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   18699篇
  免费   946篇
  国内免费   76篇
耳鼻咽喉   159篇
儿科学   572篇
妇产科学   348篇
基础医学   2239篇
口腔科学   333篇
临床医学   1430篇
内科学   4860篇
皮肤病学   225篇
神经病学   1949篇
特种医学   995篇
外科学   2563篇
综合类   42篇
一般理论   1篇
预防医学   768篇
眼科学   164篇
药学   1216篇
中国医学   25篇
肿瘤学   1832篇
  2023年   114篇
  2022年   200篇
  2021年   482篇
  2020年   277篇
  2019年   341篇
  2018年   459篇
  2017年   323篇
  2016年   395篇
  2015年   415篇
  2014年   633篇
  2013年   767篇
  2012年   1138篇
  2011年   1219篇
  2010年   654篇
  2009年   642篇
  2008年   1008篇
  2007年   1032篇
  2006年   971篇
  2005年   932篇
  2004年   804篇
  2003年   789篇
  2002年   713篇
  2001年   477篇
  2000年   480篇
  1999年   490篇
  1998年   190篇
  1997年   135篇
  1996年   132篇
  1995年   113篇
  1994年   104篇
  1993年   96篇
  1992年   305篇
  1991年   291篇
  1990年   284篇
  1989年   264篇
  1988年   211篇
  1987年   180篇
  1986年   198篇
  1985年   225篇
  1984年   138篇
  1983年   104篇
  1982年   70篇
  1980年   54篇
  1979年   118篇
  1977年   61篇
  1976年   55篇
  1975年   58篇
  1973年   60篇
  1972年   51篇
  1971年   54篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
1.
2.
Dynamic contrast-enhanced ultrasound (DCE-US) has been proposed as a powerful tool for cancer diagnosis by estimation of perfusion and dispersion parameters reflecting angiogenic vascular changes. This work was aimed at identifying which vascular features are reflected by the estimated perfusion and dispersion parameters through comparison with acoustic angiography (AA). AA is a high-resolution technique that allows quantification of vascular morphology. Three-dimensional AA and 2-D DCE-US bolus acquisitions were used to monitor the growth of fibrosarcoma tumors in nine rats. AA-derived vascular properties were analyzed along with DCE-US perfusion and dispersion to investigate the differences between tumor and control and their evolution in time. AA-derived microvascular density and DCE-US perfusion exhibited good agreement, confirmed by their spatial distributions. No vascular feature was correlated with dispersion. Yet, dispersion provided better cancer classification than perfusion. We therefore hypothesize that dispersion characterizes vessels that are smaller than those visible with AA.  相似文献   
3.
4.
5.
6.
7.

Background

Radium 223 was introduced for metastatic castration-resistant prostate cancer based on the results of a randomized controlled trial showing risk reduction for death and skeletal events. Our aim was to evaluate the outcome of patients receiving radium 223 in a real-world setting.

Patients and Methods

We conducted a multicenter retrospective analysis in the Triveneto region of Italy.

Results

One hundred fifty-eight patients received radium 223 in our region. After a median follow-up of 9.5 months, 75 patients died. The median overall survival (OS) was 14.2 months, and the median progression-free survival (PFS) was 6.2 months. Seventy-one (45%) patients achieved progression as best response. Thirty-seven (23%) patients stopped the treatment early because of progression. Eastern Cooperative Oncology Group performance status was prognostic for OS (18.4 vs. 12.3 vs. 7.5 months; 0 vs. 1, P = .0062; 0 vs. 2, P = .0002), whereas previous prostatectomy or docetaxel exposure were not. A neutrophil to lymphocytes ratio ≥ 3 significantly impacted OS (18.1 vs. 9.7 months; P < .001) and slightly impacted PFS (6.6 vs. 5.6 months; P = .05). Patients with a baseline alkaline phosphatase (ALP) value ≥ 220 U/L had worse OS and PFS (24.1 vs. 10.5 months; 7.2 vs. 5.5 months; P < .001). Patients with changes in ALP value achieved better OS (P = .029) and PFS (P = .002). There was no difference according to the line of therapy (0 vs. ≥ 1; P = .490). The main grade 3/4 toxicities were anemia, asthenia, and thrombocytopenia.

Conclusion

This large real-world report confirms comparable OS and PFS data when compared with the pivotal study, as well as the predictive role of ALP and neutrophil to lymphocytes ratio. The definition of the optimal position of radium 223 in the treatment of metastatic castration-resistant prostate cancer has still to be defined.  相似文献   
8.
OBJECTIVE: The study aims to verify whether phonologic and rapid automatized naming (RAN) deficits are present and associated in Italian dyslexic children and whether they differentially affect dyslexics with and without a history of previous language delay (LD). BACKGROUND: According to the phonologic core deficit hypothesis, dyslexia may stem from impairment of the representation and manipulation of phonemes and may be closely associated with oral language deficits. However, deficits in tasks not requiring fine-grained phonologic representations, such as RAN, have also been described in dyslexic children. METHODS: Thirty-seven children were selected on the basis of a reading deficit and were assigned to 2 groups according to whether or not they had a history of early LD as determined retrospectively by parental report. A battery of reading and writing, verbal working memory, metaphonologic, RAN, and visual search tests were administered. RESULTS: RAN deficits were shared by most dyslexics (with and without a history of LD), whereas phonologic deficits were mainly associated with a previous LD. This last condition did not result in a more profound impairment of reading and writing decoding skills. CONCLUSION: In a shallow orthography such as Italian, RAN, not phonologic deficits, may represent the main cognitive marker of developmental dyslexia.  相似文献   
9.
Migration of Kirschner (K) wires from the upper extremity joints has often been reported, but it is less common from the lower extremities. In this report, we describe an 85-year-old man treated, during a hip replacement procedure, with a K-wire because of a trochanteric fracture; after one year, the K-wire was found in the popliteal fossa. This report illustrates the first case of K-wire migration in the popliteal area of the knee and suggests avoiding the use of free K-wires without any tension banding.  相似文献   
10.
Eledoisin has been tried as a possible treatment for dry eye based on the hypothesis that it pharmacologically stimulates tear secretion when topically applied to the eye. To determine if topically applied eledoisin pharmacologically stimulates orbital lacrimal secretion, the orbital lacrimal gland excretory duct of normal rabbits was cannulated, and eledoisin was applied topically with and without prior administration of proparacaine. To determine if topically applied eledoisin stimulated accessory lacrimal gland secretion, isotonic buffer with and without eledoisin was tested in a rabbit model with only accessory lacrimal tissue remaining after the administration of proparacaine. Topically applied eledoisin did not pharmacologically stimulate lacrimal secretion but rather increased lacrimal gland secretion only in non-anesthetized eyes through a sensory reflex mechanism that is blocked by proparacaine.  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