全文获取类型
收费全文 | 4902篇 |
免费 | 254篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 68篇 |
儿科学 | 106篇 |
妇产科学 | 149篇 |
基础医学 | 490篇 |
口腔科学 | 134篇 |
临床医学 | 437篇 |
内科学 | 1361篇 |
皮肤病学 | 84篇 |
神经病学 | 246篇 |
特种医学 | 76篇 |
外科学 | 887篇 |
综合类 | 123篇 |
一般理论 | 2篇 |
预防医学 | 283篇 |
眼科学 | 138篇 |
药学 | 320篇 |
中国医学 | 23篇 |
肿瘤学 | 261篇 |
出版年
2023年 | 45篇 |
2022年 | 118篇 |
2021年 | 197篇 |
2020年 | 100篇 |
2019年 | 149篇 |
2018年 | 191篇 |
2017年 | 110篇 |
2016年 | 152篇 |
2015年 | 147篇 |
2014年 | 193篇 |
2013年 | 217篇 |
2012年 | 373篇 |
2011年 | 369篇 |
2010年 | 196篇 |
2009年 | 180篇 |
2008年 | 308篇 |
2007年 | 300篇 |
2006年 | 265篇 |
2005年 | 302篇 |
2004年 | 264篇 |
2003年 | 220篇 |
2002年 | 201篇 |
2001年 | 66篇 |
2000年 | 36篇 |
1999年 | 48篇 |
1998年 | 33篇 |
1997年 | 23篇 |
1996年 | 28篇 |
1995年 | 25篇 |
1994年 | 21篇 |
1993年 | 15篇 |
1992年 | 33篇 |
1991年 | 25篇 |
1990年 | 27篇 |
1989年 | 13篇 |
1988年 | 26篇 |
1987年 | 17篇 |
1986年 | 12篇 |
1985年 | 9篇 |
1984年 | 13篇 |
1983年 | 7篇 |
1982年 | 12篇 |
1981年 | 10篇 |
1980年 | 8篇 |
1979年 | 6篇 |
1977年 | 7篇 |
1971年 | 6篇 |
1970年 | 9篇 |
1968年 | 9篇 |
1967年 | 9篇 |
排序方式: 共有5188条查询结果,搜索用时 15 毫秒
1.
2.
C Lee R Salim D Ofili-Yebovi J Yazbek A Davies D Jurkovic 《Ultrasound in obstetrics & gynecology》2006,28(6):837-841
OBJECTIVE: To determine the intraobserver and interobserver reproducibility of measurement of the percentage of protrusion of submucous fibroids into the uterine cavity using three-dimensional saline contrast sonohysterography (3D-SCSH). METHODS: Women diagnosed with submucous uterine fibroids on B-mode two-dimensional (2D) ultrasound scan were invited to join the study and 3D-SCSH was carried out. 3D volume datasets were stored digitally and were examined later using the technique of planar reformatted sections. The reproducibilities of the measurement of fibroid diameter and protrusion ratio into the uterine cavity (ratio of the size of the segment of the fibroid protruding into the cavity to the total diameter of the fibroid) were examined by two independent observers who were unaware of the initial 2D scan findings. Interobserver reproducibility was assessed by calculating the difference between measurements taken by the two operators (limits of agreement) and interclass correlation coefficient. Intraobserver repeatability was assessed by calculating the difference between two measurements for each variable (limits of agreement) and further expressed as an intraclass correlation coefficient. RESULTS: Thirty-three 3D ultrasound volumes were examined. There was a good agreement between the observers in classifying the fibroids as greater or less than 50% confined to the myometrium (Cohen's kappa 0.81). There was no bias in measurements for both variables either between observers or with repeated measurements by each observer. For fibroid diameter and protrusion ratio the inter- and intraclass correlation coefficients were high (0.984-0.995), with narrow limits of agreement. CONCLUSION: 3D-SCSH is a reproducible method for the quantification of the percentage of a submucous fibroid protruding into the uterine cavity. 相似文献
3.
4.
5.
M Burgin G Hopkins B Moore J Nasser A Richardson R Minchinton 《Medical laboratory sciences》1992,49(4):265-270
This Australian study monitored the effects of monthly plasmapheresis on donor serum IgG and IgM levels in 127 new and 124 established plasma donors who donated 1014 units over a five-month period. Of the 251 donors, 3% had reduced total serum protein (TSP) levels, 7% had low IgG levels and 12% had low IgM levels prior to donation on at least one occasion over the study period. Statistical analysis showed that the TSP, IgG and IgM levels of new donors who had donated plasma on less than 10 occasions were no more likely to fall below normal than those of old donors. However, new and old donors whose IgG or IgM levels fell below normal at any time during the study had significantly lower levels of the relevant parameter on entry to the study. Followed longitudinally, IgG and IgM levels in old and new donors tended to fall, although levels fluctuated throughout the study. Statistical analysis failed to show any correlation between TSP levels and IgG or IgM levels. These parameters did not correlate significantly with the number of previous plasmaphereses, donor weight, volume collected or history of infection. This study highlighted the need for regular, specific quantitation of IgG and IgM levels as well as TSP in regular plasmapheresis donors. The frequency of testing is yet to be determined, in view of the high materials and labour costs of such a programme. 相似文献
6.
A S Salim 《Clinical science (London, England : 1979)》1991,80(1):59-64
1. Reserpine (5 mg/kg intraperitoneally) produced gastric mucosal vasoconstriction and injury in all rats within 6 h (injury score 38.8 +/- 2.1 mm2, mean +/- SEM). Coeliac ganglionectomy or the beta-adrenoceptor-blocking drug propranolol (5-15 mg/kg) did not influence these effects of reserpine, but vagotomy protected the rats against them. The alpha-adrenoceptor-blocking drugs phenoxybenzamine and phentolamine at 5 mg/kg were protective against injury. However, a 10 mg/kg dose of either blocker was more effective (2.2 +/- 0.5 mm2 and 3 +/- 0.8 mm2, respectively, versus 38.8 +/- 2.1 mm2, mean +/- SEM, P less than 0.01) and a dose of 15 mg/kg afforded complete protection. 2. Methysergide, a 5-hydroxytryptamine receptor antagonist, produced a dose-dependent increase in the reserpine-induced injury; a significant (P less than 0.05) increase was noted with 15 and 20 mg/kg (47.5 +/- 2.9 mm2 and 49.4 +/- 2.2 mm2, respectively, versus 38.8 +/- 2.1 mm2, mean +/- SEM). 3. The results suggest that, in the rat, reserpine causes vagal alpha-adrenoceptor stimulation producing gastric mucosal vasoconstriction and injury. 5-Hydroxytryptamine is not implicated in the mechanism of this injury and affords protection against it. 相似文献
7.
A S Salim 《Journal of pharmaceutical sciences》1992,81(7):698-700
Reserpine (intraperitoneal, 5 mg/kg every day for 5 days) produced chronic ulceration of the rat stomach 2 weeks postdose. Gavage with 1% DL-cysteine or DL-methionine-S-methylsulfonium chloride at 1 mL/day for 2 weeks and 5 days protected against ulceration in 30% of the rats, and this protection extended to 80% of cases with 2% solutions. Similar gavage with 5% solutions protected all rats against ulceration without significantly influencing the basal H+ output [13.1 +/- 0.3 and 14.2 +/- 0.2 mumol for DL-cysteine and DL-methionine-S-methylsulfonium chloride, respectively, versus 15.1 +/- 0.4 mumol (mean +/- standard error of the mean; n = 10)]; that is, cytoprotection was achieved. 相似文献
8.
9.
Effect of the 5-lipoxygenase inhibitor ZD2138 on allergen-induced early and late asthmatic responses. 总被引:5,自引:3,他引:2
下载免费PDF全文
![点击此处可从《Thorax》网站下载免费的PDF全文](/ch/ext_images/free.gif)
S M Nasser G S Bell R J Hawksworth K E Spruce R MacMillan A J Williams T H Lee J P Arm 《Thorax》1994,49(8):743-748
BACKGROUND--Leukotrienes are lipid mediators generated from arachidonic acid by the 5-lipoxygenase pathway which may play an important part in the pathophysiology of asthma. Previous studies have demonstrated attenuation of the allergen-induced early and late asthmatic responses by leukotriene receptor antagonists. The effect of the 5-lipoxygenase inhibitor ZD2138, a non-redox lipoxygenase inhibitor which inhibits leukotriene synthesis for 24 hours after single doses of 350 mg, on allergen-induced early and late asthmatic responses has been assessed. METHODS--Eight asthmatic subjects with baseline FEV1 > 70% were studied. On screening, all subjects developed an allergen-induced biphasic asthmatic response to grass pollen, cat dander, or house dust mite. ZD2138 (350 mg) or placebo was given on two occasions separated by two weeks in a randomised double blind fashion. Allergen inhalation challenge was performed four hours after dosing and FEV1 was measured for eight hours. The inhibitory activity of ZD2138 on the 5-lipoxygenase pathway was assessed by measurements of calcium ionophore-stimulated generation of LTB4 in whole blood ex vivo and by analysis of urinary LTE4 levels before administration of drug or placebo and at regular intervals after oral drug dosing and allergen challenge. RESULTS--ZD2138 produced no significant bronchodilatation or attenuation of the early or late asthmatic response, although there was 82% inhibition of whole blood generation of LTB4 in response to calcium ionophore stimulation and 52% reduction in urinary excretion of LTE4. CONCLUSIONS--In asthmatic subjects the 5-lipoxygenase inhibitor ZD2138 did not protect against allergen-induced asthmatic responses, despite substantial inhibition of 5-lipoxygenase. 相似文献
10.
O. P. van Bijsterveld M.D. Ph.D. Y. el Batawi M.D. Ph.D. F. S. Sobhi M.D. Ph.D. M. W. Nasser M.D. 《Infection》1987,15(1):16-19
Summary A newly developed 1% eye preparation of the potent antistaphylococcal antibiotic fusidic acid, showed an excellent clinical effect in 206 Egyptian children with external eye infections. The 248 patients included in the study were randomized, in the ratio 5:1, to either fusidic acid or chloramphenicol 0.5% eye drops. Both preparations were given four to six times daily for one week. Bacterial conjunctivitis was diagnosed in 56% of the children. Offending eye pathogens were mainlyStaphylococcus aureus (60%),Haemophilus aegyptius (10%),Streptococcus pneumoniae (13%) andNeisseria gonorrhoeae (6%). The overall clinical success rate in children with bacterial conjunctivitis was 85% with fusidic acid, compared to 48% with chloramphenicol (p < 0.001). The better effect of fusidic acid could be ascribed to a lower frequency ofin vitro resistance (16%) in comparison to chloramphenicol (55%). Both drugs were apparently well tolerated and no side-effects were observed.
Fusidinsäure zur Behandlung von externen Augeninfektionen
Zusammenfassung Eine neuentwickelte 1%ige ophthalmologische Präparation des gegen Staphylokokken hochwirksamen Antibiotikums Fusidinsäure erwies sich bei 206 ägyptischen Kindern mit externen Augeninfektionen als hervorragend klinisch wirksam. Die im Rahmen der Studie behandelten 248 Kinder erhielten nach Randomverfahren im Verhältnis 5:1 entweder 1%ige Fusidinsäure- oder 0.5%ige Chloramphenicol-Augentropfen. Beide Präparate wurden eine Woche lang vier-bis sechsmal täglich verabreicht. Bei 56% der Kinder wurde eine bakterielle Konjunktivitis diagnostiziert. Die häufigsten pathogenen Erreger der Augeninfektionen warenStaphylococcus aureus (60%),Haemophilus aegyptius (10%),Streptococcus pneumoniae (13%) undNeisseria gonorrhoeae (6%). Mit Fusidinsäure wurde bei 85% der Kinder mit bakterieller Konjunktivitis ein Therapieerfolg erzielt, mit Chloramphenicol in 48% der Fälle (p < 0,001). Die therapeutische Überlegenheit von Fusidinsäure ließ sich darauf zurückführen, daß dieIn vitro-Resistenz der Erreger mit 16% der Isolate in der Fusidinsäure-Gruppe geringer war als in der Chloramphenicol-Therapiegruppe mit einer Resistenzrate von 55% der Isolate. Beide Medikamente wurden offensichtlich gut vertragen, Nebenwirkungen wurden nicht beobachtet.相似文献