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   8656篇
  免费   597篇
  国内免费   108篇
耳鼻咽喉   66篇
儿科学   234篇
妇产科学   398篇
基础医学   960篇
口腔科学   198篇
临床医学   1064篇
内科学   1768篇
皮肤病学   78篇
神经病学   730篇
特种医学   311篇
外科学   1109篇
综合类   234篇
一般理论   4篇
预防医学   481篇
眼科学   183篇
药学   713篇
中国医学   84篇
肿瘤学   746篇
  2023年   45篇
  2022年   105篇
  2021年   179篇
  2020年   107篇
  2019年   180篇
  2018年   214篇
  2017年   176篇
  2016年   177篇
  2015年   249篇
  2014年   291篇
  2013年   388篇
  2012年   552篇
  2011年   623篇
  2010年   427篇
  2009年   367篇
  2008年   505篇
  2007年   513篇
  2006年   528篇
  2005年   458篇
  2004年   408篇
  2003年   332篇
  2002年   295篇
  2001年   273篇
  2000年   231篇
  1999年   197篇
  1998年   100篇
  1997年   94篇
  1996年   85篇
  1995年   62篇
  1994年   53篇
  1993年   45篇
  1992年   116篇
  1991年   121篇
  1990年   98篇
  1989年   76篇
  1988年   81篇
  1987年   78篇
  1986年   56篇
  1985年   48篇
  1984年   38篇
  1983年   37篇
  1982年   27篇
  1981年   26篇
  1980年   20篇
  1979年   27篇
  1978年   33篇
  1977年   19篇
  1975年   19篇
  1974年   26篇
  1968年   18篇
排序方式: 共有9361条查询结果,搜索用时 0 毫秒
61.
62.
Pulmonary hemorrhage is a rare but sometimes fatal complication of hysteroscopy. We present the first case report in which a healthy patient developed lung collapse induced by pulmonary hemorrhage after operative hysteroscopy. The possible etiologies of this rare complication are also discussed.  相似文献   
63.
64.
65.
Nanoliposomal irinotecan (nal-IRI) plus 5-fluorouracil and leucovorin (NalFL) comprises the current standard for gemcitabine-failed metastatic pancreatic ductal adenocarcinoma (PDAC). As liposomes generally accumulate in the spleen, we evaluated the impact of spleen volume on prognosis. We enrolled patients with metastatic PDAC who failed gemcitabine-based therapy and were initiated on NalFL between August 2018 and November 2020. The spleen volume before NalFL administration was evaluated. They were stratified into dose subgroups (i.e. low, < 48 mg/m2; intermediate, 48 - < 64 mg/m2; high, ≥ 64 mg/m2) by the average nal-IRI dose during the entire treatment, and multivariate analysis of overall survival (OS) was performed. We included 547 patients with a median age of 63 years (range, 27-89 years) and a median of 1 (range, 0-7) palliative chemotherapy regimen. The median spleen volume was 245 mL (range, 82-817 mL). Among patients with splenomegaly (≥ 245 mL), the low-dose subgroup had the worst median time to treatment failure (TTF, 1.8 months vs. 2.5 months vs. 2.5 months, P = 0.020) and OS (3.3 months vs. 5.9 months vs. 6.6 months, P = 0.018) as against no prognostic impact in patients without splenomegaly. In the multivariate analysis of patients with splenomegaly, performance status (PS) ≥ 2, body surface area (BSA) < 1.6 m2, prior fluoropyrimidine use, liver metastasis, and low-dose subgroup were independent poor prognostic factors. A low average nal-IRI dose was significantly associated with poor prognosis, especially among patients with splenomegaly. Further pharmacological studies should validate the relevance of spleen volume on the treatment outcomes of nal-IRI.  相似文献   
66.
There is a great need for a diagnostic tool using simple clinical information collected from patients to diagnose uric acid (UA) stones in nephrolithiasis. We built a predictive model making use of machine learning (ML) methodologies entering simple parameters easily obtained at the initial clinical visit. Socio-demographic, health, and clinical data from two cohorts (A and B), both diagnosed with nephrolithiasis, one between 2012 and 2016 and the other between June and December 2020, were collected before nephrolithiasis treatment. A ML-based model for predicting UA stones in nephrolithiasis was developed using eight simple parameters—sex, age, gout, diabetes mellitus, body mass index, estimated glomerular filtration rate, bacteriuria, and urine pH. Data from Cohort A were used for model training and validation (ratio 3:2), while data from Cohort B were used only for validation. One hundred and forty-six (13.3%) out of 1098 patients in Cohort A and 3 (4.23%) out of 71 patients in Cohort B had pure UA stones. For Cohort A, our model achieved a validation AUC (area under ROC curve) of 0.842, with 0.8475 sensitivity and 0.748 specificity. For Cohort B, our model achieved 0.936 AUC, with 1.0 sensitivity, and 0.912 specificity. This ML-based model provides a convenient and reliable method for diagnosing urolithiasis. Using only eight readily available clinical parameters, including information about metabolic disorder and obesity, it distinguished pure uric acid stones from other stones before treatment.  相似文献   
67.

Background

Although radiofrequency ablation (RFA) of nonresectable hepatic metastases has gained wide acceptance by showing survival benefit in selected patients, scattered reports are available regarding risk factors of local control of percutaneous RFA. The purpose of this study was to prospectively evaluate the factors influencing local tumor progression after percutaneous RFA of hepatic metastases.

Methods

Sixty-nine hepatic metastatic lesions in 54 patients were treated by percutaneous RFA. Efficacy was evaluated by contrast-enhanced computed tomography or magnetic resonance imaging at 1 month after ablation, then at 3-month intervals for the first year and biannually thereafter.

Results

The results of the log-rank test showed that tumor size of <3 cm (p = 0.024) and the absence of tumor contiguous with large vessels (p = 0.002) significantly correlated with local control for hepatic metastases. Cox regression analysis showed that the tumor size <3 cm and the absence of tumor contiguous with large vessels were independent factors (p = 0.055 and 0.009, respectively). The results of the log-rank test showed that neither the threshold post-ablation margin of 1.8 cm (p = 0.064) nor the presence of a tumor with subcapsular location (p = 0.134) correlated with the success of local control.

Conclusions

Percutaneous RFA is more effective in achieving local control in patients with hepatic metastases when the tumor size is <3 cm and not contiguous with large vessels.  相似文献   
68.
69.
70.
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