全文获取类型
收费全文 | 2268篇 |
免费 | 108篇 |
国内免费 | 1篇 |
专业分类
2377篇 |
出版年
2021年 | 13篇 |
2018年 | 26篇 |
2017年 | 16篇 |
2016年 | 31篇 |
2015年 | 36篇 |
2014年 | 60篇 |
2013年 | 263篇 |
2012年 | 107篇 |
2011年 | 100篇 |
2010年 | 62篇 |
2009年 | 71篇 |
2008年 | 115篇 |
2007年 | 129篇 |
2006年 | 117篇 |
2005年 | 122篇 |
2004年 | 121篇 |
2003年 | 122篇 |
2002年 | 139篇 |
2001年 | 22篇 |
2000年 | 18篇 |
1999年 | 26篇 |
1998年 | 38篇 |
1997年 | 29篇 |
1996年 | 23篇 |
1995年 | 27篇 |
1994年 | 24篇 |
1993年 | 33篇 |
1992年 | 21篇 |
1991年 | 27篇 |
1990年 | 17篇 |
1989年 | 15篇 |
1988年 | 15篇 |
1987年 | 21篇 |
1986年 | 9篇 |
1985年 | 23篇 |
1984年 | 24篇 |
1983年 | 23篇 |
1982年 | 27篇 |
1981年 | 32篇 |
1980年 | 20篇 |
1979年 | 22篇 |
1978年 | 27篇 |
1977年 | 15篇 |
1976年 | 16篇 |
1975年 | 10篇 |
1974年 | 16篇 |
1973年 | 12篇 |
1972年 | 11篇 |
1968年 | 10篇 |
1967年 | 10篇 |
排序方式: 共有2377条查询结果,搜索用时 0 毫秒
111.
Atsuko Matsunaga Yutaka Harita Yoshio Shibagaki Nobutaka Shimizu Kazuhiko Shibuya Hiroshi Ono Hitoshi Kato Takashi Sekine Naoko Sakamoto Takashi Igarashi Seisuke Hattori 《PloS one》2015,10(5)
Kawasaki disease (KD), an acute vasculitis that preferentially affects coronary arteries, is still the leading cause of acquired heart disease in children. Although the involvement of immune system malfunction in the onset of KD is suggested, its etiology still remains to be clarified. We investigated autoantibodies in KD patients, which are frequently found in sera from patients with autoimmune diseases, vasculitides and arteritides. We performed two-dimensional western blotting and LC-MS/MS to analyze the antigens of autoantibodies, detected two protein spots with 4 out of 24 sera from KD patients but not with 6 control sera, and identified the antigens as 4-trimethylaminobutyraldehyde dehydrogenase (TMABA-DH). A slot blot analysis with TMABA-DH as an antigen also revealed higher reactivities of patients'' sera than control sera (positive rates: 18/43 vs 3/41). Using an enzyme-linked immunosorbent assay (ELISA), we found that the reactivity of anti-TMABA-DH antibodies in sera from KD patients was significantly higher than that in sera from age-matched controls. The optimal cut-off value of 0.043 had a sensitivity of 83.7% and a specificity of 80.0% in detecting KD patients (positive rates: 37/43 for KD patients, 9/41 for controls). Immunohistochemistry performed on thin sections of rat heart revealed that TMABA-DH colocalized with myosin light chains in cardiac myocytes. Patient sera with high reactivity gave similar immunostaining pattern. These results suggest that the detection of anti-TMABA-DH autoantibody could be a potential strategy for a diagnosis of KD. 相似文献
112.
Noguchi M Ikarashi Y Yuzurihara M Kase Y Watanabe K Plotnikoff GA Takeda S Aburada M 《Life sciences》2005,76(18):2079-2090
The effects of Keishi-bukuryo-gan on calcitonin gene-related peptide (CGRP)-induced elevation of skin temperature were investigated in gonadotropin-releasing hormone (GnRH) analogue-treated female rats. Leupline (1.0 mg/kg) as the GnRH analogue was subcutaneously (s.c.) injected into female rats. After Keishi-bukuryo-gan (100-1,000 mg/kg, p.o.) or 17beta-estradiol (0.010 mg/kg, s.c.) was administered to GnRH analogue-treated rats for 14 days, CGRP-induced skin temperature elevation, concentration of plasma 17beta-estradiol and pituitary gonadotropin (luteinizing hormone; LH, and follicle stimulating hormone; FSH) were measured. In addition, effects of 17beta-estradiol and Keishi-bukuryo-gan on the proliferation of estrogen-dependent human breast cancer (MCF-7) cells were investigated under in vitro conditions. GnRH analogue significantly lowered the concentrations of plasma 17beta-estradiol and pituitary gonadotropins. Tissue weights of the ovaries and uterus were also decreased by the analogue. Under the condition of estrogen deficiency, intravenous (i.v.) injection of exogenous CGRP (10 microg/kg) elevated the skin temperature of the hind paws more significantly than it did in sham-treated control rats. Estrogen supplementation inhibited this elevation of skin temperature with restoration of both the lowered plasma estrogen level and the decreased uterine weight in GnRH analogue-treated rats. On the other hand, Keishi-bukuryo-gan inhibited the elevation of skin temperature in a dose-dependent manner without restoring the plasma estrogen level and uterine weight. In addition, in an in vitro study, MCF-7 cells proliferated in a dose-dependent manner by the addition of 17beta-estradiol (10(-13)-10(-8) M) to the medium. However, Keishi-bukuryo-gan (10(-6)-10(-4) mg/ml) did not activate the MCF-7 cell proliferation. These results suggest that Keishi-bukuryo-gan, which does not exhibit estrogen activity, may be useful for the treatment of hot flashes in women who are undergoing medical ovariectomy with a GnRH analogue. 相似文献
113.
Plant growth-promoting activities of alkoxycarbonylisoureas in relation to their chemical structures
Masami Ogawa Kozo Oyamada Takashi Matsui Junzo Tobitsuka Yoshio Yamazaki 《Phytochemistry》1976,15(12):1829-1835
A number of alkoxycarbonylisourea derivatives were synthesized and their plant growth-promoting activities examined by the rice (Oryza sativa) seedling test. Isourea compounds with an appropriate substituent such as a halogen atom or a methyl, ethyl or methoxy group at the para-position on a benzene ring in 1-alkoxycarbonyl-2-alkyl-3-phenylcarbamoylisoureas promoted the growth of rice seedlings and acted as a highly active gibberellic acid-synergist when used in combination with gibberellic acid. The common structural requirements of isourea derivatives applied well for a growth promoter and a gibberellic acid-synergist. 相似文献
114.
Yachiyo Sasaki Satoko Ohfuji Wakaba Fukushima Akihiro Tamori Masaru Enomoto Daiki Habu Shuji Iwai Sawako Uchida-Kobayashi Hideki Fujii Susumu Shiomi Norifumi Kawada Yoshio Hirota 《PloS one》2013,8(12)
Introduction
To date, there have been no prospective studies examining the effect of coffee consumption on serum alanine aminotransferase (ALT) level among individuals infected with the hepatitis C virus (HCV). We conducted a hospital-based cohort study among patients with chronic HCV infection to assess an association between baseline coffee consumption and subsequent ALT levels for 12 months.Materials and Methods
From 1 August 2005 to 31 July 2006, total 376 HCV-RNA positive patients were recruited. A baseline questionnaire elicited information on the frequency of coffee consumption and other caffeine-containing beverages. ALT level as a study outcome was followed through the patients’ medical records during 12 months. The association between baseline beverage consumption and subsequent ALT levels was evaluated separately among patients with baseline ALT levels within normal range (≤45 IU/L) and among those with higher ALT levels (>45 IU/L).Results
Among 229 patients with baseline ALT levels within normal range, 186 (81%) retained normal ALT levels at 12 months after recruitment. Daily drinkers of filtered coffee were three times more likely to preserve a normal ALT level than non-drinkers (OR=2.74; P=0.037). However, decaffeinated coffee drinkers had a somewhat inverse effect for sustained normal ALT levels, with marginal significance (OR=0.26; P=0.076). In addition, among 147 patients with higher baseline ALT levels, 39 patients (27%) had ALT reductions of ≥20 IU/L at 12 months after recruitment. Daily drinkers of filtered coffee had a significantly increased OR for ALT reduction (OR=3.79; P=0.034). However, in decaffeinated coffee drinkers, OR could not be calculated because no patients had ALT reduction.Conclusion
Among patients with chronic HCV infection, daily consumption of filtered coffee may have a beneficial effect on the stabilization of ALT levels. 相似文献115.
Yoshio Osada Sohsuke Yamada Atsunori Nabeshima Yasunobu Yamagishi Kenji Ishiwata Susumu Nakae Katsuko Sudo Tamotsu Kanazawa 《Experimental parasitology》2013
Some parasitic helminths are known to protect their hosts from allergic and autoimmune disorders. Here, we tested the effects of a gastrointestinal nematode, Heligmosomoides polygyrus (Hp), on streptozotocin (STZ)-induced type 1 diabetes (T1D) in mice. Hp infection significantly suppressed hyperglycemia induced by multiple low-dose administration of STZ, but did not affect hyperglycemia induced by single high-dose administration of STZ. In the multiple low dose model, Hp infection prevented a decrease in pancreatic islet size. The augmentation of TNF-α and IL-1β expression in the pancreas was abrogated by Hp infection. The genetic absence of IL-10 or STAT6 did not abrogate the anti-hyperglycemic effect of Hp. Hp has a suppressive effect on immune mechanism-mediated experimental T1D via Th2 polarization-independent mechanisms. 相似文献
116.
X-Linked inhibitor of apoptosis protein is involved in mutant SOD1-mediated neuronal degeneration 总被引:4,自引:0,他引:4
Ishigaki S Liang Y Yamamoto M Niwa J Ando Y Yoshihara T Takeuchi H Doyu M Sobue G 《Journal of neurochemistry》2002,82(3):576-584
Mutations in the superoxide dismutase 1 (SOD1) gene cause the degeneration of motor neurons in familial amyotrophic lateral sclerosis (FALS). An apoptotic process including caspase-1 and -3 has been shown to participate in the pathogenesis of FALS transgenic (Tg) mouse model. Here we report that IAP proteins, potent inhibitors of apoptosis, are involved in the FALS Tg mouse pathologic process. The levels of X-linked inhibitor of apoptosis protein (XIAP) mRNA and protein were significantly decreased in the spinal cord of symptomatic G93A-SOD1 Tg mice compared with littermates. In contrast, the levels of cIAP-1 mRNA and protein were increased in symptomatic G93A-SOD1 Tg mice, whereas the levels of cIAP-2 mRNA and protein were unchanged. In situ hybridization showed that the expression of XIAP was remarkably reduced in the motor neurons of Tg mice, and the expression of cIAP-1 was strongly increased in the reactive astrocytes of Tg mice. Overexpression of XIAP markedly inhibited the cell death and caspase-3 activity in the neuro2a cells expressing mutant SOD1. Deletional mutant analysis revealed that the N-terminal domain of XIAP, the BIR1-2 domains, was essential for this inhibitory activity. These results suggest that XIAP plays a role in the apoptotic mechanism in the progression of disease in mutant SOD1 Tg mice and holds therapeutic possibilities for FALS. 相似文献
117.
Yanagita M Shimabukuro Y Nozaki T Yoshimura N Watanabe J Koide H Terakura M Saho T Takedachi M Jang MH Kiyono H Murakami S 《Biochemical and biophysical research communications》2002,297(2):329-334
To investigate the biological activity of epithelial cells in view of host defense, we analyzed the mRNA expression of inducible NOS (iNOS) as well as NO production by human gingival epithelial cells (HGEC) stimulated with IL-15. RT-PCR analysis revealed that HGEC expressed IL-15 receptor alpha-chain mRNA. In addition, stimulation with IL-15 enhanced iNOS expression by HGEC through an increase of both mRNA and protein levels. Moreover, IL-15 up-regulated the production of NO(2)(-)/NO(3)(-), a NO-derived stable end product, from HGEC. The enhanced NO production by IL-15 was inhibited by AMT, an iNOS-specific inhibitor. These results suggest that IL-15 is a potent regulator of iNOS expression by HGEC and involved in innate immunity in the mucosal epithelium. 相似文献
118.
Toshiyuki Yamamoto Kyoji Tasaki Yoshio Sugawara Akira Tonosaki 《The Journal of cell biology》1965,25(2):345-359
The fine structure of the visual and the supporting cells and of the blood capillaries in the octopus retina is described. Lamellated structures contained in the proximal segment of the visual cell consist of compact arrays of dense membranes each of which is quintuple-layered and divides at its margins into two thinner sheets or membranes which are connected directly with the agranular or granular endoplasmic reticulum. Proximal to the deeper extremities of the rhabdomeres, the lateral plasma membranes of two adjoining visual cells contact each other forming a quintuple-layered compound membrane, which results in occlusion of the intercellular space. The central layer of the compound membrane is of high density, so that the membrane, as a whole, appears to be a single thick layer at low magnifications. The supporting cells are connected with the neighboring visual cells by two types of junctions. Long slender processes extend from the supporting cells to the surface of the retina through narrow spaces among the distal segments of the visual cells. The capillary endothelial cells are characterized by luminal surfaces irregularly contoured and by lateral surfaces elaborately interdigitated. The functional significance of the close contact between adjoining visual cells is discussed. 相似文献
119.
Jo Kitawaki Shigeo Inoue Takaya Tamura Takara Yamamoto Hideo Honjo Tadayoshi Higashiyama Yoshio Osawa Hiroji Okada 《The Journal of steroid biochemistry and molecular biology》1993,45(6):485-491
To clarify whether cigarette smoking during pregnancy causes an organic alteration in placental estrogen producing ability, we determined the catalytic activity of aromatase by the tritiated water assay, and tissue level of aromatase cytochrome P-450 (P-450arom) by the specific enzyme-linked immunosorbent assay, in placental samples from nonsmokers and smokers. As pregnancy progressed, both aromatase activity and P-450arom concentration increased in placentas from nonsmokers and smokers. However, the gradient of the increase was significantly less in heavy smokers (20 cigarettes a day) than in normal and moderate smokers (<20 cigarettes a day). At term, the mean aromatase activity and P-450arom concentration in placentas from heavy smokers were significantly lower than in nonsmokers and moderate smokers, while aromatase activity per P-450arom (turnover rate) and the mean placental weight were comparable among the three groups. In contrast, the ratio of aryl hydrocarbon hydroxylase activity to aromatase activity was higher in placentas from heavy smokers. Immunohistochemical studies showed that P-450arom was localized in the cytoplasm of syncytiotrophoblasts of chorionic villi in placentas from both nonsmokers and smokers. These results suggest that the induction of placental P-450arom during gestation is suppressed by maternal smoking, resulting in a reduction in estrogen producing ability, while placental xenobiotic P-450 is induced. 相似文献
120.
Aucuba japonica varieties are common evergreen understory shrubs in Japan.Aucuba japonica var.borealis is distributed on the Sea of Japan side of Honshu and Hokkaido where heavy snow cover lasts for more than 3 months in winter.Aucuba japonica var.japonica is distributed in areas with shallow or no snow on the Pacific Ocean side of Honshu and Shikoku. The ecophysiological characteristics
of var.borealis were compared with those of var.japonica to examine the effects of heavy and long-term snow cover on the life cycle of var.borealis. Shoots of both varieties were shaded in crushed ice for 110 days, but their photosynthetic activities, chlorophyll contents
and the chlorophylla/b ratio was not affected. The leaves of var.borealis were no less frost tolerant than those of var.japonica. In spite of the difference in environmental factors, both varieties had similar characteristics in seasonal changes of photosynthesis,
respiration and chlorophylla/b ratio. These results suggest that var.japonica could survive in areas with heavy snow where it does not normally occur. Leaf net production (LNP) was estimated based on
the microclimatic data and seasonal photosynthetic and respiration rates. The difference in the annual LNP between the two
varieties was equivalent to the difference in the LNP during the snow season. One of the major effects of snow cover is to
interrupt and reduce the production period of var.borealis. 相似文献