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271.
The urine and serum compositions in 11 species of Antarctic teleost fishes were studied. The body fluids of these fishes were hypoosmotic to seawater. Both urine and serum osmoconcentrations were conspicuously greater than those of temperate species. The elevated serum osmolality was due to increased levels of NaCl, while elevated urine osmolality was due chiefly to increased concentrations of magnesium and chloride. The kidney was unable to form a urine hyperosmotic to serum under field conditions. The renal tubular epithelium secreted magnesium and calcium against a concentration gradient, while effectively preventing the renal excretion of significant amounts of sodium and potassium. Bladder urine of Antarctic teleosts may often be supercooled by as much as 0.8°C. Coelomic fluid and the integument probably act as a barrier in preventing ice propagation in the supercooled bladder urine, since they both contain glycoprotein “antifreeze” agents. 相似文献
272.
Dr. J. Overnell 《Marine Biology》1975,32(1):99-103
Observations on sixth-stage nauplius (pre-cyprid) of the barnacle Balanus eberneus Gould treated with L-proline-3,4-H3 suggest that the cement gland in this stage is a functional organ with considerable biosynthetic activity; the activity of the cement glands in the cyprid similarly treated is relatively low, ceasing gradually during, and completely after, metamorphosis. In the early phases of this stage, the glands become highly vacuolated (degenerate), and disappear completely in 3 days. The origin of the cement apparatus in the newly metamorphosed barnacle is discussed. 相似文献
273.
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275.
We describe a 28-week-old fetus with severe non-immune hydrpps. Intrauterine cord blood sampling revealed hypercalcaemia of 3–4mmol/l (n = 2·6±0·1). Subsequently, a postmortem examination revealed supravalvular aortic and pulmonary artery stenosis together with extensive arterial calcification. The maternal calcium, 25-hydroxyvitamin D3, 1,25-dihydroxyvitamin D3, and parathyroid hormone levels were normal at delivery. This is the first time that hypercalcaemia has been diagnosed in vitro. We speculate on the fact that the disorder resulted as a consequence of abnormal vitamin D metabolism in the fetoplacental unit, and that it might be related to the Williams syndrome. 相似文献
276.
277.
The second prenatal diagnosis of galactosialidosis is reported. Neuraminidase and β-galactosidase activities in cultured amniotic cells were deficient, this being confirmed by skin fibroblast enzyme assay on the affected fetus after interruption of the pregnancy. Cultured placental cells demonstrated the same enzyme deficiencies. Analysis of deproteinized amniotic fluid showed the presence of abnormal oligosaccharides specific for a-neuraminidase deficiency. 相似文献
278.
80·2 Per cent of 111 Down syndrome pregnancies had amniotic fluid (AF) alpha fetoprotein (AFP) levels on or below the median and 10·8 per cent at or below 0·5 MoM compared with 41·9 and 1·4 per cent of controls. These differences were even more striking when the gestational age was < 18 weeks compared with ⩾ 18 weeks. No such association was seen for other chromosome abnormalities including trisomy 18,45,X and mosaics, 47,XXY, 47,XXX, and other structural abnormalities and triploidy, even when high levels due to defects such as omphalocele and cystic hygroma were excluded. All cases of trisomy 13 and 80 per cent with 47,XYY had AF-AFP levels above the median. Selection of cases for karyotyping by a low level of AF-AFP would clearly fail to detect aneuploidies other than Down syndrome and is not recommended. A possible weak association between low maternal serum (MS) and AF-AFPs in Down syndrome was most evident at < 18 weeks, suggesting that MS screening between 16 and 18 weeks may be the most informative time. 相似文献
279.
A case of congenital short femur in an otherwise healthy infant is described. Antenatal sonographic diagnosis was made at 26 weeks of gestation. The left femur was shorter than the right (ratio 0·82–0·85). In this case, the occurrence of congenital short femur was sporadic. The diagnosis was confirmed after delivery. This case illustrates the importance of ultrasound as an early detector of certain congenital anomalies and as a useful tool in their follow-up. 相似文献
280.
Fetal loss through miscarriage or termination of pregnancy for genetic reasons often provokes the grief of bereavement. This is not fully understood, and the extent of the distress is often underestimated by professionals and family alike. We have examined elements of the normal bereavement process and have found that they may occur in specific and accentuated forms in mid-trimester fetal loss. We discuss our findings in the light of the attachment theory—a psychodynamic model for understanding grief reactions. 相似文献