全文获取类型
收费全文 | 1473篇 |
免费 | 114篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 75篇 |
妇产科学 | 20篇 |
基础医学 | 194篇 |
口腔科学 | 21篇 |
临床医学 | 198篇 |
内科学 | 474篇 |
皮肤病学 | 30篇 |
神经病学 | 74篇 |
特种医学 | 151篇 |
外科学 | 168篇 |
综合类 | 28篇 |
预防医学 | 58篇 |
眼科学 | 4篇 |
药学 | 55篇 |
中国医学 | 1篇 |
肿瘤学 | 37篇 |
出版年
2021年 | 12篇 |
2018年 | 18篇 |
2017年 | 13篇 |
2015年 | 15篇 |
2014年 | 15篇 |
2013年 | 33篇 |
2012年 | 43篇 |
2011年 | 35篇 |
2010年 | 34篇 |
2009年 | 33篇 |
2008年 | 47篇 |
2007年 | 36篇 |
2006年 | 35篇 |
2005年 | 40篇 |
2004年 | 36篇 |
2003年 | 43篇 |
2002年 | 36篇 |
2001年 | 25篇 |
2000年 | 35篇 |
1999年 | 32篇 |
1998年 | 53篇 |
1997年 | 61篇 |
1996年 | 53篇 |
1995年 | 51篇 |
1994年 | 25篇 |
1993年 | 26篇 |
1992年 | 45篇 |
1991年 | 37篇 |
1990年 | 39篇 |
1989年 | 44篇 |
1988年 | 48篇 |
1987年 | 42篇 |
1986年 | 48篇 |
1985年 | 29篇 |
1984年 | 31篇 |
1983年 | 25篇 |
1982年 | 19篇 |
1981年 | 21篇 |
1980年 | 12篇 |
1979年 | 40篇 |
1978年 | 15篇 |
1977年 | 16篇 |
1976年 | 18篇 |
1975年 | 15篇 |
1974年 | 15篇 |
1973年 | 22篇 |
1972年 | 24篇 |
1971年 | 11篇 |
1969年 | 16篇 |
1967年 | 12篇 |
排序方式: 共有1591条查询结果,搜索用时 15 毫秒
1.
Anton A. Semenistyy Elena A. Litvina EA Anna G. Fedotova Chukwuweike Gwam Andrey N. Mironov 《Injury》2019,50(2):515-520
Background
Intramedullary nailing is considered a “gold standard” for treatment of tibial shaft fractures. However, some types of fractures are typically considered as “difficult for nailing”. This group includes the periarticular fractures, fractures of both bones at the same level, comminuted and segmental fractures of the tibia. Fixator-assisted nailing (FAN) is an effective method treatment of these types of fractures. The main requirements for the ideal reduction device are an ease of its installation and an ability of multiplanar fracture reduction. Fixator-assisted nailing (FAN) with the use of two perpendicular to each other monolateral tubular frames perfectly meets these requirements. In this study we present this new surgical technique and the analysis of first 30 cases.Methods
A prospective analysis was conducted for 30 patients with “difficult for nailing” tibial fractures treated with fixator-assisted nailing in our institution between September 1st, 2017, and March 1st, 2018. The duration of surgery and its different stages, the time of fluoroscopy, difficulties encountered during surgery, were analyzed. Clinical and radiological methods were used to evaluated reduction quality.Results
In all 30 cases the acceptable reduction was achieved. The mean duration of the surgical procedure was 73.7?±?3?min. The mean duration of fluoroscopy 85.9?±?4.8?s. In 7 cases we faced with technical difficulties, which were successfully addressed.Conclusion
The described technique of FAN is an effective method for the treatment of “difficult for nailing” tibial fractures. Future multi-centered studies with a larger number of patients are needed to validate our results. 相似文献2.
A national alcohol and trauma center survey. Missed opportunities, failures of responsibility 总被引:4,自引:0,他引:4
The results of a national survey of trauma centers concerning their assessment and response to the problem of alcohol and trauma are reported. Surveys were returned from 154 trauma centers located in 43 states and the District of Columbia. The profile of the 125,000 patients treated at the centers is a 30-year-old man sustaining blunt trauma, usually in a vehicular crash. Two-thirds of centers estimated that the majority of their patients had abused alcohol. While acknowledging alcohol as a significant cause of trauma, only 55.2% of centers routinely obtain admitting blood alcohol levels. Less than a third of the centers employ alcoholism counselors. Most trauma centers are not providing services that allow them to fulfill their responsibility to detect and initiate treatment of alcohol abuse, a major cause of traumatic injury. 相似文献
3.
The goals of the present study were twofold: first, to assess the renal excretory and hormonal responses to chronic water restriction in dogs whose sodium retaining mechanisms had been stimulated through dietary sodium (Na+) deprivation; second, to determine the mediator(s) of the natriuresis which was observed with water restriction in these sodium deprived dogs. Three groups of dogs maintained on a low Na+ diet (5 mEq/day) for two weeks underwent a three day period of water restriction. In normal, intact dogs Group 1 (N = 5), water restriction resulted in a significant increase in Na+ excretion with a net cumulative loss of 26.3 +/- 2.6 mEq over three days. The natriuresis was associated with a significant increase in plasma vasopressin (PAVP) (1.7 to 10.2 pg/mliter) and a significant fall in plasma aldosterone (PALDO) from the levels observed with Na+ restriction alone (24.9 to 12.4 ng/dliter). The natriuresis could not be explained by decreases in food intake as determined by control studies in four dogs. Group 2 (N = 6) dogs had a decrease in PALDO with water restriction that was prevented by means of continuous i.v. aldosterone infusion (6.0 micrograms/kg/day). Dogs in this group failed to demonstrate a natriuresis during three days of water restriction, despite the fact that PAVP rose from 3.3 +/- 0.8 to a peak level of 14.95 +/- 1.9 pg/mliter. Group 3 (N = 6) dogs underwent selective neurohypophysectomy, thus preventing the rise in PAVP during three days of water restriction. In this group, PALDO also remained unchanged from the Na+ deprived level during water restriction, and no natriuresis was observed. We conclude: 1) that the natriuresis which occurs with water restriction is a potent physiological response that occurs even in the Na+ restricted state; and 2) this natriuresis can be explained by a fall in PALDO and not the rise in PAVP. 相似文献
4.
David L. Mattson Shanhong Lu Allen W Cowley Jr 《Clinical and experimental pharmacology & physiology》1997,24(8):587-590
1. Nitric oxide (NO) has been implicated as an important controller in the short- and long-term regulation of arterial pressure. Studies performed in our laboratory have demonstrated that chronic intravenous administration of the NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) selectively decreases renal medullary blood flow, causes sodium and water retention and leads to hypertension. 2. To determine the importance of the renal medullary effects in this model of hypertension, further studies were conducted to examine the influence of selective stimulation or inhibition of renal medullary NO on whole kidney function and cardiovascular homeostasis. With the use of a unique catheter to directly infuse into the renal medullary interstitial space, stimulation (bradykinin or acetylcholine) or inhibition (L-NAME) of renal medullary NO selectively increased or decreased renal medullary blood flow. 3. The changes in medullary flow in these experiments were associated with parallel changes in sodium and water excretion independent of alterations in renal cortical blood flow or glomerular filtration rate. 4. Studies were then undertaken to examine the long-term effects of selective NO inhibition in the renal medulla on cardiovascular homeostasis. Chronic infusion of L-NAME directly into the renal medullary interstitial space of uninephrectomized Sprague-Dawley rats led to a selective decrease in renal medullary blood flow that was sustained throughout the 5 day L-NAME infusion period. The decrease in medullary blood flow was associated with retention of sodium and the development of hypertension and the effects were reversible. 5. The data reviewed indicate that NO in the renal medulla has a powerful influence on fluid and electrolyte homeostasis and the control of blood pressure. 相似文献
5.
6.
S R Dager A Khan D Cowley D H Avery J Elder P Roy-Byrne D L Dunner 《Psychopharmacology bulletin》1990,26(3):273-278
Mixed-panic disorder patients (16/60, 27%) randomly assigned to receive blind placebo during a 40-week treatment study were defined as placebo responders based on combined criteria of Hamilton Anxiety Scale score percentage decreases below the median point (-42%), moderate to marked improvement on both clinician and patient Clinical Global Impressions scores, and panic-free at final treatment visit. These criteria applied separately also resulted in a similar clinical grouping and pattern of response. Differential patterns of response between responders and nonresponders occurred across most clinical measures of panic/anxiety. Responders experienced early improvement within the first week of double-blind treatment. This response progressed during treatment and tended to persist during taper and at followup 1 month later. Post-hoc analysis of demographic and clinical features at entrance into the study failed to characterize this stringently defined group of placebo responders. 相似文献
7.
Characterization of adhesive interactions between human endothelial cells and megakaryocytes. 总被引:3,自引:0,他引:3
下载免费PDF全文
![点击此处可从《The Journal of clinical investigation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
H Avraham S Cowley S Y Chi S Jiang J E Groopman 《The Journal of clinical investigation》1993,91(6):2378-2384
Cell-cell adhesion is essential for many immunological functions and is believed to be important in the regulation of hematopoiesis. Adhesive interactions between human endothelial cells and megakaryocytes were characterized in vitro using the CMK megakaryocytic cell line as well as marrow megakaryocytes. Although there was no adhesion between unactivated human umbilical vein endothelial cells (HUVEC) and megakaryocytes, treatment of HUVEC with inflammatory cytokines such as IL-1 beta, tumor necrosis factor alpha, INF-gamma, or the phorbol ester phorbol myristate acetate (PMA) resulted in a time- and dose-dependent increase in adhesion. Stimulation of marrow megakaryocytes or CMK cells with the cytokines IL-1 beta, GM-CSF, IL-6, IL-3, or PMA augmented their adhesion to endothelium. Monoclonal antibodies against the LFA-1 subunit of the leukocyte adherence complex CD18 inhibited the binding of marrow megakaryocytes or CMK cells to HUVEC. Adhesion blocking experiments also demonstrated that the VLA-4/VCAM-1 pathway was important for megakaryocyte attachment to HUVEC. Adhesion promoted maturation of megakaryocytic cells as measured by increased expression of glycoproteins GpIb and GpIIb/IIIa and by increased DNA content. These observations suggest that alterations in megakaryocyte adhesion may occur during inflammatory conditions, mediated by certain cytokines, resulting in augmented megakaryocyte maturation. 相似文献
8.
9.
10.