全文获取类型
收费全文 | 2971篇 |
免费 | 295篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 121篇 |
妇产科学 | 45篇 |
基础医学 | 418篇 |
口腔科学 | 123篇 |
临床医学 | 388篇 |
内科学 | 500篇 |
皮肤病学 | 67篇 |
神经病学 | 138篇 |
特种医学 | 321篇 |
外国民族医学 | 1篇 |
外科学 | 324篇 |
综合类 | 60篇 |
预防医学 | 283篇 |
眼科学 | 82篇 |
药学 | 258篇 |
1篇 | |
中国医学 | 3篇 |
肿瘤学 | 152篇 |
出版年
2022年 | 18篇 |
2021年 | 28篇 |
2020年 | 30篇 |
2019年 | 37篇 |
2018年 | 46篇 |
2017年 | 28篇 |
2016年 | 35篇 |
2015年 | 52篇 |
2014年 | 70篇 |
2013年 | 115篇 |
2012年 | 112篇 |
2011年 | 120篇 |
2010年 | 107篇 |
2009年 | 93篇 |
2008年 | 98篇 |
2007年 | 119篇 |
2006年 | 103篇 |
2005年 | 121篇 |
2004年 | 83篇 |
2003年 | 95篇 |
2002年 | 80篇 |
2001年 | 95篇 |
2000年 | 61篇 |
1999年 | 86篇 |
1998年 | 102篇 |
1997年 | 85篇 |
1996年 | 81篇 |
1995年 | 70篇 |
1994年 | 43篇 |
1993年 | 61篇 |
1992年 | 47篇 |
1991年 | 65篇 |
1990年 | 58篇 |
1989年 | 82篇 |
1988年 | 79篇 |
1987年 | 63篇 |
1986年 | 53篇 |
1985年 | 55篇 |
1984年 | 36篇 |
1983年 | 33篇 |
1982年 | 35篇 |
1981年 | 29篇 |
1980年 | 29篇 |
1979年 | 23篇 |
1978年 | 42篇 |
1977年 | 33篇 |
1976年 | 37篇 |
1975年 | 37篇 |
1974年 | 18篇 |
1970年 | 25篇 |
排序方式: 共有3290条查询结果,搜索用时 0 毫秒
71.
72.
73.
74.
75.
Gonadotropin-inhibitory hormone neurons interact directly with gonadotropin-releasing hormone-I and -II neurons in European starling brain 总被引:3,自引:0,他引:3
Ubuka T Kim S Huang YC Reid J Jiang J Osugi T Chowdhury VS Tsutsui K Bentley GE 《Endocrinology》2008,149(1):268-278
Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic dodecapeptide (SIKPSAYLPLRF-NH(2)) that directly inhibits gonadotropin synthesis and release from quail pituitary. The action of GnIH is mediated by a novel G-protein coupled receptor. This gonadotropin-inhibitory system may be widespread in vertebrates, at least birds and mammals. In these higher vertebrates, histological evidence suggests contact of GnIH immunoreactive axon terminals with GnRH neurons, thus indicating direct regulation of GnRH neuronal activity by GnIH. In this study we investigated the interaction of GnIH and GnRH-I and -II neurons in European starling (Sturnus vulgaris) brain. Cloned starling GnIH precursor cDNA encoded three peptides that possess characteristic LPXRF-amide (X = L or Q) motifs at the C termini. Starling GnIH was further identified as SIKPFANLPLRF-NH(2) by mass spectrometry combined with immunoaffinity purification. GnIH neurons, identified by in situ hybridization and immunocytochemistry (ICC), were clustered in the hypothalamic paraventricular nucleus. GnIH immunoreactive fiber terminals were present in the external layer of the median eminence in addition to the preoptic area and midbrain, where GnRH-I and GnRH-II neuronal cell bodies exist, respectively. GnIH axon terminals on GnRH-I and -II neurons were shown by GnIH and GnRH double-label ICC. Furthermore, the expression of starling GnIH receptor mRNA was identified in both GnRH-I and GnRH-II neurons by in situ hybridization combined with GnRH ICC. The cellular localization of GnIH receptor has not previously been identified in any vertebrate brain. Thus, GnIH may regulate reproduction of vertebrates by directly modulating GnRH-I and GnRH-II neuronal activity, in addition to influencing the pituitary gland. 相似文献
76.
Saskia PJ Verkleij Pim AJ Luijsterburg Sten P Willemsen Bart W Koes Arthur M Bohnen Sita MA Bierma-Zeinstra 《The British journal of general practice》2015,65(637):e530-e537
Background
The effectiveness of diclofenac versus paracetamol in primary care patients with pain caused by knee osteoarthritis is unclear.Aim
To assess the effectiveness of diclofenac compared with paracetamol over a period of 2, 4, and 12 weeks in patients with knee osteoarthritis.Design and setting
Randomised controlled trial in general practice.Method
There were 104 patients included in the study, they were aged ≥45 years consulting their GP with knee pain caused by knee osteoarthritis. Patients were randomly allocated to diclofenac (n = 52) or paracetamol (n = 52) for at least 2 weeks. Primary outcomes were daily knee pain severity, and knee pain and function measured with the Knee Injury and Osteoarthritis Outcome Score (KOOS).Results
Over a period of 2- and 4-weeks follow-up, no significant difference in daily knee pain was found between the patient groups: estimated differences of 0.5 (95% CI = −0.2 to 1.3) and −0.2 (95% CI = −1.0 to 0.7), respectively. Over the 12-weeks follow-up, no significant differences were found between both groups for KOOS pain: estimated difference of −2.8 (95% CI = −10.7 to 5.1) and KOOS function of −2.7 (−10.6 to 5.0).Conclusion
Over a period of 2- and 4-weeks follow-up no significant difference in daily measured knee pain severity was found between primary care patients with knee osteoarthritis taking paracetamol or diclofenac. Also, over a period of 12-weeks follow-up no significant differences were found regarding KOOS pain and KOOS function between both groups. Patients more frequently reported minor adverse events after taking diclofenac (64%) than paracetamol (46%). 相似文献77.
J C Romero L M Ruilope M D Bentley M J Fiksen-Olsen V Lahera M J Vidal 《The American journal of cardiology》1988,62(11):59G-68G
Calcium antagonists decrease the ability of the kidney to autoregulate renal blood flow (RBF) and glomerular filtration rate (GFR). Therefore, when afferent renovascular resistance is elevated, as in essential hypertension, there is a resultant increase in RBF and GFR with the administration of calcium antagonists. These agents also induce a marked natriuresis because of direct tubular action through unknown mechanisms. The natriuresis can be dissociated from renal and systemic hemodynamic actions, indicating that the decreased sodium reabsorption could override other compensatory mechanisms explaining the absence of sodium retention during the treatment. The renal effects of converting enzyme inhibitors (CEIs) can be explained by the reduction of intrarenal formation in angiotensin II. Because the activation of the renin-angiotensin system is mainly responsible for inducing sodium retention during a decrease in systemic blood pressure, CEIs could have a protecting effect without disturbing other homeostatic mechanisms. CEIs decrease efferent glomerular resistance, reducing capillary pressure and thereby reducing GFR. This effect is not translated in sodium retention because the reduction of GFR is mild during captopril administration in kidneys with normal or increased renal perfusion pressure. At low renal perfusion pressure, the reduced glomerular afferent vasoconstriction can compromise GFR, leading to renal insufficiency. Although these situations are not likely to be encountered during the treatment of uncomplicated essential hypertension, in severe hypertension with hypertrophy of pre-glomerular vessels, glomerular perfusion may decrease. Combination therapy of calcium antagonists and CEIs has been reported to be an effective treatment of severe hypertension. Currently, little information is available on the manner in which renal function is affected by simultaneous administration of both drugs. 相似文献
78.
79.
Styles LA; Schalkwijk CG; Aarsman AJ; Vichinsky EP; Lubin BH; Kuypers FA 《Blood》1996,87(6):2573-2578
Acute chest syndrome (ACS) is associated with significant morbidity and is the leading cause of death in patients with sickle cell disease (SCD). Recent reports suggest that bone marrow fat embolism can be detected in many cases of severe ACS. Secretory phospholipase A2 (sPLA2) is an important inflammatory mediator and liberates free fatty acids, which are felt to be responsible for the acute lung injury of the fat embolism syndrome. We measured SPLA2 levels in 35 SCD patients during 20 admissions for ACS, 10 admissions for vaso-occlusive crisis, and during 12 clinic visits when patients were at the steady state. Eleven non-SCD patients with pneumonia were also evaluated. To determine if there was a relationship between sPLA2 and the severity of ACS we correlated SPLA2 levels with the clinical course of the patient. In comparison with normal controls (mean = 3.1 +/- 1.1 ng/mL), the non- SCD patients with pneumonia (mean = 68.6 +/- 82.9 ng/mL) and all three SCD patient groups had an elevation of SPLA2 (steady state mean = 10.0 +/- 8.4 ng/mL; vaso-occlusive crisis mean = 23.7 +/- 40.5 ng/mL; ACS mean = 336 +/- 209 ng/mL). In patients with ACS sPLA2 levels were 100- fold greater than normal control values, 35 times greater than values in SCD patients at baseline, and five times greater than non-SCD patients with pneumonia. The degree of SPLA2 elevation in ACS correlated with three different measures of clinical severity and, in patients followed sequentially, the rise in SPLA2 coincided with the onset of ACS. The dramatic elevation of SPLA2 in patients with ACS but not in patients with vaso-occlusive crisis or non-SCD patients with pneumonia and the correlation between levels of SPLA2 and clinical severity suggest a role for SPLA2 in the diagnosis and, perhaps, in the pathophysiology of patients with ACS. 相似文献
80.
Development of an opinion leader-led HIV prevention intervention among alcohol users in Chennai, India. 总被引:1,自引:0,他引:1
Sudha Sivaram Aylur K Srikrishnan Carl A Latkin Sethulakshmi C Johnson Vivian F Go Margaret E Bentley Suniti Solomon David D Celentano 《AIDS education and prevention》2004,16(2):137-149
In 1999, we began a community-based randomized controlled prevention trial in Chennai, which aims to test the efficacy of HIV prevention messages disseminated through members of an individual's social group called community popular opinion leaders, or CPOLs. We targeted patrons of 100 bars or wine shops in the city of Chennai, India. In this article we report on the process of development of an HIV prevention intervention for wine shop patrons. First, we conducted detailed ethnography to understand social norms and CPOL and social network characteristics, including 41 in-depth interviews among wine shop patrons and gatekeepers. Second, we tailored a generic HIV education training manual to appropriately address the needs of Chennai wine shop patrons. Field-testing involved 16 focus groups with wine shop patrons and 12 sessions of participant observations in wine shops. Finally, we piloted the intervention to determine the appropriateness of the training program and its content among wine shop patrons. Our ethnographic data indicated that wine shops are a common meeting place for men. We were able to identify CPOLs influential in these settings and train them to deliver appropriate prevention messages to their close friends and associates. We found that HIV prevention messages in this population need to dispel misperceptions about HIV transmission, provide strategies and skills to adopt and sustain condom use, and target the role of alcohol in sexual behavior. We outline specific lessons we learned in intervention development in this population. 相似文献