首页 | 官方网站   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   15860篇
  免费   936篇
  国内免费   173篇
医药卫生   16969篇
  2024年   10篇
  2023年   187篇
  2022年   222篇
  2021年   729篇
  2020年   428篇
  2019年   536篇
  2018年   639篇
  2017年   505篇
  2016年   517篇
  2015年   602篇
  2014年   708篇
  2013年   866篇
  2012年   1314篇
  2011年   1286篇
  2010年   712篇
  2009年   672篇
  2008年   1039篇
  2007年   950篇
  2006年   858篇
  2005年   821篇
  2004年   734篇
  2003年   608篇
  2002年   567篇
  2001年   160篇
  2000年   145篇
  1999年   138篇
  1998年   104篇
  1997年   79篇
  1996年   78篇
  1995年   74篇
  1994年   49篇
  1993年   51篇
  1992年   67篇
  1991年   52篇
  1990年   57篇
  1989年   40篇
  1988年   38篇
  1987年   44篇
  1986年   29篇
  1985年   33篇
  1984年   25篇
  1983年   11篇
  1982年   9篇
  1979年   27篇
  1978年   11篇
  1977年   15篇
  1976年   17篇
  1975年   18篇
  1974年   11篇
  1971年   9篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Lymph node (LN) metastases represent the most important negative prognostic factor in squamous cell carcinoma (SCC) of the oral cavity, even though controversies still exist regarding their management. The aim of this study was to retrospectively analyze our experience in surgical management of SCC of the oral cavity with particular focus on the prevalence and localization of lymph nodal metastases and recurrences. The clinical records of 89 consecutive patients treated from 1983 to 2002 by concomitant surgery on both the T and N sites, excluding those undergoing salvage surgery, were reviewed. A total of 119 neck dissections (ND) were performed. Survival outcomes were calculated by the Kaplan–Meier method, while univariate comparisons by the log-rank and non-parametric tests were performed between different groups of patients. Five-year overall and determinate survivals were 50 and 57%, respectively. LN metastases were observed in 52% (56% of these showing extracapsular spread) and their presence strongly correlated with determinate survival (p < 0.0001). The prevalence of clinical and occult nodal disease was not related to the pT status. Neck levels II (59%) and I (56%) were most frequently involved. Metastases to level IV accounted for 15% of positive LN, even though 28% of them turned out to be skip metastases. Five neck recurrences were observed, only one of which was salvaged by surgery. The high prevalence of clinical and occult LN metastases in this setting suggests that ND should be performed on a nearly routine basis, even for lesions with a low-T category and a cN0 neck. Moreover, ND should always encompass level IV due to the possibility of skip metastases, particularly in tumors involving the oral tongue. In patients with a cN+ neck, levels from I to V should be addressed, particularly in the presence of metastases at levels III and IV.  相似文献   
32.
33.
OBJECTIVE: To verify whether the distribution of paresthesias in patients with Carpal Tunnel Syndrome (CTS) is related to the degree of the neurophysiological involvement. METHODS: We performed a cross-sectional study and retrospectively evaluated 163 patients who referred to our electromyography lab and to which a clinical and electrophysiological diagnosis of CTS was made. We divided the patients into two groups: (1) patients complaining of paresthesias at the hand as a whole and (2) patients with paresthesias in the territory of the median nerve. We referred to the distribution of paresthesias at the hand as GLOVE and to the distribution in the territory of the median nerve as MEDIAN. We compared the neurophysiological impairment in GLOVE and MEDIAN distributions. Moreover, we performed multiple regression analysis to evaluate which clinical-neurophysiological variables determined GLOVE and MEDIAN distribution. RESULTS: In our sample, 70.4% of patients had GLOVE distribution and 29.6% of patients MEDIAN distribution. The risk of presenting MEDIAN distribution increases about twice (OR = 2.07; 95% IC: 1.51-2.83) for each unitary increment of neurophysiological class. CONCLUSIONS: The distribution of paresthesias reflects the degree of nerve damage at wrist; patients suffering of SEV/EXT CTS present MEDIAN distribution. SIGNIFICANCE: Our data have important clinical implications because they strongly suggest that we have to consider the possibility of a severe neurophysiological involvement of the median nerve at wrist in patients complaining of MEDIAN distribution.  相似文献   
34.
Available results highlight the lack of good level of evidence studies on the pure prognostic value of histological grade. In the present study, the prognostic relevance of histological grade and of its three components, tubule formation, nuclear pleomorphism and mitotic count, was analyzed in a series of 372 patients with node-negative breast cancer treated with locoregional therapy alone until early relapse. Histological grade was determined blindly by two observers and discordance between evaluations was resolved after joint review using a multihead microscope. No relation was observed between histological grade and any of its three components and disease-free survival. Conversely, a significant relation was observed between histological grade and distant metastasis-free survival (at 6 years, 94, 86 and 76% for grades 1, 2 and 3, respectively, P=0.013) as well as overall survival (98, 90 and 86%, P=0.001). A breakdown analysis as a function of the three components showed that neither tubule formation nor nuclear pleomorphism was associated with prognosis, and only mitotic count strongly influenced both distant metastasis-free survival (91, 82 and 74%, P=0.014) and overall survival (97, 87 and 85%, P=0.011). Histological grade suffers from a much higher subjectivity than any other microscopic evaluation of biomarkers as it is the sum of three different morphological features. Within the Italian Network for Quality Assessment of Tumor Biomarkers program we observed that histological grade is an independent prognostic variable, but also that this role is ascribable only to the number of mitotic figures. In conclusion, due to the ever smaller size of diagnosed breast cancers, resulting in less cancer tissue for biofunctional and molecular analysis, mitotic count evaluated under strict quality control conditions seems to be an accurate and feasible prognostic variable.  相似文献   
35.
36.
Aim of our study was to assess if the 2D-Echo transverse diameter of the left hepatic vein (LHV) obtained from the subcostal approach is correlated with invasive mean right atrial pressure (RAP). Thirty-two consecutive patients with acute myocardial infarction were studied by simultaneous 2D-Echo and right heart catheterization. LHV could be adequately imaged in 90% of patients. Mean RAP values at catheterization ranged from 0 to 15mmHg (mean 6±3.5 mmHg). A correlation was found between mean RAP and LHV diameter calculated after inspiration (r=0.81, SEE=1.54 mm, slope=0.71,p< 0.001) as well as after expiration (r=0.82, SEE=1.32mm, slope=0.62,p< 0.001) or during post-expiratory apnoea (r=0.85, SEE=1.3 mm, slope=0.71,p< 0.001). Moreover, percent increments of LHV diameter correlated well with percent changes of mean RAP during rapid infusion of 250–500 cc of saline in 4 patients (r=0.98,p< 0.001). Thus, the 2D-Echo LHV diameter is a feasible measurement that seems to correlate well with invasive mean RAP over a wide range of mean RAP values in patients with myocardial infarction; the changes in LHV diameter correlate well with the percent increase in central venous pressure obtained with saline infusion. Underestimation of invasive RAP occurs when mean RAP value exceeds 12 mmHg and can be explained by limited venous compliance. However these preliminary results suggest that this method may represent a valid alternative to obtain a non invasive estimate of mean RAP with 2D-Echocardiography.  相似文献   
37.
38.
39.
This preliminary study included 25 patients with primary epithelial ovarian cancer (EOC) (18 serous, 3 serous-mucinous, 1 endometrioid, 2 undifferentiated carcinomas and 1 malignant Brenner carcinoma); 2 patients with borderline ovarian tumors and 20 patients with benign ovarian tumors (9 benign cystic teratomas, 6 serous cystoadenomas and 5 mucinous cystoadenomas). Blood samples for the measurement of CA 125 and CA 19-9 were drawn from all patients before surgery. Serum CA 125 (Reference Value-RV = 65 U/ml) and CA 19-9 (RV = 40 U/ml) were measured with IRMAs using the monoclonal antibodies (MoAbs) OC 125 and 1116NS 19-9. The same antigens were detected on paraffin-embedded tissue sections by immunocytochemistry with the avidin-biotin complex method employing the same MoAbs used for serum IRMAs. Among the 25 patients with EOC serum CA 125 levels were elevated in 20: tissular OC 125 reactivity was observed in 15 (75%) of them. Of the 5 EOC patients with normal CA 125 levels, 4 showed OC 125 reactivity. Only 2 of the 25 EOC patients had elevated serum CA 19-9 levels: one of them had tissular 1116 NS 19-9 reactivity. Among the 23 patients with normal serum CA 19-9 levels only 5 had immunocytochemical reactivity for this antigen. The 2 patients with borderline ovarian tumors had negative serum CA 125 and CA 19-9 assay: tissular OC 125 reactivity was observed in both patients, while 1116 NS 19-9 reactivity was detected in only one.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
40.
Familial amyloidotic polyneuropathy (FAP) is an inherited disease characterized by an abnormal systemic deposition of a mutant protein called transthyretin (TTR) with elective involvement of the peripheral nervous system, but often determining cardiac, gastrointestinal, and urinary tract dysfunction. FAP commonly affects the liver and the heart until end-organs failure. Transthyretin amyloidosis is today an accepted indication for orthotopic liver transplantation (OLT). Combined heart and liver transplantation (CHLT) may be an attractive and rational treatment option when both organs are contemporary involved by this type of amyloidotic disease. Nowadays, surgical indications and techniques are far from being consolidated because only few cases of CHLT have been previously reported in literature. From November 1999 to May 2006, we performed five orthotopic combined heart and liver transplantations for FAP at our institution. Our surgical experience and clinical outcomes are herein reported.  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-23

京公网安备 11010802026262号