全文获取类型
收费全文 | 11288篇 |
免费 | 774篇 |
国内免费 | 9篇 |
专业分类
12071篇 |
出版年
2023年 | 44篇 |
2022年 | 111篇 |
2021年 | 201篇 |
2020年 | 126篇 |
2019年 | 163篇 |
2018年 | 170篇 |
2017年 | 136篇 |
2016年 | 269篇 |
2015年 | 450篇 |
2014年 | 484篇 |
2013年 | 628篇 |
2012年 | 782篇 |
2011年 | 800篇 |
2010年 | 523篇 |
2009年 | 464篇 |
2008年 | 664篇 |
2007年 | 705篇 |
2006年 | 629篇 |
2005年 | 626篇 |
2004年 | 618篇 |
2003年 | 581篇 |
2002年 | 547篇 |
2001年 | 112篇 |
2000年 | 81篇 |
1999年 | 118篇 |
1998年 | 141篇 |
1997年 | 105篇 |
1996年 | 94篇 |
1995年 | 88篇 |
1994年 | 83篇 |
1993年 | 92篇 |
1992年 | 84篇 |
1991年 | 56篇 |
1990年 | 69篇 |
1989年 | 50篇 |
1988年 | 62篇 |
1987年 | 58篇 |
1986年 | 51篇 |
1985年 | 63篇 |
1984年 | 72篇 |
1983年 | 59篇 |
1982年 | 81篇 |
1981年 | 77篇 |
1980年 | 68篇 |
1979年 | 45篇 |
1978年 | 43篇 |
1977年 | 47篇 |
1976年 | 43篇 |
1974年 | 39篇 |
1973年 | 49篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
102.
Rose Seth Cacho Frances Wiersma Lenny Magdaleno Anthony Anderson Nicholas Statler Traci 《Applied psychophysiology and biofeedback》2021,46(2):205-214
Applied Psychophysiology and Biofeedback - Biofeedback (BF) training has been utilized with performers for years. Previous literature highlights the effectiveness of multi-week intervention... 相似文献
103.
Bin Ma Kevin M. Guckian Edward Yin-Shiang Lin Wen-Cherng Lee Daniel Scott Gnanasambandam Kumaravel Timothy L. Macdonald Kevin R. Lynch Cheryl Black Sowmya Chollate Kyungmin Hahm Gregg Hetu Ping Jin Yi Luo Ellen Rohde Anthony Rossomando Robert Scannevin Joy Wang Chunhua Yang 《Bioorganic & medicinal chemistry letters》2010,20(7):2264-2269
Modifying FTY720, an immunosuppressant modulator, led to a new series of well phosphorylated tetralin analogs as potent S1P1 receptor agonists. The stereochemistry effect of tetralin ring was probed, and (?)-(R)-2-amino-2-((S)-6-octyl-1,2,3,4-tetrahydronaphthalen-2-yl)propan-1-ol was identified as a good SphK2 substrate and potent S1P1 agonist with good oral bioavailability. 相似文献
104.
105.
106.
107.
108.
Shara M Ohia SE Yasmin T Zardetto-Smith A Kincaid A Bagchi M Chatterjee A Bagchi D Stohs SJ 《Molecular and cellular biochemistry》2003,254(1-2):339-346
(–)-Hydroxycitric acid (HCA), a natural extract from the dried fruit rind of Garcinia cambogia (family Guttiferae), is a popular supplement for weight management. The dried fruit rind has been used for centuries as a condiment in Southeastern Asia to make food more filling and satisfying. A significant number of studies highlight the efficacy of Super CitriMax (HCA-SX, a novel 60% calcium-potassium salt of HCA derived from Garcinia cambogia) in weight management. These studies also demonstrate that HCA-SX promotes fat oxidation, inhibits ATP-citrate lyase (a building block for fat synthesis), and lowers the level of leptin in obese subjects. Acute oral, acute dermal, primary dermal irritation and primary eye irritation toxicity studies have demonstrated the safety of HCA-SX. However, no long-term safety of HCA-SX or any other (–)-hydroxycitric acid extract has been previously assessed. In this study, we have evaluated the dose- and time-dependent effects of HCA-SX in Sprague-Dawley rats on body weight, hepatic and testicular lipid peroxidation, DNA fragmentation, liver and testis weight, expressed as such and as a % of body weight and brain weight, and histopathological changes over a period of 90 days. The animals were treated with 0, 0.2, 2.0 and 5.0% HCA-SX as feed intake and the animals were sacrificed on 30, 60 or 90 days of treatment. The feed and water intake were assessed and correlated with the reduction in body weight. HCA-SX supplementation demonstrated a reduction in body weight in both male and female rats over a period of 90 days as compared to the corresponding control animals. An advancing age-induced marginal increase in hepatic lipid peroxidation was observed in both male and female rats as compared to the corresponding control animals. However, no such difference in hepatic DNA fragmentation and testicular lipid peroxidation and DNA fragmentation was observed. Furthermore, liver and testis weight, expressed as such and as a percentage of body weight and brain weight, at 30, 60 and 90 days of treatment, exhibited no significant difference between the four groups. Taken together, these results indicate that treatment of HCA-SX over a period of 90 days results in a reduction in body weight, but did not cause any changes in hepatic and testicular lipid peroxidation, DNA fragmentation, or histopathological changes. 相似文献
109.
Trewavas A 《Annals of botany》2003,92(1):1-20
Intelligence is not a term commonly used when plants are discussed. However, I believe that this is an omission based not on a true assessment of the ability of plants to compute complex aspects of their environment, but solely a reflection of a sessile lifestyle. This article, which is admittedly controversial, attempts to raise many issues that surround this area. To commence use of the term intelligence with regard to plant behaviour will lead to a better understanding of the complexity of plant signal transduction and the discrimination and sensitivity with which plants construct images of their environment, and raises critical questions concerning how plants compute responses at the whole-plant level. Approaches to investigating learning and memory in plants will also be considered. 相似文献
110.