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   10137篇
  免费   387篇
  国内免费   38篇
耳鼻咽喉   122篇
儿科学   141篇
妇产科学   152篇
基础医学   1265篇
口腔科学   242篇
临床医学   582篇
内科学   2668篇
皮肤病学   146篇
神经病学   833篇
特种医学   309篇
外科学   1813篇
综合类   44篇
一般理论   2篇
预防医学   245篇
眼科学   120篇
药学   910篇
中国医学   16篇
肿瘤学   952篇
  2022年   66篇
  2021年   158篇
  2020年   63篇
  2019年   128篇
  2018年   164篇
  2017年   124篇
  2016年   183篇
  2015年   189篇
  2014年   260篇
  2013年   304篇
  2012年   493篇
  2011年   555篇
  2010年   313篇
  2009年   286篇
  2008年   462篇
  2007年   563篇
  2006年   539篇
  2005年   591篇
  2004年   542篇
  2003年   568篇
  2002年   566篇
  2001年   196篇
  2000年   212篇
  1999年   224篇
  1998年   140篇
  1997年   117篇
  1996年   102篇
  1995年   134篇
  1994年   109篇
  1993年   109篇
  1992年   190篇
  1991年   187篇
  1990年   163篇
  1989年   193篇
  1988年   158篇
  1987年   123篇
  1986年   113篇
  1985年   96篇
  1984年   78篇
  1983年   81篇
  1982年   60篇
  1981年   58篇
  1980年   46篇
  1979年   56篇
  1978年   51篇
  1977年   41篇
  1976年   48篇
  1975年   43篇
  1974年   40篇
  1973年   36篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
ObjectiveTo verify if the relationship between pain catastrophizing and pain worsening would be mediated by muscle weakness and disability in patients with symptomatic knee osteoarthritis.MethodsThis was a cross-sectional study in a hospital out-patient setting. Convenience sampling was used with a total of 50 participants with symptomatic knee osteoarthritis. Pain and the activities of daily livings (ADL) were assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscale. Pain catastrophizing was assessed using the Coping Strategy Questionnaire (CSQ) subscale. Muscle strength of knee extension and 30-s chair stand test (30CST) were also assessed. Path analysis was performed to test the hypothetical model. Goodness of fit of models were assessed by using statistical parameters such as the chi-square value, goodness of fit index (GFI), adjusted goodness of fit index (AGFI), comparative fit index (CFI), and root mean square error of approximation (RMSEA).ResultsThe chi-square values were not significant (chi-square = 0.283, p = 0.594), and the indices of goodness of fit were high, implying a valid model (GFI = 1.000; AGFI = 0.997; CFI = 1.000; RMSEA = 0.000). Pain was influenced significantly by muscle strength and ADL; muscle strength was influenced significantly by ADL via 30CST; ADL was influenced by pain catastrophizing.ConclusionThe relationship between pain catastrophizing with pain worsening are mediated by muscle weakness and disability.  相似文献   
2.
3.
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.
Prostate thermotherapy consisting of 6 sessions of intrarectal 60 min irradiation of 915 MHz microwave generated by a prostathermer (Blodan, Isreal) was performed once or twice a week on 30 patients with benign prostatic hyperplasia. Excluding 2 cases who refused further therapy at the first session because of rectal discomfort, 28 cases were evaluated for the efficacy of the treatment. Good or fair improvement in subjective symptoms was observed in 24 (85.7%) of the cases. Nocturia was significantly relieved from 2.9 to 2.0 a night. Among the objective responses, no improvement was achieved as to residual urine or prostate size, while a significant increase of maximum or average flow rate on uroflowmetry was observed. Adverse effects were minor or moderate, including 2 cases of urethral bleeding and rectal discomfort, 2 cases of lower urinary tract infection and 1 case of hypotension, which occurred at the 5th session. The scoring criteria taking into account of both subjective and objective responses showed that the efficacy is good in 10 cases (33.3%) and fair or good in 20 cases (66.7%). These results indicated the usefulness of the prostathermer as one of non-surgical therapies for benign prostatic hyperplasia.  相似文献   
6.
H+/peptide transporter, PEPT1, is functionally expressed in some human cancer cell lines and might be a candidate molecular target for detection of cancers in vivo using PET. The aim of the present study was to establish a novel tumor-imaging technology using a PET tracer targeted to H+/peptide transporter(s). We also compared the tracer with 18F-FDG, focusing on the specificity of their accumulation between tumor and inflammatory tissues. METHODS: A dipeptide PET tracer, 11C-glycylsarcosine (11C-Gly-Sar), was injected intravenously into athymic mice transplanted with human pancreatic, prostate, and gastric cancer cells. The distribution patterns of 11C-Gly-Sar and 18F-FDG in the tumor-bearing mice, and in mice with inflammatory tissue, were assessed by imaging with a positron planar imaging system (PPIS). Tissue distributions of tracer radioactivity were also measured. The expression levels of PEPT1 and PEPT2 (PEPTs) proteins in tumor xenografts and inflammatory tissue were examined by immunohistochemical analysis. The messenger RNA expression levels of PEPTs in 58 available cancer cell lines were quantified by means of real-time polymerase chain reaction. RESULTS: All 3 tumor xenografts were well visualized with the PPIS after injection of 11C-Gly-Sar. Expression of PEPTs in those xenografts was confirmed by immunohistochemical analysis. Tumor-to-blood concentration ratios of 11C-Gly-Sar increased in a time-dependent manner and were much higher than unity. Most of the radioactivity found in the tumor tissue was recovered as the intact tracer. These results indicated that 11C-Gly-Sar was taken up by the PEPTs in tumor xenografts. It is noteworthy that 11C-Gly-Sar was minimally present in inflammatory tissues that expressed no PEPT1 or PEPT2 protein, whereas 18F-FDG was highly accumulated, with the values of the selectivity index being >25.1 and 0.72 for 11C-Gly-Sar and 18F-FDG, respectively. The mRNAs of PEPT1 and PEPT2 were expressed in 27.6% and 93.1%, respectively, of the cancer cell lines examined in the present study. CONCLUSION: The present study indicates that 11C-Gly-Sar is a promising tumor-imaging agent and is superior to 18F-FDG for distinguishing between tumors and inflammatory tissue. Because PEPTs were ubiquitously expressed in various types of tumor cells examined, 11C-Gly-Sar could be useful for the detection of many types of cancers.  相似文献   
7.
We have found that steroid bolus withdrawal prior to graft reperfusion increased the incidence of acute cellular rejection (ACR). This study aims to clarify how initial steroid bolus (ISB) injection at reperfusion influences the kinetics of CD8(+) alloreactive immune responses immediately after living donor liver transplantation (LDLT). A total of 49 hepatitis C virus (HCV)-infected recipients were classified into 3 groups according to hierarchical clustering by preoperative CD8(+)CD45 isoforms. The naive T cell proportion was considerably higher in Group I than in Groups II and III, whereas Group II recipients had the highest effector memory (EM) T cells and Group III the highest effector T cells. The frequency of ACR was significantly higher in recipients without ISB than in those with ISB. In particular, the ACR rates were the highest in Group II without ISB. Following ISB, the proportion of effector T cells was promptly upregulated within 6 hours after graft reperfusion, simultaneously with the upregulation of CD27(-)CD28(-) subsets, interferon-gamma (IFN-gamma), tumor necrosis factor-alpha and perforin expression, which significantly correlated with increasing interleukin (IL)-12 receptor beta 1 cells. These were then downregulated to below preoperative levels by tacrolimus (Tac) administered at 24 hours. These changes did not occur in the absence of ISB. In Group II without ISB, the downregulation of IL-12Rbeta1(+) cells was the greatest, consistent with the highest rates of ACR and mortality (60%). In conclusion, ISB must be done in place, especially in Group II with preexisting high EM T cells, to enable the development of early allograft acceptance.  相似文献   
8.
9.
10.
OBJECTIVES: Laparoscopic surgery for kidney treatment is a common procedure. However, the efficacy of this procedure in patients with several comorbidities has not been well investigated. We conducted a retrospective comparison of results of laparoscopic surgery between patients with several comorbidities and patients with no comorbidity to access the efficacy and safety of this procedure. METHODS: The subjects were 20 patients with three or more comorbidities (group A) and 46 patients with less than three comorbidities (group B). These 66 patients were 48 men and 18 women with a mean age of 62.3 years (age range, 24-83 years). The data from these two groups were compared for American Society of Anesthesiology (ASA) physical status score, previous surgical history, duration of surgery, estimated blood loss, tumor size, complications during and after surgery, conversion rates, time to oral intake, and length of hospital stay. RESULTS: The initial ASA score and age were significantly higher for the patients with comorbidities (P < 0.0001, P = 0.0008, respectively). All other variables before, during, and after surgery were similar for both laparoscopic groups. However, the incidence of atelectasis of laparoscopy was higher than that of open surgery. CONCLUSIONS: Laparoscopic nephrectomy for patients with comorbidities is safe and minimally invasive. Further investigation to prevent atelectasis is necessary.  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