全文获取类型
收费全文 | 2528篇 |
免费 | 210篇 |
国内免费 | 1篇 |
专业分类
2739篇 |
出版年
2023年 | 14篇 |
2022年 | 41篇 |
2021年 | 63篇 |
2020年 | 48篇 |
2019年 | 47篇 |
2018年 | 79篇 |
2017年 | 66篇 |
2016年 | 86篇 |
2015年 | 102篇 |
2014年 | 131篇 |
2013年 | 157篇 |
2012年 | 195篇 |
2011年 | 193篇 |
2010年 | 113篇 |
2009年 | 97篇 |
2008年 | 105篇 |
2007年 | 111篇 |
2006年 | 120篇 |
2005年 | 101篇 |
2004年 | 91篇 |
2003年 | 66篇 |
2002年 | 61篇 |
2001年 | 56篇 |
2000年 | 39篇 |
1999年 | 39篇 |
1998年 | 19篇 |
1997年 | 30篇 |
1996年 | 22篇 |
1995年 | 26篇 |
1994年 | 11篇 |
1993年 | 11篇 |
1992年 | 29篇 |
1991年 | 27篇 |
1990年 | 26篇 |
1989年 | 22篇 |
1988年 | 21篇 |
1987年 | 17篇 |
1986年 | 17篇 |
1985年 | 24篇 |
1984年 | 22篇 |
1983年 | 14篇 |
1982年 | 27篇 |
1981年 | 13篇 |
1980年 | 19篇 |
1979年 | 15篇 |
1977年 | 20篇 |
1974年 | 11篇 |
1973年 | 10篇 |
1972年 | 12篇 |
1967年 | 10篇 |
排序方式: 共有2739条查询结果,搜索用时 0 毫秒
81.
82.
83.
K.B. Devaraj Parigi Ramesh Kumar V. Prakash 《International journal of biological macromolecules》2009,45(3):248-254
Effect of pH on the conformational behaviour of ficin (EC 3.4.22.3), a cysteine protease from the latex of Ficus carica was monitored by circular dichroism, fluorescence spectroscopy, ANS binding and hydrodynamic studies. The results obtained from near- and far-UV CD, intrinsic fluorescence and ANS binding studies demonstrate that ficin exhibits the characteristic properties of molten globule at acidic conditions between pH 1.4 and 2.0. Ficin at pH 1.4 retained about 74% secondary structure with a substantial loss of tertiary structure. The acid-induced state was found to have a compact shape as measured by Stokes radius on size exclusion chromatography. 相似文献
84.
Ved Prakash Meena V. Seenu M. C. Sharma Saumya Ranjan Mallick Ashu Seith Bhalla Nandita Gupta Anant Mohan Randeep Guleria Ravindra M. Pandey Kalpana Luthra Naval K. Vikram 《PloS one》2014,9(9)
Background
Enlargement of adipocyte is associated with their dysfunction and alterations in metabolic functions.Objectives
We evaluated the association of adipocyte size of subcutaneous and omental adipose tissue with body composition and cardiovascular risk factors in Asian Indians.Methodology
Eighty (40 males and 40 females) non-diabetic adult subjects undergoing elective abdominal surgery were included. Pre-surgery evaluation included anthropometric measurements, % body fat by bioimpedance, abdominal fat area at L2–3 level (computed tomography) and biochemical investigations (fasting blood glucose and insulin, lipids and hsCRP). During surgery, about 5 grams each of omental and subcutaneous adipose tissue was obtained for adipocyte size determination.Results
Females had higher BMI, % body fat, skinfold thickness, total and subcutaneous abdominal fat area as compared to males. Overweight was present in 42.5% and 67.5%, and abdominal obesity in 5% and 52.5% males and females, respectively. Subcutaneous adipocyte size was significantly higher than omental adipocyte size. Omental adipocyte size correlated more strongly than subcutaneous adipocyte size with measures of adiposity (BMI, waist circumference, %BF), total and subcutaneous abdominal fat area and biochemical measures (fasting glucose, total cholesterol, triglycerides and HOMA-IR), the correlations being stronger in females. The correlation of adipocyte size with metabolic parameters was attenuated after adjusting for measures of adiposity.Conclusion
Omental adipocyte size, though smaller than the subcutaneous adipocyte size, was more closely related to measures of adiposity and metabolic parameters. However, the relationship was not independent of measures of adiposity. 相似文献85.
Venkatachalam Sankar Seppan Prakash Rathinasamy Muthusamy Krishnaswami Kamakshi 《Primates; journal of primatology》2000,41(1):89-92
Dracunculiasis, popularly known as Guinea worm disease, has been eradicated from Tamil Nadu, India, and there have been no
indigenous cases reported since 1981. This report describes a female bonnet monkey with dracunculiasis. She presented with
fever and a blister in left hind limb. The blister ruptured on exposure to water and a 7-cm-long worm was extruded. The worm
died before it could be histologically examined. The diagnosis was based on the typical clinical course, which was pathognomonic
of dracunculiasis. Review of literature did not reveal any previous report of dracunculiasis in South Indian bonnet monkeys
(Macaca radiata). This paper raises the question whether wild monkeys might act as reservoirs of human infection and cause resurgence of
the disease in South India.
Animal experiments were approved by the ethical committee of our institute and animal maintenance was according to the recommendations
of the Canadian Council for Experimental Animal Care and the Laboratory Animal Science Association of India. 相似文献
86.
The activity of cotyledon and embryo diamine oxidase was reduced by feeding ethrel and chloroethanol to the seedlings. The inhibitory effect of 2,4-D on the activity of enzyme in the cotyledon which may be mediated through ethylene was reversed by exposure of seeds to red light. 相似文献
87.
88.
This study describes the enantioseparation of three chiral amines as naphthaldimine derivatives, using normal phase HPLC with amylose and cellulose tris(3,5-dimethylphenylcarbamate) chiral stationary phases (CSPs). Three chiral amines were derivatized using three structurally similar naphthaldehyde derivatizing agents, and the enantioselectivity of the CSPs toward the derivatives was examined. The degree of enantioseparation and resolution was affected by the amylose or cellulose-derived CSPs and aromatic moieties as well as a kind of chiral amine. Especially, efficient enantiomer separation was observed for 2-hydroxynapthaldimine derivatives on cellulose-derived CSPs. Molecular docking studies of three naphthaldimine derivatives of leucinol on cellulose tris(3,5-dimethylphenylcarbamate) were performed to estimate the binding energies and conformations of the CSP–analyte complexes. The obtained binding energies were in good agreement with the experimentally determined enantioseparation and elution order. 相似文献
89.
Studies on mobilization of chromium with reference to its plant availability – Role of organic acids
Metal-organic acid interactions with special reference to their plant availability have been studied. The role of organic acids in the mobilization of Cr by converting it into labile organically bound form, enhancing its availability, is highlighted. Pot experiments are conducted to investigate the effect of various organic acids on the uptake and translocation of root absorbed trivalent and hexavalent chromium by maize (z. mays) plants grown in sand and soil culture. Statistically significant increases in chromium accumulation from CrIII-treated plants in the presence of increasing concentrations of organic acid suggest the existence of CrIII – organic acid interactions in the soil plant system. In order to support the above mentioned hypothesis of formation of organically bound CrIII in the presence of various organic acids (carboxylic and amino acids), separate experiments have been performed to synthesize and estimate its respective organically bound forms. Amendments with organic acids, however, do not appear to markedly affect chromium accumulation from CrVI treatment. The results are discussed on the basis of the potential of organic acids to form complexes with CrIII. 相似文献
90.
High frequency, direct regeneration of shoots was induced in leaf cultures ofPaulownia tomentosa, P. fortunei x P. tomentosa andP. kawakamii. The optimum culture medium for the leaf explants derived from shoot cultures was Murashige-Skoog (MS) medium supplemented with 10 M indole-3-acetic acid and 50 M benzyladenine. Up to 40 shoots were obtained over a 4 month culture period from each leaf explant. Rooting occurred spontaneously in the shoots that were about 1 cm tall when subcultured on phytohormone-free MS medium. The plantlets could be transplanted successfully. Some of the transplantedP. tomentosa plantlets flowered in the greenhouse one year after transplanting. The protocol is suitable not only for rapid multiplication of the various species ofPaulownia, but also for analytical studies associated with adventitious shoot regeneration. 相似文献