全文获取类型
收费全文 | 6069篇 |
免费 | 392篇 |
国内免费 | 8篇 |
出版年
2023年 | 48篇 |
2022年 | 90篇 |
2021年 | 183篇 |
2020年 | 135篇 |
2019年 | 128篇 |
2018年 | 187篇 |
2017年 | 167篇 |
2016年 | 233篇 |
2015年 | 269篇 |
2014年 | 357篇 |
2013年 | 445篇 |
2012年 | 506篇 |
2011年 | 522篇 |
2010年 | 319篇 |
2009年 | 260篇 |
2008年 | 296篇 |
2007年 | 293篇 |
2006年 | 271篇 |
2005年 | 234篇 |
2004年 | 202篇 |
2003年 | 156篇 |
2002年 | 166篇 |
2001年 | 96篇 |
2000年 | 65篇 |
1999年 | 68篇 |
1998年 | 42篇 |
1997年 | 46篇 |
1996年 | 33篇 |
1995年 | 37篇 |
1994年 | 33篇 |
1993年 | 22篇 |
1992年 | 53篇 |
1991年 | 39篇 |
1990年 | 37篇 |
1989年 | 29篇 |
1988年 | 28篇 |
1987年 | 21篇 |
1986年 | 26篇 |
1985年 | 38篇 |
1984年 | 26篇 |
1983年 | 18篇 |
1982年 | 34篇 |
1981年 | 18篇 |
1980年 | 28篇 |
1979年 | 18篇 |
1978年 | 15篇 |
1977年 | 28篇 |
1974年 | 13篇 |
1973年 | 13篇 |
1972年 | 18篇 |
排序方式: 共有6469条查询结果,搜索用时 15 毫秒
121.
Jason D. Roh Nicholas Houstis Andy Yu Bliss Chang Ashish Yeri Haobo Li Ryan Hobson Carolin Lerchenmüller Ana Vujic Vinita Chaudhari Federico Damilano Colin Platt Daniel Zlotoff Richard T. Lee Ravi Shah Michael Jerosch‐Herold Anthony Rosenzweig 《Aging cell》2020,19(6)
Heart failure with preserved ejection fraction (HFpEF) is the most common type of HF in older adults. Although no pharmacological therapy has yet improved survival in HFpEF, exercise training (ExT) has emerged as the most effective intervention to improving functional outcomes in this age‐related disease. The molecular mechanisms by which ExT induces its beneficial effects in HFpEF, however, remain largely unknown. Given the strong association between aging and HFpEF, we hypothesized that ExT might reverse cardiac aging phenotypes that contribute to HFpEF pathophysiology and additionally provide a platform for novel mechanistic and therapeutic discovery. Here, we show that aged (24–30 months) C57BL/6 male mice recapitulate many of the hallmark features of HFpEF, including preserved left ventricular ejection fraction, subclinical systolic dysfunction, diastolic dysfunction, impaired cardiac reserves, exercise intolerance, and pathologic cardiac hypertrophy. Similar to older humans, ExT in old mice improved exercise capacity, diastolic function, and contractile reserves, while reducing pulmonary congestion. Interestingly, RNAseq of explanted hearts showed that ExT did not significantly modulate biological pathways targeted by conventional HF medications. However, it reversed multiple age‐related pathways, including the global downregulation of cell cycle pathways seen in aged hearts, which was associated with increased capillary density, but no effects on cardiac mass or fibrosis. Taken together, these data demonstrate that the aged C57BL/6 male mouse is a valuable model for studying the role of aging biology in HFpEF pathophysiology, and provide a molecular framework for how ExT potentially reverses cardiac aging phenotypes in HFpEF. 相似文献
122.
Pratima Yadav Kumar Ranjeet Tewari Ashish Kumar 《Russian Journal of Bioorganic Chemistry》2020,46(6):1148-1155
Russian Journal of Bioorganic Chemistry - In the present studies, novel pyrazole derivatives have been synthesized linked through various linkers for the anti-inflammatory evaluation. The... 相似文献
123.
Nripendra Vikram Singh Shilpa Parashuram Jyotsana Sharma Roopa Sowjanya Potlannagari Dhinesh Babu Karuppannan Ram Krishna Pal Prakash Patil Dhananjay M. Mundewadikar Vipul R. Sangnure P.V. Parvati Sai Arun Naresh V.R. Mutha Bipin Kumar Abhishek Tripathi Sathish Kumar Peddamma Harish Kothandaraman Sailu Yellaboina Dushyant Singh Baghel Umesh K. Reddy 《Saudi Journal of Biological Sciences》2020,27(12):3514-3528
124.
U. Sivagurunathan Prem Prakash Srivastava Subodh Gupta Gopal Krishna 《Saudi Journal of Biological Sciences》2020,27(12):3593-3600
This study assessed the responses of vitamin-D3 intraperitoneally injected to Rohu, Labeo rohita @ of 0 IU/kg bw (only solvent), 100 IU/kg bw and 500 IU/kg bw reared in 20 and 40 ppm of calcium (Ca) enriched water. The cellular changes in Corpuscles of Stannius (CS) gland, serum Ca, and inorganic phosphate (Pi) level were analysed up to the 60th day. Rohu administered with 100 IU/kg bw D3 and exposed to 40 ppm Ca-rich water exhibited notable hyperplasia of CS compared with their control groups. Notable changes with high serum Ca level (13.87 ± 0.3 mg/dl) was detected on the 5th day in fish exposed to 40 ppm Ca-rich water, while related values attained (13.74 ± 0.1 mg/dl) only after 7 days in 20 ppm Ca-rich water of 500 IU/kg bw vitamin D3 injection. Similarly, high serum Pi level (7.66 ± 0.2 mg/dl) in 40 ppm Ca injected with D3 at 500 IU/kg bw. The results demonstrated that the Ca homeostasis of Labeo rohita is influenced by intra-peritoneal vitamin D3. Progressive studies should be conducted by increasing the dose of vitamin D3 to investigate optimum dose/supplement in feed for commercially important aquaculture teleost Labeo rohita for maximum and sustainable absorption of Ca from the variable water Calcium levels to maintain Ca2+ homeostasis. 相似文献
125.
Deepa Geeta Devi Yadav Pooja Chaudhary Mohd Jubair Aalam Dhan Raj Meena Surendra Singh 《Chirality》2020,32(1):64-72
Imidazolidin-4-one is used as a recoverable organocatalyst for the asymmetric Diels-Alder reaction in the presence of catalytic amount of dicationic ionic liquid and trifluoroacetic acid as a co-catalyst. The Diels-Alder reaction between model substrate cyclopentadiene and crotonaldehyde gave the product in 95% conversion and 87% ee of the endo-product. The catalyst was shown better reusability when the 20 mol% of dicationic ionic liquid was used and catalyst was reused upto 5 cycles, conversion remains upto 3 recycles but ee of endo- 9 was slightly droped. 相似文献
126.
Ravi Velumani Pushpaleela Ancy Raju Saravanan Gangadharan Byju More Sanket Jijabrao 《Physiology and Molecular Biology of Plants》2020,26(1):189-194
Physiology and Molecular Biology of Plants - The future CO2 concentration is projected to reach 900–1000 ppm levels by the end of twenty-first century, pertaining to global climatic... 相似文献
127.
Patil Prakash G. Jamma Shivani M. Singh N. V. Bohra Abhishek Parashuram Shilpa Injal Archana S. Gargade Vaishali A. Chakranarayan Manasi G. Salutgi Unnati D. Dhinesh Babu K. Sharma Jyotsana 《Physiology and Molecular Biology of Plants》2020,26(6):1249-1261
Physiology and Molecular Biology of Plants - The present study investigates the genetic diversity and population structure among 42 diverse pomegranate genotypes using a set of twenty one class I... 相似文献
128.
Astha Gupta Vandana Jaiswal Samir V. Sawant Hemant Kumar Yadav 《Physiology and Molecular Biology of Plants》2020,26(5):1021-1034
Genome wide quantitative trait loci (QTL) mapping was conducted in Arabidopsis thaliana using F2 mapping population (Col-0 × Don-0) and SNPs markers. A total of five linkage groups were obtained with number of SNPs varying from 45 to 59 per linkage group. The composite interval mapping detected a total of 36 QTLs for 15 traits and the number of QTLs ranged from one (root length, root dry biomass, cauline leaf width, number of internodes and internode distance) to seven (for bolting days). The range of phenotypic variance explained (PVE) and logarithm of the odds ratio of these 36 QTLs was found be 0.19–38.17% and 3.0–6.26 respectively. Further, the epistatic interaction detected one main effect QTL and four epistatic QTLs. Five major QTLs viz. Qbd.nbri.4.3, Qfd.nbri.4.2, Qrdm.nbri.5.1, Qncl.nbri.2.2, Qtd.nbri.4.1 with PVE > 15.0% might be useful for fine mapping to identify genes associated with respective traits, and also for development of specialized population through marker assisted selection. The identification of additive and dominant effect QTLs and desirable alleles of each of above mentioned traits would also be important for future research. 相似文献
129.
Yadav Arpita Ravindran Nevedha Singh Deeksha Rahul Puthan Valappil Datta Sourav 《Journal of plant biochemistry and biotechnology.》2020,29(4):623-635
Journal of Plant Biochemistry and Biotechnology - Light regulates numerous aspects of plant growth and development like seed germination, seedling de-etiolation, pigment accumulation, cotyledon... 相似文献
130.
Priti Sharma Preeni Bawa Bharat Yadav Parampreet Kaur Suruchi Jindal Inderjit Yadav Satinder Kaur Kuldeep Singh Parveen Chhuneja 《Journal of plant biochemistry and biotechnology.》2020,29(1):47-55
Stripe rust (Puccinia striiformis f. sp. tritici) is one of the major devastating disease which causes large reduction in wheat yield. T. monococcum is an attractive diploid species for gene discovery in wheat with smaller genome size of 5700 Mb compared to 17,300 Mb of bread wheat. An adult plant stripe rust resistance QTL QYrtm.pau-2A was mapped on chromosome 2A flanked by two SSR markers Xwmc170 and Xwmc407. In the present study, two gene based markers Pau_Ta2AL_Gene45 and Pau_Ta2AL_Gene54 developed from 2A specific ESTs were found to map close to QYrtmpau-2A to narrow down the region for candidate gene identification. Utilizing sequence information of these two markers, four BAC clones were identified from the Minimum Tiling Path of 2AL assembly and were sequenced. SSR markers were designed from these BAC sequences and mapped to chromosome 2A. A 50 Mb region of wheat chromomse 2A was identified to harbor stripe rust resistance gene of T. monococcum. Gene based markers identified in the present investigation can be used for marker assisted introgression of QYrtm.pau-2A from T. monococcum to cultivated wheat. 相似文献