全文获取类型
收费全文 | 1812篇 |
免费 | 206篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 38篇 |
妇产科学 | 35篇 |
基础医学 | 232篇 |
口腔科学 | 27篇 |
临床医学 | 213篇 |
内科学 | 463篇 |
皮肤病学 | 27篇 |
神经病学 | 144篇 |
特种医学 | 78篇 |
外科学 | 249篇 |
综合类 | 50篇 |
一般理论 | 1篇 |
预防医学 | 119篇 |
眼科学 | 32篇 |
药学 | 259篇 |
中国医学 | 1篇 |
肿瘤学 | 70篇 |
出版年
2021年 | 25篇 |
2020年 | 13篇 |
2019年 | 23篇 |
2018年 | 35篇 |
2017年 | 27篇 |
2016年 | 25篇 |
2015年 | 23篇 |
2014年 | 43篇 |
2013年 | 58篇 |
2012年 | 65篇 |
2011年 | 68篇 |
2010年 | 49篇 |
2009年 | 46篇 |
2008年 | 82篇 |
2007年 | 85篇 |
2006年 | 92篇 |
2005年 | 81篇 |
2004年 | 69篇 |
2003年 | 70篇 |
2002年 | 60篇 |
2001年 | 63篇 |
2000年 | 58篇 |
1999年 | 60篇 |
1998年 | 53篇 |
1997年 | 26篇 |
1996年 | 25篇 |
1995年 | 17篇 |
1994年 | 26篇 |
1993年 | 27篇 |
1992年 | 45篇 |
1991年 | 41篇 |
1990年 | 31篇 |
1989年 | 28篇 |
1988年 | 38篇 |
1987年 | 41篇 |
1986年 | 37篇 |
1985年 | 29篇 |
1984年 | 26篇 |
1983年 | 19篇 |
1982年 | 23篇 |
1981年 | 14篇 |
1980年 | 14篇 |
1979年 | 29篇 |
1978年 | 14篇 |
1977年 | 20篇 |
1975年 | 17篇 |
1974年 | 17篇 |
1973年 | 14篇 |
1970年 | 14篇 |
1968年 | 12篇 |
排序方式: 共有2041条查询结果,搜索用时 15 毫秒
1.
Quality of object relations versus interpersonal functioning as predictors of therapeutic alliance and psychotherapy outcome 总被引:1,自引:0,他引:1
W E Piper H F Azim A S Joyce M McCallum G W Nixon P S Segal 《The Journal of nervous and mental disease》1991,179(7):432-438
The purpose of the study was to compare an interview measure of quality of object relations to questionnaire and interview measures of recent interpersonal functioning with respect to the prediction of therapeutic alliance and psychotherapy outcome. The sample consisted of 64 patients who had received approximately 20 sessions of short-term individual psychotherapy within a controlled, clinical-trial investigation. Ratings of therapeutic alliance were provided independently by the patient and the therapist after each session. Outcome measures, which were provided by three sources (patient, therapist, and independent assessor), covered the areas of interpersonal functioning, psychiatric symptomatology, self-esteem, and life satisfaction. Quality of object relations, which characterizes the patient's lifelong pattern of relationships, was the best predictor. It was significantly related to patient-rated and therapist-rated therapeutic alliance and to patient improvement of both general symptomatology and specific target problems. The study also replicated previous studies that have reported significant relationships between therapeutic alliance and therapy outcome. The advantages of pretherapy predictors of therapy outcome, such as quality of object relations, are discussed. 相似文献
2.
3.
4.
Nonsteroidal anti-inflammatory drug use and increased risk for peptic ulcer disease in elderly persons 总被引:25,自引:0,他引:25
M R Griffin J M Piper J R Daugherty M Snowden W A Ray 《Annals of internal medicine》1991,114(4):257-263
OBJECTIVE: To evaluate the relative risk for peptic ulcer disease that is associated with the use of nonaspirin nonsteroidal anti-inflammatory drugs. DESIGN: Nested case-control study. SETTING: Tennessee Medicaid program. PARTICIPANTS: Medicaid enrollees 65 years of age or older were included in the study. The 1415 case patients had been hospitalized for confirmed peptic ulcer disease at some point from 1984 through 1986. The 7063 control persons represented a stratified random sample of other Medicaid enrollees. MEASUREMENTS AND MAIN RESULTS: The estimated relative risk for the development of peptic ulcer disease among current users of nonaspirin nonsteroidal anti-inflammatory drugs, compared with that among nonusers, was 4.1 (95% CI, 3.5 to 4.7). For current users, the risk increased with increasing dose, from a relative risk of 2.8 (CI, 1.8 to 4.3) for the lowest to a relative risk of 8.0 (CI, 4.4 to 14.8) for the highest dose category. The risk was greatest in the first month of use (relative risk, 7.2; CI, 4.9 to 10.5). If the association is fully causal, 29% of peptic ulcers in the study sample resulted from the use of these drugs, and the excess risk associated with such use was 17.4 hospitalizations for ulcer disease per 1000 person-years of exposure. CONCLUSIONS: These data support other findings indicating that a clinically significant risk for serious ulcer disease is associated with the use of nonaspirin nonsteroidal anti-inflammatory drugs. The data show that this risk increases with dose and recency of use and that use of these drugs may be responsible for a large proportion of peptic ulcer disease among elderly persons. 相似文献
5.
Reduction by prostaglandin E1 or prostaglandin E0 of myocardial infarct size in the rabbit by activation of ATP-sensitive potassium channels. 总被引:10,自引:2,他引:8
下载免费PDF全文
![点击此处可从《British journal of pharmacology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
E. J. Hide P. Ney J. Piper C. Thiemermann J. R. Vane 《British journal of pharmacology》1995,116(5):2435-2440
1. This study examined whether pretreatment of rabbits with infusions of prostaglandin E1 (PGE1) or prostaglandin E0 (PGE0) (which were terminated prior to the onset of ischaemia) reduce myocardial infarct size arising from coronary artery occlusion (60 min) and reperfusion (120 min). In addition, we investigated whether the observed cardioprotective effects of these two prostaglandins were due to the activation of ATP-sensitive potassium (KATP) channels. 2. In the anaesthetized rabbit, infarct size (expressed as a percentage of the area at risk) after 60 min of coronary artery occlusion followed by 2 h of reperfusion was 59 +/- 4% (n = 10). PGE1 or PGE0 treatment (1.0 micrograms kg-1 min-1), administered as 1 h pretreatments (0.05 ml min-1, i.v.), significantly reduced infarct size to 44 +/- 6% (n = 6) or 42 +/- 1% (n = 6), respectively. PGE1 or PGE0 pretreatment resulted in a significant reduction in mean arterial blood pressure, which returned to baseline within 15 min of discontinuation of the infusion (i.e. prior to LAL ligation). 3. The reduction in infarct size afforded by PGE1 was abolished by pretreatment of rabbits with the KATP channel blockers, glibenclamide (60 +/- 4%; n = 8) or 5-hydroxydecanoate (58 +/- 6%; n = 6). Similarly, glibenclamide also largely attenuated the reduction in infarct size afforded by PGE0 (52 +/- 3%; n = 8). 4. We propose that a 1 h pretreatment of PGE1 or PGE0 reduces infarct size by activating protein kinase C resulting in the opening of KATP channels. 相似文献
6.
7.
8.
Piper I. R.; Garrioch M. A.; Souter M. J.; Andrews PJD.; Thomson D. 《British journal of anaesthesia》1998,80(5):639-643
Diaspirin cross-linked haemoglobin (DCLHb) is a new oxygen carrying blood
substitute with vasoactive properties. Vasoactive properties may be
mediated via high affinity binding of nitric oxide by the haem moiety.
Using a rodent model of head injury combined with ischaemia, we studied the
effects of DCLHb on cerebral blood flow (CBF) and intracranial pressure
(ICP). Twenty anaesthetized rats were allocated randomly to receive
treatment with DCLHb 400 mg kg-1 i.v. or placebo (oncotically matched
plasma protein substitute 4.5% i.v.). To produce diffusely increased ICP,
after a severe weight drop injury, all animals underwent a 30-min period of
bilateral carotid ligation combined with a period of induced hypotension.
After reperfusion, DCLHb or placebo was infused and the animals
instrumented for measurement of intraventricular ICP and CBF in the region
of the sensorimotor cortex using the hydrogen clearance technique. Mean
arterial pressure (MAP), ICP, cerebral perfusion pressure (CPP) (CPP = MAP
- ICP) and CBF were measured 4 h after injury in all animals. DCLHb
significantly reduced ICP from mean 13 (SEM 2) to 3 (1) mm Hg (P <
0.001), increased CPP from 52 (8) to 95 (6) mm Hg (P < 0.001) and
increased CBF from 21 (2) to 29 (2) ml 100 g-1 min-1 (P = 0.032). We
conclude that DCLHb improved CPP without a reduction in CBF in a rodent
model of post-traumatic brain swelling.
相似文献
9.
J. E. Barker Y. S. Bakhle J. Anderson T. Treasure P. J. Piper 《British journal of pharmacology》1996,118(3):643-648
1. Angiotensin II (AII) causes contraction of isolated rings of human saphenous vein, responses that are attenuated by the presence of functional endothelium. In this study, we have investigated the mechanisms controlling the release by AII of two endothelial-derived vasorelaxants, prostacyclin (PGI2) and nitric oxide (NO). 2. Myotropic and biochemical changes were measured in response to AII. The biochemical responses measured were the output of PGI2 (as 6-oxo-PGF1 alpha) and of NO (as cyclic GMP). Inhibitors of cyclo-oxygenase (COX; piroxicam) or NO synthase (NOS; L-NAME), were added to the system to determine the influence of endogenous prostaglandins and NO on both myotropic and biochemical responses. Furthermore, to mimic the effects of endogenous, PGI2 or NO, exogenous forms of these relaxants were added, during inhibition of their endogenous release. 3. Contractions of the rings of saphenous vein in response to AII (1-100 nM) were unaffected by treatment with either piroxicam (5 microM) or L-NAME (200 microM) individually. However, when these two inhibitors were used together, there was an increase in the contractions in response to AII. 4. Biochemical analyses revealed that during stimulation by AII, levels of PGI2 and NO were enhanced when synthesis of the other vasodilator was inhibited, suggesting that endogenous NO inhibits PGI2 synthesis and endogenous, PGI2 or another vasorelaxant PG can inhibit NO synthesis. 5. Exogenous PGI2 (as iloprost) or NO (from glyceryl trinitrate) inhibited the increased output of endogenous NO or PGI2 respectively. 6. These results demonstrate the presence, in human saphenous vein, of a mechanism which ensures that levels of vasodilatation are maintained through a compensatory increase in one relaxant agonist when output of the other is decreased. If present in vivo such a mechanism would be important in maintaining saphenous vein graft patency as both PGI2 and NO are not only vasodilators, but inhibit platelet aggregation and myoinitimal hyperplasia, processes implicated in degeneration of graft function. 相似文献
10.
Using the artificial beta-cell (Biostator), we determined the insulin requirements in five nonobese type I (insulin-dependent) diabetic subjects who received isocaloric 40 and 60% mixed-carbohydrate diets in a crossover randomized fashion for 4 days, each day consisting of four equal meals. This was followed on day 5 by a "Big Mac Attack" lunch consisting of a Big Mac, french fries, and milk shake. Insulin requirements to maintain normoglycemia were calculated for each 24-h period and for the 2 h after each meal. The mean 24-h insulin requirements to maintain normoglycemia was greater for the 60% carbohydrate diet than the 40% diet. Although the four meals were of equal size, in all patients the insulin required to cover breakfast greater than lunch greater than dinner greater than or equal to snack. Expressed as milliunits per kilocalorie, the amount of insulin to cover breakfast was greater for the 60% (P less than .05) than the 40% carbohydrate diet and greater for breakfast than the other meals (P less than .01). Insulin requirements for the Big Mac (43% carbohydrate) were 58% greater than for the 40% carbohydrate diet, even after correction for caloric differences. In summary, 1) increasing dietary carbohydrate from 40 to 60% results in an increased insulin requirement for meals only; 2) insulin requirements are greater in the morning than in the evening, even when meal size is constant; and 3) very large meals with high fat and carbohydrate content result in a major increase in insulin requirement. These data indicate that diet has an important impact on insulin requirements in diabetes. 相似文献