全文获取类型
收费全文 | 1045篇 |
免费 | 1篇 |
专业分类
安全科学 | 18篇 |
废物处理 | 2篇 |
环保管理 | 86篇 |
综合类 | 824篇 |
基础理论 | 67篇 |
污染及防治 | 36篇 |
评价与监测 | 8篇 |
社会与环境 | 2篇 |
灾害及防治 | 3篇 |
出版年
2021年 | 4篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 7篇 |
2014年 | 10篇 |
2013年 | 39篇 |
2012年 | 6篇 |
2010年 | 12篇 |
2009年 | 5篇 |
2008年 | 10篇 |
2007年 | 6篇 |
2005年 | 5篇 |
2004年 | 5篇 |
2003年 | 12篇 |
2002年 | 10篇 |
1999年 | 4篇 |
1998年 | 12篇 |
1997年 | 4篇 |
1995年 | 56篇 |
1994年 | 50篇 |
1993年 | 38篇 |
1992年 | 32篇 |
1991年 | 26篇 |
1990年 | 32篇 |
1989年 | 25篇 |
1988年 | 35篇 |
1987年 | 29篇 |
1986年 | 21篇 |
1985年 | 14篇 |
1984年 | 12篇 |
1983年 | 14篇 |
1982年 | 10篇 |
1981年 | 4篇 |
1979年 | 5篇 |
1976年 | 6篇 |
1975年 | 9篇 |
1974年 | 4篇 |
1973年 | 10篇 |
1971年 | 4篇 |
1962年 | 3篇 |
1961年 | 4篇 |
1950年 | 3篇 |
1919年 | 47篇 |
1918年 | 44篇 |
1917年 | 36篇 |
1916年 | 54篇 |
1915年 | 37篇 |
1914年 | 71篇 |
1913年 | 107篇 |
排序方式: 共有1046条查询结果,搜索用时 876 毫秒
951.
Dr. S. Kanokpongsakdi S. Fucharoen C. Vatanasiri V. Thonglairoam P. Winichagoon J. Manassakorn 《黑龙江环境通报》1990,10(12):809-813
In nine pregnant women at risk for fetal alpha-thalassaemia, the two affected fetuses were diagnosed by ultrasonography at 18–20 weeks' gestation. In countries with limited resources, ultrasonography provides a cost-effective method of prenatal screening for this condition. 相似文献
952.
Samples of pure fetal blood from 116 fetuses of 15–21 weeks' gestation were obtained by direct vision fetoscopy. Ninety nine of these fetuses, presumed to be haematologically normal, were suitable for analysis. The data obtained show that the erythropoietic system is evolving rapidly in this gestational age range. The myeloid series shows no significant increase or decrease in numbers apart from eosinophils and basophils which increase significantly with gestational age whereas the platelet count remains constant. The growing application of fetoscopic blood sampling to the prenatal diagnosis and management of fetal blood disorders renders mandatory a knowledge of normal fetal blood values. 相似文献
953.
Dr. W. J. Kleijer M. Van Der Kraan J. G. M. Huijmans C. M. M. Van Den Heuvel C. Jakobs 《黑龙江环境通报》1995,15(6):527-533
Isovaleric acidaemia (IVA) is caused by a deficiency of isovaleryl CoA dehydrogenase. The diagnosis can be established biochemically by the demonstration of increased levels of isovalerylglycine (IVG) and 3-hydroxyisovaleric acid in urine and by the deficiency of incorporation of radiolabel from [14C]isovaleric acid in macromolecules in cultured fibroblasts. This paper reports a consecutive series of 24 prenatal diagnoses in pregnancies at high risk, using both methods-metabolite and indirect enzyme assay. Affected fetuses were diagnosed in four pregnancies: three in the second trimester and one recent case in the first trimester. The latter represents the first reported case of a first-trimester diagnosis of IVA by direct analysis of chorionic villi. We also report the first demonstration of strongly accumulated IVG in the amniotic fluid in the 12th week of an affected pregnancy. 相似文献
954.
We describe a method for the isolation and functional characterization of insulin receptors from chorionic villi and cultured amniotic fluid cells. The functionality of these receptors is assayed by measuring the insulin-induced stimulation of autophosphorylation of the receptor β-chain. The method is expected to allow the prenatal diagnosis of those forms of lep-rechaunism and related diseases which are the result of a decreased stimulation by insulin of receptor autophosphorylation. A pregnancy at risk for leprechaunism was examined and an unaffected child was correctly predicted by study of the functionality of the insulin receptor on cultured amniocytes and by echoscopic examination. 相似文献
955.
Dr. Georg Keckstein Sonja Tschurtz Volker Schneider Wolfgang Mütter Rainer Terinde Wolf-Dietrich Jonatha 《黑龙江环境通报》1990,10(1):59-65
Between October 1985 and February 1989, 49 ultrasound-guided intravascular fetal blood transfusions were performed in 16 patients (14 with rhesus (Rh) isoimmunization, 2 with non-immunologic hydrops fetalis (NIHF)). As an intra-operative complication, perivascular haematoma of the cord occurred in three patients (7 per cent). In two cases, fetal bradycardia necessitated delivery by Caesarean section at 30 and 32 weeks' gestation, respectively. In the third case, fetal bradycardia developed during transfusion, at 31 weeks' gestation, but normalized within 3 min. The baby was delivered as planned at 36 weeks of gestation, after another transfusion at 34 weeks. Dislodgement of the needle tip into perivascular tissue, caused by sudden fetal or maternal movements, is the reason for this complication. The haematoma develops as a result of delayed recognition and continuous transfusion into Wharton' s jelly. Cord haematoma may be diagnosed in time by continuous ultrasound imaging, as illustrated in case 3. To minimize the risk of needle dislodgement during transfusion, sedation of the mother and complete immobilization of the fetus by injecting a short-acting muscle relaxant into the umbilical vessel are recommended. 相似文献
956.
In order to verify if fetal behavioural states could affect cardiac parameters, thirty-one healthy fetuses were studied near term. We evaluated systolic time intervals (pre-ejection period and ventricular ejection time), M-mode parameters (fractional shortening and mean circumferential shortening) and Doppler flow velocities (mean peak velocity of aortic and pulmunary arteries) of left and right ventricles. Both fetal breathing movements and fetal heart rate patterns seem to modify these parameters with an increase of cardiac contractility during active phases of fetal behaviour. 相似文献
957.
An 18 week abortus had been prenatally diagnosed as a 45,X/46,XY mosaic. The fetus was a phenotypic male with glandular hypospadias, a horseshoe kidney and asymmetric gonadal dysgenesis. This case represents a rare instance of prenatally diagnosed 45,X/46,XY mosaicism with an abnormal phenotype. 相似文献
958.
Dr Wayne S. Stanley G. Shashidhar Pai Edgar O. Horger III Yan Yongshan Karen S. McNeal 《黑龙江环境通报》1988,8(8):565-569
Premature centromere separation (PCS) was detected in amniocytes after an amniocentesis was done because of markedly elevated maternal serum alpha-fetoprotein values in a healthy primiparous young woman. PCS has been associated with the Roberts-SC phocomelia syndrome (RS). By 23 weeks' gestation, ultrasonic evaluations did not reveal abnormal fetal development. The pregnancy continued and a male infant was born with mild manifestations of RS. PCS was confirmed in cord blood lymphocytes. This case illustrates that PCS, when detected in amniotic fluid cell cultures, requires a thorough evaluation. 相似文献
959.
Prenatal diagnosis of a fetus at risk for hypochondroplasia, a short limb dwarfism condition similar to achondroplasia, was performed by ultrasound at 22 weeks' gestation. The limb bones were measured and shown to be decreased in length. The pregnancy was terminated. Post abortion X-ray did not show caudal narrowing in the lumbar spine but the pelvis had the features of hypochondroplasia. 相似文献
960.
Paul E. Bibbins JR. Robert L. Anderson Dr. Jack M. Rary Howard W. Jones JR. 《黑龙江环境通报》1982,2(2):123-125
A 48,XXYY fetus was diagnosed prenatally in a 34-year old female who was seen at 18-5 weeks of pregnancy for genetic counselling and amniocentesis for advanced maternal age. The pregnancy was terminated, and skin and peripheral blood samples were obtained at the time of delivery. These samples also exhibited the 48,XXYY chromosomal complement. 相似文献