首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   986篇
  免费   0篇
化学工业   3篇
机械仪表   1篇
轻工业   1篇
水利工程   1篇
一般工业技术   3篇
冶金工业   977篇
  2013年   1篇
  2008年   1篇
  2005年   1篇
  2003年   1篇
  1999年   27篇
  1998年   269篇
  1997年   158篇
  1996年   111篇
  1995年   53篇
  1994年   66篇
  1993年   54篇
  1992年   11篇
  1991年   10篇
  1990年   6篇
  1989年   17篇
  1988年   13篇
  1987年   14篇
  1986年   18篇
  1985年   14篇
  1984年   1篇
  1983年   4篇
  1982年   5篇
  1981年   8篇
  1980年   11篇
  1979年   1篇
  1978年   1篇
  1977年   33篇
  1976年   75篇
  1975年   1篇
  1965年   1篇
排序方式: 共有986条查询结果,搜索用时 15 毫秒
1.
2.
Arterial blood pressures were taken by the Doppler ultrasound method in 134 unselected mature neonates (birthweights 2,600-3,900 grams) who were managed in the same manner after birth. Blood pressures were measured at 3-5, 10 and 30 minutes of life and, if indicated, intermittently during the next 24-48 h. Left and right arm pressures were identical or differed by only 1-2 mm Hg. Lower than normal blood pressures were found in 4 groups of infants: those born by cesarean section, those recovering from intrauterine asphyxia, those exposed to maternal anti-hypertensive therapy, and those whose mothers received thiopental within four minutes of delivery. Return of the low pressures to within the normal range was fastest following thiopental induction in the absence of fetal asphyxia and slowest after antihypertensive therapy.  相似文献   
3.
Two methods of assessing personal space in young children were examined in a group of 24 boys and 24 girls, aged 3 to 6 yr. When sex of peer figures and affect attributed to them were varied, 3-yr.-olds made distance-cue judgements based on affect but failed to use affect cues in structuring personal space. However, 4- to 6-yr.-olds readily perceived and used distance to communicate the affective quality of peer relations. On both measures, perception of distance cues increased with age. Only girls also used sex of figures as a social cue in depicting appropriate distances.  相似文献   
4.
Members of the immediate families of twenty children with specific reading disability were examined to determine the prevalence of reading disability within the families. A procedure was developed for identifying adults who may have compensated for a disability manifested more clearly in childhood. Forty-five percent of 75 first-degree relatives of the parents were affected and there was a significantly greater number of affected male relatives than females. No single mode of genetic transmission is evident after inspection of the pedigrees. It is suggested that the disorder is genetically heterogeneous and that subgroups of disabled readers should be looked for.  相似文献   
5.
6.
Field and pot trials were conducted to determine optimum management practices for usingLeucaena leucocephala (Lam. de Wit) leaves as a N source for crop production. Field trials with maize showed no benefit from split application of leucaena leaves or from application of fresh as opposed to dried material. Field trials also failed to show any difference between incorporation as opposed to surface application of leucaena leaves. This may be attributed to the low nitrogen response observed. Pot trials however, showed that soil incorporation of leucaena leaves was more effective than surface application in increasing plant dry weight.Leucaena leaves were not as effective as inorganic N in increasing maize grain yield (field trials) or dry matter production (pot trial). Unlike inorganic N, leucaena leaves had a significant residual effect on the succeeding maize crop. In decomposition studies, buried leucaena leaves decomposed more quickly than surface-applied leaves, and fresh leaves decomposed more rapidly than dried leaves.  相似文献   
7.
Intensity of glycolysis was studied under conditions of immobilization stress and adrenalectomy as well as with administration of adrenaline and hydrocortisone. The processes of aerobic glycolysis, activity of enzymes of the tricarboxylic acid cycle and mitochondria respiratory chain, content of total, free and protein-bound glycogen, glucose-I-phosphate, glucose-6-phosphate, pyruvate, alpha-ketoglutarate, cytrate and macroergs in the brain are shown to depend on the level of adrenal hormones producing a multilateral effect on a series of energy metabolism links.  相似文献   
8.
In this large series of patients treated for medullary carcinoma of the breast by radical mastectomy, the over-all five year survival rate was 63.7 per cent and the ten year survival rate, 49.5 per cent. Although survival was adversely affected by axillary lymph node involvement, there was an equal incidence of such involvement, there was an equal incidence of such involvement in tumors less than 4 centimeters compared with those greater than 4 centimeters in size; however, patients with tumors greater than 4 centimeters in size fared poorer categorically than did those with smaller lesions. Women in the premenopausal period had one-third of the cancers and had a significantly better survival rate than did those in the postmenopausal period, despite a similar incidence of axillary lymph node involvement. Medullary carcinoma is among the small group of malignant tumors of the breast that have distinctly better five and ten year survival rates than other more common varieties.  相似文献   
9.
The paper presents the results of a 6-year investigation of hemopoiesis of dogs which were exposed to double irradiations (with a 1.5-month interval) with protons at a dose of 350 rad when different parts of the body (head, chest, abdomen, pelvis) were shielded. Throughout the entire period the dogs showed moderate leucopenia and by the end of the investigation insignificant anemia. The dogs irradiated with shielded abdomen displayed disturbances in bone marrow hemopoiesis, whereas other dogs exhibited relative, although transient, normalization. All the dogs showed a significant decrease of erythropoiesis and a relative stability of leucopoiesis as well as a significant elevation of the number of reticulocytes, monocytes and plasmocytes 5.5 year after irradiation.  相似文献   
10.
An abnormal accumulation of radionuclide was identified within the right juxtadiaphragmatic and juxtahepatic spaces during gallium-67 citrate scintigraphy in a post-pyeloplasty patient. Its mode of presentation, the recent pyeloplasty and the known biologic distribution of gallium suggested that it represented gallium-67 concentration within a postoperatively created urinoma. Diagnosis was confirmed by excretory urography and laparotomy.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号