitial capillaries and arterioles. We reviewed the recent literature and found that pulmonary thromboemboli, fat embolization, fluid overload, and lidocaine and epinephrine intoxication are found at autopsy in many cases. Forensic pathologists responsible for determining the cause and manner of death should become familiar with the postmortem findings and risks of liposuction therapy and communicate them to their clinical colleagues and communities. 相似文献
810.
Fraudulent substitution of a page within a multiple page document such as a will or business contract, the counterfeit manufacture of paper banknotes, and linking ransom or extortion notes have all been the focus of criminal investigations at one time or another. In a recent homicide investigation, document examiners were requested to compare a threatening letter received by a business partner of the deceased with paper samples seized under warrant from a suspect's house. Through a quantitative elemental analysis of the concentrations of nine elements (Na, Mg, Al, Mn, Sr, Y, Ba, La, and Ce) within the questioned and specimen documents, determined by inductively coupled plasma-mass spectrometry (ICP-MS), it was concluded that (i) the paper of the threatening letter originated from a different source to that of the paper seized from the suspect's house and (ii) all six pages of paper seized from the suspect's house originated from the same source. This discrimination of paper is presented as both a statistical t-test analysis (99.9% confidence limit) as well as construction of an elemental fingerprint for individual replicates within the questioned and specimen sample populations. This is the first reported use of the comparison of the elemental composition of document paper, determined by ICP-MS, to assist in a criminal investigation. 相似文献