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   48375篇
  免费   3320篇
  国内免费   1220篇
耳鼻咽喉   567篇
儿科学   747篇
妇产科学   1100篇
基础医学   7080篇
口腔科学   765篇
临床医学   5003篇
内科学   8607篇
皮肤病学   1176篇
神经病学   3329篇
特种医学   2072篇
外国民族医学   5篇
外科学   6097篇
综合类   2918篇
现状与发展   9篇
一般理论   12篇
预防医学   2599篇
眼科学   1140篇
药学   4525篇
  15篇
中国医学   1165篇
肿瘤学   3984篇
  2024年   68篇
  2023年   489篇
  2022年   1325篇
  2021年   1939篇
  2020年   1078篇
  2019年   1269篇
  2018年   1484篇
  2017年   1141篇
  2016年   1378篇
  2015年   1974篇
  2014年   2407篇
  2013年   2719篇
  2012年   3941篇
  2011年   4019篇
  2010年   2411篇
  2009年   1996篇
  2008年   2873篇
  2007年   2761篇
  2006年   2481篇
  2005年   2403篇
  2004年   1936篇
  2003年   1634篇
  2002年   1410篇
  2001年   1173篇
  2000年   1145篇
  1999年   930篇
  1998年   392篇
  1997年   322篇
  1996年   251篇
  1995年   228篇
  1994年   201篇
  1993年   147篇
  1992年   340篇
  1991年   339篇
  1990年   285篇
  1989年   226篇
  1988年   195篇
  1987年   201篇
  1986年   172篇
  1985年   131篇
  1984年   109篇
  1983年   95篇
  1982年   57篇
  1981年   53篇
  1980年   59篇
  1979年   88篇
  1978年   67篇
  1977年   58篇
  1974年   64篇
  1972年   69篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
BACKGROUND: The tuberous breast presents a problem for which many surgical solutions have been described. Current teaching describes how the tuberous breast deformity is the result of skin shortage as well as herniation of breast tissue through the nipple-areola complex. However, through careful clinical observation we now believe that the only abnormality present is herniation of breast tissue through the nipple-areola complex. METHODS: Using this principle, we have refined a one-stage surgical procedure that can be used to correct any type of tuberous breast deformity. Since 2001 we have performed our technique on a series of 13 tuberous breasts of widely varying appearances in eight patients (age 17-24 years) with a follow up varying between 3 and 56 months. Our new understanding of the tuberous breast deformity has also made it possible to develop an objective, reproducible method for defining the tuberous breast based on the degree of areola herniation. RESULTS: All patients reported high levels of satisfaction with the procedure. Assessment of the results by an independent panel of attending surgeons showed all results to be good/excellent. Moreover, the results have improved with time and no revisions have been needed. Our method of defining the tuberous breast (based on the ratio of areola herniation:areola diameter) enabled us to identify a cut-off to decide (objectively) when a breast was tuberous. This allowed us to anticipate when an areola reduction/tightening procedure would be necessary to avoid a 'double-bubble' deformity. CONCLUSION: We propose a one-stage surgical procedure which is applicable to all degrees of tuberous breast deformity. The results appear to confirm our theory that the only abnormality present in the tuberous breast is herniation of breast tissue through the nipple-areola complex. In patients with small breasts and a tuberous deformity, correction of the herniation changes the tuberous breast into a simple hypoplastic breast. The volume deficit can then be corrected by augmentation (if desired by the patient). In patients with sufficient breast volume, correction of the herniation alone will correct the deformity.  相似文献   
82.
OBJECTIVE: The recent development of fetal ultrasonography has allowed for an increasing number of prenatal diagnoses for congenital cystic adenomatoid malformation (CCAM). However, the appropriate surgical timing of these patients has not been studied as of yet. The aim of this study is to suggest a safe strategy for the treatment of CCAM by identifying the relationship between the timing of surgery and postoperative outcome. METHODS: Between 1987 and 2003, 40 patients (28 males, 12 females) underwent surgical resection for CCAM. The mean age was 38.6+/-9.1 (2 days-13 years) months. CCAM was diagnosed by prenatal ultrasonography in eight patients. Early operations were performed in four out of the eight. Operation was deferred until 2-12 months of age for the remaining four patients. RESULTS: Type I CCAM was found in 20 patients, type II in 20 and no patient exhibited type III. Five patients had associated pectus excavatum anomaly. There were no cases of operative mortality. Seventeen minor postoperative complications developed in 16 patients (40.0%): prolonged chest tube drain in 10, wound infection in 4, and 1 case of pneumonia, empyema and pleural space, respectively. The average hospital stay was 11.8 (6-29) days. During the mean follow-up period of 67.5 months, one patient died of accidental aspiration 7 months after operation during the postoperative recovery course of Ravich operation for pectus excavatum. The remaining patients reported doing well with normal physical activity. All five patients who underwent surgery at the age of under 1 month did not exhibit increased postoperative morbidity. CONCLUSIONS: We concluded that surgery for CCAM could be safely performed in all age groups with satisfactory long-term outcomes. It is suggested that early elective surgical correction can be recommended for a patient whose diagnosis was made in utero.  相似文献   
83.
Background/aims  Surgical resection of choledochal cysts (CC) has become standard treatment. However, surgery is not universally recommended in early infancy and/or asymptomatic patients. In order to investigate the optimal timing of CC excision, we analyzed clinicopathological data and surgical results from different age groups. Material and methods  This retrospective review included 107 patients (77 females, 30 males) who underwent CC resection at the National Taiwan University Hospital between January 1988 and December 2005. Patient demographic, clinical, and surgical data were collected and analyzed. Results  The patients were divided into three groups according to age at the time of surgery: <1 year old (group I, n = 26), 1−16 years old (group II, n = 48), and >16 years old (group III, n = 33). About two thirds of the patients in group I had jaundice, while abdominal pain related to inflammation was the commonest symptom in groups II and III. Group I suffered significantly fewer surgical complications and less severe liver fibrosis than groups II or III. Conclusion  CC surgery in infancy and in asymptomatic patients is safe and may prevent the complications of this condition. The results support a recommendation for early excision.  相似文献   
84.
目的探讨食管癌贲门癌术后胸胃排空障碍的诱因、诊断和治疗。方法回顾性分析1990年1月-2003年12月我院施行1369例食管癌贲门癌切除术的病人临床资料。结果本组病例发生胸胃排空障碍17例,发生率1.24%,其中机械性胸胃排空障碍5例,功能性胸胃排空障碍12例,均发生于术后3~12d,再次手术治疗5例;治愈16例,死亡1例。结论上消化道造影、胃镜是鉴别机械性胃排空障碍和功能性胃排空障碍的重要方法,对食管癌术后机械性胃排空障碍应采取手术治疗,而功能性胃排空障碍采取保守治疗多能好转。  相似文献   
85.
86.
87.
对耳轮过度前突为对耳轮的角度过锐,致使耳轮的位置相应后移,表现为与招风耳完全相反的畸形。畸形虽不十分明显,但影响美观。自1992年4月开始应用患侧耳廓软骨和耳后皮瓣对5例患者8只外耳进行治疗得到满意效果。认为文中所述方法是矫正对耳轮过度前突畸形的良好方法。  相似文献   
88.
Pathological and experimental studies have shown that cerebral aneurysms develop in part as a result of injury to the blood vessel wall. One of the peculiar aspects of aneurysm development is a defective proliferative or healing response to such injury. To examine this phenomenon, blood coagulation Factor XIII, which is known to enhance the healing process of wounds in general, was given to rats to induce experimental cerebral aneurysms. The rats were subjected to ligation of one common carotid artery and induction of hypertension, and were fed beta-aminoproprionitrile. Two weeks thereafter, Factor XIII was injected intravenously daily for 5 days (10 U/100 gm body weight/day). Twelve days after the start of Factor XIII injections, the rats were sacrificed and examined under light and electron microscopy. In seven of 12 bifurcations which developed small aneurysms, prominent intimal thickening was observed in the aneurysm lumen. In the most advanced cases, the aneurysm lumen was completely filled with proliferated smooth-muscle cells and collagen. In five of nine bifurcations that showed no aneurysm development, apparent intimal thickening was found at the site where aneurysms might be expected to grow. In the group of rats studied for induction of cerebral aneurysms but not given Factor XIII, none of 11 bifurcations with or without aneurysms showed such intimal thickening. The results indicated that the proliferative response at the sites of aneurysm development was modified by exogenous Factor XIII.  相似文献   
89.
Intestinal schistosomiasis japonica: CT-pathologic correlation   总被引:1,自引:0,他引:1  
  相似文献   
90.
The susceptibilities of Nagase analbuminemic rats (NAR) and control Sprague-Dawley rats (SDR) to N-ethyl-N-nitrosourea (ENU) were compared. In Experiment I, the rats were given daily subcutaneous injections of 10 mg/kg of ENU for a week from 4 weeks of age. In Experiment II, mother rats were given a single subcutaneous injection of 60 mg/kg of ENU on day 17 of pregnancy and tumor development in their offspring was examined. In Experiment I, the incidence of neurogenic tumors was slightly, but not significantly, higher in NAR than in control rats. In Experiment II, the incidence of total tumors including neurogenic tumors was significantly higher in NAR (40/43, 93.0%) than in SDR (13/61, 21.3%). NAR showed particularly high susceptibility to induction of neurogenic tumors (34/43, 79.1%) and renal tumors (15/43, 34.9%). In an attempt to elucidate the underlying mechanisms of the increased susceptibility of NAR to ENU, O6-ethylguanine, a major premutagenic ethylated DNA adduct, was quantitated in fetal brain DNA of NAR and SDR after a pulse exposure to 60 mg/kg ENU. No significant difference in the initial formation or subsequent repair of O6-ethylguanine was observed in the two strains, indicating that abnormality at some later stage(s) of chemical carcinogenesis may lead to the increased susceptibility of NAR to induction of neurogenic tumors.  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