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   7471篇
  免费   353篇
  国内免费   39篇
耳鼻咽喉   30篇
儿科学   117篇
妇产科学   61篇
基础医学   912篇
口腔科学   189篇
临床医学   481篇
内科学   1937篇
皮肤病学   83篇
神经病学   584篇
特种医学   240篇
外科学   1246篇
综合类   26篇
预防医学   222篇
眼科学   251篇
药学   552篇
中国医学   3篇
肿瘤学   929篇
  2023年   59篇
  2022年   103篇
  2021年   153篇
  2020年   101篇
  2019年   123篇
  2018年   140篇
  2017年   112篇
  2016年   132篇
  2015年   151篇
  2014年   196篇
  2013年   225篇
  2012年   376篇
  2011年   419篇
  2010年   231篇
  2009年   223篇
  2008年   350篇
  2007年   451篇
  2006年   405篇
  2005年   398篇
  2004年   373篇
  2003年   325篇
  2002年   310篇
  2001年   225篇
  2000年   215篇
  1999年   209篇
  1998年   96篇
  1997年   63篇
  1996年   50篇
  1995年   54篇
  1994年   65篇
  1993年   57篇
  1992年   152篇
  1991年   137篇
  1990年   104篇
  1989年   107篇
  1988年   99篇
  1987年   95篇
  1986年   105篇
  1985年   83篇
  1984年   55篇
  1983年   53篇
  1980年   24篇
  1979年   30篇
  1977年   42篇
  1973年   30篇
  1972年   27篇
  1971年   30篇
  1970年   33篇
  1969年   48篇
  1968年   31篇
排序方式: 共有7863条查询结果,搜索用时 15 毫秒
81.
A 60-year-old obese woman was admitted to our hospital to receive surgical treatment for "slow-growing mediastinal lipoma". With the non-invasive examination such as CT scan and ultrasonography, she was revealed as Morgagni's hernia containing a greater omentum. With a trans-abdominal approach, we could take a good surgical field for the bilateral foramina of Morgagni. Several discussions were described for availability of CT scan, ultrasonography and a trans-abdominal approach.  相似文献   
82.
A 26-year-old female patient complicated with reflux nephropathy and pheochromocytoma is reported. We could not find either intrinsic or extrinsic factor of urinary tract obstruction. The open bilateral renal biopsy was performed at the time of resection of the tumor. The renal biopsy specimen demonstrated minor glomerular change, severe tubular "thyroid-like" appearance and cast formation in the obvious reflux side. Otherwise focal glomerular sclerosis (FGS) lesion was found in less reflux side. In reflux nephropathy, FGS lesion is reported as main cause of progression, but mechanism of FGS lesion is unknown. This case which has both vesicoureteral reflux the high plasma nor-epinephrine concentration was considered to be important to emphasize circulative factor in the pathogenesis of FGS like lesion.  相似文献   
83.
Pediatric patients with inguinal hernia can be good candidates for day surgery. Since 1986, 1273 such patients have been treated under our day surgery system. Although 8 patients (0.6%) were unable to go home after surgery due to perioperative complications and 21 (1.6%) visited earlier than scheduled after discharge, no major complications were noted and postoperative complications did not differ from those seen in the inpatient setting. Our questionnaire survey demonstrated that 96% of the families were satisfied with the system. Based on our own experience and a literature review of day surgery for inguinal hernia repair in children, the problems surrounding the day care system are discussed. Patient selection, preoperative assessment, general anesthesia, postoperative care including oral intake and analgesia, and postoperative follow-up are considered the most important issues in the day care system. A team approach including pediatric surgeons, anesthesiologists, and pediatric nurses is considered indispensable for the safe and satisfactory day surgery treatment.  相似文献   
84.
Between November 1983 and December 1992, 136 hips (119 patients) with coxarthritis were operated on using joint-preserving techniques based on the rationale of Pauwels' osteotomy. The criterion for selection was a patient in whom the height of the joint space in the weight-bearing area of the hip was less than 1 mm. The mean age at operation was 48 years and the mean follow-up 109 months (60 to 171). Hips were categorised using Bombelli's classification of osteoarthritis, into atrophic and non-atrophic types. The endpoint was defined as that at which the height of the joint space became less than 1 mm again. The Kaplan-Meier curve showed that the rate of survival of the non-atrophic group was significantly better than that of the atrophic group. Cox's proportional hazard model indicated that the factors influencing the results of joint-preserving operations included Bombelli's classification, postoperative incongruence of the joint and the height of the joint space.  相似文献   
85.
The present study was undertaken to evaluate juvenile stroke-prone spontaneously hypertensive rats (SHRSP) as an animal model of attention-deficit/hyperactivity disorder (AD/HD). Juvenile SHRSP showed significant increases in horizontal ambulatory activity and vertical rearing activity in the open field as compared with genetic control Wistar-Kyoto rats (WKY). Anxiety-related behavior assessed by elevated plus-maze as an index of impulsivity, the entries into open arms and the spent time in the open arms of SHRSP were significantly higher than those of WKY. Spontaneous alternation behavior requiring attention and working memory in the Y-maze was significantly impaired in male, but not female, SHRSP when compared with sex-matched WKY. Hippocampal long-term potentiation formation, a cellular model of learning and memory, was not impaired in SHRSP. Methylphenidate, a first choice psychostimulant for AD/HD, significantly alleviated the hyperactivity in SHRSP. However, intense impulsivity of SHRSP was not improved by methylphenidate. Methylphenidate dose-dependently and significantly ameliorated the impaired spontaneous alteration behavior in male SHRSP. These results suggest that juvenile male SHRSP manifest problematic behavior resembling ADHD, namely inattention, hyperactivity and impulsivity. Methylphenidate alleviates the behavioral symptoms of hyperactivity and inattention. Thus, juvenile male SHRSP might be a useful behavioral animal model of AD/HD, from behavioral and pharmacological perspectives.  相似文献   
86.
Adeno-associated virus (AAV) vectors have a number of attractive features, including lack of cytotoxicity, ability to transduce nondividing cells, and long-term transgene expression. We investigated whether rat renal cells could be efficiently transduced with AAV vectors. Rat glomerular mesangial cells were transduced with AAV-lacZ vector containing beta-galactosidase gene in vitro, and the expression of beta-galactosidase was evaluated by X-gal staining and ELISA. For ex vivo experiments, sections of rat kidneys were incubated with AAV-lacZ, and then evaluated by X-gal histochemical staining. The level of beta-galactosidase expression in cultured rat mesangial cells increased in a dose-dependent manner (ranging from 1 x 10(5) to 5 x 10(6) particles/cell). When transduced with 5 x 10(6) vector particles/cell of AAV-lacZ, about 50% of mesangial cells were stained positively with X-gal, and the level of beta-galactosidase expression reached 9.9 +/- 1.5 ng/mg protein. Expression was detectable during the culture period for at least 7 days. X-gal histochemical examination of the ex vivo transduced renal tissue revealed tubular cell and interstitial tissue staining. However, gene transfer was not clearly observed in glomeruli. These findings suggest that AAV vectors have the potential for gene therapy of renal diseases.  相似文献   
87.
AIM: Large multicenter, randomized trials have revealed the advantages of using tamoxifen for 5 years vs 2 years in breast cancer patients. The aim of this report is to confirm the optimal duration of tamoxifen administration in a study of Japanese breast cancer patients. METHODS: Japanese post-menopausal estrogen receptor-positive breast cancer patients treated with mastectomy were randomly assigned to either a 5-year or 2-year course of tamoxifen. The primary endpoint was disease-free survival, with secondary endpoints of overall survival and a reduction in the development of metachronous contra-lateral breast cancer. RESULTS: A total of 256 breast cancer patients were randomized to a 5-year or 2-year tamoxifen administration group. After a median follow-up time of 81 months, there were no significant differences seen in terms of disease-free or overall survival (p=0.65 and 0.56, respectively). Furthermore, the impact of the 5-year use of tamoxifen on the development of contra-lateral breast cancer did not reach statistical significance (p=0.0511). However, 5-year tamoxifen use was closely associated with gynaecological complications (p=0.0081). CONCLUSION: We could not show a beneficial effect of using tamoxifen for 5 years over 2 years in Japanese estrogen receptor-positive patients. This is likely due to the small number of patients enrolled in our study; however, racial disparity may influence this result. A reevaluation is necessary to study the advantages of the 5-year use of tamoxifen in the Japanese racial subgroup.  相似文献   
88.
PURPOSE: Selection of appropriate protocols for treatment of superficial esophageal squamous cell carcinoma (SESCC) is dependent on lymph node metastasis status. Therefore, it is important to know whether lymph node metastasis is present before treatment. EXPERIMENTAL DESIGN: In this study, we examined the relation between DNA sequence copy number aberrations detected by comparative genomic hybridization and lymph node metastasis in 26 surgically resected SESCCs (training samples). We then assessed whether the genetic information is predictive for nodal status in biopsy specimens from eight newly enrolled patients with SESCC (blinded samples). RESULTS: Pathological examination revealed that 17 of 26 training samples (65.4%) did not have associated lymph node metastasis. Gains of 8q24 and/or 20q12-qter were observed in 12, including all (nine of nine) with nodal metastasis. Fourteen training samples did not have gain of either 8q24 or 20q12-qter. Of the blinded samples, two showed no gain of 8q24 or 20q12-qter, and as anticipated the postoperative pathological examination revealed no nodal metastasis. The remaining six blinded samples had gains of 8q24 and/or 20q12-qter, and lymph node metastasis was detected by postoperative examination in four of these tumors. CONCLUSIONS: Absence of gains of 8q24 and/or 20q12-qter appears to be associated with absence of lymph node metastasis in patients with SESCC; therefore, less invasive surgery can be chosen.  相似文献   
89.
In two hemiplegic patients with acquired cerebral lesions, transcranial magnetic stimulation (TMS) was carried out to examine the contribution of the ipsilateral motor pathways to recovery from hemiplegia. A 13-year-old girl (patient 1) had acute hemiplegia due to a rupture of an arteriovenous malformation, and a 13-year-old boy (patient 2) had subacute hemiplegia due to a brain tumour. They showed complete upper limb palsy but recovered after therapy; patient 1 had slightly disabled motor function of the arm, and patient 2 recovered completely. Motor evoked potentials (MEPs) were recorded from the biceps brachii muscles on both sides. The MEPs of the paretic biceps were only elicited by TMS of the intact hemisphere at the beginning of recovery from hemiplegia, but not by TMS of the affected hemisphere. The MEP amplitudes increased and cortical representation areas for the paretic biceps by TMS were enlarged temporarily during recovery. They regressed in patient 1 and MEPs were not evoked at all in patient 2 after recovery. Conversely, MEPs were obtained by TMS of the affected hemisphere after recovery in both patients. These data indicate that ipsilateral motor pathways play a role in recovery from hemiplegia, especially at the beginning, and become inactivated when the contralateral motor pathways recover.  相似文献   
90.
Liver metastasis of primary tumor is a clinically major problem. KRN7000, an alpha-galactosylceramide, significantly augments natural killer (NK) activity of spleen cells and shows strong antitumor activity in mice with lung metastasis of melanoma B16 cells. To test whether KRN7000 has an antitumor activity in mice with hepatic metastasis of tumors, we examined the effect of KRN7000 on NK activity of hepatic mononuclear cells (MNC) and the antitumor activity in mice with liver metastasis of EL-4 cells. The in vivo administration of KRN7000 significantly augmented NK activity of hepatic MNC and inhibited tumor growth of EL-4 cells in the liver more markedly than chemotherapeutic agents, leading to a relatively high rate of cured mice. In addition, it appeared that the KRN7000 treatment is effective in mice with established EL-4 tumors. Moreover, we found that KRN7000 can produce significant amounts of interleukin 2 (IL-2), IL-4, IL-12, and interferon-gamma in a dose-dependent manner. These results suggest that KRN7000 will be useful for the treatment of cancer liver metastasis.  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