全文获取类型
收费全文 | 13401篇 |
免费 | 201篇 |
国内免费 | 21篇 |
专业分类
教育 | 9351篇 |
科学研究 | 1521篇 |
各国文化 | 125篇 |
体育 | 1148篇 |
综合类 | 6篇 |
文化理论 | 98篇 |
信息传播 | 1374篇 |
出版年
2021年 | 138篇 |
2020年 | 195篇 |
2019年 | 268篇 |
2018年 | 367篇 |
2017年 | 350篇 |
2016年 | 357篇 |
2015年 | 238篇 |
2014年 | 314篇 |
2013年 | 2309篇 |
2012年 | 291篇 |
2011年 | 316篇 |
2010年 | 278篇 |
2009年 | 218篇 |
2008年 | 268篇 |
2007年 | 238篇 |
2006年 | 232篇 |
2005年 | 209篇 |
2004年 | 227篇 |
2003年 | 204篇 |
2002年 | 175篇 |
2001年 | 444篇 |
2000年 | 291篇 |
1999年 | 253篇 |
1998年 | 117篇 |
1997年 | 155篇 |
1996年 | 132篇 |
1995年 | 123篇 |
1994年 | 144篇 |
1993年 | 110篇 |
1992年 | 181篇 |
1991年 | 191篇 |
1990年 | 192篇 |
1989年 | 198篇 |
1988年 | 165篇 |
1987年 | 158篇 |
1986年 | 167篇 |
1985年 | 205篇 |
1984年 | 160篇 |
1983年 | 148篇 |
1982年 | 128篇 |
1981年 | 121篇 |
1980年 | 115篇 |
1979年 | 163篇 |
1978年 | 131篇 |
1977年 | 116篇 |
1976年 | 92篇 |
1975年 | 112篇 |
1974年 | 100篇 |
1973年 | 107篇 |
1971年 | 98篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
This paper describes a method of analysing teacher growth in the context of science education. It focuses on the identification of pathways in the development of secondary school teachers’ pedagogical content knowledge (PCK) by the use of the interconnected model of teachers’ professional growth (IMTPG).The teachers (n = 12) participated in a one-year action research project focused on their individual concerns related to teaching science. The use of the IMTPG revealed that teachers use different pathways of learning to develop different aspects of their PCK. For each PCK component, three distinct pathways could be identified, two of which clearly were associated with professional growth. When examining these two pathways in detail, it was found that (1) teachers learned about new instructional strategies and assessment methods mostly through literature reviews and discussions with peers and (2) teachers who analyzed and reflected on student learning as it happened in their classrooms developed understandings that helped them to select and apply instructional strategies to further promote student learning. Both the analytical method as well as the identification of the different developmental pathways help to better understand teacher development in the context of classroom practices. 相似文献
962.
Adam C. Pace Joy Greene Joseph E. Deweese Dana A. Brown Ginger Cameron James M. Nesbit 《Christian Higher Education》2017,16(4):200-210
The objective of this study was to develop and validate an instrument to assess the attitude of student pharmacists toward prayer in general and in particular as it relates to their academic performance. To fulfill the study objective, faculty from seven colleges of pharmacy located at Christian universities collaboratively developed the Student Prayer Attitude Scale (SPAS). The items were used to assess the attitudes of student pharmacists toward prayer as well as the effects of prayer on personal lives and academic performance. Faculty investigators asked 1,563 students to complete the survey and received 677 valid responses. A principal components analysis with promax rotation was conducted and revealed a two-factor structure: (a) general attitude toward prayer and (b) specific attitude regarding the impact of prayer on academic performance. Analysis of variance was used to compare student responses by religious identity. Students identifying as atheist or agnostic were significantly different in their responses than students from theistic religions; however, the responses of students from various theistic religions were not significantly different from one another. Faculty concluded that SPAS is a reliable tool for measuring student attitudes toward prayer. The use of such a tool could help faculty tailor educational opportunities to allow pharmacy students to explore prayer more fully and be aware of its impact on the patients they serve. 相似文献
963.
Charles C. Morse Janet Dee Spoltore Paul Galvinhill 《Journal of College Student Psychotherapy》2017,31(4):325-335
Research points to significant numbers of students on college campuses experiencing mental health distress and an ever increasing number of college students who are choosing to make an off-campus educational experience a part of their college careers. When we consider both of these trends together, it is quite apparent that a significant number of students with mental health concerns will spend periods of time studying away from campus, with converging concerns among college mental health and study away professionals about how to best support these students. This article seeks to outline both challenges and opportunities inherent in the collaboration between campus professionals in supporting students with mental health issues before and during their study away experiences. 相似文献
964.
965.
966.
C. S. Parameswari B. Vijayageetha R. Vijayakumar 《Indian journal of clinical biochemistry : IJCB》2006,21(1):131-136
The oxidative modification of lipoprotein especially low density lipoprotein (LDL) plays a key role in the initiation and
progression of atherosclerosis. Serum apolipoproteinB (apoB) level is found to be an important marker for atherosclerosis.
The present paper focuses on the measurement of serum apoB levels and the effect of Vitamin E, Vitamin C and reduced glutathione
on the copper ion induced oxidation of LDL + VLDL (VLDL-Very Low Density Lipoprotein) lipoprotein fraction isolated from the
serum of chronic renal failure (CRF) and renal transplanted patients. The level of apoB is significantly higher in the serum
of transplanted patients when compared to CRF patients and normal subjects. The level of TBARS formed in oxidized LDL + VLDL
lipoprotein fraction of CRF and renal transplanted patients are significantly increased than normal even in the presence of
antioxidants but the level of TBARS produced, with antioxidants is comparatively lesser than that produced by oxidized lipoprotein
fraction without antioxidants. It may be concluded than that produced by oxidized lipoprotein fraction without antioxidants.
It may be concluded that oxidation of LDL can be prevented at an earlier stage by Vitamin E supplementation. The supplementation
with Glutathione serves as the best method of preventing the lipoprotein oxidation among the renal diseased patients. 相似文献
967.
The primary objective for modeling of machining processes is to develop a predictive capability of machining performance in order to facilitate effective planning of machining operations. This capability leads to faster implementation, higher performance, quality at a lower cost. This comes about due to improved selection of machining parameters, optimal fixture design and the avoidance of tool failure. The simulation system presented simultaneously considers the effect of cutter geometry, the cutter's initial position errors, workpiece geometry, machine tool dynamics, and workpiece/fixture system dynamics on the machining process.The integration of all of the above in one model provides an off-line tool to simulate and optimize the machining parameters and the fixture configuration cutting both lead and production time. The modular nature of the simulation system presented allows for the study of many different machining processes. The cutting forces in this system are modeled using a mechanistic approach. NURBS curves and surfaces are utilized for the geometric modeling and simulation of the machining process. While a finite element method is used to model and analyze the workpiece/fixture dynamics. Two case studies are presented to demonstrate the practical application of the presented simulation. The first case presents the optimization of the fixture configuration of a generic automotive component. While the second case presents the results of simulations performed on a novel mill/grind machining process. This process is a combination of face milling and grinding in one operation. Some simulated results are presented along with experimental validation. 相似文献
968.
S. Suchalatha C. S. Shyamala Devi 《Indian journal of clinical biochemistry : IJCB》2004,19(2):184-189
To study the protective role of Arogh on isoproterenol induced myocardial damage in rats. The effect of Arogh pretreatment
on isoproterenol induced myocardial damage was assessed by studying the levels of lipid peroxides and changes in the activity
of marker enzymes such as creatine kinase, lactate dehydrogenase and transaminases in serum and heart tissue. In isoproterenol
administered rats, a significant decrease was observed in the activity of marker enzymes in the heart with a corresponding
increase in their levels in serum. Lipid peroxide levels increased significantly in the serum and heart. In rats pretreated
with arogh, the level of lipid peroxides and the activity of marker enzymes were maintained at near normal values. Pretreatment
with Arogh offered a protective effect against isoproterenol induced myocardial damage in rats as evidenced by LDH isoenzyme
patterm and histopathological studies of heart tissue. 相似文献
969.
970.
Two indigenous drugsPremna latifolia Roxb (Agnimandha) andImperata arundinacea Cyril (Darbha) were studied for their anticalculogenic effect at 20 and 100 mg concentrations. Both the concentrations were found to be equally effective in reducing the size of oxalate crystal growthin vitro over a period of 30 days. There was no change in infra red spectra while scanning electron microscope analysis showed development of cracks in the interior of the crystals and a tendency for rupture of crystals. Chemolysis appears to be the mechanism of action of the drugs. 相似文献