全文获取类型
收费全文 | 19375篇 |
免费 | 1478篇 |
国内免费 | 73篇 |
专业分类
耳鼻咽喉 | 167篇 |
儿科学 | 626篇 |
妇产科学 | 534篇 |
基础医学 | 2910篇 |
口腔科学 | 287篇 |
临床医学 | 2208篇 |
内科学 | 3834篇 |
皮肤病学 | 591篇 |
神经病学 | 1952篇 |
特种医学 | 487篇 |
外科学 | 1855篇 |
综合类 | 159篇 |
一般理论 | 20篇 |
预防医学 | 2188篇 |
眼科学 | 339篇 |
药学 | 1165篇 |
中国医学 | 36篇 |
肿瘤学 | 1568篇 |
出版年
2024年 | 41篇 |
2023年 | 279篇 |
2022年 | 504篇 |
2021年 | 964篇 |
2020年 | 586篇 |
2019年 | 764篇 |
2018年 | 824篇 |
2017年 | 622篇 |
2016年 | 705篇 |
2015年 | 718篇 |
2014年 | 879篇 |
2013年 | 1133篇 |
2012年 | 1646篇 |
2011年 | 1677篇 |
2010年 | 848篇 |
2009年 | 746篇 |
2008年 | 1150篇 |
2007年 | 1166篇 |
2006年 | 995篇 |
2005年 | 963篇 |
2004年 | 878篇 |
2003年 | 783篇 |
2002年 | 674篇 |
2001年 | 110篇 |
2000年 | 85篇 |
1999年 | 104篇 |
1998年 | 128篇 |
1997年 | 110篇 |
1996年 | 76篇 |
1995年 | 80篇 |
1994年 | 65篇 |
1993年 | 48篇 |
1992年 | 49篇 |
1991年 | 51篇 |
1990年 | 47篇 |
1989年 | 29篇 |
1988年 | 24篇 |
1987年 | 28篇 |
1986年 | 21篇 |
1985年 | 31篇 |
1984年 | 30篇 |
1983年 | 26篇 |
1982年 | 21篇 |
1981年 | 30篇 |
1980年 | 21篇 |
1979年 | 11篇 |
1978年 | 24篇 |
1977年 | 11篇 |
1976年 | 11篇 |
1973年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Summary The antitumor activity of the three air-stable bis(cyclopentadienyl)rhenium derivatives [(C5H5)2ReCL2]+Cl–,[(C5H5)2ReCl2]+[AsF6]–, and [(C5H5)2ReCl2]+[SbF6]– was tested against Ehrlich ascites tumor in female CF1 mice. All three compounds contain the group-7 transition metal rhenium in the +5 oxidation state as their central metal atom. They are ionic, salt-like complexes that are composed of the cationic [(C5H5)2ReCl2]+ moiety and one of the negatively charged counterions Cl–, AsF6
–, or SbF6
–. Both the chloro and the hexafluoroarsenate complexes induced a maximal cure rate of 100% when given either in a dose range of 120–160 mg/kg (rhenocene trichloride) or at a single dose of 180 mg/kg (hexafluoroarsenate derivative). The hexafluoroantimonate complex effected a maximal cure rate of only 50% at 60 mg/kg. For the two former compounds, the values for the therapeutic index (Tl) amounted to 1.7 and 2.1, respectively. No impairment of the general condition or pathologic symptoms in the viscera could be detected by observation of the animals during the days following treatment with therapeutic doses or by autopsy of the surviving animals on the key data (day 90). The rhenocene derivatives investigated in the present study represent a new class of antitumor metallocene compounds as well as the first rhenium(V) complexes exerting cytostatic activity. 相似文献
42.
Manic episode with psychotic symptoms induced by subthalamic nucleus stimulation in a patient with Parkinson's disease. 总被引:5,自引:0,他引:5
Jan Herzog Julia Reiff Paul Krack Karsten Witt Bettina Schrader Dieter Müller Günther Deuschl 《Movement disorders》2003,18(11):1382-1384
Deep brain stimulation of the subthalamic nucleus (STN-DBS) is an established therapy for Parkinson's disease (PD). A manic episode with psychotic symptoms induced by STN-DBS occurred in a previously psychiatrically healthy patient, focusing on the role of STN-DBS in influencing not only motor but also emotional behaviour. 相似文献
43.
Julia Valderrama Fernando Zacarías Rafael Mazin 《Pan American journal of public health》2004,16(3):211-217
From the data submitted to the Pan American Health Organization (PAHO) by nationwide programs against sexually transmitted diseases (STD), HIV infection, and AIDS (2002), one can estimate the overall prevalence of syphilis among pregnant women to be 3.1% and to range from 1.00% in Peru to 6.21% in Paraguay. According to these data, the incidence of congenital syphilis ranges from 1.4 per 1000 live births in El Salvador to 12.0 per 1000 live births in Honduras. Among men who engage in sex with other men, who often classify themselves as heterosexual, as well as in female sex workers, the prevalence of syphilis ranged from 5% to 15%. Factors that determine the persistence of congenital syphilis as public health problem include a lack of awareness of the seriousness of the problem among politicians, health officials, and health care providers, difficult access to prenatal care, and screening services, a low demand for the test among users, and the stigma and discrimination that surround sexually transmitted diseases (STD). This paper seeks to focus the attention of health professionals on maternal and congenital syphilis so they will undertake actions, using an interprogrammatic approach, to eliminate congenital syphilis from Latin America and the Caribbean. Eliminating congenital syphilis will only become possible if interventions targeting vulnerable groups are also implemented. PAHO's role in eliminating congenital syphilis includes determining the baseline situation in the Region as a whole and in each country, developing communication and procurement strategies, supporting nationwide programs, promoting operational research, and facilitating interprogrammatic coordination. 相似文献
44.
Marjolein Gysels Rhidian Hughes Fiona Aspinal Julia M Addington-Hall Irene J Higginson 《International journal for quality in health care》2004,16(5):375-381
OBJECTIVE: To investigate the opinions of stakeholders (service commissioners and providers) on how performance data should be presented, in order to develop effective feedback methods to facilitate the use of these data in decision making. DESIGN: A qualitative analysis of semi-structured face-to-face and telephone interviews. League tables and fictional box plots were presented as an illustrative guide. The themes covered in the interviews were the effectiveness of these two feedback formats, their positive and negative characteristics, and ideas for new and improved feedback mechanisms. PARTICIPANTS: Thirty-six stakeholders representing a range of clinical and non-clinical roles within palliative care and the wider health care system across a variety of statutory and non-statutory organizations from London and the West Midlands. RESULTS: Box plots were received more positively than league tables, and qualitative information was considered more appropriate than pictorial feedback. Conventional methods such as league tables and box plots were judged to lack essential information on which important decisions could be based, such as additional contextual information and the methodological assumptions of the instrument. Both feedback methods were considered useful as an impetus to further discussion. There was a consensus that feedback should be constructive and able to be adapted to the organizational realities in which UK health services function. CONCLUSION: Qualitative research was viewed as the right evidence for gaining an understanding of the quality of end of life care. Stakeholders highlighted the importance of the lay perspective, which requires approaches that illuminate the subjective meanings of patient experience. 相似文献
45.
46.
Julia E. Ledger MSc Graham J. Watson Dr. Juliet E. Compston MD 《Digestive diseases and sciences》1986,31(4):361-368
The biliary excretion of radioactivity after intravenous [3H]25-hydroxyvitamin D3 was studied in nine patients with T-tube bile drainage. The mean +/- SD 24-hr radioactivity excretion in T-tube bile expressed as a percentage of the administered dose was 6.7 +/- 2.9%; after correction for incomplete bile collection, the value obtained was 16.0 +/- 11.1%. Chloroform solubility of biliary radioactivity increased from 27.4 +/- 8.9% to 72.9 +/- 10.1% following incubation with beta-glucuronidase. High-performance liquid chromatographic analysis of chloroform extracts of bile revealed that most of the eluted radioactivity was more polar than [3H]25-hydroxyvitamin D3. No free [3H]25-hydroxyvitamin D3 was demonstrated. Thus in man, most of the biliary radioactivity excreted following [3H]25-hydroxyvitamin D3 is in the form of water-soluble compounds, mainly glucuronides. However, our results suggest that glucuronides of metabolites other than 25-OHD3 are predominantly formed. 相似文献
47.
48.
Background
Persisting neck pain is common in society. It has been reported that the prevalence of neck pain in office workers is much higher than in the general population. The costs to the worker, employer and society associated with work-related neck pain are known to be considerable and are escalating. The factors that place office workers at greater risk of developing neck pain are not understood. The aim of this study is to investigate the incidence and risk factors of work-related neck pain in Australian office workers. 相似文献49.
Exhaled nitric oxide in healthy children: Variability and a lack of correlation with atopy 总被引:1,自引:0,他引:1
Nitric oxide (NO) is a free radical produced by several lung cells via the enzyme nitric oxide synthetase (NOS) and can be easily measured in exhaled air by chemiluminescence analysis. As the iso-enzyme iNOS may be induced by cytokines and endotoxin, NO is elevated in several chronic inflammatory airway diseases. Prior to using exhaled nitric oxide (eNO) as a non-invasive marker of airway inflammation in daily routine, the role of possibly influencing factors such as age, time of the day, smoking exposure and intra-individual variability have to be clarified. NO concentrations were measured in 107 healthy children aged 4–18 years at an expiratory flow of 184 ml/s. Spirometry and a skin-prick test were performed and a questionnaire on family history of atopy, personal symptoms of atopic disease and smoke exposure was completed. For intra-individual variability nitric oxide was measured in six children three times daily on 6 consecutive days. Median eNO concentration was 5.7 p.p.b., and increased significantly with age but did not vary with gender. No correlation was found between eNO and smoke exposure, positive skin-prick test, FEV 1 , MEF25 and time of the day. There was no circadian rhythm found in the six children measured on 6 consecutive days, but the eNO showed an intra-individual coefficient of variation of 25.9%. With the help of a two-compartment model of the lung the alveolar NO concentration was estimated to be 4.1 p.p.b and was shown to be constant with age, whereas the airway part of NO steadily increased with age. When comparing eNO values with standardized measurement techniques, the age of the children and the large intra-subject coefficient of variation have to be taken into account, whereas in healthy children subject-specific factors such as atopic history, gender and skin test reactivity did not affect eNO measurement. 相似文献
50.
Lukas Foggensteiner Julia Baylis Heather Moss Paul Williams 《Peritoneal dialysis international》2002,22(4):471-476
OBJECTIVE: To establish the effectiveness and patient acceptability of initiating peritoneal dialysis (PD) according to published guidelines. SETTING: A university teaching hospital and a neighboring district general hospital. DESIGN: Nonrandomized prospective pilot study. PATIENTS: 39 patients with a Kt/V > 2.0 attending predialysis clinics at both hospitals agreed to participate in this study. METHODS: Patients were started on a single exchange of dialysate overnight. Dialysis adequacy was monitored at least every 2 months and incremental increases in dialysis were used to maintain combined urinary and dialysis Kt/V above 2.0. Routine laboratory parameters and complications of dialysis were monitored during the follow-up period. RESULTS: The mean weekly Kt/V at initiation of dialysis was 2.09. Median actuarial survival on a single exchange before requiring incremental dialysis was 297 days. At the end of the study period, all patients were still alive: 8 remained on 1 exchange, 18 were on more than 1 exchange, 8 had switched to hemodialysis, and 5 had received renal transplants. During the 12,665 patient-days on single-exchange dialysis, there were 14 hospital admissions of 12 patients. This resulted in a mean of 1.64 hospital days per patient-year for the whole group. During the follow-up period there were 2 episodes of bacterial peritonitis, 3 pleural leaks, 1 patent processus vaginalis, and 1 inguinal hernia that required surgical intervention. The use single daily icodextrin exchanges was associated with a 46% incidence of culture-negative peritonitis. CONCLUSIONS: This pilot study has shown that a timely start of dialysis with a single overnight PD exchange is acceptable to patients. Incremental dialysis as residual renal function falls is easily managed and patients also find this acceptable. Complication and hospitalization rates were low. The presence of residual renal function often allows complications to be managed without the need for hemodialysis. The use of icodextrin as a single-exchange dialysate is associated with sterile peritonitis in a significant proportion of cases. 相似文献