全文获取类型
收费全文 | 693篇 |
免费 | 31篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 12篇 |
妇产科学 | 4篇 |
基础医学 | 93篇 |
临床医学 | 77篇 |
内科学 | 65篇 |
皮肤病学 | 147篇 |
神经病学 | 30篇 |
特种医学 | 10篇 |
外科学 | 61篇 |
预防医学 | 86篇 |
药学 | 120篇 |
肿瘤学 | 20篇 |
出版年
2023年 | 3篇 |
2022年 | 7篇 |
2021年 | 9篇 |
2020年 | 14篇 |
2019年 | 22篇 |
2018年 | 16篇 |
2017年 | 13篇 |
2016年 | 13篇 |
2015年 | 12篇 |
2014年 | 19篇 |
2013年 | 39篇 |
2012年 | 51篇 |
2011年 | 67篇 |
2010年 | 22篇 |
2009年 | 31篇 |
2008年 | 37篇 |
2007年 | 52篇 |
2006年 | 28篇 |
2005年 | 42篇 |
2004年 | 43篇 |
2003年 | 40篇 |
2002年 | 35篇 |
2001年 | 6篇 |
2000年 | 8篇 |
1999年 | 7篇 |
1998年 | 8篇 |
1997年 | 15篇 |
1996年 | 7篇 |
1995年 | 12篇 |
1994年 | 8篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有726条查询结果,搜索用时 0 毫秒
1.
Previous epidemiologic studies have assessed the role of the exposure to ambient air pollution in the development of cardiac birth defects, but they have provided somewhat inconsistent results. To assess the associations between exposure to ambient air pollutants and the risk of cardiac defects, a population-based case-control study was conducted using 1087 cases of cardiac defects and a random sample of 10,870 controls from 1,533,748 Taiwanese newborns in 2001 to 2007.Logistic regression was performed to calculate odds ratios for 10 ppb increases in O3 and 10 μg/m3 increases in PM10. In addition, we compared the risk of cardiac defects in 4 categories-high exposure (>75th percentile); medium exposure (75th to 50th percentile); low exposure (<50th–25th percentile); reference (<25th percentile) based on the distribution of each pollutant. The risks of ventricular septal defects (VSD), atrial septal defects (ASD), and patent ductus arteriosus (PDA) were associated with 10 ppb increases in O3 exposure during the first 3 gestational months among term and preterm babies. In comparison between high PM10 exposure and reference category, there were statistically significant elevations in the effect estimates of ASD for all and terms births. In addition, there was a negative or weak association between SO2, NO2, CO, and cardiac defects.The study proved that exposure to outdoor air O3 and PM10 during the first trimester of gestation may increase the risk of VSD, ASD, and PDA. 相似文献
2.
Medical and Surgical Dermatology - 相似文献
3.
Jouni Sirvi Hannele Lahtinen Paavo Riekkinen Jr. Paavo J. Riekkinen 《Experimental neurology》1994,125(2)
The present experiment studied whether a dysfunction of the noradrenergic neurons is related to spatial learning impairment by investigating the levels of noradrenaline in the brain and periphery as well as the acquisition of water maze task in saline-pretreated young rats, in noradrenergic neurotoxin (DSP-4)-pretreated young rats and in saline-pretreated aged rats. Aged rats, which had an increased escape latency onto the hidden platform, revealed a decreased noradrenaline content in the heart, but not in the hippocampus, striatum, or hypothalamus, whereas DSP-4-pretreated rats had decreased noradrenaline content in the brain; the acquisition of water maze task was not impaired. These results suggest that the peripheral noradrenergic system can show age-related changes different from those in the central noradrenergic system, and they failed to provide support for the hypothesis that decreased activity of the central noradrenergic nerves is related to impairment in the acquisition of the water maze task. 相似文献
4.
Paavo Riekkinen Jr. Jouni Sirvi Pekka Jkl Maria Mazurkiewicz Antti Valjakka Minna Riekkinen Paavo Riekkinen 《Brain research bulletin》1991,27(2):287-289
Quisqualic acid NBM lesions had no effect on water maze performance, but slightly impaired passive avoidance acquisition. GammavinylGABA treatment alone had no effect on the passive avoidance and water maze performance, but aggravated acquisition deficit in rats subjected to NBM lesioning. However, gammavinylGABA-treated NBM-lesioned rats reached control level of performance. 相似文献
5.
Paavo Riekkinen Jr. Minna Riekkinen Antti Valjakka Paavo Riekkinen Jouni Sirvio
《Brain research》1992,570(1-2):293-299
The present study examines the effects of noradrenergic lesions (either DSP-4 i.p. or 6-hydroxydopamine (6-OHDA) into the dorsal noradrenergic bundle on biochemical (noradrenaline (NA), dopamine (DA), serotonin (5-HT) and choline acetyltransferase (ChAT) activity) and cortical EEG (quantitative EEG (qEEG) and high-voltage spindle (HVS) activity in young and aged rats. Near complete 6-OHDA NA lesions, but not partial DSP-4 NA lesions, increased HVS activity in young rats. DSP-4 and 6-OHDA lesions produced no significant changes in the 5-HT or DA levels or in the ChAT activity in young rats. In some of the aged rats, DSP-4 produced similar biochemical and HVS effects, as it induced in young rats. In the remainder of the aged rats, NA levels were greatly and 5-HT levels slightly decreased. DA levels and ChAT activity were unaltered in either set of aged rats. HVS activity was increased only in that group of aged rats with the greatly lowered NA content. These results suggest that: (1) some of the aged rats are more sensitive to DSP-4 treatment than young adult rats; and (2) NA depletions have to be complete to produce an increase in HVS activity in young and aged rats. 相似文献
6.
Sanna Toppila Jouni Lauronen Pirkko Mattila Juha Pekka Turunen Leena Penttil Timo Paavonen Ossi Renkonen Risto Renkonen 《European journal of immunology》1997,27(6):1360-1365
Lymphocyte homing is initiated by their tethering to and rolling on the high endothelium and is followed by extravasation into the lymph nodes. We show here that glycosylated cell adhesion molecule-1 (GlyCAM-1), CD34, and sialyl Lewis x (sLex) are present on rat lymph node high endothelium analyzed by using monoclonal antibodies. α(1,3)fucosyltransferase VII (Fuc-TVII), the last enzyme involved in the synthesis of the sLex sequence is also expressed on the rat lymph node high endothelium. We have synthesized a family of sLex-decorated oligosaccharide structures and used them to inhibit lymphocyte binding to high endothelium in the Stamper-Woodruff assay. Monovalent sLex, branched di- and tetravalent sLex, as well as a linear tetravalent sLex significantly reduce lymphocyte binding to endothelium. The branched and linear forms of tetravalent sLex were clearly superior inhibitors of the L-selectin-dependent lymphocyte adhesion, with IC50 values in low nanomolar range. In contrast, the fucose-free analogs having the same charge and approximately the same size as the corresponding sLex glycans had no effect on lymphocyte binding and served as negative controls. Taken together, these data show the crucial importance of sLex in the endothelial ligands for L-selectin. Furthermore, we suggest that L-selectin acts as an oligomer on the lymphocyte surface as it binds multivalent sLex glycans. 相似文献
7.
Jaakkola JJ Jaakkola N Piipari R Jaakkola MS 《The Journal of allergy and clinical immunology》2002,109(5):784-788
BACKGROUND: Studies of exposure to pets and the risk of asthma have provided conflicting results. OBJECTIVE: We conducted a population-based incident case-control study to assess the relationship of current and previous pet keeping with the risk of adult-onset asthma. We also investigated whether genetic propensity as a result of parental atopy modifies these relations. METHODS: From the source population of 441,000 inhabitants of a geographically defined area in South Finland, we systematically recruited, during a 2.5-year period, all new cases of asthma in 21- to 63-year-old adults and randomly selected control subjects. The clinically diagnosed case series consisted of 521 adults with newly diagnosed asthma and a control series of 932 control subjects. Information on current and past exposure to hairy pets was collected by using a self-administered questionnaire. RESULTS: In logistic regression analysis the risk of asthma was lower among subjects with pets during the past 12 months (adjusted odds ratio [OR], 0.74; 95% confidence interval [CI], 0.57-0.96) but higher among subjects with pets more than 12 months previously (adjusted OR, 1.39; 95% CI, 1.05-1.84). Parental atopy increased the risk of asthma (OR, 1.88; 95% CI, 1.47-2.41), but there was no interaction between parental atopy and pet exposure. CONCLUSIONS: The present results are consistent with the hypothesis that both keeping furry pets and parental atopy increase the risk of asthma development in adulthood. Parental atopy does not modify the effects of pet exposure. The negative association between current pets and the risk of asthma is consistent with selective avoidance of these pets by symptomatic individuals. 相似文献
8.
Semiquantitative detection by real-time PCR of Aspergillus fumigatus in bronchoalveolar lavage fluids and tissue biopsy specimens from patients with invasive aspergillosis
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Rantakokko-Jalava K Laaksonen S Issakainen J Vauras J Nikoskelainen J Viljanen MK Salonen J 《Journal of clinical microbiology》2003,41(9):4304-4311
A real-time PCR method was developed and used to detect Aspergillus fumigatus mitochondrial DNA (mtDNA) in bronchoalveolar lavage (BAL) fluids and tissue biopsy specimens. The analytical sensitivity of the assay was one A. fumigatus conidium per reaction, and the assay was linear at least over 4 orders of magnitude above the detection limit. BAL fluids from 66 immunocompromised patients at risk of invasive pulmonary aspergillosis (IPA) and 33 immunocompetent controls and tissue biopsy specimens from 10 immunocompromised patients were analyzed. The results were related to the clinical diagnosis established according to recently published consensus criteria. A. fumigatus mtDNA positivity was encountered in 16 of 81 (20%) BAL fluid specimens from patients at risk and 1 of 33 (3%) specimens from immunocompetent controls. PCRs were positive in six of seven, two of four, and four of five of the patients with proven, probable, and possible IPA, respectively, as well as in four patients at risk but without any other evidence of IPA. With qualitative detection, the diagnostic sensitivity of PCR was 73%, specificity was 93%, and predictive values of positive (PPV) and negative (NPV) results were 73 and 95%, respectively. Using a threshold cycle of <35 as a limit for positive PCR, the specificity and PPV of PCR in the diagnosis of invasive aspergillosis were 100%, but its sensitivity was only 45% and NPV was 92%. PCR was positive in tissue biopsy specimens from all patients with invasive aspergillosis caused by A. fumigatus. Semiquantitative detection of A. fumigatus mtDNA in BAL fluid may be helpful in the diagnosis of IPA. PCR is well suited for the verification of the presence of A. fumigatus in tissue biopsy specimens. 相似文献
9.
Johanna Raiman Maija Koljonen Katri Huikko Risto Kostiainen Jouni Hirvonen 《European journal of pharmaceutical sciences》2004,21(2-3):371-377
Poor absorption and stability of peptides are the major obstacles concerning the development of therapeutically relevant iontophoretic devices for the transdermal delivery of peptides. The present study examined the impact of constant and pulsed (direct/alternating) current profiles on the transport and stability of two decapeptides LHRH and Nafarelin. The stability of these peptides was studied in a physiological buffer solution, with electrical current, and when the peptide solution was exposed to the stratum corneum or to the epidermal/dermal side of human skin. Pulsed direct current profile was shown to be the most efficient in transporting both LHRH and Nafarelin across the human epidermis. Furthermore, the percentage of intact LHRH in the receiver phase was slightly higher when a pulsed current profile was used. Both the peptides were stable in a physiological buffer and under the influence of current, but LHRH was degraded especially in contact with the dermal side of the skin. Altogether five hydrolytic degradation products of LHRH were observed, and they were identified by LC-ESI/MS and LC-ESI/MS/MS. No degradation products of Nafarelin were observed. It is concluded that the pulsed direct current profile may provide at least a partial solution for the transdermal delivery of peptides in terms of improved transport efficacy and peptide stability. 相似文献
10.
Protocol for digital intervention for effective health promotion of small children—A cluster randomized trial
下载免费PDF全文
![点击此处可从《Journal of advanced nursing》网站下载免费的PDF全文](/ch/ext_images/free.gif)