全文获取类型
收费全文 | 5173篇 |
免费 | 382篇 |
国内免费 | 28篇 |
学科分类
医药卫生 | 5583篇 |
出版年
2024年 | 8篇 |
2023年 | 39篇 |
2022年 | 61篇 |
2021年 | 126篇 |
2020年 | 109篇 |
2019年 | 154篇 |
2018年 | 178篇 |
2017年 | 108篇 |
2016年 | 144篇 |
2015年 | 144篇 |
2014年 | 178篇 |
2013年 | 245篇 |
2012年 | 393篇 |
2011年 | 421篇 |
2010年 | 223篇 |
2009年 | 208篇 |
2008年 | 310篇 |
2007年 | 348篇 |
2006年 | 306篇 |
2005年 | 334篇 |
2004年 | 277篇 |
2003年 | 252篇 |
2002年 | 250篇 |
2001年 | 81篇 |
2000年 | 68篇 |
1999年 | 65篇 |
1998年 | 59篇 |
1997年 | 26篇 |
1996年 | 29篇 |
1995年 | 21篇 |
1994年 | 21篇 |
1993年 | 21篇 |
1992年 | 44篇 |
1991年 | 29篇 |
1990年 | 25篇 |
1989年 | 26篇 |
1988年 | 24篇 |
1987年 | 24篇 |
1986年 | 14篇 |
1985年 | 17篇 |
1984年 | 9篇 |
1983年 | 13篇 |
1981年 | 11篇 |
1980年 | 9篇 |
1979年 | 13篇 |
1974年 | 7篇 |
1973年 | 7篇 |
1971年 | 11篇 |
1970年 | 8篇 |
1969年 | 12篇 |
排序方式: 共有5583条查询结果,搜索用时 15 毫秒
1.
2.
In the first part of this series on issues in ward management facing charge nurses, Helen Evers addresses the problem of communication between hospital and community on patient discharges. Recent years have seen the development of liaison and co-ordinator posts whose incumbents aim to facilitate planned and organised discharge procedures, but the appointment of such personnel may not provide a complete answer to the problem. The ultimate arbiter of effective transition from hospital to home is more likely to be the quality of communication between charge and district nurse. 相似文献
3.
K. Bischoff J. Pichner W. E. Braselton C. Counard D. C. Evers W. C. Edwards 《Archives of environmental contamination and toxicology》2002,42(1):71-76
Mercury and selenium act as mutual antagonists in mature birds, but their toxicity is additive or synergistic in avian embryos
and immature birds. Twenty eggs and livers from 18 mature and 9 immature common loon carcasses found in Minnesota were collected.
Livers and eggs were analyzed for mercury and selenium by atomic emission and atomic absorption spectroscopy. Liver mercury
concentrations were significantly higher in mature loons compared to those of immature loons and eggs. Liver selenium concentrations
were significantly higher in mature loons than those of immature loons, and selenium concentrations in immature loon livers
were significantly higher than levels in eggs. There was a significant positive correlation between mercury and selenium in
loon livers. There was a negative correlation between mercury and selenium in eggs.
Received: 2 February 2001/Accepted: 28 May 2001 相似文献
4.
Cora E Lewis Susan K Ewing Brent C Taylor James M Shikany Howard A Fink Kristine E Ensrud Elizabeth Barrett-Connor Steven R Cummings Eric Orwoll 《Journal of bone and mineral research》2007,22(2):211-219
We examined determinants of nonvertebral fracture in elderly men from six U.S. communities followed an average of 4.1 years. Six clinical risk factors predicted fracture risk independent of hip BMD: tricyclic antidepressant use, previous fracture, inability to complete a narrow walk trial, falls in previous year, age > or =80 years, and depressed mood. INTRODUCTION: There are few prospective studies of fracture determinants in men. We examined the associations between a comprehensive set of clinical risk factors and risk of nonspine fracture in older men and whether determinants of fracture risk were independent of total hip BMD. MATERIALS AND METHODS: A total of 5995 men > or =65 years of age were recruited from six communities in the Unites States and followed prospectively for an average of 4.1 years. Baseline assessments of demographic, lifestyle, medical history, functional status, anthropometry, and cognitive, visual, and neuromuscular function were assessed by questionnaire or examination. Triannual mailed questionnaires ascertained incident fracture; reported fractures were adjudicated by physicians using medical records and X-ray reports. Proportional hazards models were used to develop multivariable models, selecting variables and controlling for BMD. RESULTS: Of 5876 men, 4.7% (N = 275) reported an incident nonspine fracture during follow-up (11.46/1000 person-years). Tricyclic antidepressant use (hazard ratio [HR], 2.36; 95% CI, 1.25-4.46), history of fracture at or after age 50 (HR, 2.07; 95% CI, 1.62-2.65), inability to complete a narrow walk trial (HR, 1.70; 95% CI, 1.23-2.34), falls in previous year (HR, 1.59; 95% CI, 1.23-2.05), age > or =80 years (HR, 1.33; 95% CI, 1.01-1.76), depressed mood (HR, 1.72; 95% CI, 1.00-2.95), and decreased total hip BMD (HR, 1.53; 95% CI, 1.34-1.74) were independently related to increased risk. Compared with having none (48.0% of men), having three or more of the clinical risk factors (4.9% of men) increased fracture risk 5-fold, independent of BMD. Having three or more risk factors and being in the lowest tertile of BMD was associated with a 15-fold greater risk than having no risk factors and being in the highest BMD tertile. CONCLUSIONS: Several clinical risk factors were independently associated with nonspine fractures in elderly men. The combination of multiple risk factors and low BMD was a very powerful indicator of fracture risk. 相似文献
5.
Martin A Ritter Achim Frese Rainer Dziewas Stefan Knecht Stefan Evers 《Movement disorders》2006,21(10):1787-1788
Synkinesias secondary to nerve lesions and aberrant re-innervation are well-known phenomena especially after lesions of the facial nerve. Synkinesias can successfully be treated with botulinum toxin A (BTx A). Synkinesias of the cremaster muscle have not been described or treated to date. We present the case of a 62-year-old man who developed synkinesias of both cremaster muscles after extensive laparatomy for esophageal cancer. Treatment of synkinesias with various oral medications had been unsuccessful. Electromyography-guided injections of BTx A in both cremaster muscles (15 MU on the right and 10 on the left) led to significant symptom relief for an average of 8 weeks. We present the case including pre- and posttreatment video clips. 相似文献
6.
Age and gender interactions on verbal memory performance. 总被引:1,自引:0,他引:1
Joel H Kramer Kristine Yaffe Jeanne Lengenfelder Dean C Delis 《Journal of the International Neuropsychological Society》2003,9(1):97-102
Age and gender effects on verbal episodic memory are well established. However, the possibility of interactions between age and gender has been raised by studies linking estrogen and verbal memory performance, and by research suggesting gender differences in age-related cortical atrophy. We evaluated whether age by gender interactions in verbal memory were present. Subjects within three years of the median age of menopause were excluded from a large cohort of normal subjects, resulting in a younger sample (16-47 years) of 288 men and 285 women, and an older sample (55-89 years) of 201 men and 245 women. All subjects were administered the CVLT-2, a multiple-trial list-learning task. Verbal memory was negatively correlated with age for younger men, older men, and older women, but not for younger women. Multivariate analyses indicated age by gender interactions on memory for the younger group but not the older group. Results indicate that verbal memory declines with age for younger men but not younger women, whereas both older men and older women show age-related declines. These findings are consistent with hypotheses linking estrogen and verbal memory performance, and with imaging data suggesting that age-related hippocampal atrophy is found in younger men but not younger women. The role of estrogen on cognition in normal aging warrants further study. 相似文献
7.
Thanh GN Ton Mary Anne Rossing Deborah J Bowen Sengkeo Srinouanprachan Kristine Wicklund Federico M Farin 《Behavioral and brain functions : BBF》2007,3(1):22-10
Background
Genes involved in dopaminergic neurotransmission have been suggested as candidates for involvement in smoking behavior. We hypothesized that alleles associated with reduced dopaminergic neurotransmission would be more common in continuing smokers than among women who quit smoking. 相似文献8.
Causes for failure of pregnancy after tubal reconstructive surgery are incompletely understood. The impact of microsurgical resection reanastomosis on ovum recovery was studied in the rabbit oviduct. One hundred sixty rabbits were divided into three groups: one experimental group in which a resection reanastomosis was made in the ampullar or isthmic tubal segment, respectively, and two control groups. After mating, ovum recovery was evaluated. In ampullary operated oviducts the ovum recovery rate was significantly lower compared with recovery rates in isthmically operated and in control oviducts. Furthermore, in ampullary operated oviducts peritoneal transmigration of ova was frequently observed. Disturbances in ovum pickup from the ovarian surface or the peritoneal cavity seem to be responsible for the decrease in recovery rate found in the ampullary operated oviducts. 相似文献
9.
The effect of halothane on isolated calcium (Ca2+) current of clonal (GH3) pituitary cells was investigated using standard whole-cell clamp techniques at room temperature. Halothane (0.1-5.0 mM) reversibly reduced both the low-threshold, transient [low-voltage-activated (LVA)] component and the high-threshold [high-voltage-activated (HVA)] component of Ca2+ current. Halothane had little effect on the voltage dependence of activation or inactivation of either component of Ca2+ current. Inhibition of the peak high-threshold Ca2+ current was half-maximal at about 0.8 mM halothane, with maximal inhibition (100%) occurring with 5 mM halothane. When measured at the end of a 190-msec command step, half-maximal reduction of high-threshold current occurred at less than 0.5 mM halothane. The low-threshold transient current was less sensitive to halothane, with half-maximal inhibition of peak transient current activated at -30 mV occurring at approximately 1.3 mM. The effect of halothane on the HVA current was apparently not mediated by changes in intracellular Ca2+ concentration. The ability of halothane to inhibit Ca2+ current was unaffected by either the inclusion of the rapid Ca2+ buffer 1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid (BAPTA) in the recording pipette or exposure of the cell to 10 mM caffeine. To assess the selectivity of the effect of halothane, the actions of halothane on two components of voltage-activated potassium (K+) current observed in the absence of extracellular Ca2+ and on voltage-dependent sodium (Na+) current were also examined. Halothane had no effect on the voltage-dependent, inactivating K+ current of GH3 cells at concentrations up to 1.2 mM. In contrast, the non-inactivating K+ current, though less sensitive to halothane than either Ca2+ current, was reduced by about 40% by 1.2 mM halothane at +20 mV. Peak Na+ current was also blocked by halothane, but 50% block required around 2.6 mM halothane with little effect at 1.6 mM. Reduction of Na+ current was associated with a substantial negative shift in the steady-state inactivation curve. Although the results indicate that a number of voltage-dependent ionic currents are sensitive to halothane, both components of Ca2+ current exhibit a greater sensitivity to halothane than any of three other voltage-dependent currents in GH3 cells. These results show that GH3 cell Ca2+ currents are selectively inhibited by clinically appropriate concentrations of halothane and that the reduction of Ca2+ current can account for the inhibition by halothane of TRH- or KCl-induced prolactin secretion in GH3 cells. 相似文献
10.
Kristine Jones Ph.D. Paul Colson Ph.D. Elie Valencia J.D. Ezra Susser M.D. Dr.P.H. 《The Psychiatric quarterly》1994,65(4):243-256
The Critical Time Intervention Project is a three-year clinical trial which tests a time-limited, supportive intervention
to reduce recurrent homelessness among mentally ill men moving from a shelter to the community. Along with a comparison of
nights spent homeless and other outcomes, the evaluation of the Critical Time Intervention includes a comparison of the relative
costs of the intervention, compared to usual treatment. Such cost effectiveness analyses are difficult to perform and are
rarely applied to mental health treatments. This paper presents the general scheme of this analysis and discusses critical
issues in the construction and measurement of cost variables. Preliminary results which have implications for the cost analysis
are presented. 相似文献