全文获取类型
收费全文 | 6941篇 |
免费 | 397篇 |
国内免费 | 20篇 |
出版年
2024年 | 11篇 |
2023年 | 95篇 |
2022年 | 254篇 |
2021年 | 371篇 |
2020年 | 343篇 |
2019年 | 493篇 |
2018年 | 382篇 |
2017年 | 270篇 |
2016年 | 358篇 |
2015年 | 385篇 |
2014年 | 465篇 |
2013年 | 599篇 |
2012年 | 561篇 |
2011年 | 544篇 |
2010年 | 294篇 |
2009年 | 253篇 |
2008年 | 281篇 |
2007年 | 279篇 |
2006年 | 247篇 |
2005年 | 200篇 |
2004年 | 155篇 |
2003年 | 113篇 |
2002年 | 100篇 |
2001年 | 18篇 |
2000年 | 16篇 |
1999年 | 22篇 |
1998年 | 20篇 |
1997年 | 19篇 |
1996年 | 14篇 |
1995年 | 8篇 |
1994年 | 8篇 |
1993年 | 15篇 |
1992年 | 8篇 |
1991年 | 14篇 |
1990年 | 7篇 |
1989年 | 12篇 |
1988年 | 6篇 |
1987年 | 14篇 |
1986年 | 15篇 |
1985年 | 14篇 |
1984年 | 15篇 |
1983年 | 8篇 |
1982年 | 8篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1976年 | 4篇 |
1975年 | 3篇 |
1974年 | 7篇 |
1973年 | 3篇 |
1962年 | 2篇 |
排序方式: 共有7358条查询结果,搜索用时 15 毫秒
101.
Phosphodiesterase inhibitors (PDEIs) are a class of drugs that are widely used because of their various pharmacological properties including cardiotonic, vasodilator, smooth muscle relaxant, antidepressant, antithrombotic, bronchodilator, antiinflammatory and enhancer of cognitive function. In the recent years, interest in drugs of plant origin has been progressively increased. Some pharmacologically active substances that come from plants demonstrate PDEI activity. They mainly belong to alkaloids, flavonoids, and saponins. In this review, studies on herbal PDEI were reviewed and their possible therapeutic applications were discussed. Screening plants for PDE inhibitory activity may help to develop standardized phytotherapeutic products or find new sources for new lead structures with PDEI pharmacological activity. The studies discussed in this paper are mainly in vitro and for more reasonable and conclusive results, it is required to conduct in vivo and finally human and clinical tests. 相似文献
102.
Eswari J. Satya Majdoubi Jihen Naik Sweta Gupta Sneha Bit Arindam Rahimi-Gorji Mohammad Saleem Anber 《Biomechanics and modeling in mechanobiology》2020,19(5):1697-1711
Biomechanics and Modeling in Mechanobiology - Blood flow analysis in the artery is a paramount study in the field of arterial stenosis evaluation. Studies conducted so far have reported the... 相似文献
103.
Maryam Ghodrati Siahmazgi Mohammad Ali Nasiri Khalili Mehdi Zeinoddini Fathollah Ahmadpour Sirus Khodadadi 《International journal of peptide research and therapeutics》2020,26(2):767-774
Immunotoxin is a recombinant fusion toxin which has been developed to kill cancer cells selectively. DT389GCSF as a new immunotoxin consists of a truncated 相似文献
104.
Omid Haghighi Soheila Davaeifar Hossein Shahbani Zahiri Hadi Maleki Kambiz Akbari Noghabi 《International journal of peptide research and therapeutics》2020,26(2):783-793
Glutamate dehydrogenase (GDH), which is present in most bacteria and eukaryotes’ mitochondria, plays an important role in amino acid metabolism. In g 相似文献
105.
Pirkhezranian Zana Tanhaeian Abbas Mirzaii Mehdi Sekhavati Mohammad Hadi 《International journal of peptide research and therapeutics》2020,26(3):1503-1512
International Journal of Peptide Research and Therapeutics - Cancer remains one of the leading causes of death worldwide. Introduction of natural compounds with anticancer properties can be an... 相似文献
106.
Effect of Drought Stress on Certain Morphological and Physiological Characteristics of a Resistant and a Sensitive Canola Cultivar 总被引:1,自引:0,他引:1
Ghorban Khodabin Zeinolabedin Tahmasebi‐Sarvestani Amir Hossein Shirani Rad Seyed Ali Mohammad Modarres‐Sanavy 《化学与生物多样性》2020,17(2)
Water stress is one of the main abiotic factors that reduces plant growth, mainly due to high evaporative demand and low water availability. In order to evaluate the effects of drought stress on certain morphological and physiological characteristics of two canola cultivars, we conducted a factorial experiment based on a completely randomized design. The findings show that drought stress exacerbations result in the plant's response to stress due to increased canola resistance caused by changes in plant pigments, proline, catalase, ascorbate peroxidase, peroxidase, superoxide dismutase and malondialdehyde, glucose, galactose, rhamnose and xylose. These in turn ultimately influence the morphological characteristics of canola. Drought stress reduces the concentration of carotenoids, chlorophyll a, chlorophyll b, total chlorophylls; however, glucose, galactose, rhamnose, xylose, proline, catalase, ascorbate peroxidase, peroxidase, superoxide dismutase, malondialdehyde (in leaves and roots) and the chlorophyll a and b ratios were increased. Reduction of plant height, stem height, root length, fresh and dry weight of canola treated with 300 g/l PEG compared to non‐treatment were 0.264, 0.236, 0.394, 0.183 and 0.395, respectively. From the two canola cultivars, the morphological characteristics of the NIMA increased compared to the Ks7 cultivar. Interaction effects of cultivar and drought stress showed that NIMA cultivar without treatment had the highest number of morphological characteristics such as carotenoid concentration, chlorophyll a, chlorophyll b, total chlorophylls a and b, whereas the cultivar with 300 g/l PEG (drought stress) had the highest amount of proline, malondialdehyde, soluble sugars and enzymes in leaves and roots. Increasing activity of oxidative enzymes and soluble sugars in canola under drought stress could be a sign of their relative tolerance to drought stress. 相似文献
107.
Hosseini Zohreh Habibi Najafi Mohammad Bagher Yavarmanesh Masoud Ataei-Pirkooh Angila 《International journal of peptide research and therapeutics》2020,26(2):911-919
International Journal of Peptide Research and Therapeutics - LL-37 is a 37 amino acid long cationic peptide belonging to the cathelicidin family of antimicrobial peptides. Limited investigations... 相似文献
108.
Rahbar Mohammad Reza Zarei Mahboubeh Jahangiri Abolfazl Khalili Saeed Nezafat Navid Negahdaripour Manica Fattahian Yaser Ghasemi Younes 《International journal of peptide research and therapeutics》2020,26(3):1269-1282
International Journal of Peptide Research and Therapeutics - Acinetobacter baumannii is an important pathogen responsible for nosocomial infections worldwide. Trimeric autotransporters, the... 相似文献
109.
Kien Nguyen Dang El-Qushayri Amr Ehab Ahmed Ali Mahmoud Safi Adnan Mageed Sarah Abdel Mehyar Samar Muhammed Hashan Mohammad Rashidul Karimzadeh Sedighe Hirayama Kenji Huy Nguyen Tien 《中国病毒学》2020,35(1):83-92
The relationship between the severity of dengue infection and allergy is still obscure. We conducted an electronic search across 12 databases for relevant articles reporting allergic symptoms, dengue infection, and dengue classification. These studies were categorized according to dengue severity and allergy symptoms, and a meta-analysis was performed by pooling the studies in each category. Among the included 57 articles, pruritus was the most common allergic sign followed by non-specified allergy and asthma(28.6%, 13%, and 6.5%, respectively). Despite the reported significant association of dengue with pruritus and total Ig E level(P \ 0.05), in comparison with non-dengue cases and healthy controls, there was no association between the different severe dengue group with pruritus, skin allergy, food allergy or asthma. However,removing the largest study revealed a significant association between asthma with dengue hemorrhagic fever(DHF) rather than dengue fever(DF). In comparison with DF, DHF was associated with Ig E positivity. Furthermore, specific-Ig E level was higher in secondary DF rather than primary DF. There was a possible association between allergy symptoms and dengue severity progression. Further studies are needed to clarify this association. 相似文献
110.