全文获取类型
收费全文 | 217篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
教育 | 155篇 |
科学研究 | 42篇 |
各国文化 | 1篇 |
体育 | 10篇 |
文化理论 | 6篇 |
信息传播 | 5篇 |
出版年
2022年 | 3篇 |
2021年 | 6篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 3篇 |
2014年 | 8篇 |
2013年 | 47篇 |
2012年 | 6篇 |
2010年 | 3篇 |
2009年 | 4篇 |
2008年 | 5篇 |
2007年 | 9篇 |
2006年 | 6篇 |
2005年 | 2篇 |
2003年 | 2篇 |
2002年 | 8篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1994年 | 3篇 |
1992年 | 3篇 |
1989年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 6篇 |
1980年 | 1篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 8篇 |
1976年 | 7篇 |
1975年 | 6篇 |
1973年 | 1篇 |
1967年 | 2篇 |
1966年 | 3篇 |
1965年 | 1篇 |
1964年 | 1篇 |
1963年 | 1篇 |
1962年 | 1篇 |
1961年 | 1篇 |
1959年 | 1篇 |
1943年 | 1篇 |
1833年 | 1篇 |
1828年 | 1篇 |
排序方式: 共有219条查询结果,搜索用时 0 毫秒
201.
Santosh C. Das Uche P. Isichei Aminu Z. Mohammed Abraham A. Otokwula Abiodun Emokpae 《Indian journal of clinical biochemistry : IJCB》2005,20(2):35-42
The effect of iodine deficiency (ID) on thyroid function in African women during pregnancy and postnatal period was examined,
for which very limited information is available. Serum T4, T3, TSH, TBG, thyroxine binding capacity (TBK), free thyroxine index (FT4I=T4/TBK) and T4/TBG were determined by ELISA technique in 32 pregnant women (resident of Plateau state, Nigeria- an ID zone) through pregnancy
upto term delivery, and in 5 women up to 6 weeks post delivery. Urinary iodide level was measured at delivery to determine
the degree of iodine deficiency. Results were matched with a non pregnant control comprising 44 subjects. 5555 birth weights
(BW) of term babies in the region were analysed to determine the prevalence of ‘small for dates’ (SFD) babies in the population.
Results show that the level of serum FT4I was elevated very significantly at late gestation (P<.001) but the women were not hyperthyroid, suggesting a marked disturbance
in binding of T4 with TBG during pregnancy. Five women with SFD babies were found in ‘compensated hypothyroid state’ and showed a significant
depression (p<.01) in serum T4/TBG, T4, FT4I and T3 levels to a low normal range, with a concurrent significant rise (p.<.001) in TSH level (above normal range) throughout pregnancy.
Incidence of SFD babies was higher (p.<.001) in ID zone (Bassa 15.2%) compared to control zone (Jos 9.8%). It is concluded
that a state of maternal ‘subclinical (compensated) hypothyroidism’ during pregnancy possibly plays an important role in the
aetiopathogenesis of SFD babies in Africans. A normal reference range for thyroid parameters at various stages of pregnancy
in healthy African women is established for the first time. 相似文献
202.
This study compares 183 high school chemistry students' applied and theoretical knowledge of selected concepts based on the particulate theory. The concepts are dissolution, diffusion, effusion, and states of matter. A two-form instrument called the Physical Changes Concepts Test (PCCT) was developed for this study. The application form measures students' knowlege using everyday language. The theoretical form measures students' knowledge using scientific language. Students' formal reasoning ability was measured using the Test Of Logical Thinking (TOLT). The overall results of the two forms of the PCCT indicate that more than 40% of the students displayed alternative conceptions (ACs) of the concepts covered in the PCCT. The study found that students' formal reasoning ability and their preexisting knowledge are associated with their conceptions and use of the particulate theory. The analysis of the nature of students' ACs and their use of the particulate theory revealed a significant difference between students' applied and theoretical knowledge. 相似文献
203.
This paper examines international standard-setting in the toxicology of pharmaceuticals during the 1990s, which has involved both the pharmaceutical industry and regulatory agencies in an organization known as the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH). The analysis shows that the relationships between innovation, regulatory science and 'progress' may be more complex and controversial than is often assumed. An assessment of the ICH's claims about the implications of 'technical' harmonization of drug-testing standards for the maintenance of drug safety, via toxicological testing, and the delivery of therapeutic progress, via innovation, is presented. By demonstrating that there is not a technoscientific validity for these claims, it is argued that, within the ICH, a discourse of technological innovation and scientific progress has been used by regulatory agencies and prominent parts of the transnational pharmaceutical industry to legitimize the lowering and loosening of toxicological standards for drug testing. The mobilization and acceptance of this discourse are shown to be pivotal to the ICH's transformation of reductions in safety standards, which are apparently against the interests of patients and public health, into supposed therapeutic benefits derived from promises of greater access to more innovative drug products. The evidence suggests that it is highly implausible that these reductions in the standards of regulatory toxicology are consistent with therapeutic progress for patients, and highlights a worrying aspect embedded in the 'technical trajectories' of regulatory science. 相似文献
204.
In this paper, we present a microfluidic platform for the continuous generation of stable, monodisperse lipid vesicles 20–110 μm in diameter. Our approach utilizes a microfluidic flow-focusing droplet generation design to control the vesicle size by altering the system’s fluid flow rates to generate vesicles with narrow size distribution. Double emulsions are first produced in consecutive flow-focusing channel geometries and lipid membranes are then formed through a controlled solvent extraction process. Since no strong solvents are used in the process, our method allows for the safe encapsulation and manipulation of an assortment of biological entities, including cells, proteins, and nucleic acids. The vesicles generated by this method are stable and have a shelf life of at least 3 months. Here, we demonstrate the cell-free in vitro synthesis of proteins within lipid vesicles as an initial step towards the development of an artificial cell. 相似文献
205.
206.
Rebecca Abraham V. Srinivasa Murugan P. Pukazhvanthen S. K. Sen 《Indian journal of clinical biochemistry : IJCB》2009,24(1):52-59
Thyroid stimulating hormone (TSH), Free Thyroxine (FT4) and Free Triiodothyronine (FT3) were assayed in 505 women of this region. 60 women had previous history of thyroid disease. The remaining 445 women formed
the “Disease free group”. A “Reference group” was obtained by excluding women with previous and present history of thyroid
dysfunction. Of the total 505 women examined 15.8% had thyroid dysfunction and 84.2% were euthyroid. 11.5% were hypothyroid
(9.5% sub-clinical) and 1.8% hyperthyroid (1.2% clinical). The geometric mean TSH for the total population was 2.65 μIU/ml.
It was significantly (p=0.025) lower in the reference population 2.17 μIU/ml. There was no significant difference in the FT3 and FT4 values between groups. 19% of women over 60 years had elevated TSH above 4.5 μIU/ml. The 2.5 and 97.5 percentiles of the
reference population was 1.1–5.2 μIU/ml. 6.1% of women in the reference group had TSH levels above the reference intervals.
Hypothyroidism particularly sub-clinical hypothyroidism is predominantly present amongst women in this iodine sufficient region.
Evaluation of thyroid status could help in early detection and treatment. 相似文献
207.
This study investigated facilitators and challenges to designing, implementing and evaluating school-based sexual health education in sub-Saharan Africa, using interviews with intervention designers and researchers. At the pre-planning and planning stages, participants reported that facilitating factors included addressing the reproductive health needs of participants, contextual (culture, religion, economic and social) considerations and the adoption of holistic approach to sexuality education. Lack of open communication about sexual health matters between young people and adults; concerns that sexual health education could encourage sexual activity; and inadequate funding, were key barriers. Implementation was facilitated by the involvement of relevant stakeholders, the training of facilitators and adopting strategies to overcome resistance to sexual health education. The provision of structured, detailed lessons plans and monitoring with supportive supervision optimised fidelity of delivery. Barriers to implementation included facilitators’ resistance to teaching safe sex promotion and logistical challenges in school environments. Participants also reported that the validity of self-reported adolescent sexual behaviour (as part of evaluation) may be improved by complementing well-designed self-report surveys with computerised audio devices for data collection, qualitative interviews and participant observation. Study findings generate recommendations to improve future forms of school-based sexual health education in sub-Saharan Africa. 相似文献
208.
209.
210.