全文获取类型
收费全文 | 8519篇 |
免费 | 97篇 |
国内免费 | 8篇 |
专业分类
教育 | 5804篇 |
科学研究 | 1123篇 |
各国文化 | 50篇 |
体育 | 607篇 |
综合类 | 3篇 |
文化理论 | 53篇 |
信息传播 | 984篇 |
出版年
2022年 | 55篇 |
2021年 | 104篇 |
2020年 | 132篇 |
2019年 | 178篇 |
2018年 | 296篇 |
2017年 | 272篇 |
2016年 | 265篇 |
2015年 | 159篇 |
2014年 | 268篇 |
2013年 | 1381篇 |
2012年 | 206篇 |
2011年 | 239篇 |
2010年 | 201篇 |
2009年 | 183篇 |
2008年 | 224篇 |
2007年 | 188篇 |
2006年 | 169篇 |
2005年 | 153篇 |
2004年 | 173篇 |
2003年 | 126篇 |
2002年 | 131篇 |
2001年 | 194篇 |
2000年 | 200篇 |
1999年 | 180篇 |
1998年 | 94篇 |
1997年 | 127篇 |
1996年 | 106篇 |
1995年 | 75篇 |
1994年 | 96篇 |
1993年 | 68篇 |
1992年 | 164篇 |
1991年 | 124篇 |
1990年 | 116篇 |
1989年 | 144篇 |
1988年 | 127篇 |
1987年 | 102篇 |
1986年 | 107篇 |
1985年 | 108篇 |
1984年 | 79篇 |
1983年 | 92篇 |
1982年 | 60篇 |
1981年 | 72篇 |
1980年 | 61篇 |
1979年 | 103篇 |
1978年 | 66篇 |
1977年 | 63篇 |
1976年 | 55篇 |
1975年 | 50篇 |
1974年 | 60篇 |
1973年 | 56篇 |
排序方式: 共有8624条查询结果,搜索用时 15 毫秒
181.
The number of university–industry R&D partnerships (UIPs) has increased significantly over the past decade, in most OECD countries and in Australia, yet the study of risk in such commercially focused collaborative ventures is still a developing area. This review paper seeks to contribute to debate on this increasingly important phenomenon by addressing three key areas of risks for universities in entering such collaborations. The commercialization of research findings presents particular risks to universities, most notably the possibility of financial loss, which has a greater impact than for companies in cross‐sector collaborations. Another major type of risk faced by universities is relational risk, and this can significantly alter the trust dynamics that underpin research and innovation. There are also institutional risks to universities and their research staff engaged in commercializable R&D and, ultimately, to their reputation as a neutral source of expertise. It is argued there is a need for universities in Australia to develop comprehensive policies to manage the risks of commercialization and R&D collaboration with industry partners. 相似文献
182.
Roberts J. Kyle Henson Robin K. Tharp Barbara Z. Moreno Nancy P. 《Journal of Science Teacher Education》2001,12(3):199-213
Journal of Science Teacher Education - 相似文献
183.
Rita Christopher K. Taranath Shetty 《Indian journal of clinical biochemistry : IJCB》1996,11(1):81-84
The renal Fanconi syndrome which results from renal tubular dysfunction can be either associated with various inbom errors of metabolism or acquired from various etiology. We report a case of gentamycin-induced Fanconi syndrome in a 4-month old infant who presented with aminoaciduria, glucosuria, phosphaturia and compensated metabolic acidosis. 相似文献
184.
Yashika Gupta V. Mallika D. K. Srivastava 《Indian journal of clinical biochemistry : IJCB》2005,20(1):87-94
Platelets play a vital role in the progression of atherosclerosis and thrombosis, a major cause of death worldwide. Platelets
are activated by many triggers like elevated LDL in blood resulting in aggregation and formation of plaque. The purpose of
this study was to investigate the effect of LDL and signal transduction inhibitor on the activation of platelets in Ischaemic
risk subjects. Platelets from IHD and hyperlipidemic subjects were hypersensitive to ADP, as higher levels of platelet aggregation
were observed in these groups. LDL from IHD hyperlipidemic subjects was more effective in activating platelets from any other
group. Ox-LDL was more effective in activating platelets than native-LDL as monitored by level of platelet aggregation induced
by PAF and thrombin. Calcium channel blocker, nifedipine and verapamil inhibited platelet aggregation at micromolar level.
Protein kinase inhibitor, staurosporine was effective in inhibiting ADP induced aggregation at nanomolar level. 相似文献
185.
Urinary citric acid and calcium levels have been estimated in the urine of 20 normal healthy persons as well as 12 urinary
stone patients. Inhibition efficiency of these urine samples towards the mineralisation of urinary stone forming minerals,
viz., calcium phosphate, oxalate or carbonate, has been studied in an experimental model. Statistical correlation of the above
data has been made by computing the coefficient of determination and unexplained variance. Clinico-biochemical indexing of
calcium urolithiasis risk factor has been attempted in the light of the data. 相似文献
186.
187.
K. S. S. Saibaba P. V. L. N. Srinivasa Rao K. V. Dakshina Murty M. Vijaya Bhaskar 《Indian journal of clinical biochemistry : IJCB》1997,12(2):139-141
Selecting the correct method for routine analysis by ‘method evaluation’ is an important component of quality assurance. It
is a step-wise procedure that evaluates various analytical parameters like accuracy, precision etc of the given method. Finally
reference intervals are established for selected population. We evaluated an enzymatic method for serum creatinine. The results
show that it is an acceptable method based on the above mentioned criteria. 相似文献
188.
189.
K. A. Faseehuddin Shakir Basavaraj Madhusudhan 《Indian journal of clinical biochemistry : IJCB》2007,22(1):117-121
Rats fed with hypercholesterolemic diet showed a significant increase in serum total—cholesterol, liver homogenate total-cholesterol,
HDL-cholesterol and changed LDL-cholesterol, and HDL/LDL ratio in comparison to control. Flaxseedchutney (FC) supplemented diet (15%, w/w) was found to be more effective in restoring lipid profile changes in rats fed with cholesterol,
(1.0%). The activities of serum marker enzymes glutamate oxaloacetate transminase (GOT), glutamate pyruvate transaminase (GPT)
and alkaline phosphatase (ALP) were elevated significantly in carbon tetrachloride induced rats. Administration of flaxseedchutney (15%, w/w) resulted in depletion of serum marker enzymes and exhibited recoupment thus showing significant hepatoprotective
effect. It was observed that flaxseedchutney supplemented diet could lower the serum cholesterol and as a potential source of antioxidants it could exert protection against
hepatotoxic damage induced by carbon tetrachloride (CCl4) in rats. 相似文献
190.
Ramesh Chander Farhan Rizvi A. K Khanna Ram Pratap 《Indian journal of clinical biochemistry : IJCB》2003,18(2):71-79
Guggulsterone, a mixture of cis (E) and trans (Z) isomers (7∶3 w/w) was synthesized from 16-DPA. The isomers were separated
by column chromatography and evaluated for cardioprotective and antioxidant activities. Myocardial necrosis induced by isoproterenol
in rats caused marked increase in serum creatine phosphokinase and glutamate pyruvate transaminase. Simultaneously in ischemic
heart, phospholipase, xanthine oxidase and lipid peroxides were enhanced following depletion of glycogen, phospholipids and
cholesterol. Treatment with guggulsterone and its both isomers at the dose of 50 mg/kg po., significantly protected cardiac
damage as assessed by the reversal of blood and heart biochemical parameters in ischemic rats. The cardioprotective activity
of guggulsterone and of both the isomers were compared with that of gemfibrozil at the same doses. Guggulsterone and both
the isomers at tested concentrations (5–20mM) inhibited oxidative degradation of lipids in human low-density lipoprotein and
rat liver microsomes induced by metal ionsin vitro. The drug counteracted against the generation of superoxide anions (O2) and hydroxyl radicals (OH−) in non-enzymic test systems. It is suggested that cardioprotective and antioxidant activities of synthetic guggulsterone
and guggulsterone obtained from gum resinCommiphora mukul that contains isomers E & Z in the ratio of 46∶54w/w are the same. 相似文献