全文获取类型
收费全文 | 1375篇 |
免费 | 94篇 |
国内免费 | 1篇 |
出版年
2023年 | 4篇 |
2022年 | 13篇 |
2021年 | 35篇 |
2020年 | 24篇 |
2019年 | 15篇 |
2018年 | 25篇 |
2017年 | 30篇 |
2016年 | 35篇 |
2015年 | 68篇 |
2014年 | 80篇 |
2013年 | 90篇 |
2012年 | 103篇 |
2011年 | 90篇 |
2010年 | 49篇 |
2009年 | 47篇 |
2008年 | 75篇 |
2007年 | 56篇 |
2006年 | 62篇 |
2005年 | 52篇 |
2004年 | 48篇 |
2003年 | 52篇 |
2002年 | 48篇 |
2001年 | 39篇 |
2000年 | 46篇 |
1999年 | 39篇 |
1998年 | 10篇 |
1997年 | 7篇 |
1996年 | 11篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 10篇 |
1992年 | 19篇 |
1991年 | 23篇 |
1990年 | 16篇 |
1989年 | 16篇 |
1988年 | 9篇 |
1987年 | 11篇 |
1986年 | 16篇 |
1985年 | 11篇 |
1983年 | 9篇 |
1982年 | 6篇 |
1980年 | 4篇 |
1979年 | 9篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1974年 | 3篇 |
1973年 | 6篇 |
1972年 | 3篇 |
1970年 | 9篇 |
排序方式: 共有1470条查询结果,搜索用时 31 毫秒
131.
Osamu Hashimoto Hirofumi Ohtsuki Takehiko Kakizaki Kento Amou Ryo Sato Satoru Doi Sara Kobayashi Ayaka Matsuda Makoto Sugiyama Masayuki Funaba Takashi Matsuishi Fumio Terasawa Junji Shindo Hideki Endo 《PloS one》2015,10(2)
Brown adipose tissue (BAT) plays an important role in thermoregulation in species living in cold environments, given heat can be generated from its chemical energy reserves. Here we investigate the existence of BAT in blubber in four species of delphinoid cetacean, the Pacific white-sided and bottlenose dolphins, Lagenorhynchus obliquidens and Tursiops truncates, and Dall’s and harbour porpoises, Phocoenoides dalli and Phocoena phocoena. Histology revealed adipocytes with small unilocular fat droplets and a large eosinophilic cytoplasm intermingled with connective tissue in the innermost layers of blubber. Chemistry revealed a brown adipocyte-specific mitochondrial protein, uncoupling protein 1 (UCP1), within these same adipocytes, but not those distributed elsewhere throughout the blubber. Western blot analysis of extracts from the inner blubber layer confirmed that the immunohistochemical positive reaction was specific to UCP1 and that this adipose tissue was BAT. To better understand the distribution of BAT throughout the entire cetacean body, cadavers were subjected to computed tomography (CT) scanning. Resulting imagery, coupled with histological corroboration of fine tissue structure, revealed adipocytes intermingled with connective tissue in the lowest layer of blubber were distributed within a thin, highly dense layer that extended the length of the body, with the exception of the rostrum, fin and fluke regions. As such, we describe BAT effectively enveloping the cetacean body. Our results suggest that delphinoid blubber could serve a role additional to those frequently attributed to it: simple insulation blanket, energy storage, hydrodynamic streamlining or contributor to positive buoyancy. We believe delphinoid BAT might also function like an electric blanket, enabling animals to frequent waters cooler than blubber as an insulator alone might otherwise allow an animal to withstand, or allow animals to maintain body temperature in cool waters during sustained periods of physical inactivity. 相似文献
132.
Soji Morishita Kochi Takahashi Marito Araki Yumi Hironaka Yoshitaka Sunami Yoko Edahiro Miyuki Tsutsui Akimichi Ohsaka Satoshi Tsuneda Norio Komatsu 《PloS one》2015,10(3)
Detection of the JAK2V617F mutation is essential for diagnosing patients with classical myeloproliferative neoplasms (MPNs). However, detection of the low-frequency JAK2V617F mutation is a challenging task due to the necessity of discriminating between true-positive and false-positive results. Here, we have developed a highly sensitive and accurate assay for the detection of JAK2V617F and named it melting curve analysis after T allele enrichment (MelcaTle). MelcaTle comprises three steps: 1) two cycles of JAK2V617F allele enrichment by PCR amplification followed by BsaXI digestion, 2) selective amplification of the JAK2V617F allele in the presence of a bridged nucleic acid (BNA) probe, and 3) a melting curve assay using a BODIPY-FL-labeled oligonucleotide. Using this assay, we successfully detected nearly a single copy of the JAK2V617F allele, without false-positive signals, using 10 ng of genomic DNA standard. Furthermore, MelcaTle showed no positive signals in 90 assays screening healthy individuals for JAK2V617F. When applying MelcaTle to 27 patients who were initially classified as JAK2V617F-positive on the basis of allele-specific PCR analysis and were thus suspected as having MPNs, we found that two of the patients were actually JAK2V617F-negative. A more careful clinical data analysis revealed that these two patients had developed transient erythrocytosis of unknown etiology but not polycythemia vera, a subtype of MPNs. These findings indicate that the newly developed MelcaTle assay should markedly improve the diagnosis of JAK2V617F-positive MPNs. 相似文献
133.
Koji Sugano Toru Okuyama Shinsuke Iida Hirokazu Komatsu Takashi Ishida Shigeru Kusumoto Megumi Uchida Tomohiro Nakaguchi Yosuke Kubota Yoshinori Ito Kazuhisa Takahashi Tatsuo Akechi 《PloS one》2015,10(8)
Background
Decision-making capacity to provide informed consent regarding treatment is essential among cancer patients. The purpose of this study was to identify the frequency of decision-making incapacity among newly diagnosed older patients with hematological malignancy receiving first-line chemotherapy, to examine factors associated with incapacity and assess physicians’ perceptions of patients’ decision-making incapacity.Methods
Consecutive patients aged 65 years or over with a primary diagnosis of malignant lymphoma or multiple myeloma were recruited. Decision-making capacity was assessed using the Structured Interview for Competency and Incompetency Assessment Testing and Ranking Inventory-Revised (SICIATRI-R). Cognitive impairment, depressive condition and other possible associated factors were also evaluated.Results
Among 139 eligible patients registered for this study, 114 completed the survey. Of these, 28 (25%, 95% confidence interval [CI]: 17%-32%) were judged as having some extent of decision-making incompetency according to SICIATRI-R. Higher levels of cognitive impairment and increasing age were significantly associated with decision-making incapacity. Physicians experienced difficulty performing competency assessment (Cohen’s kappa -0.54).Conclusions
Decision-making incapacity was found to be a common and under-recognized problem in older patients with cancer. Age and assessment of cognitive impairment may provide the opportunity to find patients that are at a high risk of showing decision-making incapacity. 相似文献134.
Ayaka Endo Akio Kawamura Hiroaki Miyata Shigetaka Noma Masahiro Suzuki Takashi Koyama Shiro Ishikawa Susumu Nakagawa Shunsuke Takagi Yohei Numasawa Keiichi Fukuda Shun Kohsaka JCD-KICS Investigators 《PloS one》2015,10(6)
Objective
We devised a percutaneous coronary intervention (PCI) scoring system based on angiographic lesion complexity and assessed its association with in-hospital complications.Background
Although PCI is finding increasing application in patients with coronary artery disease, lesion complexity can lead to in-hospital complications.Methods
Data from 3692 PCI patients were scored based on lesion complexity, defined by bifurcation, chronic total occlusion, type C, and left main lesion, along with acute thrombus in the presence of ST-segment elevation myocardial infarction (1 point assigned for each variable).Results
The patients’ mean age was 67.5 +/- 10.8 years; 79.8% were male. About half of the patients (50.3%) presented with an acute coronary syndrome, and 2218 (60.1%) underwent PCI for at least one complex lesion. The patients in the higher-risk score groups were older (p < 0.001) and had present or previous heart failure (p = 0.02 and p = 0.01, respectively). Higher-risk score groups had significantly higher in-hospital event rates for death, heart failure, and cardiogenic shock (from 0 to 4 risk score; 1.7%, 4.5%, 6.3%, 7.1%, 40%, p < 0.001); bleeding with a hemoglobin decrease of >3.0 g/dL (3.1%, 11.0%, 13.1%, 10.3%, 28.6%, p < 0.001); and postoperative myocardial infarction (1.5%, 3.1%, 3.8%, 3.8%, 10%, p = 0.004), respectively. The association with adverse outcomes persisted after adjustment for known clinical predictors (odds ratio 1.72, p < 0.001).Conclusion
The complexity score was cumulatively associated with in-hospital mortality and complication rate and could be used for event prediction in PCI patients. 相似文献135.
136.
Yoko Maruyama Yu-Shin Sou Shun Kageyama Takao Takahashi Takashi Ueno Keiji Tanaka Masaaki Komatsu Yoshinobu Ichimura 《Biochemical and biophysical research communications》2014
Autophagy is a unique intracellular protein degradation system accompanied by autophagosome formation. Besides its important role through bulk degradation in supplying nutrients, this system has an ability to degrade certain proteins, organelles, and invading bacteria selectively to maintain cellular homeostasis. In yeasts, Atg8p plays key roles in both autophagosome formation and selective autophagy based on its membrane fusion property and interaction with autophagy adaptors/specific substrates. In contrast to the single Atg8p in yeast, mammals have 6 homologs of Atg8p comprising LC3 and GABARAP families. However, it is not clear these two families have different or similar functions. The aim of this study was to determine the separate roles of LC3 and GABARAP families in basal/constitutive and/or selective autophagy. While the combined knockdown of LC3 and GABARAP families caused a defect in long-lived protein degradation through lysosomes, knockdown of each had no effect on the degradation. Meanwhile, knockdown of LC3B but not GABARAPs resulted in significant accumulation of p62/Sqstm1, one of the selective substrate for autophagy. Our results suggest that while mammalian Atg8 homologs are functionally redundant with regard to autophagosome formation, selective autophagy is regulated by specific Atg8 homologs. 相似文献
137.
Masaki Uchida Ayaka Kishimoto Hiroyuki Muraoka Takayuki Nakatsubo Hiroshi Kanda Hiroshi Koizumi 《Journal of plant research》2010,123(1):79-85
We examined factors controlling temporal changes in net ecosystem production (NEP) in a high Arctic polar semi-desert ecosystem
in the snow-free season. We examined the relationships between NEP and biotic and abiotic factors in a dominant plant community
(Salix polaris–moss) in the Norwegian high Arctic. Just after snowmelt in early July, the ecosystem released CO2 into the atmosphere. A few days after snowmelt, however, the ecosystem became a CO2 sink as the leaves of S. polaris developed. Diurnal changes in NEP mirrored changes in light incidence (photosynthetic photon flux density, PPFD) in summer.
NEP was significantly correlated with PPFD when S. polaris had fully developed leaves, i.e., high photosynthetic activity. In autumn, NEP values decreased as S. polaris underwent senescence. During this time, CO2 was sometimes released into the atmosphere. In wet conditions, moss made a larger contribution to NEP. In fact, the water
content of the moss regulated NEP during autumn. Our results indicate that the main factors controlling NEP in summer are
coverage and growth of S. polaris, PPFD, and precipitation. In autumn, the main factor controlling NEP is moss water content. 相似文献
138.
139.
140.
Fan-Jiang Kong Atsushi Oyanagi Setsuko Komatsu 《Biochimica et Biophysica Acta - Proteins and Proteomics》2010,1804(1):124-136
Cell wall proteins (CWPs) are important both for maintenance of cell structure and for responses to abiotic and biotic stresses. In this study, a destructive CWP purification procedure was adopted using wheat seedling roots and the purity of the CWP extract was confirmed by minimizing the activity of glucose-6-phosphate dehydrogenase, a cytoplasmic marker enzyme. To determine differentially expressed CWPs under flooding stress, gel-based proteomic and LC-MS/MS-based proteomic techniques were applied. Eighteen proteins were found to be significantly regulated in response to flood by gel-based proteomics and 15 proteins by LC MS/MS-based proteomics. Among the flooding down-regulated proteins, most were related to the glycolysis pathway and cell wall structure and modification. However, the most highly up-regulated proteins in response to flooding belong to the category of defense and disease response proteins. Among these differentially expressed proteins, only methionine synthase, β-1,3-glucanases, and β-glucosidase were consistently identified by both techniques. The down-regulation of these three proteins suggested that wheat seedlings respond to flooding stress by restricting cell growth to avoid energy consumption; by coordinating methionine assimilation and cell wall hydrolysis, CWPs played critical roles in flooding responsiveness. 相似文献