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   4340篇
  免费   324篇
  国内免费   23篇
耳鼻咽喉   29篇
儿科学   191篇
妇产科学   90篇
基础医学   515篇
口腔科学   45篇
临床医学   570篇
内科学   728篇
皮肤病学   82篇
神经病学   360篇
特种医学   210篇
外科学   558篇
综合类   219篇
一般理论   7篇
预防医学   373篇
眼科学   32篇
药学   229篇
  1篇
中国医学   41篇
肿瘤学   407篇
  2023年   24篇
  2022年   30篇
  2021年   74篇
  2020年   49篇
  2019年   74篇
  2018年   77篇
  2017年   57篇
  2016年   66篇
  2015年   91篇
  2014年   112篇
  2013年   152篇
  2012年   205篇
  2011年   216篇
  2010年   159篇
  2009年   150篇
  2008年   206篇
  2007年   191篇
  2006年   222篇
  2005年   194篇
  2004年   169篇
  2003年   147篇
  2002年   122篇
  2001年   129篇
  2000年   150篇
  1999年   122篇
  1998年   86篇
  1997年   98篇
  1996年   77篇
  1995年   63篇
  1994年   60篇
  1993年   55篇
  1992年   88篇
  1991年   83篇
  1990年   56篇
  1989年   87篇
  1988年   67篇
  1987年   60篇
  1986年   53篇
  1985年   50篇
  1984年   50篇
  1983年   31篇
  1982年   39篇
  1981年   28篇
  1980年   30篇
  1979年   23篇
  1978年   25篇
  1976年   24篇
  1975年   22篇
  1974年   24篇
  1973年   28篇
排序方式: 共有4687条查询结果,搜索用时 15 毫秒
1.
2.
The levels of residual radioactivity induced in Havar foils at the entrance of a high-pressure 18O-enriched water target used for the production of 18F- in a medical cyclotron with 16 MeV protons have been determined using high-resolution gamma-ray spectrometry. Whole body and skin dose rates arising from exposure to these foils during their periodic replacement have been estimated. The results indicate that irradiated foils do not represent a significant radiological hazard for the cyclotron operating staff and that no waste disposal difficulties should be encountered after an appropriate 'cooling' period of 2 years.  相似文献   
3.
Auditory P300 and eye tracking dysfunction in schizophrenic pedigrees   总被引:4,自引:0,他引:4  
Several psychophysiological abnormalities associated with schizophrenia have been proposed as genetic trait markers of vulnerability to the disorder. Smooth pursuit eye tracking dysfunction and abnormal long latency event-related potentials are the most promising candidates. Both are independent of the effects of psychotropic medication or mental state at the time of testing, and twin studies demonstrate that each has a high level of heritability. Having recorded smooth pursuit eye tracking and event-related potentials in 20 high-density schizophrenic families, we find abnormalities in one or both measures in most of the families studied. The abnormalities, when present, occur in the family members with schizophrenia and other forms of functional psychosis, and they have a bimodal distribution with approximately half the nonschizophrenic relatives also showing eye tracking dysfunction and/or abnormal event-related potentials. Some of these relatives had psychiatric symptoms; others were normal. Our results suggest that psychophysiological examination can help to clarify the boundaries of schizophrenia spectrum disorder. By helping to decide the phenotypic status of nonschizophrenic family members, this should increase the power of DNA linkage studies.  相似文献   
4.
Dilatation and curettage (D+C) is the most common operation performed in Britain. The liberal use of D+C has been criticised. The objective of this study was to evaluate the use of outpatient endometrial pipelle biopsy and determine its safety in terms of detecting abnormalities. Complications and financial costs were also evaluated. Data were reviewed from an active gynaecological unit from February 1993 to January 1995. A total of 303 D+Cs and 104 endometrial pipelle biopsies were performed in this period. Nine malignancies were detected by D+C and 1 by pipelle biopsy. A total of 24 and 3 benign abnormalities were detected by each method respectively. There was a higher complication rate in the D+C group but the failure rate was higher in the endometrial pipelle biopsy group. The monetary savings over this period is estimated at £20,307. There were no missed malignancies to our knowledge over the 8 yr period since endometrial pipelle biopsy was introduced to the hospital.  相似文献   
5.
Suppurative corneal ulceration in Bangladesh   总被引:8,自引:0,他引:8  
Suppurative keratitis is an important preventable cause of blindness, particularly in the developing world. This study analyses 142 cases of suppurative keratitis referred to Chittagong Eye Infirmary, Bangladesh. Some 53.5% of cases were bacterial and 35.9% were fungal. The five most common pathogens were: Pseudomonas sp. 24%, Streptococcus pneumoniae 17%, Aspergillus sp. 13%, Fusarium sp. 7% and Curvularia sp. 6%. Gram stain and culture results were consistent in 62.6% of cases. Previous antibiotic treatment was a significant factor for failure of culture isolation and less so for Gram stain failure. On Gram stain, 55.9% of pseudomonal cases were missed, but only 2% of fungal cases were missed. Over all, Gram stain had a sensitivity of 62% and positive predictive value of 84% for bacterial cases, and 98% and 94% for fungal cases, respectively. Fungal ulcers were typically filamentous, but an antecedent history of trauma was not common. The most frequent injury was due to rice grains, but the inoculum appeared to be introduced during eye washing with contaminated water. Pseudomonal ulcers occurred most frequently in the monsoon season, and Fusarium cases were seen only in the hot, dry season.  相似文献   
6.
7.
The pedicle patch urethroplasty provides an alternative single-stage vascularised graft procedure for the repair of moderately severe hypospadias. Over a 7-year period, 38 primary hypospadias repairs were performed employing this technique. The fistula rate was 18% in the 34 patients reviewed, but there were few other significant complications. The operation is recommended when the urethral plate can be preserved and the penis straightened in boys who are unsuitable for a meatal-based flap.  相似文献   
8.
9.
Objective: Our aim was to investigate the prevalence of intra-operative nerve damage and its association with chronic pain. Methods: Our prospective study of 33 patients used nerve conduction studies to assess intercostal nerve function during elective thoracic surgical procedures. We used two methods to study nerve conduction: pre-operative magnetic stimulation (in 10 patients) and intra-operative nerve conduction studies (in all patients) We correlated these findings with specific intra-operative parameters, pain and psychological questionnaires pre-op and 3 month post-op and altered cutaneous sensation. Results: Magstim (magnetic stimulation) assessments were not reliable and were therefore abandoned. Intraoperative intercostal nerve studies revealed two distinct patterns of nerve injury and also that nerve injury was less in those cases where a rib was not resected. However, intercostal nerve damage detected at the time of operation is not associated with chronic pain or altered cutaneous sensation at 3 months post-op. Conclusions: The study findings suggest that either the amount of intra-operative intercostal nerve damage is not indicative of long-term nerve damage or that there is a more significant cause for chronic pain other than intercostal nerve injury.  相似文献   
10.
OBJECTIVE: There are limited and conflicting data available concerning the incidence of inadvertent splenectomy and its impact on the outcome in patients who have undergone oesophagectomy. The aim of this study is to identify the factors associated with a likelihood of inadvertent splenectomy and its influence on early and long-term outcome in patients having oesophagectomy for oesophageal carcinoma. METHODS: A consecutive series of 738 oesophagectomies performed between 1991 and 2004 was analysed. In our practice, the spleen was removed only if damaged intraoperatively. Routine chemo- and immunoprophylaxis would subsequently be used. Multivariate analysis with logistic and Cox models determined significant variables. RESULTS: Of the 738 oesophagectomies, 48 (6.5%) had splenectomy. Neoadjuvant chemotherapy was administered to a minority of patients; none subsequently had splenectomy. There were significant differences between types of operation (Ivor-Lewis 18 (9.0%), left thoracolaparotomy 14 (9.9%) and left thoracophrenotomy 15 (3.9%), p=0.01). Splenectomy was more common with advanced N stage disease (OR=0.44 [0.20-0.95]; p=0.04). Splenectomy resulted in more blood transfusions (median, 2 units vs 0 units; p=0.03) more anastomotic leaks (7 [14.6%] vs 42 [6.1%]; p=0.02) but not an increase in pulmonary complications (p=0.64) or in-hospital mortality (1 [4.6%] vs 37 [5.4%]; p=0.30). Splenectomy did not significantly affect median survival (551 [332-770] days vs 627 [554-700] days; p=0.63). CONCLUSION: Although inadvertent splenectomy increased the morbidity of oesophagectomy, it did not impair survival. Type of operation and advanced N stage are important risks for splenectomy. Though best avoided, most of the consequences of splenectomy can be managed. An unexpected relationship between splenectomy and anastomotic leaks needs further investigation.  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