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   18855篇
  免费   1201篇
  国内免费   84篇
耳鼻咽喉   179篇
儿科学   487篇
妇产科学   384篇
基础医学   2135篇
口腔科学   323篇
临床医学   1554篇
内科学   3987篇
皮肤病学   229篇
神经病学   1043篇
特种医学   537篇
外科学   3341篇
综合类   648篇
一般理论   17篇
预防医学   1438篇
眼科学   518篇
药学   1875篇
中国医学   221篇
肿瘤学   1224篇
  2023年   174篇
  2022年   531篇
  2021年   669篇
  2020年   432篇
  2019年   542篇
  2018年   659篇
  2017年   456篇
  2016年   370篇
  2015年   512篇
  2014年   707篇
  2013年   880篇
  2012年   1316篇
  2011年   1299篇
  2010年   744篇
  2009年   571篇
  2008年   1012篇
  2007年   998篇
  2006年   927篇
  2005年   858篇
  2004年   784篇
  2003年   698篇
  2002年   586篇
  2001年   542篇
  2000年   486篇
  1999年   390篇
  1998年   146篇
  1997年   113篇
  1996年   107篇
  1995年   115篇
  1994年   60篇
  1993年   75篇
  1992年   202篇
  1991年   186篇
  1990年   163篇
  1989年   170篇
  1988年   135篇
  1987年   152篇
  1986年   123篇
  1985年   134篇
  1984年   110篇
  1983年   86篇
  1982年   59篇
  1981年   60篇
  1979年   97篇
  1978年   64篇
  1977年   66篇
  1975年   60篇
  1974年   51篇
  1973年   54篇
  1972年   50篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
患者,女,62岁,因颈部肿块就诊。既往32年前因胆囊疾病行胆囊切除术。15年前因多发性甲状腺结节行甲状腺次全切除术,病理结果为小灶性甲状腺癌。10年前因血尿诊断为肾癌,行右肾切除术。.体格检查:锁骨上可触及一5.0cm×3.0cm大小肿块(穿刺细胞学检查结果不能定性)。.辅助检验:腹  相似文献   
105.
Mood symptoms are reported frequently in asthma patients, particularly during corticosteroid therapy. This investigation compared the Internal State Scale (ISS), a self-report measure of symptoms of mania and depression, to the Hamilton Rating Scale for Depression (HRSD), Young Mania Rating Scale (YMRS), and Brief Psychiatric Rating Scale (BPRS) in a group of asthma patients (n=60 at baseline) before, during, and after a 1-2 week burst of prednisone. The depression and well being subscales of the ISS correlated well with HDRS scores. The perceived conflict subscale correlated with the BPRS scores. However, none of the ISS subscales correlated consistently and specifically with the YMRS in this population. Possible explanations for differences observed in bipolar versus asthma patients given the ISS are discussed. These data suggest the ISS may be a useful tool for depression symptoms and overall psychopathology in asthma patients and in patients receiving corticosteroid therapy. However, its ability may be attenuated outside of the population for which it was designed.  相似文献   
106.
BACKGROUND: The purpose of this study was to determine whether significant regression of left ventricular hypertrophy is seen after implantation of small sizes (19 to 23 mm) of the Carpentier-Edwards (CE) pericardial valve, a stented pericardial valve. METHODS: Echocardiograms and electrocardiograms (ECGs) were performed at least 1 year after surgery (mean 18 months) in patients with 19-, 21-, and 23-mm CE pericardial aortic valves and compared with preoperative echocardiograms and ECGs. RESULTS: A total of 41 patients, mean age 79 +/- 9 years (range 46 to 93 years), were studied, including 7 19-mm, 22 21-mm, and 12 23-mm patients. The mean postoperative gradient was 22 +/- 7 mm Hg for 19-mm valves, 18 +/- 5 mm Hg for 21-mm valves, and 16 +/- 4 mm Hg for 23-mm valves. The postoperative valve areas were 1.1 +/- 0.3 cm2 for the 19-mm, 1.3 +/- 0.3 cm2 for the 21-mm, and 1.5 +/- 0.4 cm2 for the 23-mm valves. Left ventricular end diastolic diameter, end systolic diameter, septal thickness, and posterior wall thickness all decreased significantly (p <0.05) postoperatively. The proportion of patients with significant left ventricular hypertrophy on ECG decreased from 63% to 47% (p = 0.001). Left ventricular mass decreased significantly by echocardiography from 265 g preoperatively to 208 g postoperatively (p = 0.004). Left ventricular mass decreased for each valve size, and the greatest absolute reduction in mass occurred in the 19-mm valve recipients. CONCLUSIONS: Implantation of the 19-, 21-, and 23-mm CE pericardial valves results in significant reductions in left ventricular mass. These findings suggest that stented pericardial valves can be used in the small aortic root without the need for aortic root enlargement procedures.  相似文献   
107.
OBJECTIVE: The authors present a 12-year (1986-98) study of a new procedure called percutaneous nephropexy (PCNP). This procedure was performed on 51 renal ptosis patients at two urological departments (in Pakistan and Hungary) with satisfactory results. The idea for PCNP was adapted from the observation that after drain insertion following nephrostomy a scar is quite sufficient to hold the kidney in place. That idea was used to fix the kidney at the required level. MATERIAL AND METHODS: Thirteen patients complained of a palpable mobile mass in the abdomen while others suffered from pain in their affected flank with recurrent attacks of urinary tract infection. On ultrasonic examination the kidney was found to be lower than the normal position. This observation was confirmed by a standing intravenous urography (IVU) examination that also showed a tortuous ureter. Nine patients also had a stone in the affected kidney. The operation involved puncture and dilatation of a channel through the lower calyx. RESULTS: Control IVU examination was performed after wound healing and was repeated 2 months after the operation, followed by consecutive ultrasonic examinations. Standing X-ray films obtained after contrast material injection showed the kidney to be at a higher level with a straight ureter. Forty-five patients (88.2%) recovered completely. CONCLUSION: In the authors' opinion PCNP is a good alternative to open nephropexy operations in renal ptosis cases, particularly when laparoscopic surgery facilities are not available. Although PCNP was developed in circumstances in which the availability of equipment was restricted, in terms of benefits it is comparable with laparoscopic nephropexy.  相似文献   
108.
Cancer is the second leading cause of death all around the world. The natural compounds derived from the endophytic flora of fungi are possible solutions to cancer treatment because they are safe for health, cost-effective, biocompatible and have fewer toxicity issues. The active ingredients in endophytic fungi that are responsible for anti-cancer activities are alkaloids, terpenoids, glycosides, saponin, peptides, steroids, phenols, quinones, and flavonoids. This review highlights the anti-cancer activities of entophytic fungus against human papillary thyroid carcinoma (IHH4), human pancreatic (PANC-1), ovarian (OVCAR-3), hepatic (HepG2), lung (A-549), human lymphoma (U937), human skin carcinoma (A431), breast (MCF-7), and Kaposi’s sarcoma. The emerging evidence suggested that bioactive compounds isolated from endophytic fungi showed their anti-cancer activities by revealing the disturbance of the microtubule network caused by increased levels of Bax and Bcl-2 proteins that triggers cell cycle arrest at the G2-M phase, by inhibiting the DNA replication via binding with topoisomerase II, by regulating the activity of extracellular signal-regulated kinase and NF-kB, by evaluating the levels of p21, p27, and cyclins B/D1/E that led to cell death by apoptosis and cell cycle arrest. This review will assist readers in better comprehending bioactive chemicals and the beneficial interaction between the fungal endophytes and medicinal plants.  相似文献   
109.
Maffucci syndrome is a non-hereditary congenital condition that affects the skin and skeleton. Enchondromas (benign cartilage enlargements), bone abnormalities, and venous anomalies (hemangiomas) are all symptoms. Enchondromas occur as a result of mesodermal dysplasia and have the potential to become cancerous. They are most commonly found on the phalanges and long bones. Venous abnormalities commonly manifest themselves as soft lumps or tumors on the distal extremities. A 19-year-old boy presented with swellings on his fingers and left foot since the age of 5, along with a few bluish soft tissue swellings on his left heel. Multiple expansile lytic lesions and soft tissue swellings with phleboliths were seen on X-ray. Histology confirmed the diagnosis of hemangiomas and enchondromas. Soft tissue swellings were found to have hyper echoic areas, as well as modest marginal blood flow on Doppler, which could indicate hemangiomas. Maffucci syndrome was identified, and treatment with a multidisciplinary approach was initiated. Maffucci syndrome is a rare genetic illness reported in the literature less than 200 times. The enchondromas and hemangiomas have a strong link to malignant changes, with chondrosarcomas accounting for 30% of the associated malignancies. On X-ray, enchondromas are easily identified as osteolytic lesions with cortex thinning and endosteal scalloping while color Doppler ultrasound detects the presence of hemangiomas. Phleboliths are easily identified as small calcifications on X-rays. Radiographic examinations should be considered in patients presenting with bone or soft tissue swellings for an early diagnosis of Maffucci syndrome.  相似文献   
110.
Background:Virtual reality (VR) is an advanced technique used in physical rehabilitation of neurological disorders, however the effects of VR on balance, gait, and motor function in people with Parkinson’s (PD) are still debated. Therefore, the systematic review aimed to determine the role of VR on motor function, balance and gait in PD patients.Methods:A comprehensive search to identify similar randomised controlled trials was conducted targeting 5 databases including Web of Science, PubMed, CINHAL, Cochrane Library, and Physiotherapy Evidence Database. A total of 25 studies were found eligible for this systematic review, and the methodological assessment of the quality rating of the studies was accomplished using the physiotherapy evidence database scale by 2 authors.Results:Out of the 25 included studies, 14 studies reported on balance as the primary outcome, 9 studies were conducted to assess motor function, and 12 assessed gait as the primary outcome. Most studies used the Unified Parkinson disease rating scale UPDRS (part-III) for evaluating motor function and the Berg Balance Scale as primary outcome measure for assessing balance. A total of 24 trials were conducted in clinical settings, and only 1 study was home-based VR trainings. Out of 9 studies on motor function, 6 reported equal improvement of motor function as compared to other groups. In addition, VR groups also revealed superior results in improving static balance among patient with PD.Conclusion:This systemic review found that the use of VR resulted in substantial improvements in balance, gait, and motor skills in patients with PD when compared to traditional physical therapy exercises or in combination with treatments other than physical therapy. Moreover, VR can be used as a supportive method for physical rehabilitation in patients of PD. However, the majority of published studies were of fair and good quality, suggesting a demand for high quality research in this area.  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