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   15590篇
  免费   649篇
  国内免费   73篇
耳鼻咽喉   168篇
儿科学   239篇
妇产科学   304篇
基础医学   1844篇
口腔科学   244篇
临床医学   977篇
内科学   3688篇
皮肤病学   492篇
神经病学   1185篇
特种医学   660篇
外科学   2402篇
综合类   46篇
预防医学   374篇
眼科学   572篇
药学   1119篇
中国医学   23篇
肿瘤学   1975篇
  2023年   55篇
  2022年   117篇
  2021年   240篇
  2020年   133篇
  2019年   183篇
  2018年   301篇
  2017年   211篇
  2016年   299篇
  2015年   279篇
  2014年   392篇
  2013年   474篇
  2012年   733篇
  2011年   777篇
  2010年   486篇
  2009年   427篇
  2008年   836篇
  2007年   908篇
  2006年   920篇
  2005年   929篇
  2004年   925篇
  2003年   816篇
  2002年   905篇
  2001年   377篇
  2000年   324篇
  1999年   392篇
  1998年   249篇
  1997年   216篇
  1996年   184篇
  1995年   177篇
  1994年   147篇
  1993年   144篇
  1992年   226篇
  1991年   234篇
  1990年   223篇
  1989年   236篇
  1988年   209篇
  1987年   196篇
  1986年   168篇
  1985年   161篇
  1984年   123篇
  1983年   115篇
  1982年   70篇
  1981年   61篇
  1980年   62篇
  1979年   77篇
  1978年   52篇
  1977年   69篇
  1976年   50篇
  1974年   50篇
  1969年   51篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.

Background

There were few studies assessed the postoperative sarcopenia in patients with cancers. The objective of present study was to assess whether postoperative development of sarcopenia could predict a poor prognosis in patients with adenocarcinoma of esophagogastric junction, (AEG) and upper gastric cancer (UGC).

Methods

Patients with AEG and UGC who were judged as non-sarcopenic before surgery were reassessed the presence of postoperative development of sarcopenia 6 months after surgery. Patients were divided into the development group or non-development group, and clinicopathological factors and prognosis between these two groups were analyzed.

Results

The 5-year overall survival rates were significantly poorer in the development group than non-development group (68.0% vs. 92.6%, P?=?0.0118). Multivariate analyses showed that postoperative development of sarcopenia was an independent prognostic factor for poor overall survival (P?=?0.0237).

Conclusions

Postoperative development of sarcopenia was associated with a poor prognosis in patients with AEG and UGC.  相似文献   
2.
3.
We report a case of biliary cystadenocarcinoma which recurred 41 months postoperatively. A 60-year-old woman was admitted for further examination of multiple metastatic tumors and a large amount of ascites. Systemic administration of 5FU and CDDP caused her CEA level to decrease gradually and abdominal computed tomography revealed considerable reduction of the metastatic tumors and ascites. Since her general condition had improved, chemotherapy was continued in the outpatient clinic.  相似文献   
4.
Thirty-seven patients with primary aldosteronism were treated by unilateral total adrenalectomy during a 7-year period (1981–1987). The 37 patients were classified into 3 groups on the basis of adrenal pathology: unilateral solitary adenoma, 23 cases (group 1); unilateral adenomas, 3 cases (group 2); and adenoma with multiple macro- or microscopic nodules, 11 cases (group 3). The preoperative conditions of the patients (age, duration of hypertension, plasma renin activity, plasma aldosterone concentration, and serum potassium concentration), postoperative sequential changes of hormone levels, and outcome of hypertension were compared among the groups in order to determine whether the differences of adrenal pathology would affect the postoperative course. The preoperative parameters excluding age at surgery did not differ significantly among the 3 groups. The mean age in group 3, however, was slightly higher than in groups 1 and 2 (47.8 versus 42.8 versus 42.7 years). Postoperative hormonal changes were also similar, particularly in groups 1 and 3, staying within the normal range throughout the follow-up period (mean, 31 months; range, 3–86 months). However, postoperative improvement of hypertension showed marked differences, being significantl retarded in patients with multinodular lesions (group 3), about half of whom remained hypertensive even after 1 year. Nodular lesions other than adenoma(s) were, therefore, thought not to contribute to hormonal excess but to result from intractable hypertension.
Resumen Treinta y siete pacientes con aldosteronismo primario fueron tratados mediante adrenalectomía total unilateral en un período de 7 años (1981–1987). Los 37 pacientes fueron clasificados en 3 grupos con base en la patología adrenal: adenoma solitario unilateral, 23 casos (grupo I); adenomas unilaterales, 3 casos (grupo 2); y adenoma con múltiples macro-o micronódulos, 11 casos (grupo 3). Las condiciones preoperatorias de los pacientes (edad, duración de la hipertensión, actividad de renina plasmática, concentración plasmática de aldosterona, y concentración sérica de potasio), los cambios postoperatorios secuenciales en los niveles hormonales, y el resultado de la hipertensión fueron comparados en los 3 grupos, con el objeto de determinar si las diferencias en la patología adrenal podrían afectar la evolución postoperatoria. Los parámetros preoperatorios, excluyendo la edad en el momento de la cirugía, no diferieron significativamente en los 3 grupos. La edad promedio en el grupo 3, sin embargo, fue ligeramente superior en los grupos 1 y 2 (47.8 versus 42.8 versus 42.7 años).Los cambios hormonales postoperatorios también fueron similares, particularmente en los grupos 1 y 3, manteniéndose dentro del rango normal a través del seguimiento (promedio, 31 meses; rango, 3–86). Sin embargo, la mejoría postoperatoria de la hipertensión exhibió diferencias marcadas, con aparación significativamente tardía en pacientes con lesiones nodulares (grupo 3); aproximadamente la mitad de éstos permanecieron hipertensos aún después de un año. Por consiguiente, se piensa que las lesiones nodulares diferentes del adenoma(s) no contribuyen al exceso hormonal sino que resultan de la hipertensión intratable.

Résumé Trente-sept patients ayant un hyperaldostéronisme primaire ont eu une surrénalectomie totale unilatérale entre 1981 et 1987. Ces 37 patients ont été classés en 3 groupes selon la pathologie surrénalienne: adénome solitaire unilatéral, 23 cas (groupe 1); adénome unilatéral, 3 cas (groupe 2); et adénome avec nodules micro ou macroscopiques multiples, 11 cas (groupe 3). On a comparé les données préopératoires (âge, durée de l'hypertension, activité rénine plasmatique, concentration d'aldostérone plasmatique et kaliémie), les changements hormonaux postopératoires, et l'évolution de l'hypertension afin de déterminer si des différences de pathologie surrénalienne peuvent influencer l'évolution postopératoire. Les paramètres préopératoires (excepté l'âge) ne différaient pas de façon significative parmi les 3 groupes. L'âge moyen était plus élevé dans le groupe 3 que dans les groupes 1 et 2 (47.8 versus 42.8 versus 42.7 ans).Les variations hormonales postopératoires étaient également similaires, surtout dans les groupes 1 et 3, restant dans les limites de la normale pendant la période de suivi (moyenne, 31 mois; extrêmes, 3 à 86 mois). Cependant l'amélioration de l'hypertension postopératoire était différente, retardée de façon significative chez les patients ayant des lésions multinodulaires (groupe 3), la moitié d'entre eux restant hypertendus après un an. Les lésions nodulaires, étant donné que les adénomes ne donnent pas d'hypersécrétion hormonale, peuvent traduire plutôt une hypertension prolongée.


Presented at the International Association of Endocrine Surgeons in Toronto, Ontario, Canada, September, 1989.  相似文献   
5.
The antitumor effects of two polyamine antimetabolites, alpha-difluoromethylornithine (DFMO) and methylglyoxal-bis-guanylhydrazone (MGBG), when combined with cis-diamminedichlroplatinum (CDDP) or mitomycin C (MMC), were studied using human gastric cancer cells xenotransplanted into nude mice. DFMO 1000 mg/kg and MGBG 50 mg/kg were given intraperitoneally for 6 successive days, while CDDP 3 mg/kg or MMC 2 mg/kg was given every second day. Although DFMO and MGBG plus MMC did suppress the tumor growth, the combination with CDDP led to no suppression, and rapid growth occurred after the cessation of therapy. The inhibition of tumoral DNA biosynthesis and a decline in polyamine levels, were also not observed. The polyamine antimetabolites when used with CDDP did not produce the desired antitumor efficacy, even though the platinum concentration in the tumor tissue was high. On the contrary, however, DFMO and MGBG when combined with MMC did suppress tumor growth, inhibited DNA biosynthesis, and tissue polyamine levels were low. These results suggest that though CDDP and MMC belong to a similar category of DNA attacking, bifunctional alkylating agents, the findings of these two drugs are contradictory. Here, the mechanism of action no doubt plays a contributory role.  相似文献   
6.
Although aortic valve replacement (AVR) is an effective treatment for patients with aortic valvular disease, the implantation of a small aortic prosthesis may result in residual left ventricular outflow stenosis and transvalvular gradient. In this study, the outcome in the long-term period of patients treated with a small aortic prosthesis was analyzed retrospectively. Twenty-four patients with AVR were divided into two groups, group A and group B. Group A consisted of 16 patients with 21 mm-sized prosthetic valves, and group B consisted of 8 patients with 19 or 16 mm-sized prosthetic valves. There were no significant differences in preoperative cardiac function or operative procedure in the two groups. The mean follow-up period (months) was 55.0 in group A and 51.3 in group B. RESULTS: One patient died of cerebral infarction in group A. There were no significant differences in cardiothoracic ratio (CTR), left ventricular ejection fraction (LVEF), and left ventricular mass index (LVMI) between the two groups. Postoperative physical activity according to the New York Heart Association (NYHA) classification showed no significant differences in the two groups. Despite using a small prostheses for AVR, the postoperative course was good in the long-term period, although careful follow-up is necessary.  相似文献   
7.
Living-donor liver transplantation (LDLT) has become an established technique to treat children with end-stage liver disease. Biliary atresia (BA), one of the most common indications for liver transplantation in children, can be associated with situs inversus (SI). In the past, the presence of SI has been considered to be an absolute contraindication for liver transplantation because of the technical difficulties. Recently, some reports of successful diseased-donor liver transplantation in patients with BA complicated by SI have been published; however, few reports of that with LDLT exist. The technical difficulties involved with LDLT for such cases have not been described. Herein, we present 4 successful cases of LDLT for BA with SI. Complex anomalies associated with SI, such as a hepatic artery arising from the supraceliac aorta, a preduodenal portal vein, and absence of the retrohepatic inferior vena cava, increase the technical difficulties involved with the operation. Additional caution is required in LDLT because a living-donor graft has short vessels and the availability of vascular grafts from the donor is limited. In conclusion, LDLT for BA complicated by SI can be managed successfully with technical modifications and scrupulous attention. This series represents the largest reported group of patients with BA complicated by SI who underwent a successful LDLT procedure.  相似文献   
8.
Kenji Ohtsuka, MD and his colleagues at the Sapporo Medical University have investigated the central organization of the near response with anatomical and neurophysiologic studies in cats. Based on their data and clinical observations, they proposed that the rostral pole of the superior colliculus has a critical role in the control of accommodation, vergence, and fixation. Although the central pathways have yet to be fully worked out, the contributions of Dr. Ohtsuka, who died in 2005, have laid an important foundation in the understanding of these functions.  相似文献   
9.
10.
PURPOSE: The aim of this study is (1) to develop a new method of risk classification for clinically localized prostate cancer; (2) to examine it in terms of compatibility with existing data such as nomograms; and (3) to compare it with existing risk-grouping methods. MATERIAL AND METHODS: The new grading system introduced here consists of three factors. The first is a prostate-specific antigen (PSA) of 4.1-10.0 ng/ml (score 0), 10.1-20.0 ng/ml (score 1), and >20.0 ng/ml (score 2). The second is a Gleason score (GS) of 6 (score 0), 7 (score 1), and 8-10 (score 2). The third is T classifications (UICC 2002) of T1c-T2a (score 0), T2b-T2c (score 1), and T3a (score 2). The sum of the three scores was named Prostate Risk Index (PRIX). Then, the compatibility of PRIX with the Partin Table, Kattan Nomogram, and Roach's formula was examined. At the same time, PRIX was compared with D'Amico, the National Comprehensive Cancer Network (NCCN), and Seattle classifications. RESULTS: PRIX 0 corresponded to 1-2% of pathologic lymph node involvement (pLN+) according to the Partin Table; PRIX 1 to 3-4%; PRIX 2 to 7-10%; PRIX 3 to 14-18%; PRIX 4 to 24-29%; PRIX 5 to 32-37%; and PRIX 6 to 42%. PRIX well separated the risks with relatively narrow ranges of probability, while D'Amico, NCCN, and Seattle classifications generally gave wide ranges especially for high-risk groups, both in the Partin Table and Kattan Nomogram. Roach's formula sometimes overestimated the risk compared to the Partin Table. CONCLUSION: PRIX fully corresponded to the Partin Table in terms of pLN+, and corresponded to the other nomograms better than any existing risk-grouping method. PRIX may thus function as a prognostic factor or contribute to patient selection in clinically localized prostate cancer.  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