全文获取类型
收费全文 | 2227篇 |
免费 | 32篇 |
专业分类
各国政治 | 161篇 |
工人农民 | 9篇 |
世界政治 | 244篇 |
外交国际关系 | 439篇 |
法律 | 944篇 |
中国共产党 | 73篇 |
中国政治 | 241篇 |
政治理论 | 71篇 |
综合类 | 77篇 |
出版年
2021年 | 25篇 |
2018年 | 25篇 |
2017年 | 13篇 |
2016年 | 15篇 |
2015年 | 20篇 |
2014年 | 108篇 |
2013年 | 32篇 |
2012年 | 109篇 |
2011年 | 96篇 |
2010年 | 77篇 |
2009年 | 81篇 |
2008年 | 93篇 |
2007年 | 113篇 |
2006年 | 128篇 |
2005年 | 96篇 |
2004年 | 95篇 |
2003年 | 67篇 |
2002年 | 84篇 |
2001年 | 71篇 |
2000年 | 57篇 |
1999年 | 24篇 |
1998年 | 12篇 |
1997年 | 17篇 |
1996年 | 12篇 |
1994年 | 28篇 |
1992年 | 14篇 |
1991年 | 26篇 |
1990年 | 20篇 |
1989年 | 20篇 |
1988年 | 108篇 |
1987年 | 23篇 |
1986年 | 23篇 |
1985年 | 27篇 |
1984年 | 25篇 |
1983年 | 21篇 |
1982年 | 14篇 |
1981年 | 33篇 |
1980年 | 25篇 |
1979年 | 29篇 |
1978年 | 12篇 |
1977年 | 39篇 |
1976年 | 30篇 |
1975年 | 12篇 |
1973年 | 13篇 |
1964年 | 27篇 |
1963年 | 25篇 |
1962年 | 40篇 |
1961年 | 18篇 |
1960年 | 22篇 |
1959年 | 29篇 |
排序方式: 共有2259条查询结果,搜索用时 0 毫秒
71.
72.
73.
Hinkle W 《Indiana law review》2002,35(2):593-619
This Note argues that prisoners, whether executed or living, should not become organ donors. The introduction acknowledges the shortage of transplantable organs in the United States and the steps that have been taken to ameliorate the crisis. Part I discusses the procurement of organs from executed prisoners, beginning with a brief examination of China, a country where this type of procurement is routinely practiced. Part I also examines organ procurement legislation pertaining to executed prisoners. Finally, Part I asserts the reasons that prisoners should not become donors, including the dead donor rule, the ban against physicians as executioners, the Oath of Hippocrates, the risk of transmissible diseases, and the negative perception that would result if organ procurement was tied to executions. Part II of this Note discusses prisoners donating their organs in return for mitigated sentences. Part II then argues that this practice should not be adopted because of the lack of informed consent and voluntary choice. Finally, Part III of this Note introduces potential solutions to the possibility of maintaining a voluntary system, moving to a presumed consent system, and using financial inducements to create a larger supply of transplantable organs. 相似文献
74.
Aebi B Sturny-Jungo R Bernhard W Blanke R Hirsch R 《Forensic science international》2002,128(1-2):84-89
Time-of-flight mass spectrometry (TOF-MS) offers new perspectives for forensic toxicology. Qualitative and quantitative analyses of a mixture of three selected benzodiazepines (diazepam, nordazepam and bromazepam) were used to compare gas chromatography (GC-TOF-MS, quadrupole GC-MS, GC-ECD) and liquid chromatography (HPLC-DAD) data. Method validation parameters like LOD, LOQ, S/N-ratios reflect the capabilities of GC-TOF-MS. Five-point calibrations for bromazepam in human peripheral blood (50, 100, 160, 200, 300 ng/ml) using medazepam as internal standard (1000 ng/ml) were performed. The calibrations using GC-TOF-MS (using the fragments of m/z 236 and 288), GC-ECD (dual system) and HPLC-DAD (at 235 nm) all showed correlation coefficients close or superior to 0.99. Quadrupole GC-MS data was not used in the comparison of extracted samples due to the low sensitivity in the full scan mode. Two analyses of real cases concerning bromazepam are presented. In the first case, the presence or absence of bromazepam could not be established with both HPLC-DAD and GC-ECD due to background signals. The extracted ion chromatograms and spectrum traces after the analysis with the GC-TOF-MS could clearly excluded the presence of bromazepam. The second case illustrates the quantitation of bromazepam, where both HPLC-DAD and GC-ECD were unable to give satisfactory results, again due to interfering background signals. The analyses performed on the GC-TOF-MS-system demonstrated high sensitivity and also high selectivity due to the high quality of mass spectra obtained. The advantages of GC-TOF-MS make it a promising analytical technique for forensic toxicology. 相似文献
75.
Morphine-3-D glucuronide stability in postmortem specimens exposed to bacterial enzymatic hydrolysis
Carroll FT Marraccini JV Lewis S Wright W 《The American journal of forensic medicine and pathology》2000,21(4):323-329
Medical examiners frequently rely on the finding of free morphine present in postmortem specimens to assist in certifying deaths associated with narcotics. In vitro hydrolysis of morphine-3-D glucuronide (M3DG) to free morphine was studied using variable specimen pH, initial degree of specimen putrefaction, storage temperature and time, and the effectiveness of sodium fluoride (NaF) preservation. Reagent M3DG was added to opiate-free fresh blood and urine and to autopsy-derived blood specimens. Reagent bovine glucuronidase was also added to certain specimens. Freshly collected and refrigerated NaF-preserved blood produced minimal free morphine, whereas four of five autopsy blood specimens produced free morphine from M3DG. Increased storage time, temperature, and initial degree of putrefaction resulted in greater free morphine generation despite the absence of viable bacteria. Hydrolysis occurring during specimen storage can generate free morphine from M3DG and may result in erroneous conclusions in certifying narcotic deaths. 相似文献
76.
77.
Weinmann W Vogt S Goerke R Müller C Bromberger A 《Forensic science international》2000,113(1-3):381-387
A fast method using liquid-liquid extraction and HPLC/tandem-mass spectrometry (LC/MS/MS) was developed for the simultaneous detection of 11-Nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid beta-glucuronide (THC-COOH-glucuronide) and 11-Nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in urine samples. This highly specific method, which combines chromatographic separation and MS/MS analysis, can be used for the confirmation of positive immunoassay results even without hydrolysis of the sample or derivatisation of extracts. Liquid-liquid extraction was optimised: with ethylacetate/diethylether (1:1, v/v) THC-COOH-glucuronide and THC-COOH could be extracted in one step. Molecular ions of the glucuronide (MH(+), m/z 521) and THC-COOH (MH(+), m/z 345) were generated using a PE/SCIEX turboionspray source in positive ionisation mode; specific fragmentation was performed in the collision cell of an API 365 triple-quadrupole mass spectrometer and yielded major fragments at m/z 345 (for THC-COOH-glucuronide) and m/z 327 as well as m/z 299 for both cannabinoids. Chromatographic separation was performed using a reversed-phase C8 column and gradient elution with 0.1% formic acid/1 mM ammonium formate and acetonitrile/0.1% formic acid. Retention times were 22.2 min for the glucuronide and 26.8 min for THC-COOH. After enzymatic hydrolysis of urine samples with beta-glucuronidase/arylsulfatase (37 degrees C, 5 h), THC-COOH-glucuronide was no longer detectable by LC/MS/MS in urine samples. However, the THC-COOH concentration was increased. For quantitation of THC-COOH, THC-COOH-D(3) was added to the urine samples as internal standard prior to analysis. From the difference of THC-COOH in the native urine and urine after enzymatic hydrolysis, molar concentration ratios of THC-COOH-glucuronide/THC-COOH in urine samples of cannabis users were determined and found to be between 1.3 and 4.5. 相似文献
78.
Pontocerebellar hypoplasia (PCH) is a very rare congenital (autosomal recessive) condition with fetal onset. Only a few cases have been published on the basis of both clinical data (symptoms/neuroradiological imaging) and autopsy results. This paper reports on such a case involving a 1.5-year-old male infant. The child suffered from severe psychomotor delay, extrapyramidal dyskinesia and epileptic seizures, but did not exhibit signs of spinal muscular atrophy as related to PCH type 1. Magnetic resonance imaging (MRI) at the age of 6 months demonstrated olivo-pontine and bilateral cerebellar hypoplasia. The boy was unexpectedly found dead. Autopsy disclosed a severe aspiration of gastric contents as the final cause of death. The neuropathological examination confirmed PCH type 2 (according to Barth [Brain Dev., 15 (1993) 411-422]) with marked microcephaly and olivopontocerebellar hypoplasia. Histologically, decreased density of olivo-pontine neurons, reduction of granular and Purkinje's cell layers of the cerebellum, slight astroglial proliferation and fragmented appearance of the dentate nuclei were observed. The immunohistochemical expression pattern was determined using antibodies against glial fibrillary acidic protein, synaptophysin and neurofilament protein. Summarizing, typical features of PCH type 2 were present and proved by clinical course, MRI and autopsy. Despite severe symptoms due to a natural disease this rare neurogenetic entity can become of forensic interest, when sudden unexpected death occurs. 相似文献
79.
3,4-methylenedioxyamphetamine (MDA) derivatives are increasingly abused central nervous system stimulants with neurotoxic properties. In recent years a number of controlled substance analogs (designer drugs) with high structural variety reached the illegal market making their identification an arduous task. The underivatized compounds give very similar or even virtually identical electron impact mass spectra containing mainly intense C(n)H(2n+2)N(+) immonium ions. Using tandem mass spectrometry (MS-MS) the additional structural information contained in the collision induced dissoziation (CID) mass spectra of molecular ions using electron impact (EI) and especially chemical ionization (CI) allowed an unequivocal differentiation of 18 studied regioisomeric 1-(methylenedioxyphenyl)-2-propanamines and 1-(methylenedioxyphenyl)-2-butanamines.Further synthetic methods are presented for 1-(3,4-methylenedioxyphenyl)-N-propyl-2-butanamine, N-isopropyl-1-(3,4-methylenedioxyphenyl)-2-butanamine and four 1-(2, 3-methylenedioxyphenyl)-2-butanamines. N-alkylated 1-(3, 4-methylenedioxyphenyl)-2-butanamine compounds (e.g. MBDB) are also known to be abused psychoactive agents (entactogenes) without the sympatomimetic effects of the 3,4-methylenedioxyamphetamines. 相似文献
80.