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   719篇
  免费   91篇
医药卫生   810篇
  2021年   16篇
  2019年   15篇
  2018年   6篇
  2016年   7篇
  2015年   12篇
  2014年   15篇
  2013年   20篇
  2012年   24篇
  2011年   34篇
  2010年   17篇
  2009年   20篇
  2008年   37篇
  2007年   42篇
  2006年   33篇
  2005年   31篇
  2004年   36篇
  2003年   41篇
  2002年   29篇
  2001年   21篇
  2000年   27篇
  1999年   22篇
  1998年   10篇
  1997年   5篇
  1996年   9篇
  1995年   4篇
  1994年   6篇
  1993年   6篇
  1992年   13篇
  1991年   14篇
  1990年   30篇
  1989年   17篇
  1988年   12篇
  1987年   16篇
  1986年   8篇
  1985年   12篇
  1984年   5篇
  1981年   4篇
  1980年   4篇
  1979年   5篇
  1978年   12篇
  1977年   9篇
  1976年   11篇
  1975年   11篇
  1974年   5篇
  1973年   6篇
  1972年   5篇
  1970年   12篇
  1969年   6篇
  1968年   10篇
  1967年   6篇
排序方式: 共有810条查询结果,搜索用时 343 毫秒
1.
Weaning of infants.   总被引:5,自引:0,他引:5  
The WHO 2001 global recommendation is a one size fits all approach to weaning, an approach which may not take sufficient account of the special needs of some infants and fails to allow for the different problems encountered in the industrialised nations compared with economically developing countries. For the healthy normal birth weight full term infant born in an industrialised country, current research supports the benefit of exclusive breast milk feeding until 4-6 months. Evidence of harm through introducing solid food to these infants earlier than this is weak. Infants should be managed individually according to their needs.  相似文献   
2.
Managers in the NHS are facing financial reforms which will impact greatly on their role. In general terms, service managers tend to be functionally trained and their financial awareness has not been a pre-requisite for their selection. Their ability to respond to their new role requirements is therefore untested, but it represents a crucial factor in the success of the reforms. This article examines the financial awareness of a group of managers who need financial skills, drawn from a range of work categories. The results indicate that there is room for the managers in the sample to improve their financial awareness, and reports that significant differences between work categories may be expected. However, the managers expressed satisfaction with the financial information they received although this information could be better presented. Given the increased complexities of financial information produced in the reformed NHS, these managers will require further training if they are to fulfil their new role to their true potential.  相似文献   
3.
A series of dihydro-1H-pyrrolizine-3,5(2H,6H)-diones were synthesized and evaluated for their ability to reverse electroconvulsive shock (ECS) induced amnesia in mice. Among the structure-activity relationships explored were the effects of ring size, the presence of heteroatoms (sulfur) in the ring system, and the introduction of alkyl substituents. The optimal ring size for the bicyclic system was 5.5 with dihydro-1H-pyrrolizine-3,5(2H,6H)-dione (3), although some activity was present in the corresponding 5.6 [hexahydro-3,5-indolizinedione (7)] and 6.6 [tetrahydro-2H-quinolizine-4,6(3H,7H)-dione (9)] analogues. Replacement of the C-1 carbon atom in compound 3 with a sulfur [dihydropyrrolo[2,1-b]thiazole-3,5(2H,6H)-dione (10)] abolished activity, and the introduction of methyl groups resulted in poorer biological profiles except when the substitution was made at the 7a position [dihydro-7a-methyl-1H-pyrrolizine-3,5(2H,6H)-dione (4)]. In several instances, hydrolysis of the parent bicyclic compound was carried out to furnish the corresponding lactam acids, which were further derivatized. Several exhibited interesting activity, especially the 5-oxo-2-pyrrolidinepropanoic acid derivatives such as 5-oxo-2-pyrrolidinepropanoic acid (12), 5-oxo-2-pyrrolidinepropanoic acid phenylmethyl ester (17), 5-oxo-2-pyrrolidinepropanoic acid (3-chlorophenyl)methyl ester (20), N-4-pyridyl-5-oxo-2-pyrrolidinepropanoic acid amide (25), and N-(2,6-dimethylphenyl)-5-oxo-2-pyrrolidinepropanoic acid amide (27). Compound 3 (CI-911; rolziracetam) was also observed to improve performance on a delayed-response task in aged rhesus monkeys and was selected for evaluation in cognitively impaired human subjects on the basis of its biological profile and a wide margin of safety in animals.  相似文献   
4.
5.
6.
Staphylococcus aureus and Salmonella spp. are common causes of bone diseases; however, the immune response during such infections is not well understood. Colony-stimulating factors (CSF) have a profound influence on osteoclastogenesis, as well as the development of immune responses following infection. Therefore, we questioned whether interaction of osteoblasts with two very different bacterial pathogens could affect CSF expression by these cells. Cultured mouse and human osteoblasts were exposed to various numbers of S. aureus or Salmonella dublin bacteria, and a comprehensive analysis of granulocyte-macrophage (GM)-CSF, granulocyte (G)-CSF, macrophage (M)-CSF, and interleukin-3 (IL-3) mRNA expression and cytokine secretion was performed. Expression of M-CSF and IL-3 mRNAs by mouse osteoblasts was constitutive and did not increase significantly following bacterial exposure. In contrast, GM-CSF and G-CSF mRNA expression by mouse osteoblasts was dramatically upregulated following interaction with either viable S. aureus or Salmonella. This increased mRNA expression also translated into high levels of GM-CSF and G-CSF secretion by mouse and human osteoblasts following bacterial exposure. Viable S. aureus and Salmonella induced maximal levels of CSF mRNA expression and cytokine secretion compared to UV-killed bacteria. Furthermore, GM-CSF and G-CSF mRNA expression could be induced in unexposed osteoblasts separated by a permeable Transwell membrane from bacterially exposed osteoblasts. M-CSF secretion was increased in cultures of exposed human osteoblasts but not in exposed mouse osteoblast cultures. Together, these studies are the first to define CSF expression and suggest that, following bacterial exposure, osteoblasts may influence osteoclastogenesis, as well as the development of an immune response, via the production of these cytokines.  相似文献   
7.
The purpose of this study was to examine the validity of the use of ratings of perceived exertion (RPE) to estimate and regulate exercise intensity during rowing ergometry. Nine competitive male rowers [mean age 28.6 years, (SD 6.3)] completed two rowing trials on an ergometer. The first trial (estimation) consisted of an incremental protocol designed to elicit a range of work outputs (WO) and heart rates (HR). The subjects indicated their perception of effort using a 15-point scale at each intensity level. In the second trial (production), 7–14 days later, the subjects were asked to produce exercise intensities corresponding to five levels of RPE: 15,11,17,13, and 19. Data analysis revealed high Pearson correlation coefficients between HR and RPE (r = 0.95,P < 0.01) and WO and RPE (r = 0.96,P < 0.01) during the estimation trial. In addition, significant correlations (P < 0.01) were obtained between the estimation and production trials for HR (r = 0.82) and WO (r = 0.84). Posthoc analysis of variance revealed that the observed differences in mean HR were not significant (P > 0.05) at three of the five intensity levels (RPE 15,17 and 19), but were at the two lowest RPE levels (11 and 13). Significant mean differences in WO were seen at all but RPE 17. These data support the validity of the RPE scale as a measure of physiological strain among competitive male rowers, and offer support for its use as a method of regulating the intensity of rowing ergometry, especially at higher levels.  相似文献   
8.
Microsporidia are zoonotic protozoa which were rare human pathogens prior to 1985, when Enterocytozoon bieneusi was described in human immunodeficiency virus-infected patients with chronic diarrhea. Another species, Encephalitozoon (Septata) intestinalis, is associated with diarrhea and chronic sinusitis, and approximately 25 cases have been reported in the literature. However, other microsporidial infections in human immunodeficiency virus-infected patients remain extremely rare. We report the first case of a Pleistophora sp.-like microsporidian infection presenting as a progressive severe myosotis associated with fever and weight loss. The organism was demonstrated by light microscopy and electron microscopy in corneal scrapings, skeletal muscle, and nasal discharge. Electron microscopy showed an electron-dense surface coat with "sunflare"-like projections surrounding all stages of development of meronts (two to four nuclei, dividing by binary fission), sporonts, and sporoblasts. Division of sporonts, in which sporonts separate from the thick outer coat, creating a sporophorous vesicle, is by binary fission, differentiating this organism from Pleistophora sp. The spore measures 4.0 by 2.5 microns and has a rugose exospore. A new genus and species, Trachipleistophora hominis, has been established for this parasite. The patient was treated with albendazole, sulfadiazine, and pyrimethamine, and the clinical symptoms resolved.  相似文献   
9.
There has been an explosion of interest recently in sexual abuse and incest, with reported causal links to a wide variety of psychiatric disorders. The integrity of Freud's seduction theory has been challenged by Jeffrey Masson and sexual abuse activists. What is the position of a therapist who finds out that a patient's reports of incest and sexual abuse turn out to be fabrications? These issues are presented and discussed in the context of a brief, illustrative case history. There is also a review of the concept of "pseudologia fantastica", as well as a brief review of a feminist critique of Freudian theory.  相似文献   
10.
Reports of state in relation to the menstrual cycle were investigated using daily measures of state in a group of 65 family planning clinic attenders without pre-existing menstrual complaint. Women reported significant changes in their physical and psychological state prior to menstruation which reverted to "normal' levels 3-5 days after the onset of menstruation. No statistically significant differences were found between the patterns of oral contraceptive users and non-users.  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