全文获取类型
收费全文 | 652篇 |
免费 | 48篇 |
国内免费 | 2篇 |
专业分类
702篇 |
出版年
2022年 | 5篇 |
2021年 | 8篇 |
2020年 | 8篇 |
2019年 | 4篇 |
2018年 | 15篇 |
2017年 | 5篇 |
2016年 | 14篇 |
2015年 | 21篇 |
2014年 | 35篇 |
2013年 | 47篇 |
2012年 | 50篇 |
2011年 | 35篇 |
2010年 | 34篇 |
2009年 | 29篇 |
2008年 | 36篇 |
2007年 | 35篇 |
2006年 | 33篇 |
2005年 | 21篇 |
2004年 | 18篇 |
2003年 | 10篇 |
2002年 | 21篇 |
2001年 | 15篇 |
2000年 | 18篇 |
1999年 | 13篇 |
1998年 | 9篇 |
1997年 | 12篇 |
1996年 | 11篇 |
1995年 | 7篇 |
1994年 | 6篇 |
1993年 | 7篇 |
1992年 | 24篇 |
1991年 | 14篇 |
1990年 | 12篇 |
1989年 | 14篇 |
1988年 | 13篇 |
1987年 | 8篇 |
1986年 | 4篇 |
1985年 | 8篇 |
1984年 | 3篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有702条查询结果,搜索用时 15 毫秒
41.
Wang FI Chiou MT Chang CH Chang PH Liu CH Jeng CR Pang VF 《Proceedings of the National Science Council, Republic of China. Part B, Life sciences》2001,25(3):193-196
A 10-year-old male aardwolf (Proteles cristatus) was presented abdominal distention and emaciation for 3 months. Physical examination revealed firm abdominal masses with effusions. Cytologic assessment of the effusion showed uniform round tumor cells with a surface brush border. Necropsy showed white velvety masses covering the peritoneal surface of the liver, gall bladder, stomach, omentum, mesentery, spleen, intestine, abdominal wall and diaphragm. Histologic examination demonstrated papillary projections, lined with cuboidal tumor cells supported by fibrous connective tissue cores, arising from the serosa of visceral organs. Cytoplasmic vacuolation and a surface brush border were evident on some cells under light microscopy. Tumor cells stained positive for both cytokeratin (AE1/AE3) and vimentin. Electron microscopy showed prominent surface microvilli, rough endoplasmic reticulum, mitochondria and desmosomes in tumor cells. This may be the first reported case of peritoneal mesothelioma in a captive wild aardwolf. 相似文献
42.
Undecaprenyl pyrophosphate synthase (UPPs) catalyzes the condensation of eight molecules of isopentenyl pyrophosphate (IPP) with farnesyl pyrophosphate (FPP) to generate C(55) undecaprenyl pyrophosphate. We investigated the kinetics and mechanism of this reaction pathway using Escherichia coli UPPs. With a variety of different ratios of enzyme to substrate and FPP to IPP in the presence or absence of Triton, different product distributions were found. In the presence of excess FPP, the intermediates (C(25)-C(50)) accumulated. Under a condition with enzyme and FPP in excess of IPP, instead of C(20)-geranylgeranyl pyrophosphate, C(20), C(25), and C(30) were the major products. The UPPs steady-state k(cat) value (2.5 s(-1)) in the presence of 0.1% Triton was 190-fold larger than in the absence of Triton (0.013 s(-1)). The k(cat) value matched the rate constant of each IPP condensation obtained from the enzyme single-turnover experiments. This suggested that the IPP condensation rather than product release was the rate-limiting step in the presence of Triton. In the absence of Triton, the intermediates formed and disappeared in a similar manner under enzyme single turnover in contrast to the slow steady-state rate, which indicated a step after product generation was rate limiting. This was further supported by a burst product formation. Judging from the accumulation level of C(55), C(60), and C(65), their dissociation from the enzyme cannot be too slow and an even slower enzyme conformational change with a rate of 0.001 s(-1) might govern the UPPs reaction rate under the steady-state condition in the absence of Triton. 相似文献
43.
Fan CK Su KE Chung WC Tsai YJ Chiou HY Lin CF Su CT Tsai MC Chao PH 《Japanese journal of medical science & biology》1998,51(1):35-42
Atayal aborigines, living at an altitude of 1,500-1,600 m in northeastern Taiwan, still hunt for wild animals with the help of hunting dogs. In this study, the latex agglutination test (LAT) was used to detect sera anti-toxoplasma antibodies in this community as a measure of their exposure to Toxoplasma gondii. The positive rates for sera anti-toxoplasma antibodies were 21.8% and 19.6%, respectively, in 422 Atayal and 51 hunting dogs tested. Neither of the positive rates were found to be significantly different between male (22.1%) and female Atayal (21.4%), or between humans (21.8%) and dogs (19.6%) (P > 0.05) when compared by the Chi-Squared test (chi 2-test). A significant difference was observed between the positive rates in adults (28.3%) and children (18.7%) (P < 0.05), and the age pattern of prevalence is consistent with an increasing duration of exposure to Toxoplasma gondii with age. The consumption of raw liver of wild animals or insufficiently cooked meat may be the major mode of transmission of toxoplasmosis in Atayal. 相似文献
44.
Chiou S Cerstiaens A Kotanen SP De Loof A Schoofs L 《Journal of insect physiology》1998,44(5-6):405-411
Acidic methanolic extracts of larvae of nine different insect species were found to contain substances that cause a lethal effect in the adult stage of the same species and of other species. These endogenous toxic substances, apparently being widely spread over the class of insects, were designated as paralysins, because of their immediate and observable paralytic effect upon injection. The developmental concentration curves of five different species of insects (Galleria mellonella (Lepidoptera), Neobellieria bullata (Diptera), Spodoptera frugiperda (Lepidoptera), Tenebrio molitor (Coleoptera) and Schistocerca gregaria (Orthoptera) indicate that the toxins are not present throughout all the developmental stages in the same concentration. The strongest paralytic activity was found in late instar larvae or in the early pupal stage. The temporal distribution of paralysins during development suggests that they might be involved in metamorphosis. 相似文献
45.
46.
Li-Nien Chien Quinn T. Ostrom Haley Gittleman Jia-Wei Lin Andrew E. Sloan Gene H. Barnett J. Bradley Elder Christopher McPherson Ronald Warnick Yung-Hsiao Chiang Chieh-Min Lin Lisa R. Rogers Hung-Yi Chiou Jill S. Barnholtz-Sloan 《PloS one》2015,10(6)
Background
High grade gliomas are the most common type of malignant brain tumor, and despite their rarity, cause significant morbidity and mortality. This study aimed to compare the treatment patterns of high grade glioma to examine survival patterns in patients who receive specific treatments between cohorts in Ohio and Taiwan.Method
Patients aged 18 years and older at age of diagnosis with World Health Organization (WHO) grade III or IV astrocytoma from 2007-2012 were selected from the Ohio Brain Tumor Study and the Taiwan Cancer Registry. The treatment information was derived from medical chart reviews in Ohio and National Health Insurance Research Data in Taiwan. Treatment examined included surgical procedure (brain biopsy and/or resection), radiotherapy (radiation and/or radiosurgery), and alkylating chemotherapy. Kaplan-Meier and parametric survival models were used to examine the effect of treatment on survival, adjusted for age, sex, and comorbidities.Results
294 patients in Ohio and 1,097 patients in Taiwan met the inclusion criteria. 70.3% patients in Ohio and 51.4% in Taiwan received surgical resection, followed by concurrent chemoradiation. Patients who received this treatment had the highest survival rate, with a 1-year survival rate of 72.8% in Ohio and 73.4% in Taiwan. Patients who did not receive surgical resection, followed by concurrent chemoradiation had an increased risk of death (hazard ratio of 5.03 [95% confidence interval (CI): 3.61-7.02] in Ohio and 1.49 [95% CI: 1.31-1.71] in Taiwan) after adjustment for age, sex, and comorbidities.Conclusion
Surgical resection followed by concurrent chemoradiation was associated with higher survival rate of patients with high grade glioma in both Ohio and Taiwan; however, one-third of patients in Ohio and half in Taiwan did not receive this treatment. 相似文献47.
Frank Fang-Yao Lee Hsiang-Chieh Chuang Nai-Yu Chen Govindarajulu Nagarajan Pinwen Peter Chiou 《PloS one》2015,10(5)
Toll-like receptor 9 (TLR9) recognizes and binds unmethylated CpG motifs in DNA, which are found in the genomes of bacteria and DNA viruses. In fish, Tlr9 is highly diverse, with the number of introns ranging from 0 to 4. A fish Tlr9 gene containing two introns has been reported to express two alternatively spliced isoforms, namely gTLR9A (full-length) and gTLR9B (with a truncated Cʹ-terminal signal transducing domain), whose regulation and function remain unclear. Here, we report a unique regulatory mechanism of gTLR9 signaling in orange-spotted grouper (Epinephelus coioides), whose gTlr9 sequence also contains two introns. We demonstrated that the grouper gTlr9 gene indeed has the capacity to produce two gTLR9 isoforms via alternative RNA splicing. We found that gTLR9B could function as a negative regulator to suppress gTLR9 signaling as demonstrated by the suppression of downstream gene expression. Following stimulation with CpG oligodeoxynucleotide (ODN), gTLR9A and gTLR9B were observed to translocate into endosomes and co-localize with ODN and the adaptor protein gMyD88. Both gTLR9A and gTLR9B could interact with gMyD88; however, gTLR9B could not interact with downstream IRAK4 and TRAF6. Further analysis of the expression profile of gTlr9A and gTlr9B upon immune-stimulation revealed that the two isoforms were differentially regulated in a time-dependent manner. Overall, these data suggest that fish TLR9B functions as a negative regulator, and that its temporal expression is mediated by alternative RNA splicing. This has not been observed in mammalian TLR9s and might have been acquired relatively recently in the evolution of fish. 相似文献
48.
Purpose
To estimate the rate of hospitalized eye trauma in Taiwan and investigate the role between principal and secondary diagnoses of such trauma.Methods
Nationwide fixed cohort study of 1,000,000 beneficiaries from the Taiwan Longitudinal Health Database was used and 4819 patients who were hospitalized for eye trauma during 1996-2010 were analyzed.Results
During 1996-2010, the incidence rates of hospitalized eye trauma (per 100 000 person-years) were 35.0 (95% confidence interval (CI), 34.0 to 36.0) for total diagnosis, 9.8 (95% CI, 9.3 to 10.3) for a principal diagnosis, and 25.3 (95% CI, 24.4 to 26.1) for a secondary diagnosis. The sex risk ratio was 3.1 for a principal diagnosis and 2.1 for a secondary diagnosis. The main causes of eye trauma were traffic accident, work accident, assault (among males <60 years of age), and falls (among elderly men and women). The proportion admitted to an ophthalmic department among those with a principal diagnosis of eye trauma (64.8%) was significantly higher than among those with a secondary diagnosis (2.3%) (p<.0001). Patients with a principal diagnosis of eye trauma had shorter hospital stays (7.1±10.2 days) and lower fatality (0.07%) than those with a secondary diagnosis of eye trauma (10.0±31.6 days and 0.3%, respectively).Conclusion
Data only from ophthalmic admissions tends to underestimate the true incidence rate of hospitalized eye trauma. Patients with a principal diagnosis of eye trauma had less severe injuries than did those with a secondary diagnosis. 相似文献49.
Objective
The transition from childhood to teenaged years is associated with increased testosterone and a decreased iron status. It is not clear whether higher testosterone levels cause the decreased iron status, and to what extent, obesity-related inflammation influences the iron-testosterone relationship. The aim of the present study was to examine relationships of testosterone, iron status, and anti-/proinflammatory cytokines in relation to nutritional status in boys and young adolescent Taiwanese males.Methods
In total, 137 boys aged 7~13 yr were included. Parameters for obesity, the iron status, testosterone, and inflammatory markers were evaluated.Results
Overweight and obese (ow/obese) boys had higher mean serum testosterone, interleukin (IL)-1β, and nitric oxide (NO) levels compared to their normal-weight counterparts (all p<0.05). Mean serum ferritin was slightly higher in ow/obese boys compared to normal-weight boys, but this did not reach statistical significance. A multiple linear regression showed that serum ferritin (β = -0.7470, p = 0.003) was inversely correlated with testosterone, while serum IL-10 (β = 0.3475, p = 0.009) was positively associated with testosterone after adjusting for covariates. When normal-weight boys were separately assessed from ow/obesity boys, the association between testosterone and serum ferritin became stronger (β = -0.9628, p<0.0001), but the association between testosterone and IL-10 became non-significant (β = 0.1140, p = 0.4065) after adjusting for covariates. In ow/obese boys, only IL-10 was weakly associated with serum testosterone (β = 0.6444, p = 0.051) after adjusting for age.Conclusions
Testosterone and serum ferritin are intrinsically interrelated but this relationship is weaker in ow/obese boys after adjusting for age. 相似文献50.
A Systematic Approach to Species–Level Identification of Chile Pepper (Capsicum spp.) Seeds: Establishing the Groundwork for Tracking the Domestication and Movement of Chile Peppers through the Americas and Beyond The chile pepper (Capsicum spp.), a plant held in great esteem throughout history, was independently domesticated in a series of places including highland Bolivia, central Mexico, the Amazon, the Caribbean, and other locales with a particularly long history of cultivation and use in the central Andes of South America. Though identification of chile pepper species through fruit morphology is possible and has been utilized by botanists studying modern and archaeological specimens, species–level identification of Capsicum seeds has remained undetermined. Given the greater abundance of seed remains in the archaeological record due to the higher likelihood of preservation, the ability to identify specific Capsicum domesticates has profound implications for tracking the domestication and spread of chile peppers prehistorically through the Americas and historically through trade and exchange to the rest of the world. This article presents a systematic procedure to identify Capsicum seeds to the species level created by adopting a morphometric approach to compare attributes of modern Capsicum seeds to archaeological seeds. 相似文献