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   6290篇
  免费   532篇
  国内免费   149篇
耳鼻咽喉   122篇
儿科学   77篇
妇产科学   210篇
基础医学   292篇
口腔科学   72篇
临床医学   612篇
内科学   772篇
皮肤病学   69篇
神经病学   148篇
特种医学   416篇
外国民族医学   2篇
外科学   1564篇
综合类   677篇
预防医学   165篇
眼科学   36篇
药学   200篇
  5篇
中国医学   61篇
肿瘤学   1471篇
  2024年   14篇
  2023年   113篇
  2022年   195篇
  2021年   283篇
  2020年   281篇
  2019年   287篇
  2018年   281篇
  2017年   265篇
  2016年   267篇
  2015年   278篇
  2014年   483篇
  2013年   379篇
  2012年   420篇
  2011年   404篇
  2010年   304篇
  2009年   336篇
  2008年   326篇
  2007年   342篇
  2006年   314篇
  2005年   203篇
  2004年   161篇
  2003年   148篇
  2002年   136篇
  2001年   116篇
  2000年   87篇
  1999年   79篇
  1998年   77篇
  1997年   44篇
  1996年   47篇
  1995年   32篇
  1994年   34篇
  1993年   24篇
  1992年   18篇
  1991年   20篇
  1990年   19篇
  1989年   16篇
  1988年   18篇
  1987年   15篇
  1986年   11篇
  1985年   14篇
  1984年   9篇
  1983年   6篇
  1982年   11篇
  1981年   14篇
  1980年   11篇
  1979年   9篇
  1978年   9篇
  1976年   4篇
  1975年   5篇
  1972年   1篇
排序方式: 共有6971条查询结果,搜索用时 312 毫秒
41.
目的消除手术患者的不良心理刺激,防止身心疾病的发生,提高患者对手术的耐受性。方法在术前访视中通过心理调查表了解到患者存在的心理问题,运用个性化的心理护理的方法,帮助患者解答心理问题,减轻心理负担,轻松愉快地接受手术治疗。结果在术前访视中运用个性化的心理护理,很大程度上拉近了护患之间的距离,提高了患者对医务人员的信赖,使患者对手术的耐受性大大提高。结论在术前访视中做好患者的心理护理,消除患者对手术的顾虑是提高手术成功率的有效措施。  相似文献   
42.
43.
OBJECTIVE: Pre-operative staging of rectal cancer should identify patients with extrarectal spread, who might benefit from pre-operative radiotherapy, and patients with minimal sphincteral involvement, who can avoid permanent colostomy. The aim of this study was to assess the accuracy of Magnetic Resonance Imaging (MRI) to predict tumour stage and sphincter status. PATIENTS AND METHODS: Thirty-three patients with a rectal tumour were pre-operatively assessed by MRI with a phased-array coil. Imaging results were correlated with the final pathological findings. RESULTS: The overall accuracy of pre-operative staging with MRI was 88% (k = 0.75) for extramural tumour invasion and 59% (k = 0.26) for lymph node metastases. MRI correctly evaluated the infiltration of the anal sphincters in 87% of patients (7 of 8 patients with low rectal tumour). CONCLUSION: MRI provides the surgeon with valuable information regarding extramural tumour spread and sphincteral involvement, enabling appropriate selection of patients for pre-operative adjuvant therapy or sphincter-saving surgery.  相似文献   
44.
The ability to compare various results that measure clinical deficits and outcome is a necessity for successful worldwide discussion about cervical spondylogenic myelopathy (CSM) and its treatment. There is hardly any information in literature how to value and compare outcome assessed by different scores. In a retrospective study we objectively evaluated the Nurick-score, Japanese-orthopaedic-association-score (JOA-Score), Cooper-myelopathy-scale (CMS), Prolo-score and European-myelopathy-score (EMS) using the data of 43 patients, all of whom showed clinical and morphological signs of CSM and underwent operative decompression. The scores were assessed pre- and postoperatively. The correlation between the score-results, anamnesis, clinical and diagnostic data was investigated. All the scores show a statistically significant correlation and measure postoperative improvement. With exception of the Prolo-score all scores reflect clinical deficits of CSM. The Prolo-score rates the severity of CSM on the state of the economic situation above clinical symptoms. The main differences of the scores are shown in the number of patients showing postoperative improvement, varying between 33% (Nurick-score) and 81% (JOA-score). The recovery-rates, as a measure of the cumulative improvement of all the symptoms, show less variation (23–37%). The differences of the recovery-rate were only statistically significant between JOA-score, Nurick-score and EMS (P < 0.05), whereas all the other scores showed no significant differences. To assess the postoperative successes, the evaluation of the recovery-rate is essential. There is no significant difference in the recovery-rate amongst the majority of the scores, which allows a good comparison of the results from different studies. Nevertheless, it is always important to differentiate the therapy results of CSM published worldwide.  相似文献   
45.
Molecular staging of head and neck squamous carcinoma   总被引:3,自引:0,他引:3  
The staging system of head and neck cancer is a Tumor-Node-Metastases system that was developed by the American Joint Committee on Cancer. The stage of the head and neck cancer defines the extent of the lesion and is determined by physical examination, radiologic studies, and pathologic examination. Accurate staging of head and neck cancer is critical since it will determine the treatment modalities used to cure the disease. Recent advances in the field of molecular genetics have allowed clinicians to detect occult cancer cells previously missed by physical examination and standard histopathologic techniques. Molecular assays are 500 times more sensitive in identifying cancer cells than standard techniques and provide more objective analyses with fewer sampling errors. Consequently, these techniques are currently being used to perform molecular staging of head and neck cancer patients. Preliminary results show that molecular staging will accurately identify those patients at significantly increased risk for recurrence of their head and neck cancer.  相似文献   
46.
An extensive review of the currently available literature on primary fallopian tube carcinoma is presented. The role of vaginal ultrasonography and the importance of an aggressive evaluation of every tubal deformity is stressed. A staging system which takes into account recent data on the biology of this malignancy is proposed. We emphasize the largely underestimated importance of early lymphatic spread of this disease, necessitating a thorough staging laparotomy with pelvic and para-aortic lymph node sampling in the apparent early stages. The need for adjuvant treatment is obvious, but until now no firm data exist as to what the optimal strategy should be. We recommend that until more representative studies are available, ovarian carcinoma protocols should be used in clinical practice.  相似文献   
47.
Objective. The objective of this clinical study was to define the diagnostic value of plain radiography, digital subtraction arthrography and two-phase bone scintigraphy in patients with clinically loose or infected hip prostheses. Design. Digital subtraction arthrograms, scintigrams and plain radiographs of 70 consecutive patients who underwent revision hip arthroplasty were scored individually and in masked fashion for the presence or absence of features indicating loosening of femoral and/or acetabular components. The operative findings acted as the gold standard. Results. Digital subtraction arthrography was best (P<0.001) for predicting a loose acetabular component, while no significant additional predictive value was found for plain radiographs (P=0.24) and scintigraphy (P=0.27). Digital subtraction arthrography was also the most important modality for predicting a loose femoral component (P=0.001), while the plain radiograph was of significant (P=0.04) additional value and scintigraphy was of no additional value (P=0.13) on multivariate analysis. Conclusion. Digital subtraction arthrography gives the best results in the prediction of loosening of acetabular and femoral components. Plain radiographs give additional information on loosening of the femoral component, but scintigraphy offers no additional advantage.  相似文献   
48.
基于股骨正位X片的人工髋关节术前优选系统的研究   总被引:2,自引:0,他引:2  
目的研究开发人工髋关节术前优选系统,为患者选择最优的人工髋关节。方法综合国内外人工髋关节选择的最新成果,对人工髋关节假体的形状尺寸特征进行了全面分析,结合股骨正位X片,制订了人工髋关节的选择原则,并进行几何和力学评价;使用MATLAB和VB混合编程开发人工髋关节术前优选系统。结果制订了优选准则与评价方法,开发人工髋关节术前优选系统。临床初步应用,已为患者成功进行了人工髋关节置换术。结论根据患者股骨正位X片及其股骨特征尺寸,该系统可以准确的为患者选择最优的假体。  相似文献   
49.
A computer model was designed as a relational database to assess breast cancer screening in a cohort of women where the growth and development of breast cancer originates with the first malignant cell. The concepts of thresholds for growth, axillary spread, and distant sites are integrated. With tumor diagnosis, staging was performed that includes clinical and sub-clinical states. The model was parameterized to have staging characteristics similar to data published by the Surveillance, Epidemiology, and End-Results (SEER) Program. Validation was accomplished by comparing simulated staging results with non-SEER sources, and simulated survival with independent clinical survival data.  相似文献   
50.
Early stages of chick somite development   总被引:17,自引:0,他引:17  
We report on the formation and early differentiation of the somites in the avian embryo. The somites are derived from the mesoderm which, in the body (excluding the head), is subdivided into four compartments: the axial, paraxial, intermediate and lateral plate mesoderm. Somites develop from the paraxial mesoderm and constitute the segmental pattern of the body. They are formed in pairs by epithelialization, first at the cranial end of the paraxial mesoderm, proceeding caudally, while new mesenchyme cells enter the paraxial mesoderm as a consequence of gastrulation. After their formation, which depends upon cell-cell and cell-matrix interactions, the somites impose segmental pattern upon peripheral nerves and vascular primordia. The newly formed somite consists of an epithelial ball of columnar cells enveloping mesenchymal cells within a central cavity, the somitocoel. Each somite is surrounded by extracellular matrix material connecting the somite with adjacent structures. The competence to form skeletal muscle is a unique property of the somites and becomes realized during compartmentalization, under control of signals emanating from surrounding tissues. Compartmentalization is accompanied by altered patterns of expression of Pax genes within the somite. These are believed to be involved in the specification of somite cell lineages. Somites are also regionally specified, giving rise to particular skeletal structures at different axial levels. This axial specification appears to be reflected in Hox gene expression. MyoD is first expressed in the dorsomedial quadrant of the still epithelial somite whose cells are not yet definitely committed. During early maturation, the ventral wall of the somite undergoes an epithelio-mesenchymal transition forming the sclerotome. The sclerotome later becomes subdivided into rostral and caudal halves which are separated laterally by von Ebner's fissure. The lateral part of the caudal half of the sclerotome mainly forms the ribs, neural arches and pedicles of vertebrae, whereas within the lateral part of the rostral half the spinal nerve develops. The medially migrating sclerotomal cells form the peri-notochordal sheath, and later give rise to the vertebral bodies and intervertebral discs. The somitocoel cells also contribute to the sclerotome. The dorsal half of the somite remains epithelial and is referred to as the dermomyotome because it gives rise to the dermis of the back and the skeletal musculature. The cells located within the lateral half of the dermomyotome are the precursors of the muscles of the hypaxial domain of the body, whereas those in the medial half are precursors of the epaxial (back) muscles. Single epithelial cells at the cranio-medial edge of the dermomyotome elongate in a caudal direction, beneath the dermomyotome, and become anchored at its caudal margin. These post-mitotic and muscle protein-expressing cells form the myotome. At limb levels, the precursors of hypaxial muscles undergo an epithelio-mesenchymal transition and migrate into the somatic mesoderm, where they replicate and later differentiate. These cells express the Pax-3 gene prior to, during and after this migration. All compartments of the somite contribute endothelial cells to the formation of vascular primordia. These cells, unlike all other cells of the somite, occasionally cross the midline of the developing embryo. We also suggest a method for staging somites according to their developmental age.  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