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   1918篇
  免费   112篇
  国内免费   11篇
耳鼻咽喉   27篇
儿科学   52篇
妇产科学   70篇
基础医学   262篇
口腔科学   103篇
临床医学   193篇
内科学   337篇
皮肤病学   13篇
神经病学   163篇
特种医学   63篇
外科学   311篇
综合类   9篇
一般理论   4篇
预防医学   155篇
眼科学   20篇
药学   170篇
中国医学   1篇
肿瘤学   88篇
  2021年   21篇
  2020年   18篇
  2019年   15篇
  2018年   22篇
  2017年   13篇
  2016年   22篇
  2015年   23篇
  2014年   39篇
  2013年   91篇
  2012年   79篇
  2011年   76篇
  2010年   52篇
  2009年   58篇
  2008年   111篇
  2007年   104篇
  2006年   96篇
  2005年   117篇
  2004年   83篇
  2003年   81篇
  2002年   93篇
  2001年   46篇
  2000年   38篇
  1999年   44篇
  1998年   31篇
  1997年   24篇
  1996年   16篇
  1995年   20篇
  1994年   20篇
  1993年   26篇
  1992年   27篇
  1991年   31篇
  1990年   27篇
  1989年   37篇
  1988年   25篇
  1987年   26篇
  1986年   33篇
  1985年   56篇
  1984年   30篇
  1983年   24篇
  1982年   20篇
  1981年   17篇
  1980年   12篇
  1979年   27篇
  1978年   16篇
  1977年   21篇
  1976年   10篇
  1975年   16篇
  1974年   12篇
  1973年   13篇
  1970年   12篇
排序方式: 共有2041条查询结果,搜索用时 31 毫秒
1.
The present paper deals with a Finnish long-term prospective study, the objective of which is to shed light on adjustment to retirement and old age. In this phase, only the preliminary findings of the initial survey carried out in 1982 are available. For the purposes of the study, a random sample of 200 individuals was drawn from among Turku inhabitants born in 1920. Another sample, consisting of 189 persons of the same age, was drawn from rural municipalities in the neighborhood of Turku. An extensive structured psychosocial interview could be conducted with a total of 339 subjects. The research methods used included e.g. the 36-item version of Goldberg's General Health Questionnaire (GHQ). Relatively little mental disturbance was revealed in the interview, and no major differences occurred between the urban and the rural sample. Somewhat over one-third of both samples were probable psychiatric cases as defined according to the GHQ.  相似文献   
2.
To assess whether initial surgery is beneficial for patients with primary dislocation of the patella, we carried out a prospective randomized study. Knee stability was examined under anesthesia, and associated injuries were excluded by diagnostic arthroscopy. 55 patients then had closed treatment and 70 patients were operated on with individually adjusted proximal realignment procedures.

Surgery gave no benefit based on 2 years of follow-up. The subjective result was better in the non-operative group in respect of mean Houghston VAS knee score (closed 90, operative 87), but similar in terms of the patient's own overall opinion and mean Lysholm II knee score. Recurrent instability episodes (redislocation or recurrent subluxation) occurred in 20 nonoperated and in 18 operated patients. Of these, 15 and 12, respectively, then suffered redislo-cations. Function was better after closed treatment. Serious complications occurred after surgery in 4 patients.

In conclusion, the recurrence of patellar dislocation may be more frequent than reported, whatever the form of treatment. Routine operative management cannot be recommended for primary dislocation of the patella.  相似文献   
3.
The effects of 10% dietary xylitol supplementation in ovariectomized rats were studied on the degradation of bone organic and inorganic structures. The osseal concentrations of hydroxyproline, pyridinoline, and deoxypyridinoline were analyzed by high-performance liquid chromatography. Bone resorption was measured in [3H]tetracycline-prelabeled rats by urinary excretion of 3H, and by the amount of 3H preserved in bone. Bone trabeculation was measured by a computer image analyzer from sections stained by the method of von Kossa. The amount of collagen in bone organic fraction was lower in ovariectomized rats as compared with the sham-operated controls. This most likely is partly a consequence of an increased resorption, and partly a consequence of a higher proportion of immature periosteal bone in the ovariectomized animals, leading to a higher ratio of noncollagenous protein to collagen. The number of pyridinium crosslinks was lower in proportion, indicating no selective changes in the structure of collagen. Dietary xylitol significantly retarded the ovariectomy-associated decrease in the relative amount of collagen and the number of its mature crosslinks. Ovariectomy doubled the excretion of 3H and caused a significant decrease in the amount of 3H preserved in bone; both these changes were significantly retarded by the 10% dietary xylitol supplementation. Ovariectomy significantly decreased the volume of bone trabeculae, but this effect was also significantly inhibited by the xylitol supplementation in the diet. In conclusion, these findings suggest a dietary xylitol-induced normalizing effect on the rate of bone turnover in ovariectomized rats. Received: 12 February 1996 / Accepted: 20 August 1996  相似文献   
4.
Between November 1984 and January 1994 in our department, a total of 2500 patients were treated with totally absorbable internal fixation devices. We studied these patients and analyzed results with regard to the volume of the absorbable implants and the development of wound infection. Of the 2500 patients 2044 were trauma patients and 456 were operated on for orthopedic disease. In 1466 patients treated with implants made of self-reinforced polyglycolic acid (SR-PGA) only, the patients who developed wound infection had a higher implant volume (P=0.07) than those who did not; this difference was close to statistical significance. In the 446 patients who received only implants made of self-reinforced poly-l-lactic acid (SR-PLLA), the 5 who developed wound infection had a mean implant volume more than three times that of the non-infected patients (P=0.01). We found that in the patients treated with the earlier SR-PGA implants, which contained a green staining material, there was no correlation between implant volume and incidence of wound infections. On the other hand, both the non-stained SR-PGA implants, which have been in clinical use since 1989, and the SR-PLLA implants, seem to be more predictable in terms of wound infections. We believe that this difference, is largely due to the lower level of tissue reactions with these newer implants.  相似文献   
5.
Intrascrotal adenomatoid tumors   总被引:1,自引:0,他引:1  
Adenomatoid tumors are regarded as uncommon neoplasms of the paratesticular tissues, probably of mesothelial origin. The majority of cases reported have involved the epididymis. We report our experience with 8 cases of testicular tumors and 11 of epididymal adenomatoid tumors during a 13-year period, and review the relevant literature. The incidence of adenomatoid tumors relative to all tumors in the testis was 6.9% (8 of 116), exceeding that of Leydig cell tumors, which were previously believed to be the most common benign testicular neoplasms. The adenomatoid tumors included 38% epididymal tumors (11 of 29). The clinical course of the tumors was benign, without recurrences. Local excision is regarded as the treatment of choice for epididymal and testicular adenomatoid tumors.  相似文献   
6.
The pH of the rument contents of cattle was recorded at slaughter; pH ranged from 5.5 to 7.8 and was not correlated with the period from saleyard to slaughter. Volatile fatty acids (VFA) were measured in 43 rumen samples; acetic, propionic and butyric were the major acids present, and the total VFA ranged from 75.9 mM/l for samples between pH 6-7, to 7.1 mM/l for samples of pH 8-9. Ten Salmonella strains belonging to 8 serotypes were grown in these 43 rumen samples. Where acid levels of these samples were high and pH low, most Salmonella sp. were inhibited; as the pH rose (pH 7-8) all Salmonella serotypes grew, some vigorously; as the total acid declined and pH continued to rise, growth of salmonella ceased. Serotypes and strains of the same serotype differed in their ability to grow in rumen contents, particularly when the pH was low.  相似文献   
7.
Sclerotherapy with 5% ethanolamine oleate was used to treat 102 hydroceles in 100 patients and 63 spermatoceles in 58 patients. Scrotal ultrasound examination was performed before the sclerotherapy and at each followup visit. Of the hydroceles 98% were cured completely and 68% were cured after only 1 sclerosant instillation, while 60% of the spermatoceles resolved completely and 33% partially, with 7% failures. No hydroceles recurred during an average followup of 43 months, whereas spermatocele recurred in 4 patients more than 1 year after successful treatment, with a mean followup of 46 months. Approximately half of the patients experienced pain after treatment, 3 had infection and 2 had hematoma. No changes in the structure or size of the testicles were found by ultrasound during followup. Ethanolamine oleate sclerotherapy is a safe, effective and economical form of outpatient therapy that can be recommended as primary treatment for hydroceles in adults and as an alternative to surgery for spermatoceles with 1 to 3 cysts in elderly men in whom fertility is not important.  相似文献   
8.
This study, which was carried out as part of the TURVA project on psychosocial adaptation in old age, is concerned with the significance of social support to people approaching retirement age. The population consisted of 200 urban dwellers and 189 rural dwellers, who were studied at the age of 62. The subjects were either about to retire in the near future or had already retired, and it was assumed that this event causes a certain amount of stress, which may lead to mental disturbance regardless of the amount of social support available to the individual. Intimate relationship and close friendship served as the measures of social support. Mental disturbances were assessed on the basis of the General Health Questionnaire (36-item version) and the number of psychic and especially depressive symptoms. The prevalence of mental disturbance and depressive symptoms was lowest in those people who lived in a close marital relationship and who also described their spouse as empathic. Psychic symptoms were most common in those people who said their relationship to their spouse was distant and who described them as unempathic. The subjects who were not married fell in-between these 2 groups regardless of whether they had an intimate relationship with someone of the opposite sex. A positive marital relationship seemed to provide a shield against depression, while a negative marital relationship tended to make the individual more vulnerable to depression. The role of a close non-marital friendship depended on the respondent's sex. In women, it was associated with a high prevalence of depressive symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
9.
Tumour DNA ploidy as an independent prognostic factor in breast cancer   总被引:2,自引:0,他引:2  
We determined nuclear DNA content from 308 archival paraffin-embedded malignant breast tumours and evaluated the survival of the patients by univariate and multivariate statistical analyses. The overall 8-year survival rate of stage I-III breast cancer patients was 74.3% in DNA-diploid and 51.2% in DNA-aneuploid tumours (P less than 0.0001). DNA ploidy had prognostic significance in both node-negative and node-positive breast cancer, primarily in cases with steroid receptor-positive tumours. In a Cox multivariate analysis DNA ploidy (P = 0.001), primary tumour size (P = 0.0007), nodal status (P = 0.04) and the content of progesterone receptors (P = 0.0008) emerged as significant independent prognostic factors, whereas oestrogen receptor status, age and menopausal status of the patients had no significant independent prognostic value. If the histological grade of ductal carcinomas was also included in the Cox model, both grade and DNA ploidy had independent prognostic effect. In conclusion, our results indicate that the analysis of DNA ploidy is a useful adjunct in the assessment of prognosis for breast cancer patients.  相似文献   
10.
Cerebrospinal fluid beta-endorphin-like immunoreactivity (CSF BLI) was determined for 69 patients who met DSM-III criteria for delirium and for 8 controls. The CSF BLI was significantly lower in the delirious patient group than in the controls (12.5 +/- 3.0 pg/ml versus 15.0 +/- 3.4 pg/ml, p less than 0.05). CSF BLI had no correlation with age or neuroleptic drug dosage, but did have a significant positive correlation with cognitive functioning as evaluated by the Mini-Mental State. Our findings suggest a role for beta-endorphinergic dysfunction in the development of delirium.  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