全文获取类型
收费全文 | 599篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
教育 | 273篇 |
科学研究 | 282篇 |
各国文化 | 3篇 |
体育 | 6篇 |
文化理论 | 3篇 |
信息传播 | 35篇 |
出版年
2024年 | 1篇 |
2023年 | 8篇 |
2022年 | 7篇 |
2021年 | 20篇 |
2020年 | 5篇 |
2019年 | 11篇 |
2018年 | 39篇 |
2017年 | 26篇 |
2016年 | 27篇 |
2015年 | 30篇 |
2014年 | 29篇 |
2013年 | 65篇 |
2012年 | 18篇 |
2011年 | 20篇 |
2010年 | 26篇 |
2009年 | 30篇 |
2008年 | 27篇 |
2007年 | 19篇 |
2006年 | 29篇 |
2005年 | 24篇 |
2004年 | 15篇 |
2003年 | 25篇 |
2002年 | 10篇 |
2001年 | 8篇 |
2000年 | 8篇 |
1999年 | 7篇 |
1998年 | 11篇 |
1997年 | 8篇 |
1996年 | 3篇 |
1995年 | 6篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有602条查询结果,搜索用时 0 毫秒
121.
Bhupendra Pal Singh Shailendra Dwivedi Urmila Dhakad Ramesh Chandra Murthy Vimal Kumar Choubey Apul Goel Satya Narayan Sankhwar 《Indian journal of clinical biochemistry : IJCB》2016,31(1):50-56
Deficiency or excess of certain trace elements has been considered as risk factor for prostate cancer. This study was aimed to detect differential changes and mutual correlations of selected trace elements in prostate cancer tissue versus benign prostatic hyperplasia tissue. Zinc, copper, iron, calcium and selenium were analysed in histologically proven 15 prostate cancer tissues and 15 benign prostatic hyperplasia tissues using atomic absorption spectrophotometer. Unpaired two tailed t test/Mann–Whitney U test and Pearson correlation coefficient were used to compare the level of trace elements, elemental ratios and their interrelations. As compared to benign prostatic tissue, malignant prostatic tissue had significantly lower selenium (p = 0.038) and zinc (p = 0.043) concentrations, a lower zinc/iron ratio (p = 0.04) and positive correlation of selenium with zinc (r = 0.71, p = 0.02) and iron (r = 0.76, p = 0.009). Considerably divergent interrelationship of elements and elemental ratios in prostate cancer versus benign prostatic hyperplasia was noted. Understanding of differential elemental changes and their interdependence may be useful in defining the complex metabolic alterations in prostate carcinogenesis with potential for development of element based newer diagnostic, preventive and therapeutic strategies. Further studies may be needed to elucidate this complex relationship between trace elements and prostate carcinogenesis. 相似文献
122.
123.
Shivam Kumar 《Resonance》2007,12(9):25-39
Are there perfect squares which on division by 7 leave remainder 3? Are there perfect squares which on division by 3 leave
remainder 7? (A “remainder of 7” on division by 3 is the same as a remainder of 1.) The answers: ‘NO’ and ‘YES’, respectively.
These facts are stated by number theorists as follows: 3 is a quadratic non-residue modulo 7; 7 is a quadratic residue modulo 3. The notion of quadratic residue is far reaching, and the key theorem here is the Law of Quadratic Reciprocity, first stated
by Euler in 1783, but without proof, and first proved by Gauss, in 1796. The theorem is easy to state but is mysterious, as
it reveals a connection between two questions that appear unconnected. Let p, q be distinct odd primes; then the questions are: “Is p a quadratic residue modulo q?” and “Is q a quadratic residue modulo p?” Gauss had a high regard for this result and called it Theorema Aureum, the Golden Theorem. Though it has been proved in many different ways, it retains its mystery. In this two part article we
give three proofs of the theorem. The first one, described in this part, is based on group theory. 相似文献
124.
Santosh Kumar Singh Achyut Narayan Kesari Prashant Kumar Rai Geeta Watal 《Indian journal of clinical biochemistry : IJCB》2007,22(2):48-52
The present study reveals the effect of Musa paradisiaca stem juice on blood glucose level (BGL) of normal & diabetic rats.
The dose of 500 mg/kg bodyweight produces a significant rise of 28.3% in blood glucose level after 6h of oral administration
in normal rats. Whereas, in sub diabetic rats the same dose produces a rise of 16.4% in blood glucose levels within 1h during
glucose tolerance test (GTT) and a rise of 16% after 4 h in fasting blood glucose levels of severe diabetic cases. These results
were unexpected and important to report as other species of Musa like Musa sapientum has been reported for its hypoglycemic
effect. 相似文献
125.
The white spot syndrome virus (WSSV) is one of the deadly pathogens of penaeid shrimps and other crustaceans. The WSSV virion
consists of an enveloped rod-shaped nucleocapsid enclosing a large circular double stranded DNA genome of 305 Kb with 181
open reading frames. The two major structural genes, VP19 and VP28 were amplified from the genomic DNA of Chinese isolate
of WSSV and cloned in pUCm-T vector and sub cloned in pET-30a (+) vector. The expressions of genes inE. coli (BL21) were confirmed by SDS-PAGE analysis. The clones were sequenced, submitted to the gene bank and the Xiang Shan strain
of WSSV were compared with the previous reported sequence of WSSV of various regions which revealed that VP19 and VP28 gene
sequences had certain differences from the sequences of similar genes of the isolate already reported. The recombinant proteins
expressed, purified and characterized. 相似文献
126.
127.
Anshita Aggarwal Sant Ram Abhilasha Garg Rimesh Pal Anil Bhansali Priyanka Singh Sadhna Sharma J. S. Thakur Naresh Sachdeva Sanjay Kumar Bhadada 《Indian journal of clinical biochemistry : IJCB》2021,36(1):67
We aimed to estimate metabolic bone profile in a large cohort of healthy, adult Indian population to generate reference standards of serum calcium, phosphate and alkaline phosphatase (ALP), 25 (OH) Vitamin D and iPTH, and also to find out the prevalence of Vitamin D deficiency in healthy population. Apparently healthy people in the age group of 20–80 years, residing in the union territory of Chandigarh were chosen. Fasting samples for serum calcium, phosphate, albumin, alkaline phosphatase (ALP), 25 (OH) D and iPTH were collected and were processed on the same day. We recruited 930 healthy subjects from different subsectors of Chandigarh. Final analysis was done for 915 subjects. Out of this, 530 (58%) were women and 385 (42%) were men. The study participants were divided into two groups, less than and more than 50 years for the men and pre and post-menopausal for the women. The serum calcium, phosphate, ALP and iPTH were significantly higher in the post-menopausal women compared to the pre-menopausal women. The median plasma 25 (OH) D in men and women was 12.5 ng/mL and 14.3 ng/mL, respectively. 25 (OH) D deficiency was seen in 65.4% of individuals. 25 (OH) D levels co-related negatively with iPTH levels (r = − 0.4, p < 0.0001), and showed an increasing trend with age. We have thus presented metabolic bone profile of healthy, adult north Indian population. These reference values can be used for diagnosis and monitoring of various MBDs. Vitamin D deficiency is still rampant in our population in spite of increasing awareness. 相似文献
128.
Santosh Kumar 《Resonance》1998,3(3):32-40
Extremozymes that function in the extreme environmental conditions of temperature, pressure, pH, and salinity are of great importance for industrial processes and scientific research. Apart from understanding the principle behind the stability of such enzymes, there has been considerable effort to isolate enzymes from extremophiles (organisms that live in extreme environmental conditions) as well as modify enzymes from mesophiles (organisms that live in normal environmental conditions) to convert them into extremozymes. 相似文献
129.
130.