全文获取类型
收费全文 | 4752篇 |
免费 | 244篇 |
国内免费 | 36篇 |
专业分类
耳鼻咽喉 | 49篇 |
儿科学 | 125篇 |
妇产科学 | 96篇 |
基础医学 | 746篇 |
口腔科学 | 100篇 |
临床医学 | 395篇 |
内科学 | 1070篇 |
皮肤病学 | 49篇 |
神经病学 | 411篇 |
特种医学 | 151篇 |
外科学 | 877篇 |
综合类 | 20篇 |
预防医学 | 308篇 |
眼科学 | 86篇 |
药学 | 340篇 |
中国医学 | 9篇 |
肿瘤学 | 200篇 |
出版年
2022年 | 23篇 |
2021年 | 50篇 |
2020年 | 35篇 |
2019年 | 38篇 |
2018年 | 44篇 |
2017年 | 47篇 |
2016年 | 62篇 |
2015年 | 75篇 |
2014年 | 97篇 |
2013年 | 128篇 |
2012年 | 183篇 |
2011年 | 222篇 |
2010年 | 146篇 |
2009年 | 150篇 |
2008年 | 259篇 |
2007年 | 269篇 |
2006年 | 257篇 |
2005年 | 280篇 |
2004年 | 276篇 |
2003年 | 261篇 |
2002年 | 240篇 |
2001年 | 113篇 |
2000年 | 145篇 |
1999年 | 134篇 |
1998年 | 90篇 |
1997年 | 57篇 |
1996年 | 53篇 |
1995年 | 61篇 |
1994年 | 59篇 |
1993年 | 57篇 |
1992年 | 68篇 |
1991年 | 80篇 |
1990年 | 56篇 |
1989年 | 61篇 |
1988年 | 50篇 |
1987年 | 49篇 |
1986年 | 50篇 |
1985年 | 44篇 |
1984年 | 34篇 |
1983年 | 39篇 |
1982年 | 35篇 |
1981年 | 46篇 |
1980年 | 42篇 |
1979年 | 25篇 |
1978年 | 30篇 |
1977年 | 30篇 |
1976年 | 22篇 |
1975年 | 38篇 |
1973年 | 19篇 |
1961年 | 17篇 |
排序方式: 共有5032条查询结果,搜索用时 15 毫秒
71.
Eberhard Schlicker Walter Schunack Manfred Göthert 《Naunyn-Schmiedeberg's archives of pharmacology》1990,342(5):497-501
Summary Discs of pig retina were preincubated with 3H-noradrenaline, 3H-dopamine or 3H-serotonin and then superfused. Electrical field stimulation increased the outflow of tritium from discs preincubated with 3H-noradrenaline or 3H-dopamine, but no from discs preincubated with 3H-serotonin. The tritium content at the end of superfusion was similar in discs preincubated with 3H-noradrenaline or 3H-dopamine but about tenfold lower in discs preincubated with 3H-serotonin. The tritium content in discs preincubated with 3H-noradrenaline was markedly reduced when desipramine was present during preincubation but was not affected by selective inhibitors of dopamine and serotonin uptake. The tritium content in discs preincubated with 3Hdopamine and 3H-serotonin, in contrast, was reduced or tended to be reduced by a selective dopamine and serotonin uptake inhibitor, respectively.The electrically evoked overflow of tritium from discs preincubated with 3H-noradrenaline was abolished by tetrodotoxin or omission of Ca2+. In discs superfused with desipramine, the electrically evoked overflow was enhanced by phentolamine but not affected by histamine. When both desipramine and phentolamine were present in the superfusion medium, histamine inhibited the evoked overflow (pIC15 6.85). This effect was mimicked by the histamine H3 receptor agonist R-(–)--methylhistamine as well as by its S-(+)-enantiomer (pIC15 7.85 and 5.30, respectively) but not by the H1 receptor agonist 2-(2-thiazolyl)ethylamine and the H2 receptor agonist dimaprit (each 10 mol/l). The inhibitory effect of histamine was abolished by the H3 receptor antagonist thioperamide 0.32 mol/l and attenuated by impromidine 3.2 mol/l but not affected by the H1 receptor antagonist dimetindene 3.2 mol/l and the H2 receptor antagonist ranitidine 10 mol/l.The results suggest that, in the pig retina, noradrenaline is taken up into, and released from, noradrenergic neurones (most likely vascular postganglionic sympathetic nerve fibres, less probably tissue-specific noradrenergic neurones of the retina) and that noradrenaline release is subject to modulation via H3 receptors and probably also a-adrenoceptors.Send offprint requests to E. Schlicker at the above address 相似文献
72.
Transoral laser surgery for early glottic carcinoma 总被引:2,自引:0,他引:2
H. E. Eckel W. Thumfart Markus Jungehülsing Christian Sittel Eberhard Stennert 《European archives of oto-rhino-laryngology》2000,257(4):221-226
This prospective study evaluates the oncological results of transoral laser surgery (TLS) for glottic carcinoma categorized
Tis, T1 and T2 in a large, unselected group of 285 consecutive patients from a university-based referral center that uses
transoral laser surgery as the standard approach to these tumors. Patients were treated between 1 January 1987 and 31 December
1996. Thirty-three patients had Tis disease, 174 T1 tumors and 113 T2. Main outcome measures were local control with initial
therapy, ultimate local control, regional control, organ preservation, overall survival and cause-specific survival. The 5-year
uncorrected actuarial survival for all 285 patients was 71.1%, and cause-specific actuarial survival was 98.7%. Local control
with initial treatment was 85.9%, ultimate local control with salvage for local treatment failures 98.5%, and regional control
98.4%. In all, 94.3% had their larynges preserved after 5 years. Although favorable oncological results for early laryngeal
carcinoma treated with laser surgery are supported this study, no definitive recommendations can be given for the best single
treatment. Partial laryngectomies lead to the highest local control rates reported so far, radiotherapy is believed to preserve
voice best and laser surgery is associated with time- and cost-effectiveness, low morbidity, fair local control rates and
excellent re-treatment options in case of local failure. All specialists dealing with the treatment of early glottic carcinoma
should be able to offer these different treatment modalities to their patients and to deal specifically with each patient’s
individual needs and preferences.
Received: 29 October 1998 / Accepted: 2 July 1999 相似文献
73.
Involvement of nitric oxide synthase in the physiology and pathophysiology of facial nerve function and dysfunction 总被引:1,自引:0,他引:1
O. Michel Alexander Hess Martin Krolzig Eberhard Stennert Klaus Addick Wilhelm Bloch 《European archives of oto-rhino-laryngology》2000,257(4):188-192
To date few reports have discussed the presence and function of nitric oxide (NO) in structures of the facial nerve. We performed
nicotinamide adenine dinucleotide phosphate (NADPH-d)-diaphorase-histochemistry and immunohistochemistry on the intratemporal
portion of the facial nerve, including the geniculate ganglion, of guinea pigs using specific antibodies to the three known
isoforms of NO synthase and soluble guanylyl-cyclase (sGC). Normal facial nerves were compared to those treated intratympanically
with bacterial lipopolysaccharides (LPS) and tumor necrosis factor-α (TNF-α). Both constitutive NOS isoforms and sGC could
be detected in the bipolar ganglion cells of normal animals, while the inducible isoform (iNOS or NOS II) was not found. Endothelial
NOS (NOS III) and sGC were present in blood vessels and were predominantly found in the perineurial sheath and less in the
endoneurium. sGC could be detected in all fibers in a cross section of the facial nerve. LPS and TNF treatment led to the
detection of iNOS in the perikaryia of the geniculate ganglion and the perineural sheath. These findings imply that NO may
be involved in neurotransmission at least in the visceroafferent system. NO regulates vascular tone of nutrient blood vessels
in the perineural sheath and endoneurium. The presence of sGC indicates that NO acts via its second messenger cGMP. NOS II
expression may be a contributing factor to facial nerve palsy via two different mechanisms: NOS II-generated NO may lead to
an overstimulation of the visceroefferent nerve fibers and motor fibers of the facial nerve. Dysregulation in facial nerve
blood vessels could lead to edema and elevated pressure on the nerve within its osseous canal.
Received: 13 April 1999 / Accepted: 12 August 1999 相似文献
74.
U. Zwettler D. Fliser M. Nowicki E. Ritz 《European journal of clinical pharmacology》1994,46(3):185-189
The influence of angiotensin converting enzyme (ACE) inhibition on acute extrarenal and renal potassium elimination in stable chronic renal failure has been examined in 10 male patients median age 44 y; mean CLCR 42 ml·min–1·1.73 m–2. In a double blind, placebo-controlled cross-over study, K+ 0.3 or 0.4 mmol·kg–1 body weight was infused IV on two occasions while the patients also received an infusion either of placebo or 0.5 mg of the ACE inhibitor perindoprilat in random order. Plasma K+ levels and urinary K+ excretion were measured at regular intervals. During the study patients adhered to an isocaloric diet providing a standardised daily intake of potassium and sodium (50 mmol K+ and 40 mmol Na+).The median rise in plasma K+ was not significantly different after placebo ( K 0.66 mmol·1–1) compared with to the infusion of perindoprilat ( K 0.66 mmol·1–1). The median baseline urinary K+ excretion rate was 6.5 mmol·3 h–1 before the placebo infusion and 5.9 mmol·3 h–1 before infusion of perindoprilat. During the potassium load, the urinary excretion rate rose to 16.1 mmol·3 h–1 (after placebo) and 15.1 mmol·3 h–1 after perindoprilat in the first 3 h, and it returned almost to the baseline value within the next 3 h (5.6 mmol·3 h–1 after placebo and 5.7 mmol·3 h–1 after perindoprilat); the differences were not statistically significant.With perindoprilat a decrease in mean arterial blood pressure and ACE activity, an increase in renin plasma activity and a decrease in aldosterone concentrations were observed compared to the placebo infusion. There was no significant differences plasma in adrenaline or insulin levels after either infusion.Thus, ACE inhibition did not interfere either with the extrarenal or the renal disposal of an acute potassium load in patients with chronic renal failure. 相似文献
75.
Hans Juha Exner Eberhard Schlicker 《Naunyn-Schmiedeberg's archives of pharmacology》1995,351(1):46-52
Mouse or rat brain cortex slices were preincubated with 3H-noradrenaline and superfused with physiological salt solution containing desipramine. We studied the effects of prostaglandin E2 (PGE2), prostaglandin D2 (PGD2) and related drugs on the electrically evoked (50 mA, 2 ms, 0.3 Hz) tritium overflow.PGE2 inhibited the electrically evoked tritium overflow from mouse brain cortex slices; the maximum effect of PGE2 (79010) was attenuated by the 2-adrenoceptor agonist talipexole (to 52010) and enhanced by the 2-adrenoceptor antagonist rauwolscine (to 92%). Rauwolscine was added to the superfusion medium in all subsequent experiments. The effect of PGE2 was readily reversible upon withdrawal from the medium and remained constant upon prolonged exposure of the tissue to the prostanoid. Studies with EP receptor agonists, mimicking the inhibitory effect of PGE2, showed the following potencies (pIC50): sulprostone (8.22); misoprostol (8.00); PGE2 (7.74); PGEZ (7.61); iloprost (5.86). The concentration-response curve of PGE2 was marginally shifted to the right by the EP1 receptor antagonist AH 6809 (6-isopropoxy-9-oxoxanthene-2-carboxylic acid; apparent pA2 3.97) and by the TP receptor antagonist vapiprost (4.50). AH 6809, by itself, did not affect the evoked overflow whereas vapiprost increased it. PGD2 inhibited the evoked overflow at high concentrations (pIC50 4.90); this effect was not altered by the DP receptor antagonist BW A868C (3-benzyl-5-(6-carboxyhexyl)-1-(2-cyclohexyl-2hydroxyethylamino)hydantoin), which, by itself, did not affect the evoked overflow. Indometacin slightly increased the evoked overflow and tended to increase the inhibitory effect of PGE2. PGE2 inhibited the electrically evoked tritium overflow also in rat brain cortex slices. The maximum effect (obtained in the presence of rauwolscine) was 61%; the pIC30 value was 7.67.The present study suggests that PGE2 inhibits noradrenaline release from mouse brain cortex via EP3 receptors and that its maximum effect is more marked in the mouse than in the rat. The inhibitory effect of PGD2 (in the mouse brain) does not involve DP receptors and may also be related to EP3 receptors. The EP3 receptors interact with a2-adrenoceptors and may be activated by endogenous prostanoids. 相似文献
76.
A. Wiecek M. Nowicki D. Fliser E. Ritz 《European journal of clinical pharmacology》1995,48(3-4):203-208
Moxonidine and related compounds have been recently introduced into antihypertensive therapy. It is thought that these drugs exert their blood pressure lowering effect through interaction with nonadrenergic receptors in the central nervous system, i.e. imidazoline receptors, although the contribution of specific interaction with 2-receptors is still under debate. Imidazoline receptors have recently been documented in the renal proximal tubule. In experimental studies, interaction of imidazolines with these receptors decreased the activity of the Na+/H+ antiporter and induced natriuresis. To quantitate the effect of the imidazoline receptor agonist moxonidine on renal sodium handling and renal haemodynamics in man, we examined ten healthy normotensive males (aged 25 ± 4 years) in a double blind placebo-controlled study using a crossover design. Subjects were studied on a standardized salt intake (50 mmol per day). On the 7th and 10th study day they were randomly allocated to receive either i.v. placebo or i.v. 0.2 mg moxonidine. Urinary electrolyte excretion, lithium clearance (as an index of proximal tubular sodium handling), glomerular filtration rate (GFR), effective renal plasma flow (ERPF), renal vascular resistance (RVR), mean arterial blood pressure (MAP), plasma renin activity (PRA) and plasma noradrenaline (NA) levels were assessed. Injection of moxonidine did not increase fractional sodium excretion or lithium clearance. Specifically, antinatriuresis was not observed after injection of moxonidine despite a significant decrease in MAP from 91 to 85 mmHg and a significant increase in PRA. MAP and PRA did not change with administration of placebo. Injection of moxonidine did not affect GFR and RVR; ERPF decreased slightly but not significantly. Acute administration of 0.2 mg i.v. moxonidine decreased blood pressure in healthy volunteers on standardized salt intake, but did not affect natriuresis, proximal tubular sodium reabsorption or glomerular filtration rate. The absence of an antinatriuretic response despite a decrease in blood pressure suggests a direct facilitation of natriuresis by moxonidine. 相似文献
77.
The effect of ambient carbon monoxide on low birth weight among children born in southern California between 1989 and 1993. 总被引:13,自引:6,他引:7
We evaluated the effect of carbon monoxide (CO) exposures during the last trimester of pregnancy on the frequency of low birth weight among neonates born 1989-1993 to women living in the Los Angeles, California, area. Using birth certificate data for that period, we assembled a retrospective cohort of infants whose mothers resided within 2 miles of 1 of 18 CO monitoring stations. Based on the gestational age and birth date of each child, we estimated last-trimester exposure by averaging the corresponding 3 months of daily CO concentrations registered at the monitoring station closest to the mother's residence (determined from the birth certificate). Where data were available (at 6 stations), we also averaged measurements taken daily for nitrogen dioxide and ozone and those taken at 6-day intervals for particulate matter [less than/equal to]10 microm (PM10) to approximate last-trimester exposures to other pollutants. Overall, the study cohort consisted of 125,573 singleton children, excluding infants born before 37 or after 44 weeks of gestation, those weighing below 1,000 or above 5,500 g at birth, those for whom fewer than 10 days of CO measurements were available during the last trimester, and those whose mothers suffered from hypertension, diabetes, or uterine bleeding during pregnancy. Within the cohort, 2,813 (2.2%) were low in birth weight (between 1,000 and 2,499 g). Exposure to higher levels of ambient CO (>5.5 ppm 3-month average) during the last trimester was associated with a significantly increased risk for low birth weight [odds ratio (OR) = 1.22; 95% confidence interval (CI), 1.03-1.44] after adjustment for potential confounders, including commuting habits in the monitoring area, sex of the child, level of prenatal care, and age, ethnicity, and education of the mother. 相似文献
78.
Due to the Hospital Statistics Regulations of the 10th April 1990, the German Hospital Diagnosis Statistics were introduced in 1993 with the intention to serve as a database of health care decisions. This purpose requires a high-quality collection of epidemiologically relevant data. From 1993 to 1996 we analysed the datasets obtainable for subarachnoid haemorrhage which is coded with ICD 430. A subset concerning the data of 1996 and the Saarland region was compared to the data of the Saarland medical school at Homburg/Saar. Cases treated in the neurosurgical department were critically reviewed. About 20% of the cases coded with ICD 430 showed no subarachnoid haemorrhage. On the other hand, again about 20% of subarachnoid haemorrhage cases were not coded with ICD 430. The statistics comprise duplicates due to transfers between hospitals. The calculation of incidence is not possible because new bleeding cases cannot be outlined. In the present form the German Hospital Diagnosis Statistics are not suitable as a reliable base of health care decisions. This is partly caused by the inadequacy of the ICD-classification but, also, by the criteria for collecting data. We propose several modifications which can improve data quality in order to meet the intended requirements. 相似文献
79.
Wetterberg L Bratlid T von Knorring L Eberhard G Yuwiler A 《European archives of psychiatry and clinical neuroscience》1999,249(5):256-262
Overnight urines were collected each month for 12–16 months from 321 normal subjects at 19 medical centers in 14 countries
distributed on 5 continents at latitudes from 31 01 South to 77 00 North. Mean melatonin concentration was found to negatively
correlate with age, weight, and height. When the sexes were considered separately melatonin only correlated with age for female
and with age and weight for males. A weak correlation with latitude, but not longitude, was also found.
Received: 26 February 1998 / Accepted: 9 September 1999 相似文献
80.