全文获取类型
收费全文 | 976篇 |
免费 | 77篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 27篇 |
妇产科学 | 44篇 |
基础医学 | 97篇 |
口腔科学 | 37篇 |
临床医学 | 119篇 |
内科学 | 157篇 |
皮肤病学 | 37篇 |
神经病学 | 83篇 |
特种医学 | 38篇 |
外科学 | 69篇 |
综合类 | 34篇 |
预防医学 | 123篇 |
眼科学 | 5篇 |
药学 | 113篇 |
中国医学 | 25篇 |
肿瘤学 | 54篇 |
出版年
2023年 | 4篇 |
2022年 | 10篇 |
2021年 | 14篇 |
2020年 | 16篇 |
2019年 | 25篇 |
2018年 | 25篇 |
2017年 | 17篇 |
2016年 | 21篇 |
2015年 | 18篇 |
2014年 | 26篇 |
2013年 | 31篇 |
2012年 | 57篇 |
2011年 | 61篇 |
2010年 | 40篇 |
2009年 | 55篇 |
2008年 | 71篇 |
2007年 | 47篇 |
2006年 | 56篇 |
2005年 | 37篇 |
2004年 | 32篇 |
2003年 | 32篇 |
2002年 | 29篇 |
2001年 | 23篇 |
2000年 | 22篇 |
1999年 | 19篇 |
1998年 | 18篇 |
1997年 | 11篇 |
1996年 | 9篇 |
1995年 | 12篇 |
1994年 | 5篇 |
1993年 | 8篇 |
1992年 | 21篇 |
1991年 | 10篇 |
1990年 | 14篇 |
1989年 | 6篇 |
1988年 | 16篇 |
1987年 | 11篇 |
1986年 | 13篇 |
1985年 | 17篇 |
1984年 | 24篇 |
1983年 | 11篇 |
1982年 | 8篇 |
1981年 | 9篇 |
1980年 | 4篇 |
1979年 | 11篇 |
1978年 | 8篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1969年 | 4篇 |
1966年 | 3篇 |
排序方式: 共有1067条查询结果,搜索用时 0 毫秒
51.
Background
Early sexual maturation has been associated with overweight that may persist after the completion of biological growth and development. We have prospectively examined the influence of early sexual maturation on subsequent overweight in late adolescence and assessed if this association was modified by central adiposity in early adolescence. 相似文献52.
S T Nilsen P Bergsj? A L?kling K W Skarsten K H Johannessen H G Blaas 《Acta obstetricia et gynecologica Scandinavica》1983,62(6):555-561
The two largest Norwegian obstetrical departments, in the cities of Bergen and Stavanger, differ markedly with regard to the frequency of Cesarean section. During the 1970's the proportions rose in both departments, but the Stavanger rate remained about half of that in Bergen, the latter following the national average. These differences were not reflected in the perinatal mortality, which had the same rates and fell equally in both hospitals. To search for explanations, all records of Cesarean section cases from the years 1974 and 1979 were studied in both hospitals. We found that mechanical indications, meaning disproportion and prolonged labor, accounted for most of the difference, whereas there was no significant rise in the frequencies for the indication fetal asphyxia in either of the hospitals, these being numerically the most important indications. In fact, there was no significant rise for mechanical indications in Stavanger between 1974 and 1979, whereas in Bergen the increased frequency for this indication gave the highest significance level for any of the seven subgroups of indications. It is suggested that the chain of command may be an important cause of the observed differences between the two departments, although this is not reflected in any stated or conscious policy in either place. 相似文献
53.
Smedbold HT Ahlen C Unimed S Nilsen AM Norbäck D Hilt B 《Archives of environmental health》2002,57(2):155-161
In this study, the authors sought to address the relationships between measured indoor environmental factors and nasal patency (i.e., minimum cross-sectional area) and volume and markers of nasal inflammation in nasal lavage fluid. Clinical data were obtained for 115 females who worked at 36 geriatric nursing departments. The indoor climates in the nursing departments were characterized by high room temperatures (median = 23 degrees C), low relative air humidities (median = 24%), and high air exchange rates indicated by low carbon dioxide levels (median = 570 ppm). Evidence of microbial amplification was observed in the ventilation unit in 3 of the departments. Decreased nasal patency was observed relative to microbial amplification in the ventilation units (minimum cross-sectional area 1 = 0.80 cm2 vs. 0.64 cm2, p = .003, minimum cross-sectional area 2 = 0.80 cm2 vs. 0.67 cm2, p = .02) and in relation to elevated indoor temperature (volume 1 = 3.46 cm3 vs. 3.22 cm3, p = .03). The authors concluded that the indoor environment may have affected the nasal mucosa of nursing personnel, thus causing nasal mucosal swelling. The results support the view that fungal contamination of air-supply ducts may be a source of microbial pollution, which can affect the nasal mucosa. 相似文献
54.
One mechanism by which estrogen may modulate cognitive function is through potentiation of glutamate-mediated rises in intracellular calcium ([Ca2+]i) with resultant effects on neuronal morphology and signaling. Since progesterone is a component of hormone replacement therapy (HRT), we sought to determine whether therapeutically relevant progestins attenuated or blocked estrogen potentiation of glutamate-induced [Ca2+]i rises. 17beta-estradiol and progesterone, alone or in combination, significantly potentiated the rise in [Ca2+]i. When co-administered, progesterone attenuated the estrogen response to the level seen with progesterone alone. In contrast, medroxyprogesterone acetate (MPA) had no effect when administered alone and completely blocked the 17beta-estradiol-induced potentiation when co-administered. These results may have important implications for effective use of HRT to maintain cognitive function during menopause and aging. 相似文献
55.
Brion F Nilsen BM Eidem JK Goksøyr A Porcher JM 《Environmental toxicology and chemistry / SETAC》2002,21(8):1699-1708
In this study, an enzyme-linked immunosorbent assay (ELISA) was developed to quantify vitellogenin (Vtg) in zebrafish (Danio rerio). Zebrafish Vtg (zf-Vtg) was purified from whole-body homogenates of estradiol-exposed zebrafish, and polyclonal antibodies against zf-Vtg were raised. Using purified zf-Vtg as a standard and anti-zf-Vtg antibodies (DR-264), a competitive ELISA method was set up and validated. The working range of the assay is from 1 to 30 ng/ml (20-80% binding), and the detection limit is 0.4 ng/ml for purified zf-Vtg. In whole-body homogenates samples, the practical detection limit is higher than that for purified Vtg (40 ng/ml) due to matrix effect. The intra- and interassay variations were 4.7% and 14%, respectively, at 50% binding (n = 36). Its usefulness to detect changes in Vtg concentration in other cyprinid fish was also tested. In addition, the assay was used to assess Vtg induction in male zebrafish exposed to 17beta-estradiol (E2). Exposure of male zebrafish to 0.1, 1, 10, and 100 microg/L of E2 for 7 d led to a Vtg induction from the lowest concentration. The results show the suitability of the developed ELISA to quantify Vtg inductions in zebrafish, the cross-reactivity of DR264 antibodies with commonly used cyprinids, and the potential of zf-Vtg induction as a sensitive biochemical endpoint that could be used to detect estrogenic properties of chemical substances. 相似文献
56.
Nilsen A Mwakagile D Marsden H Langeland N Matre R Haarr L 《Epidemiology and infection》2005,133(5):915-925
The prevalence of specific HSV-2 antibodies was studied in Tanzanian and Norwegian sexually transmitted disease (STD) patients (1095) and non-STD patients (488). Correlates to demographic and behavioural factors were evaluated. Seropositivity was determined by the non-commercial peptide-55 enzyme-linked immunoassay. The prevalence of HSV-2 antibodies was 70% in Tanzanian and 17% in Norwegian STD patients, 35% in Tanzanian blood donors and pregnant women, and 4, 7 and 14% in Norwegian medical students, blood donors and pregnant women respectively. A higher HSV-2 prevalence was associated with female sex, increasing age, previous STDs, history of genital HSV infection, coitarchal age (age at first intercourse) <15 years and HIV seropositivity. Compared to previous data, the prevalence of HSV-2 antibodies in Tanzanian STD patients has increased remarkably. In Norwegian STD patients our results are consistent with, or lower than, the prevalence previously reported in Western Europe. Demographic rather than behavioural factors were associated with higher prevalence of HSV-2 antibodies in STD patients. 相似文献
57.
Evaluation of low back pain and assessment of lumbar corsets with and without back supports. 下载免费PDF全文
A method is described for evaluating the progress of patients with back pain. Various symptoms were scored on analogue scales and spinal motion was measured by various techniques. These data were integrated to make subjective and objective indices respectively. Reasonable reproducibility of the measurements was obtained. This technique was used to elucidate the role of the lumbar support in surgical corsets in relief of back pain. Sufferers from back pain were randomly allocated to corsets with and without lumbar supports. There was significant improvement in those with a support compared with those without. On the other hand objective changes measured with the corset removed did not differ between the 2 groups. This study indicates that the spinal support in a lumbosacral corset makes a significant contribution towards the relief of symptoms. 相似文献
58.
The single oral dose pharmacokinetics of tiaprofenic acid (Surgam) has been investigated in fasting and non-fasting healthy volunteers (200 and 300 mg) and in fasting patients with severe renal insufficiency (200 mg). A dose independent pharmacokinetics of tiaprofenic acid was shown in fasting healthy volunteers and the following parameters were calculated after administration of 200 mg: tl = 0.53 +/- 0.15 h, tm = 1.28 +/- 0.19 h, cm = 27.1 micrograms/ml, ka = 2.79 +/- 0.93 h-1, lambda 2 = 1.06 +/- 0.14 h-1, t1/2 = 3.0 +/- 0.2 h, AUCl-infinity = 80 +/- 7 mg X h/l, Clt = 43.8 +/- 3.7 ml/min and V beta = 11.1 +/- 0.8 l. A small, but significant positive deviation from linearity was observed with increasing dose for cm and AUCl-infinity in non-fasting healthy volunteers, probably due to a slightly higher bioavailability of the 300 mg formulation in the non-fasting state as compared with the 200 mg formulation. Intake of food decreased cm significantly at both dosage levels from 27.1 to 19.1 micrograms/ml and from 47.9 to 39.1 micrograms/ml for 200 and 300 mg, respectively. The absorption kinetics of tiaprofenic acid was not significantly different in fasting healthy volunteers and in fasting patients with severe renal insufficiency. However, a significant increase in t1/2 and AUCl-infinity to 5.8 +/- 0.9 h and 173 +/- 34 mg X h/l, respectively, and a significant decrease in total body clearance to 25.5 +/- 5.3 ml/min were observed in this category of patients. No correlation was found between creatinine clearance and tiaprofenic acid clearance. 相似文献
59.
Characterization of the tetanus toxin model of refractory focal neocortical epilepsy in the rat 总被引:3,自引:0,他引:3
PURPOSE: To characterize in detail a model of focal neocortical epilepsy. METHODS: Chronic focal epilepsy was induced by injecting 25-50 ng of tetanus toxin or vehicle alone (controls) into the motor neocortex of rats. EEG activity was recorded from electrodes implanted at the injection site, along with facial muscle electromyographic (EMG) activity and behavioral monitoring intermittently for up to 5 months in some animals. Drug responsiveness was assessed by using the antiepileptic drugs (AEDs) diazepam (DZP) and phenytoin (PHT) delivered systemically, while 1,2,3,4-tetrahydro-6-nitro-2,3-dioxo-benzo[f]quinoxaline-7-sulfonamide (NBQX), a competitive antagonist at AMPA receptors, was administered directly to the brain to investigate the potential benefits of focal drug delivery. RESULTS: Tetanus toxin induced mild behavioral seizures that persisted indefinitely in all animals. EEG spiking activity, occurring up to 80% of the time, correlated with clinical seizures consisting of interrupted behavioral activity, rhythmic bilateral facial twitching, and periods of abrupt motor arrest. Seizures were refractory to systemic administration of DZP and PHT. However, focal delivery of NBQX to the seizure site reversibly reduced EEG and behavioral seizure activity without detectable side effects. CONCLUSIONS: This study provides a long-term detailed characterisation of the tetanus toxin model. Spontaneous, almost continuous, well-tolerated seizures occur and persist, resembling those seen in neocortical epilepsy, including cortical myoclonus and epilepsia partialis continua. The seizures appear to be similarly resistant to conventional AEDs. The consistency, frequency, and clinical similarity of the seizures to refractory epilepsy in humans make this an ideal model for investigation of both mechanisms of seizure activity and new therapeutic approaches. 相似文献
60.
Role of routine ultrasonography in monitoring the outcome of medical abortion in a clinical setting 总被引:3,自引:0,他引:3
Acharya G Haugen M Bråthen A Nilsen I Maltau JM 《Acta obstetricia et gynecologica Scandinavica》2004,83(4):390-394
BACKGROUND: Clinical methods generally used to evaluate the completeness of medical abortion are not accurate. There are no published reports evaluating the role of routine ultrasonography in monitoring the outcome of medical abortion. The purpose of this study was to investigate whether routine transvaginal ultrasonography (TVS) at the follow-up visit after medical abortion can accurately identify women who will require surgical intervention. DESIGN: Retrospective review of medical records and charts of all women undergoing medical abortion in the first trimester of pregnancy between January 1999 and December 2001. METHODS: Medical abortion was performed using oral mifepristone and a vaginal prostaglandin analog before 63 days gestation. All women had an initial TVS to confirm intrauterine pregnancy and gestational age, and another TVS at the follow-up visit 2-3 weeks later to assess the completeness of abortion. Surgical evacuation of the uterus was allowed as indicated on clinical grounds but not on the basis of ultrasound findings only. RESULTS: A total of 690 women consented to medical abortion during the study period. Eleven of these women were excluded from the study for various reasons. Of the remaining 679 cases, 95% (645/679) had a documented follow-up at the hospital. The pregnancy termination rate among these women was 99.2% (640/645) and TVS identified all five cases of continuing pregnancy at the follow-up. A total of 66 (10.2%) patients had complications. The uterine cavity was empty on TVS at the follow-up visit in 84.8% (547/645) of cases and only 3.1% (17/547) of them required surgical aspiration/curettage due to excessive or prolonged vaginal bleeding. In the remaining 15.2% (98/645) the uterine cavity was not empty, and 43.9% (43/98) of them had a curettage. The risk of requiring a surgical intervention was significantly higher [odds ratio (OR) 24.4; 95% confidence interval (95% CI) 14.9-39.7] when the uterine cavity was not demonstrated to be empty at the follow-up visit 2-3 weeks after medical abortion. However, 59.1% (55/93) of women did not require surgical intervention despite ultrasound evidence of thick endometrial echo-complex. CONCLUSION: Routine TVS 2-3 weeks after medical abortion appears to be an efficient means of accurately identifying the cases of ongoing pregnancy and diagnosing a complete abortion. Although TVS could be used as an adjunct to clinical examination to diagnose an incomplete expulsion, it does not accurately differentiate those women who require surgical intervention from those who do not. 相似文献