首页 | 官方网站   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   774篇
  免费   113篇
医药卫生   887篇
  2021年   9篇
  2020年   7篇
  2019年   11篇
  2018年   13篇
  2017年   11篇
  2016年   20篇
  2015年   21篇
  2014年   16篇
  2013年   37篇
  2012年   40篇
  2011年   35篇
  2010年   16篇
  2009年   27篇
  2008年   31篇
  2007年   46篇
  2006年   40篇
  2005年   48篇
  2004年   36篇
  2003年   26篇
  2002年   20篇
  2001年   29篇
  2000年   24篇
  1999年   28篇
  1998年   8篇
  1997年   7篇
  1996年   5篇
  1995年   6篇
  1994年   9篇
  1993年   9篇
  1992年   28篇
  1991年   15篇
  1990年   14篇
  1989年   24篇
  1988年   10篇
  1987年   22篇
  1986年   12篇
  1985年   9篇
  1984年   5篇
  1983年   7篇
  1982年   6篇
  1981年   5篇
  1980年   5篇
  1979年   9篇
  1978年   8篇
  1977年   12篇
  1974年   5篇
  1971年   6篇
  1970年   10篇
  1968年   5篇
  1965年   4篇
排序方式: 共有887条查询结果,搜索用时 533 毫秒
1.
2.
3.
4.
5.
Pregnancies after in vitro fertilization and transfer of human blastocysts   总被引:10,自引:0,他引:10  
In a study of 29 cycles of IVF, ET was performed on day 5 after oocyte recovery when embryos had developed to the morula/blastocyst stage. Three preclinical pregnancies and three live births resulted (2 singleton and 1 twin), giving a viable PR per ET of 10%. It is concluded that while day 5 ET may well be important in terms of embryo biopsy for the preimplantation diagnosis of genetic disease, day 2 ET remains preferable for therapeutic IVF. Although these data would not support the introduction of day 5 ET into routine therapeutic IVF, delayed ET should be considered as an alternative approach to preimplantation diagnosis. Indeed, because the latter will generally involve the treatment of normal, fertile couples, it might be predicted that embryo survival rates, and thus the rate of pregnancy after day 5 ET, would be better than those presented here.  相似文献   
6.
For 3 months in 1969 a family in the United States that included a pregnant mother consumed pork containing methylmercury. Children, aged 20, 13, and 8 years and a neonate, developed severe neurological signs. Twenty-two years later, the 2 oldest had cortical blindness or constricted visual fields, diminished hand proprioception, choreoathetosis, and atentional deficits. Magnetic resonance images showed tissue loss in the calcarine and parietal cortices and cerebellar folia. The youngest had quadriplegia, blindness, and severe mental retradation until their deaths. The brain of the 8-year-old who died at age 30 showed cortical atrophy, neuronal loss, and gliosis, most pronounced in the paracentral and parietooccipital regions. The total mercury level in formalin-fixed, left occipital cortex was 1,974 ng/gm as measured by atomic absorption. Regional brain mercury levels correlated with extent of brain damage. A control patient had 38.5 ng of mercury/gm in the occipital cortex. Systemic organs in the patient and a control subject had comparable mercury levels. In mercury-intoxicated rats, we found that only 5 to 10% of total brain mercury was lost by formalin fixation. Brain inorganic mercury in the patient ranged from 82 to 100%. Since inorganic mercury crosses the blood-brain barrier poorly, biotransformation of methyl to inorganic mercury may have occurred after methylmercury crossed the blood-brain barrier, accounting for its persistence in brain and causing part of the brain damage.  相似文献   
7.
A double-blind trial with clonidine and a placebo to treat hot flushes   总被引:2,自引:0,他引:2  
A double-blind crossover study that compared clonidine and a placebo, which were administered to 19 postmenopausal women who were suffering from hot flushes, failed to demonstrate any statistical reduction in the number of hot flushes. Therefore, clonidine is not recommended as a treatment drug for this symptom.  相似文献   
8.
Twenty three patients with fragile X syndrome underwent cardiovascular assessment. Echocardiography showed dilatation of the aortic root in 12 (52%) and mitral valve prolapse in five (22%), four of whom had an apical mid-systolic click on auscultation. Patients with fragile X syndrome have cardiac defects similar to those seen in other disorders of connective tissue such as Marfan's syndrome and Ehlers-Danlos syndrome. These, and other somatic features, suggest an underlying connective tissue dysplasia.  相似文献   
9.
10.
OBJECTIVE: To determine whether transdermal progesterone cream has any effect on vasomotor symptoms, mood, sexual response, cardiovascular lipid levels, or bone mineral metabolic markers. DESIGN: A parallel, double-blind, randomized, placebo-controlled trial comparing the effect of a transdermal cream containing a progesterone (32 mg daily) with a placebo cream. Eighty postmenopausal women in the Menopause Centre at the Royal Hospital for Women, Sydney, were randomly allocated to receive either the progesterone cream or the placebo. They were evaluated using the Greene Climacteric Scale and the Menopause Quality of Life Questionnaire, as well as blood analysis for lipids and bone markers over a period of 12 weeks. Women were prescribed a cream containing either progesterone at 32 mg daily or a placebo cream for a period of 12 weeks. RESULTS: There was no detectable change in vasomotor symptoms, mood characteristics, or sexual feelings, nor was there any change in blood lipid levels or in bone metabolic markers, despite a slight elevation of blood progesterone levels. CONCLUSION: The use of the transdermal route to administer progesterone at 32 mg daily does not seem to allow sufficient hormone to enter the body to achieve a biological effect on lipid levels, bone mineral metabolic markers, vasomotor symptoms, or moods.  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-23

京公网安备 11010802026262号