全文获取类型
收费全文 | 2932篇 |
免费 | 9篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 34篇 |
金属工艺 | 1篇 |
机械仪表 | 1篇 |
矿业工程 | 1篇 |
能源动力 | 5篇 |
轻工业 | 21篇 |
无线电 | 14篇 |
一般工业技术 | 11篇 |
冶金工业 | 2831篇 |
原子能技术 | 6篇 |
自动化技术 | 15篇 |
出版年
2021年 | 2篇 |
2020年 | 3篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2014年 | 5篇 |
2013年 | 4篇 |
2012年 | 4篇 |
2011年 | 3篇 |
2010年 | 4篇 |
2009年 | 4篇 |
2008年 | 6篇 |
2007年 | 2篇 |
2006年 | 4篇 |
2005年 | 7篇 |
2004年 | 3篇 |
2003年 | 6篇 |
2002年 | 3篇 |
2000年 | 3篇 |
1999年 | 84篇 |
1998年 | 917篇 |
1997年 | 490篇 |
1996年 | 342篇 |
1995年 | 188篇 |
1994年 | 146篇 |
1993年 | 149篇 |
1992年 | 20篇 |
1991年 | 46篇 |
1990年 | 34篇 |
1989年 | 41篇 |
1988年 | 35篇 |
1987年 | 49篇 |
1986年 | 38篇 |
1985年 | 25篇 |
1983年 | 3篇 |
1982年 | 10篇 |
1981年 | 17篇 |
1980年 | 20篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 57篇 |
1976年 | 135篇 |
1975年 | 6篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1969年 | 3篇 |
1968年 | 2篇 |
1967年 | 3篇 |
1966年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有2941条查询结果,搜索用时 15 毫秒
961.
The relationship between right duct lymph flow and extravascular lung water was studied in 3 normal dogs and 15 dogs with pulmonary edema induced by alpha-naphthylthiourea (ANTU). Right duct lymph was collected in a pouch created by ligating jugular, subclavian, and brachiocephalic veins. Extravascular lung water was measured in vivo by double indicator dilution and post-mortem by weighting lungs before and after drying. Cardiac output, pulmonary artery and pulmonary artery wedge pressures, and the concentration of protein and electrolytes in plasma and right duct lymph were determined. Eight lungs were examined by light and electron microscopy. There was a direct relationship between right duct lymph flow (RDLF in milliters per hour per gram dry lung) and extravascular lung water (Qwl in milliliters per gram dry lung) which was best described by the equation RDLF=0.75-0.26 Qwl+0.03 (Qwl).2 Dogs with severe ANTU-induced edema had extensive lung capillary endothelial destruction but only mild interstitial swelling and no visible damage to type I alveolar epithelial cells. Cardiac output, pulmonary artery and wedge pressures, and protein and electrolyte concentrations did not correlate with either extravascular water or right duct flow. Thus, in ANTU-induced pulmonary edema right duct lymph flow was directly related to extravascular lung water with the highest flows occurring with severe edema. The absence of a rapid increase in lymph flow with small increases in extravascular water may be due to early sequestration of fluid in the alveolar space. Hemodynamic changes did not account for changes in lung water or lymph flow. The pulmonary interstitial factors relating increased extravascular water to lymph drainage remain to be determined. 相似文献
962.
The uptake of D-[(14)C]mannose by adult rat kidney cortex slices has been examined. The process involved appeared to be saturable and oxygen dependent and to be inhibited by glucose, galactose, chi-methyl-D-glucoside, and phlorizin. Extensive metabolism of the sugar occurred. (14)CO(2) was produced to an extent comparable to that from D-glucose. Radioactive compounds accumulated in the tissue, approximately 50% of which were in the form of phosphorylated or other polar intermediates. The remaining neutral fraction consisted of mannose with a small amount of label in glucose and an unidentified compound which behaves like an alditol. Mannose concentration in the intracellular fluid was never greater than that of the medium. 相似文献
963.
Good's buffer ionic liquids as relevant phase‐forming components of self‐buffered aqueous biphasic systems
下载免费PDF全文
![点击此处可从《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
964.
Drug Delivery: On‐Chip Fabrication of Paclitaxel‐Loaded Chitosan Nanoparticles for Cancer Therapeutics (Adv. Funct. Mater. 4/2014)
下载免费PDF全文
![点击此处可从《Advanced functional materials》网站下载免费的PDF全文](/ch/ext_images/free.gif)
965.
PM de Paula MA Sato JV Menani LA De Luca Júnior 《Canadian Metallurgical Quarterly》1996,214(2-3):155-158
The ultrastructural distribution of the proteins responsible for the silver staining of NORs was analyzed on serial thin sections of preembedded silver-stained rat kangaroo PtK1 metaphase chromosomes. Our results show that the Ag-NOR proteins present a crescent-shaped distribution at the secondary constriction of each chromatid. Moreover, in some cases the crescent-shaped structures of both chromatids are not symmetrically arranged but show different orientations. These observations, together with our own and previously reported light microscopy results obtained on silver-stained mammalian chromosomes, lead us to suggest a mechanism for the formation of apparent secondary constrictions at NORs. 相似文献
966.
967.
Y Miyashita M Miller PM Yen JM Harmon JA Hanover SS Simons 《Canadian Metallurgical Quarterly》1993,46(3):309-320
The binding of cell-free activated glucocorticoid receptor-steroid complexes from HTC cells to various preparations of HTC and rat liver nuclei has been examined under conditions that did or did not support the nuclear translocation of macromolecules via nuclear pores. To the best of our knowledge, this is the first such study with functionally active isolated nuclei. Conventionally prepared HTC nuclei were found to be porous, as determined from their inability to exclude the fluorescent macromolecule phycoerythrin (PE) at 4 degrees C. Thus the nuclear binding of activated complexes to these nuclei can not involve nuclear translocation. Further studies, using established conditions with sealed nuclei prepared from rat liver, revealed that nuclear translocation of PE containing a covalently linked, authentic nuclear translocation sequence could be obtained at 22 degrees C, but not at 4 degrees C. However, under the same conditions, activated glucocorticoid complexes displayed equal levels of nuclear binding at both temperatures. We therefore conclude that the current translocation conditions with intact rat liver nuclei are not sufficient to reproduce the nuclear transport of glucocorticoid complexes observed in intact cells. The nuclear binding that was seen with intact rat liver nuclei was not affected by aurintricarboxylic acid, which selectively inhibits protein-nucleic acid interactions. The antibody AP-64, shown to be specific for amino acids 506-514 of the nuclear translocation sequence of the rat glucocorticoid receptor, inhibited the nuclear binding of activated complexes, apparently by blocking receptor access to the nuclear membrane. Collectively, these data argue that activated complex binding to nuclei capable of nuclear translocation involves only an association with nuclear membrane components such as nuclear pores. Thus this system, and these reagents, may be useful in future studies of activated complex binding to nuclear pores. 相似文献
968.
This study evaluated the predictive utility of the drinking-related control orientation for successful treatment outcome among Finnish inpatient alcoholics (N = 106, 16% women). Using the Drinking-Related Locus of Control (DRIE) scale by Keyson and Janda (unpublished; see Lettieri, Nelson, & Sayers, 1985), it aimed to discover to what extent the DRIE scores measured at the end of treatment predict (a) the timing and severity of the first drinking occasion after treatment, and (b) the 6 and 12 months' total treatment outcome of the sample. The DRIE scores correlated with the time to the first drinking occasion (r = -.27, p < .02). Internal subjects started to drink later (p < .004), drank less on the first occasion (p < .001), and continued for fewer days (p < .005) than external subjects. Moreover, internal orientation was more common among abstinent and external orientation among unimproved subjects during the first 6 (p < .02) and 12 months (p < .05) after treatment. The results thus support the beneficial role of internal control attributions. 相似文献
969.
PM Renzi JP Turgeon JP Yang SP Drblik JE Marcotte L Pedneault S Spier 《Canadian Metallurgical Quarterly》1997,130(4):584-593
OBJECTIVE: To determine whether abnormalities of cellular immunity are present and linked to early wheezing after bronchiolitis. METHODS: We prospectively studied 26 infants hospitalized for a first episode of bronchiolitis and without any prior immune, cardiac, or respiratory disease. Blood was obtained at the time of enrollment and 5 months later for the assessment of the total cellular and differential counts, CD4+ (helper) and CD8+ (suppressor/cytotoxic) lymphocytes, and the activation markers CD23 (low-affinity immunoglobulin E receptor) and CD25 (interleukin-2 (IL-2) receptor). The cytokines interferon gamma (T-helper (TH) type-1 cytokine) and IL-4 (TH-2) were measured in plasma and in vitro after stimulation with IL-2 or with the house-dust mite (Dermatophagoides farinae) antigen. A daily log of episodes of wheezing was kept by parents after discharge. RESULTS: We found an increase in blood eosinophils, an increased percentage of CD4+, CD25+, and CD23+ lymphocytes in subjects at 5 months compared with the time of bronchiolitis and with healthy subjects of the same age (p < 0.05). Plasma IL-4 levels, although not different from those of healthy subjects, also increased significantly. Peripheral blood lymphocytes from infants who wheezed produced more IL-4 in vitro, 5 months after bronchiolitis, in response to D. farinae antigen. In babies who wheezed, a positive correlation was found between the total number of days that wheezing occurred and the blood eosinophil count. Babies who wheezed more often (> 20 days) had more peripheral blood basophils and eosinophils, and peripheral blood lymphocytes obtained from these subjects at the time of bronchiolitis produced less interferon gamma on stimulation with IL-2. CONCLUSIONS: Bronchiolitis is followed by activation of cellular immunity, and early wheezing in infants is associated with a TH-2 response. 相似文献
970.
PM Nilsson L Lind PE Andersson A H?nni C Berne J Baron HO Lithell 《Canadian Metallurgical Quarterly》1994,12(8):965-969
OBJECTIVE: To determine the possible correlations between ambulatory blood pressure and insulin sensitivity, compared with correlations between office blood pressure and insulin. DESIGN: Observational study. SETTING: Policlinic at the Department of Geriatrics, Uppsala, Sweden. PATIENTS: Caucasian patients (n = 149) of both sexes with untreated essential hypertension. MAIN OUTCOME MEASURES: The hyperinsulinaemic euglycaemic clamp and office blood pressure in all subjects. In subgroups, also the oral glucose-tolerance test (n = 96) and 24-h ambulatory blood pressure (n = 84). RESULTS: Significant correlations were seen between the insulin sensitivity index and ambulatory blood pressure recordings, whereas fasting plasma insulin levels were uncorrelated with office blood pressure. The insulin sum and the 2-h insulin level of the oral glucose-tolerance test were more closely correlated with ambulatory blood pressure recordings than was the fasting insulin level. In multiple regression analyses the night-time diastolic blood pressure showed a significant correlation with the insulin sensitivity index even after controlling for the effects of sex, age and body mass index. CONCLUSION: The apparent association between blood pressure and insulin resistance not only is obscured by measurement error, but is also affected by the particular measures of insulin resistance and blood pressure used. The present study provides further evidence that a relationship exists between blood pressure and hyperinsulinaemia or insulin resistance. 相似文献