全文获取类型
收费全文 | 5177篇 |
免费 | 51篇 |
专业分类
各国政治 | 168篇 |
工人农民 | 52篇 |
世界政治 | 771篇 |
外交国际关系 | 477篇 |
法律 | 3053篇 |
中国共产党 | 78篇 |
中国政治 | 248篇 |
政治理论 | 295篇 |
综合类 | 86篇 |
出版年
2021年 | 27篇 |
2018年 | 22篇 |
2016年 | 18篇 |
2015年 | 20篇 |
2014年 | 115篇 |
2013年 | 29篇 |
2012年 | 374篇 |
2011年 | 332篇 |
2010年 | 106篇 |
2009年 | 111篇 |
2008年 | 317篇 |
2007年 | 365篇 |
2006年 | 324篇 |
2005年 | 303篇 |
2004年 | 287篇 |
2003年 | 301篇 |
2002年 | 287篇 |
2001年 | 207篇 |
2000年 | 268篇 |
1999年 | 88篇 |
1998年 | 61篇 |
1997年 | 41篇 |
1996年 | 35篇 |
1995年 | 42篇 |
1994年 | 84篇 |
1993年 | 64篇 |
1992年 | 46篇 |
1991年 | 52篇 |
1990年 | 41篇 |
1989年 | 36篇 |
1988年 | 117篇 |
1987年 | 29篇 |
1986年 | 40篇 |
1985年 | 42篇 |
1984年 | 33篇 |
1983年 | 35篇 |
1982年 | 29篇 |
1981年 | 45篇 |
1980年 | 44篇 |
1979年 | 36篇 |
1978年 | 23篇 |
1977年 | 44篇 |
1976年 | 35篇 |
1975年 | 14篇 |
1964年 | 28篇 |
1963年 | 24篇 |
1962年 | 40篇 |
1961年 | 18篇 |
1960年 | 22篇 |
1959年 | 29篇 |
排序方式: 共有5228条查询结果,搜索用时 15 毫秒
221.
Baptista MJ Monsanto PV Pinho Marques EG Bermejo A Avila S Castanheira AM Margalho C Barroso M Vieira DN 《Forensic science international》2002,128(1-2):66-78
A sensitive analytical method was developed for quantitative analysis of delta(9)-tetrahydrocannabinol (delta(9)-THC), 11-nor-delta(9)-tetrahydrocannabinol-carboxylic acid (delta(9)-THC-COOH), cannabinol (CBN) and cannabidiol (CBD) in human hair. The identification of delta(9)-THC-COOH in hair would document Cannabis use more effectively than the detection of parent drug (delta(9)-THC) which might have come from environmental exposure. Ketamine was added to hair samples as internal standard for CBN and CBD. Ketoprofen was added to hair samples as internal standard for the other compounds. Samples were hydrolyzed with beta-glucuronidase/arylsulfatase for 2h at 40 degrees C. After cooling, samples were extracted with a liquid-liquid extraction procedure (with chloroform/isopropyl alcohol, after alkalinization, and n-hexane/ethyl acetate, after acidification), which was developed in our laboratory. The extracts were analysed before and after derivatization with pentafluoropropionic anhydride (PFPA) and pentafluoropropanol (PFPOH) using a Hewlett Packard gas chromatographer/mass spectrometer detector, in electron impact mode (GC/MS-EI). Derivatized delta(9)-THC-COOH was also analysed using a Hewlett Packard gas chromatographer/mass spectrometer detector, in negative ion chemical ionization mode (GC/MS-NCI) using methane as the reagent gas. Responses were linear ranging from 0.10 to 5.00 ng/mg hair for delta(9)-THC and CBN, 0.10-10.00 ng/mg hair for CBD, 0.01-5.00 ng/mg for delta(9)-THC-COOH (r(2)>0.99). The intra-assay precisions ranged from <0.01 to 12.40%. Extraction recoveries ranged from 80.9 to 104.0% for delta(9)-THC, 85.9-100.0% for delta(9)-THC-COOH, 76.7-95.8% for CBN and 71.0-94.0% for CBD. The analytical method was applied to 87 human hair samples, obtained from individuals who testified in court of having committed drug related crimes. Quantification of delta(9)-THC-COOH using GC/MS-NCI was found to be more convenient than GC/MS-EI. The latter may give rise to false negatives due to the detection limit. 相似文献
222.
Allele frequencies for nine STRs included in the APMF1STR kit were obtained from blood samples of 100 unrelated individuals born in Sinkiang Uygur Autonomy Region of China (NW China). 相似文献
223.
Sánchez-Diz P Lareu MV Brión M Skitsa I Carracedo A 《Forensic science international》2002,126(3):265-266
Allele frequencies for the nine STRs included in the AmpFlSTR Profiler Plus kit (D3S1358, VWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317 and D7S820) were estimated from a sample of 143 unrelated individuals living in different regions of Greece. 相似文献
224.
Polymorphism at 15 microsatellite loci was studied in four predominant, endogamous populations of Maharashtra state in India. The studied population included Marathas, Desasth Brahmins, Chitpavan Brahmins and Dhangars; all of whom belong to Marathi speaking linguistic group of India. The distribution of the allele pattern at 13 tetranucleotide repeat and two pentanucleotide repeat of Powerplex 16 System portrays that these markers are highly polymorphic and thus, informative in human identification and understanding diversity in the addressed populations. 相似文献
225.
Meissner C Recker S Reiter A Friedrich HJ Oehmichen M 《Forensic science international》2002,130(1):49-54
The study was performed to distinguish fatal from non-fatal blood concentrations of morphine. For this purpose, blood levels of free morphine and total morphine (free morphine plus morphine conjugates) in 207 cases of heroin-related deaths were compared to those in 27 drivers surviving opiate intoxication. The majority of both survivors and non-survivors were found to show a concomitant use of depressants including alcohol or stimulants. Blood morphine levels in both groups varied widely, with a large area of overlap between survivors (free morphine: 0-128 ng/ml, total morphine: 10-2,110 ng/ml) and non-survivors (free morphine: 0-2,800 ng/ml, total morphine: 33-5,000 ng/ml). Five (18.5%) survivors and 87 (42.0%) non-survivors exhibit intoxication only by morphine. In these cases, too, both groups overlapped (survivors-free morphine: 28-93 ng/ml, total morphine: 230-1,451 ng/ml; non-survivors-free morphine: 0-2,800 ng/ml, total morphine: 119-4,660 ng/ml). Although the blood levels of free or total morphine do not allow a reliable prediction of survival versus non-survival, the ratio of free/total morphine may be a criterion to distinguish lethal versus survived intoxication. The mean of the ratio of free to total morphine for all lethal cases (N=207) was 0.293, for those that survived (N=27) 0.135, in cases of intoxication only by morphine 0.250 (N=87) and 0.080 (N=5), respectively. Applying a cut-off of 0.12 for free/total morphine and performing ROC analyses, fatal outcome can be predicted in 80% of the cases correctly, whereas 16% of the survivors were classified as dead. Nevertheless, in this study, all cases with a blood concentration of 200 ng/ml and more of free morphine displayed a fatal outcome. 相似文献
226.
Although microsatellite diversity in autosomal chromosomes has been extensively described for many of the Indian populations, there is still a lacuna left on information about the genetic diversity of tribal populations. This paper reports the genetic data on the three tribal populations belonging to the Austroloid ethnic group from Orissa (Juang, Paroja and Saora). The 15 STR (D3S1358, THO1, D21S11, D18S51, PentaE, D5S818, D13S317, D7S820, D16S539, CSF1PO, PentaD, vWA, D8S1179, TPOX, FGA) polymorphism would help to accentuate the STR database for better understanding of population genetics and forensic applications. The microsatellites included in the system are found to be highly polymorphic, with the combined power of exclusion being greater than 0.999, in all the three investigated populations. 相似文献
227.
Use of the "SMITEST" PSA card to identify the presence of prostate-specific antigen in semen and male urine 总被引:2,自引:0,他引:2
Sato I Sagi M Ishiwari A Nishijima H Ito E Mukai T 《Forensic science international》2002,127(1-2):71-74
To determine whether the prostate-specific antigen (PSA) could be identified in semen using the "SMITEST" PSA immunochromatographic membrane test card, we examined semen and other body fluids, including urine. Although PSA activity was detected in semen with high sensitivity using the "SMITEST" PSA card, it was also detected in adult male urine. However, the lower detectable limit in the urine was 1000-fold lower than that in semen. The concentration of PSA in adult male urine was found to be 800 ng/ml using the card. PSA activity usually can be detected in urine of individuals over 14 years old and it has been detected in urine from children as young as 11 years old. Therefore, the appearance of PSA in urine may occur anytime between the age of 12 and 14 years. To determine the stability of PSA activity in urine, dried samples of urine on filter paper were kept at room temperature for up to 3 years. Although the immunoreactive line showing PSA activity became weak after storage, it was still detectable, but faint, after 3 years. In addition, PSA activity was not detected in male serum or saliva and in the urine from human females, male cats or male dogs using the PSA card. We conclude that the PSA card is useful for identification of PSA in both semen and adult male urine. 相似文献
228.
The Skinny on Body Dissatisfaction: A Longitudinal Study of Adolescent Girls and Boys 总被引:3,自引:1,他引:3
The present study tested whether theoretically derived risk factors predicted increases in body dissatisfaction and whether gender moderated these relations with data from a longitudinal study of 428 adolescent girls and boys because few prospective studies have examined these aims, despite evidence that body dissatisfaction increases risk for various psychiatric disturbances. Body dissatisfaction showed significant increases for girls and significant decreases for boys during early adolescence. For both genders, parental support deficits, negative affectivity, and self-reported dietary restraint showed significant relations to future increases in body dissatisfaction. Ideal body internalization and body mass index did not demonstrate significant relations to future increases in body dissatisfaction; peer support deficits showed a marginal relation to this outcome. Gender did not moderate these relations, despite adequate power to detect interactive effects.
相似文献
Sarah Kate BearmanEmail: |
229.
你认为自己已经具备了成为企业家的所有条件。你已经阅读了别人的成功故事,他们大获成功,这令你感到不安。你工作得很出色,人们总是说你前途无量,但是.你已经厌倦了接受平庸的人发出的平庸命令。而凡,为什么所有聪明的想法都是你的,但荣誉却总被别人得到?什么时候你能得到一次大幅提升——有可观的工资上涨.得到期权奖励和巨额奖金呢?“再等等,”他们总是说。“再等等。”是自己当老板的时候了。然而,如果你现在的工作舒适而安逸,每月定期领取工资,在现代化的办公室里工作.有一个高效率的秘书,还有一种在基础稳同的大公司工作的安全感.那么.住你辞上这份好工作之前,我有些告诫的话给你。 相似文献
230.