首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   13933篇
  免费   418篇
各国政治   528篇
工人农民   500篇
世界政治   933篇
外交国际关系   403篇
法律   8976篇
中国共产党   1篇
中国政治   97篇
政治理论   2812篇
综合类   101篇
  2020年   146篇
  2019年   203篇
  2018年   266篇
  2017年   308篇
  2016年   288篇
  2015年   222篇
  2014年   251篇
  2013年   1203篇
  2012年   297篇
  2011年   366篇
  2010年   289篇
  2009年   345篇
  2008年   365篇
  2007年   347篇
  2006年   353篇
  2005年   323篇
  2004年   327篇
  2003年   333篇
  2002年   318篇
  2001年   592篇
  2000年   484篇
  1999年   386篇
  1998年   197篇
  1997年   171篇
  1996年   169篇
  1995年   179篇
  1994年   174篇
  1993年   186篇
  1992年   308篇
  1991年   323篇
  1990年   309篇
  1989年   301篇
  1988年   298篇
  1987年   294篇
  1986年   346篇
  1985年   327篇
  1984年   275篇
  1983年   256篇
  1982年   177篇
  1981年   156篇
  1980年   131篇
  1979年   183篇
  1978年   117篇
  1977年   133篇
  1976年   111篇
  1975年   102篇
  1974年   129篇
  1973年   105篇
  1972年   106篇
  1971年   100篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
931.
Australia, like other western nations, is facing the prospect that in the decades ahead the overall population will age dramatically. This article considers legal issues associated with the aged and intergenerationally transmitted debt. It will be argued that the present legal regulation of guarantees is a complex amalgam of case law, statute and finance industry self-regulatory codes which does not necessarily or adequately take into account the particular vulnerabilities of the aged and the very old or the intergenerational pressures which they may confront. It may be necessary to take significant steps to protect vulnerable elders while still recognizing their rights to exercise personal autonomy. Some proposals for reform are made.  相似文献   
932.
933.
Korea recently introduced three major health care reforms: in financing (1999), pharmaceuticals (2000), and provider payment (2001). In these three reforms, new government policies merged more than 350 health insurance societies into a single payer, separated drug prescribing by physicians from dispensing by pharmacists, and attempted to introduce a new prospective payment system. This essay compares the three reforms in Korea and draws important lessons about the country's changing process and politics of health care policy. The change of government, the president's keen interest in health policy, and democratization in the public policy process toward a more pluralist context opened a policy window for reform. Civic groups played an active role in the policy process by shaping the proposals for reform-a major change from the previous policy process that was dominated by government bureaucrats. The three reforms also showed important differences in the role of interest groups. Strong support by the rural population and labor unions contributed to the financing reform. In the pharmaceutical reform, which was a big threat to physician income, the president and civic groups succeeded in quickly setting the reform agenda; the medical profession was unable to block the adoption of the reform but their strikes influenced the content of the reform during implementation. Physician strikes also helped block the implementation of the payment reform. Future reform efforts in Korea will need to consider the political management of vested interest groups and the design of strategies for both scope and sequencing of policy reforms.  相似文献   
934.
A study was performed to acquire urine, serum and oral fluid samples in cases of suspected driving under the influence of drugs of abuse. Oral fluid was collected using a novel sampling/testing device (Dr?ger DrugTest System). The aim of the study was to evaluate oral fluid and urine as a predictor of blood samples positive for drugs and impairment symptoms. Analysis for cannabinoids, amphetamine and its derivatives, opiates and cocaine was performed in urine using the Mahsan Kombi/DOA4-test, in serum using immunoassay and gas chromatography-mass spectrometry (GC-MS) confirmation and in oral fluid by GC-MS. Police and medical officer observations of impairment symptoms were rated and evaluated using a threshold value for the classification of driving inability. Accuracy in correlating drug detection in oral fluid and serum were >90% for all substances and also >90% in urine and serum except for THC (71.0%). Of the cases with oral fluid positive for any drug 97.1% of corresponding serum samples were also positive for at least one drug; of drug-positive urine samples this were only 82.4%. In 119 of 146 cases, impairment symptoms above threshold were observed (81.5%). Of the cases with drugs detected in serum, 19.1% appeared not impaired which were the same with drug-positive oral fluid while more persons with drug-positive urine samples appeared uninfluenced (32.7%). The data demonstrate that oral fluid is superior to urine in correlating with serum analytical data and impairment symptoms of drivers under the influence of drugs of abuse.  相似文献   
935.
The bodies of socially isolated people may remain undiscovered in their own houses for prolonged periods. Occasionally the body is in situ for sufficient time to become skeletonised, or partially so. Medico-legal investigation of these cases is complicated by degradation and contamination of evidence. Thus, a multidisciplinary forensic investigation is recommended. The potential contributions of forensic pathology, anthropology, odontology and entomology are outlined here with reference to two cases that occurred in Victoria, Australia, in 2003. Forensic pathologists are often unable to determine the cause of death in skeletonised bodies, however, they may find evidence to support either a natural or unnatural mode of death, and they may describe skeletal pathology or trauma, and identify skeletal features to support radiological identification of the deceased. Anthropologists can provide supplementary evidence of skeletal trauma. Additionally, they can assess age, sex, stature and racial affiliation from skeletal remains. Odontologists can identify individuals through comparison with ante-mortem dental records; however, potential difficulties exist in identifying the treating dentist of a socially isolated person. Odontologists may also examine the teeth and oro-facial skeleton for trauma. Entomologists may estimate minimum death time and/or season of death. Entomological examination of insect remains may also confirm that a body has lain in situ for a considerable period.  相似文献   
936.
A qualitative and quantitative analytical method was developed and validated for the determination of 49 licit and illicit drugs in oral fluid. Small oral fluid samples, volume 1mL, were collected from volunteers using a modified Omni-Sal device and the analytes were extracted from an oral fluid/buffer mixture using a single Bond Elut Certify solid phase extraction cartridge. Liquid chromatography-tandem mass spectrometry (LC-MS-MS) and gas chromatography-repetitive full scan mass spectrometry (GC-MS) were used in parallel to analyze the extracts for the targeted drugs. Extracts were analyzed by GC-MS in their underivatized form and as their pentafluoropropionyl derivatives. Deuterated internal standards were used for quantification of drugs of abuse by LC-MS-MS to minimize matrix effects. Methadone-d(9) and tumoxetine were used as the internal standards for quantification of non-derivatized and derivatized analytes respectively by GC-MS. Linearity was demonstrated over the range 5-200 ng/mL and limits of detection were less than 4 ng/mL for each drug analyzed. The method demonstrated acceptable recoveries for most of the analytes and good intra- and inter-day precision. Acquisition of data by repetitive full scan GC-MS allows the addition of further analytes to the target menu.  相似文献   
937.
In the spring of 2003, bush cutters discovered a large grain bag filled with human skeletal remains in a forest in South Africa. Differential taphonomic processes observed on the bones suggested that the individuals had not died at the same time or had decomposed under different circumstances. The remains were sorted using gross morphological techniques which included assessing the number of skeletal elements present, visual pair matching, articulation, process of elimination and taphonomy. Standard techniques were used to estimate age, sex, racial affinity and stature. A minimum number of individuals (MNI) of 10 was established, which included 7 adult males, 1 adult female and 2 juveniles. Trauma was observed on only one individual. Approximately, 80% of the skeletal remains were missing. These various skeletal elements may have been lost by accident, normal taphonomic processes or taken by scavengers. Possible origins for these skeletal remains include removal from a formal grave, found in the veldt or murdered.  相似文献   
938.
The solution parameters associated with gradient elution reversed phase high-performance liquid chromatography (HPLC) were characterized by evaluating the electrospray ionization mass spectrometry (ESIMS) response of selected smokeless powder additives. Using direct liquid infusion, the positive ion ESIMS responses were determined for three general classes of powder constituents: dialkylphthalate acid esters, N,N'-dialkyl-N,N'-diphenyl urea based stabilizers and nitroso-, nitro-, and dinitro- derivatives of diphenylamine. The relative ESIMS intensities of the powder components were investigated as a function of three solution parameters: ammonium acetate concentration, pH, and percent methanol. The effect of the ammonium acetate concentration demonstrates that the electrolyte is required for efficient ionization and the ESIMS intensity was optimal at a concentration of 2mM for the selected compounds, except 2,4'-dinitrodiphenylamine. The aqueous solution pH, corresponding to the available protons in solution, did not have a significant effect on the ESIMS intensity of the analytes. The percent methanol was evaluated with both decreasing and constant electrolyte concentrations to demonstrate the effects of droplet stability and ion transfer into the gas phase. These findings were applied to the analysis of the selected smokeless powder additives using HPLC-ESIMS to illustrate increased sensitivity for the protonated molecules.  相似文献   
939.
940.
Prevention science has produced information about risk and protective factors that predict adolescent drug use and related problem behaviors. This paper investigates the Communities That Care Youth Survey that measures multiple risk and protective factors. Using a sample of 172,628 students who participated in surveys administered in seven states in 1998, analyses were conducted to test the factor structure of these risk and protective factors and to test the equivalence of the factor models across five racial/ethnic groups (African Americans, Asians or Pacific Islanders, Caucasians, Hispanic Americans, and Native Americans), four grade levels (6th, 8th, 10th, and 12th) and both gender groups. Results support the construct validity of the surveys risk and protective factor scales and indicate that the measures are equally reliable across males and females and five racial/ethnic groups. Implications of these findings for science-based prevention planning are discussed.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号