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   2283篇
  免费   135篇
  国内免费   2篇
耳鼻咽喉   64篇
儿科学   107篇
妇产科学   47篇
基础医学   196篇
口腔科学   19篇
临床医学   153篇
内科学   566篇
皮肤病学   31篇
神经病学   139篇
特种医学   70篇
外科学   410篇
综合类   28篇
预防医学   89篇
眼科学   112篇
药学   129篇
中国医学   2篇
肿瘤学   258篇
  2023年   17篇
  2022年   40篇
  2021年   103篇
  2020年   45篇
  2019年   86篇
  2018年   101篇
  2017年   50篇
  2016年   66篇
  2015年   68篇
  2014年   110篇
  2013年   124篇
  2012年   179篇
  2011年   162篇
  2010年   82篇
  2009年   86篇
  2008年   150篇
  2007年   127篇
  2006年   109篇
  2005年   98篇
  2004年   80篇
  2003年   62篇
  2002年   50篇
  2001年   38篇
  2000年   37篇
  1999年   42篇
  1998年   9篇
  1997年   7篇
  1996年   12篇
  1995年   9篇
  1994年   11篇
  1993年   6篇
  1992年   31篇
  1991年   24篇
  1990年   22篇
  1989年   22篇
  1988年   27篇
  1987年   22篇
  1986年   11篇
  1985年   14篇
  1984年   6篇
  1983年   5篇
  1979年   4篇
  1978年   5篇
  1976年   5篇
  1974年   6篇
  1973年   6篇
  1972年   6篇
  1970年   7篇
  1968年   5篇
  1961年   3篇
排序方式: 共有2420条查询结果,搜索用时 15 毫秒
101.
102.
Sarcoma of the breast constitutes less than 1% of all malignant breast tumors and liposarcoma of the breast has an incidence of 0.3% of all the mammary sarcomas. A 90-year-old woman presented with a mass in the upper outer quadrant of the right breast measuring 25 x 15 x 7 cm. Mammography was performed and the mass was diagnosed as a liposarcoma. A wide excision was performed with a 2 cm margin of healthy tissue. The tumor was diagnosed histologically as a fibrous liposarcoma. The patient was discharged and her postoperative recovery was uneventful. We report a case of liposarcoma of the breast and discuss this rare malignant tumor together with the various diagnostic and therapeutic modalities used.  相似文献   
103.
BackgroundAnxiety disorders such as generalized anxiety disorder (GAD) impact 10% of the US population, and many patients do not completely respond to first-line treatments (e.g., selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, and psychotherapy). Given the dearth of evidence for non-pharmacologic, non-psychotherapeutic interventions, we performed a systematic review and meta-analysis of repetitive transcranial magnetic stimulation (rTMS) in adults with GAD.MethodsA systematic literature review using the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines was conducted. Pre- and post-treatment anxiety scores were extracted, and a random-effects meta-analysis was conducted to determine the magnitude of improvement (standardized mean difference). Standard assessments of heterogeneity (e.g., Q-statistic, I2, and τ 2) and publication bias were performed.ResultsThe initial search resulted in 3194 citations, of which 6 studies were included in the meta-analysis. In total, 152 patients were studied, including 97 patients who received active treatment and 55 who received sham treatment, and heterogeneity was modest (I2 13.32, Q = 5.77). In patients with GAD, rTMS produced a standardized mean difference of −1.857 (confidence interval: −2.219 to −1.494; P < .001) with a prediction interval of −2.55 to −1.16.ConclusionsThe results suggest a robust effect of rTMS in GAD in the context of limited, heterogenous studies. Rigorously designed, randomized controlled trials of rTMS for GAD and related anxiety disorders are urgently needed. These studies will provide opportunities for biomarker development and integration of concurrent evidence-based psychotherapy to maximize results.  相似文献   
104.
105.
106.
BackgroundAlthough treatment‐related lymphopenia (TRL) is common and associated with poorer survival in multiple solid malignancies, few data exist for anal cancer. We evaluated TRL and its association with survival in patients with anal cancer treated with chemoradiation (CRT).Materials and MethodsA retrospective analysis of 140 patients with nonmetastatic anal squamous cell carcinoma (SCC) treated with definitive CRT was performed. Total lymphocyte counts (TLC) at baseline and monthly intervals up to 12 months after initiating CRT were analyzed. Multivariable Cox regression analysis was performed to evaluate the association between overall survival (OS) and TRL, dichotomized by grade (G)4 TRL (<0.2k/μL) 2 months after initiating CRT. Kaplan‐Meier and log‐rank tests were used to compare OS between patients with versus without G4 TRL.ResultsMedian time of follow‐up was 55 months. Prior to CRT, 95% of patients had a normal TLC (>1k/μL). Two months after initiating CRT, there was a median of 71% reduction in TLC from baseline and 84% of patients had TRL: 11% G1, 31% G2, 34% G3, and 8% G4. On multivariable Cox model, G4 TRL at two months was associated with a 3.7‐fold increased risk of death. On log‐rank test, the 5‐year OS rate was 32% in the cohort with G4 TRL versus 86% in the cohort without G4 TRL.ConclusionTRL is common and may be another prognostic marker of OS in anal cancer patients treated with CRT. The association between TRL and OS suggests an important role of the host immunity in anal cancer outcomes.Implications for PracticeThis is the first detailed report demonstrating that standard chemoradiation (CRT) commonly results in treatment‐related lymphopenia (TRL), which may be associated with a poorer overall survival (OS) in patients with anal squamous cell carcinoma. The association between TRL and worse OS observed in this study supports the importance of host immunity in survival among patients with anal cancer. These findings encourage larger, prospective studies to further investigate TRL, its predictors, and its relationship with survival outcomes. Furthermore, the results of this study support ongoing efforts of clinical trials to investigate the potential role of immunotherapy in anal cancer.  相似文献   
107.
The “severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)” is the third member of human coronavirus (CoV) that is held accountable for the current “coronavirus disease 2019 (COVID-19)” pandemic. In the past two decades, the world has witnessed the emergence of two other similar CoVs, namely SARS-CoV in 2002 and MERS-CoV in 2013. The extent of spread of these earlier versions was relatively low in comparison to SARS-CoV-2. Despite having numerous reports inclined towards the zoonotic origin of the virus, one cannot simply sideline the fact that no animal originated CoV is thus far identified that is considered similar to the initial edition of SARS-CoV-2; however, under-sampling of the diverse variety of coronaviruses remains a concern. Vaccines are proved to be an effective tool for bringing the end to such a devastating pandemic. Many vaccine platforms are explored for the same but in this review paper, we will discuss the potential of replicating viral vectors as vaccine carriers for SARS-CoV-2.  相似文献   
108.
The persistent mullerian duct syndrome represents a rare form of male pseudohermaphroditism, secondary to mullerian inhibiting factor (MIF) deficiency. We describe imaging findings in a 30-year-old male (46 XY karyotype) with bilateral cryptorchidism and mullerian duct anomalies (presence of uterus and fallopian tubes). Grade-III teratoma with yolk sac tumour was detected in one of the undescended testis, lying in the pelvic cavity. The other testis was in the inguinal canal. The rest of the wolffian duct structures (e. g. prostate, seminal vesicles) were nearly normal. Very few reports of imaging findings of this entity have been published thus far, probably because of the rarity of entity, incidental detection of most of the cases at surgery and relatively asymptomatic clinical presentation. Received: 6 March 2000 Revised: 3 August 2000 Accepted: 8 August 2000  相似文献   
109.
110.
OBJECTIVES: In recent years, well-differentiated carcinomas of the thyroid have been stratified into low-risk and high-risk groups. The pattern of thyroid cancer in India is different from that seen in the West. Moreover, patients present with more advanced stages of the disease. Our aim was to develop protocols for the management of well-differentiated thyroid cancer, based on the analysis of our data and our experience. METHODS: Cases of thyroid carcinoma, which were surgically treated at the Tata Memorial Hospital during 1970-5, were studied. The survival curves were plotted according to the Kaplan-Meier method. Univariate analysis was done using the log rank test. The prognostic factors analyzed were age, sex, tumour size, extra-thyroid extension, distant metastases and lymph node metastases. Multivariate analysis using the Cox regression model was performed. Analyses were separate for follicular and papillary carcinomas. RESULTS: Four hundred and seventeen cases were entered in the study, of which 198 were follicular and 219 were papillary. Based on the evidence derived from this study, we stratified our cases into low- and high-risk groups. The low-risk group consisted of patients below 40 years of age, nodules smaller than 5 cm, absence of extra-thyroidal spread and absence of distant metastases. For follicular carcinoma, the low-risk group had 100% survival at 15 years, compared with 40% for the high-risk group. (p < 0.001). For papillary carcinomas, the survival at 15 years was 95% for the low-risk group and 40% for the high-risk group (p < 0.001). CONCLUSIONS: We recommend lobectomy for the low-risk group, and total thyroidectomy for the high-risk group and for cases with lymph node metastases. In the latter, total thyroidectomy facilitates the use of 131I.  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