首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   668篇
  免费   45篇
  国内免费   1篇
耳鼻咽喉   3篇
儿科学   26篇
妇产科学   38篇
基础医学   85篇
口腔科学   32篇
临床医学   67篇
内科学   75篇
皮肤病学   4篇
神经病学   26篇
特种医学   10篇
外科学   70篇
综合类   4篇
预防医学   63篇
眼科学   27篇
药学   63篇
肿瘤学   121篇
  2022年   4篇
  2021年   8篇
  2020年   9篇
  2019年   6篇
  2018年   13篇
  2017年   11篇
  2016年   6篇
  2015年   16篇
  2014年   12篇
  2013年   25篇
  2012年   22篇
  2011年   27篇
  2010年   22篇
  2009年   22篇
  2008年   34篇
  2007年   35篇
  2006年   42篇
  2005年   34篇
  2004年   43篇
  2003年   33篇
  2002年   33篇
  2001年   20篇
  2000年   38篇
  1999年   27篇
  1998年   17篇
  1997年   13篇
  1996年   9篇
  1995年   3篇
  1994年   9篇
  1993年   7篇
  1992年   16篇
  1991年   10篇
  1990年   5篇
  1989年   5篇
  1988年   5篇
  1987年   7篇
  1986年   6篇
  1985年   4篇
  1984年   4篇
  1983年   4篇
  1982年   3篇
  1979年   5篇
  1978年   2篇
  1977年   4篇
  1976年   3篇
  1974年   8篇
  1973年   3篇
  1972年   6篇
  1968年   3篇
  1967年   2篇
排序方式: 共有714条查询结果,搜索用时 31 毫秒
81.
Background Influenza A(H1N1)pdm09 virus has been circulating in human population for three epidemic seasons. During this time, monovalent pandemic and trivalent seasonal influenza vaccination against this virus have been offered to Finnish healthcare professionals. It is, however, unclear how well vaccine‐induced antibodies recognize different strains of influenza A(H1N1)pdm09 circulating in the population and whether the booster vaccination with seasonal influenza vaccine would broaden the antibody cross‐reactivity. Objectives Influenza vaccine‐induced humoral immunity against several isolates of influenza A(H1N1)pdm09 virus was analyzed in healthcare professionals. Age‐dependent responses were also analyzed. Methods Influenza viruses were selected to represent viruses that circulated in Finland during two consecutive influenza epidemic seasons 2009–2010 and 2010–2011. Serum samples from vaccinated volunteers, age 20–64 years, were collected before and after vaccination with AS03‐adjuvanted pandemic and non‐adjuvanted trivalent seasonal influenza vaccine that was given 1 year later. Results Single dose of pandemic vaccine induced a good albeit variable antibody response. On day 21 after vaccination, depending on the virus strain, 14–75% of vaccinated had reached antibody titers (≥1:40) considered seroprotective. The booster vaccination 1 year later with a seasonal vaccine elevated the seroprotection rate to 57–98%. After primary immunization, younger individuals (20–48 years) had significantly higher antibody titers against all tested viruses than older persons (49–64 years) but this difference disappeared after the seasonal booster vaccination. Conclusions Even a few amino acid changes in influenza A HA may compromise the vaccine‐induced antibody recognition. Older adults (49 years and older) may benefit more from repeated influenza vaccinations.  相似文献   
82.
The significance of the musculoskeletal function of the neck-shoulder region in different headache types in children and adolescents is not clear. The purpose of this study was to investigate the association between different types of headache and the strength and mobility of the neck-shoulder region in 13-year-old schoolchildren. A structured questionnaire on headache was sent to all 1,409 children in the sixth grade in the city of Turku. Of the 1,135 (81%) children who completed the questionnaire, a sample from different headache groups was randomly selected for clinical examination. The study consisted of 59 children with migraine, 65 with episodic tension-type headache (TTHA), and 59 headache-free controls. Dynamic muscle strength of the upper extremities (UE endurance), mobility of both shoulders (UE mobility), and the cervical range of motion (CROM) were measured. Girls with episodic TTHA had lower UE endurance of both dominant and nondominant sides than girls in the other study groups. Girls with migraine had lower UE endurance of nondominant side than girls in the control group. In boys, no significant differences were observed. An interesting association between the function of the neck-shoulder region and headache complaints in adolescents was ascertained.  相似文献   
83.
Paternal occupational lead exposure and spontaneous abortion   总被引:4,自引:0,他引:4  
A case-referent study was conducted on whether occupational exposure of men to inorganic lead is related to spontaneous abortion in their wives. The men were biologically monitored for lead exposure. The cases (213 spontaneous abortions) and referents (300 births) were identified from medical registers. Lead exposure was assessed with blood lead (PbB) measurements and data obtained from a questionnaire. The results did not show a statistically significant relationship between spontaneous abortion and paternal lead exposure among all the study subjects. A significant increase was observed in the risk of those women whose husbands had been monitored (PbB greater than or equal to 1.5 mumol/l) during or close to the time of spermatogenesis. The association between lead exposure and spontaneous abortion was modified also by the age of the wife and paternal alcohol use. The findings suggest that there may be an association between paternal lead exposure and the risk of spontaneous abortion.  相似文献   
84.
We studied the results of different durations of application of the Pavlik harness for congenital dislocation or subluxation of the hip. For this, 110 hips in 106 patients were successfully reduced and examined when 6 years old. Dislocation and subluxation cases were divided into two groups: a long-term (4 months for dislocation and 3 months for subluxation) and a short-term (3 months for the former and 2 months for the latter) group. We compared them by roentgenographic analysis. The association between the long- and short-term groups was tested using statistical analyses. There were no significant differences between them, except for one item in subluxation. Therefore, we can say that the duration of application of the Pavlik harness should be reduced to 3 months for dislocation and 2 months for subluxation.  相似文献   
85.
Fiberoptic bronchoscopy (FOB) with bronchoalveolar lavage (BAL) and transbronchial biopsies (TBB) is a widely used method to detect respiratory infections and to differentiate them from other postoperative complications in lung transplant (LTX) recipients, but the usefulness of surveillance FOBs is not yet established. The aim of this study was to evaluate the usefulness of FOB in the diagnosis and surveillance of infections in LTX recipients. We reviewed all the consecutive 609 FOBs performed on 40 lung or heart-LTX recipients between February 1994 and November 2002. The overall diagnostic yield was 115/190 (61%) and 43/282 (15%) for clinically indicated and surveillance FOBs respectively (P < 0.001). Infection was established by bronchoscopic samples in 96/190 (50.5.%) of the clinically indicated FOBs and 34/282 (12.1%) of the surveillance FOBs (P < 0.001). The diagnostic yield of the clinically indicated FOBs was highest (72%) from 1 to 6 months post-transplant (P = 0.04). Pneumocystis carinii was detected in 23 (4.9%) of the bronchoscopic specimens and 15 (65%) of the P. carinii infections were detected during adequate chemoprophylaxis. To conclude, in LTX recipients clinically indicated FOB has a good diagnostic yield in detecting infections and other postoperative complications, whereas the information received from surveillance FOB has remained less significant. With current prophylaxis and screening strategies FOB is still required to detect P. carinii infections.  相似文献   
86.
Abstract: The effect of concurrent administration of antacids on the relative bioavailability of sotalol has been examined in five healthy volunteers. Each subject received an oral 160 mg dose after an overnight fast in four different experimental schedules. Venous blood samples were drawn 1,2,3,4,5,6,7,8,12,24, and 32 hrs after the drug administration, and sotalol concentrations were determined fluorometrically. The results show that concurrent administration of calcium carbonate or aluminium hydroxide with sotalol has negligible pharmacokinetic consequences. The adsorption of sotalol onto magnesium hydroxide leads to somewhat decreased biovailability but in long term use the phenomenon is not likely to be of clinical importance.  相似文献   
87.
In 43 patients the blood flow in 48 superficial metastatic tumors was measured with the 133xenon wash-out method. In all cases the blood flow was measured before the start of radiotherapy and then one week later during radiotherapy. In 36 cases the blood flow was measured after 2 weeks during radiotherapy, and in six patients the follow-up lasted 5–6 weeks. The blood flow increased during the first week of radiotherapy in the whole series from 20.1 ± 18.0 ml/min/100g to 31.3 ± 24.9 ml/min/100g. The increase during the first week was significant (p < 0.001). During the second week of radiotherapy the blood flow decreased to 27.0 ± 19.3 ml/min/100g; the decrease was also significant (p < 0.05). The changes in the different tumor groups during radiotherapy seemed to be in the same direction. In a longer follow-up the gradual decrease in the blood flow seemed to continue.  相似文献   
88.
Increasing Prevalence of Headache in 7-Year-Old Schoolchildren   总被引:3,自引:0,他引:3  
Matti Sillanpää  MD  PhD    Pirjo Anttila  MD 《Headache》1996,36(8):466-470
Reports of increased prevalence of headache in adults end clinical impressions of similar trends in children prompted this epidemiological study on migraine and other headache. The first stage was carried out in 1974 In children starting school, and the second stage in 1992 using the identical study design, the same age group, and a similar urban child population.
The overall prevalence of present headache (having occurred in the previous 6 months) was found to he significantly increased over time, from 14.4% in 1974 to 51.5% in 1992. Similarly, the prevalence of migraine headache had Increased from 1.9% to 5.7%. The causes of the increase are as yet unknown. The highest but not significant increases were found in schools which were situated in the districts of the city with the highest social instability, which was reflected in the high percentage of council houses and also in the higher frequency of family relocations. Increase over time in the prevalence of migraine end other headaches in children pears to be at least as dear as in adults. This should alarm the community to study the underlying stress factors and to try to relieve the children's distress.  相似文献   
89.
The right upper lung lobe of a 74 year old man was resected for a central tumour. Two primary cancers were found; a central small cell carcinoma and a peripheral squamous cell carcinoma. In addition, the peripheral lung tissue showed generalised peribronchiolar fibrosis extending from the non-respiratory bronchioles to the level of the alveolar ducts. Abundant asbestos bodies and large amounts of black dust were seen around the bronchioles. Pulmonary mineral particles were studied by quantitative energy dispersive x ray microanalysis (EDS) using scanning transmission electron microscopy (STEM). The x ray spectra for mineral particles were measured in thin sections, and the characteristic peak intensities of the elements were converted to weight fractions (in oxides). The results enabled the minerals present to be identified and their presence confirmed by calculating the mineral formula. These originated from nine natural minerals, anthophyllite and chrysotile asbestos, talc, and quartz, feldspars, and muscovite, which are components of sand, and also from two artificial mullites used in fire clay. The exposure history of the patient explained the most likely origins of the minerals detected. The patient had been a mason for 23 years, repairing and demolishing stoves and fireplaces and using asbestos for insulation work.  相似文献   
90.
During male puberty, erythropoiesis is exceptionally active. Pubertal development and iron status were followed in 60 healthy boys at 3-month intervals for 24 months to evaluate changes in body iron stores with the serum transferrin receptor–ferritin ratio. The estimated amount of stored iron declined by about 50% over a 2-year period. Remarkable changes in iron stores were found even after as short an interval as 3 months and pubertal development was closely linked with a decrease in stored iron. The annual increments of estimated red blood cell (RBC) iron showed strong positive correlations with velocities in testicular volume and certainly in body height and weight. In contrast, the estimated changes in individual iron stores were not associated with any of those parameters. The lacking associations between iron stores and growth parameters are probably indicative of increasing intestinal absorption. Despite the relatively small quantitative role of iron stores in supplying iron for growth, falling iron stores probably play a more important regulatory role by stimulating iron absorption.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号