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   1527篇
  免费   93篇
  国内免费   10篇
耳鼻咽喉   8篇
儿科学   37篇
妇产科学   30篇
基础医学   199篇
口腔科学   10篇
临床医学   162篇
内科学   304篇
皮肤病学   25篇
神经病学   92篇
特种医学   31篇
外科学   281篇
综合类   23篇
预防医学   169篇
眼科学   23篇
药学   127篇
中国医学   7篇
肿瘤学   102篇
  2024年   2篇
  2023年   11篇
  2022年   30篇
  2021年   47篇
  2020年   37篇
  2019年   37篇
  2018年   46篇
  2017年   39篇
  2016年   42篇
  2015年   60篇
  2014年   51篇
  2013年   82篇
  2012年   144篇
  2011年   143篇
  2010年   64篇
  2009年   67篇
  2008年   98篇
  2007年   84篇
  2006年   87篇
  2005年   72篇
  2004年   77篇
  2003年   65篇
  2002年   62篇
  2001年   24篇
  2000年   17篇
  1999年   15篇
  1998年   11篇
  1997年   6篇
  1996年   5篇
  1995年   4篇
  1993年   4篇
  1992年   5篇
  1991年   5篇
  1990年   8篇
  1989年   7篇
  1988年   8篇
  1987年   6篇
  1986年   10篇
  1984年   6篇
  1983年   3篇
  1982年   2篇
  1981年   2篇
  1979年   2篇
  1978年   4篇
  1977年   5篇
  1975年   4篇
  1973年   2篇
  1971年   3篇
  1970年   7篇
  1965年   2篇
排序方式: 共有1630条查询结果,搜索用时 15 毫秒
11.
Entrapment of the ulnar nerve at the wrist is rare compared with the more commun site at the elbow. This condition was secondary to reccurent blunt trauma, ganglion cyst, vasculitic disorders, and fibrous bands. Compression of the ulnar nerve caused by pisiform-hamate coalition is rare entity. One case of this condition is reported.  相似文献   
12.
Both genetics and physical activity (PA) contribute to bone mineral density (BMD), but it is unknown if the benefits of physical activity on childhood bone accretion depend on genetic risk. We, therefore, aimed to determine if PA influenced the effect of bone fragility genetic variants on BMD in childhood. Our sample comprised US children of European ancestry enrolled in the Bone Mineral Density in Childhood Study (N = 918, aged 5 to 19 years, and 52.4% female). We used a questionnaire to estimate hours per day spent in total, high‐, and low‐impact PA. We calculated a BMD genetic score (% BMD lowering alleles) using adult genome‐wide association study (GWAS)‐implicated BMD variants. We used dual‐energy X‐ray absorptiometry to estimate femoral neck, total hip, and spine areal‐BMD and total body less head (TBLH) bone mineral content (BMC) Z‐scores. The BMD genetic score was negatively associated with each bone Z‐score (eg, TBLH‐BMC: estimate = –0.03, p = 1.3 × 10?6). Total PA was positively associated with bone Z‐scores; these associations were driven by time spent in high‐impact PA (eg, TBLH‐BMC: estimate = 0.05, p = 4.0 × 10?10) and were observed even for children with lower than average bone Z‐scores. We found no evidence of PA‐adult genetic score interactions (p interaction > 0.05) at any skeletal site, and there was no evidence of PA‐genetic score–Tanner stage interactions at any skeletal site (p interaction > 0.05). However, exploratory analyses at the individual variant level revealed that PA statistically interacted with rs2887571 (ERC1/WNT5B) to influence TBLH‐BMC in males (p interaction = 7.1 × 10?5), where PA was associated with higher TBLH‐BMC Z‐score among the BMD‐lowering allele carriers (rs2887571 AA homozygotes: estimate = 0.08 [95% CI 0.06, 0.11], p = 2.7 × 10?9). In conclusion, the beneficial effect of PA on bone, especially high‐impact PA, applies to the average child and those genetically predisposed to lower adult BMD (based on GWAS‐implicated BMD variants). Independent replication of our exploratory individual variant findings is warranted. © 2016 American Society for Bone and Mineral Research.  相似文献   
13.
Curve of left ventricular (LV) volume changes throughout the cardiac cycle is a fundamental parameter for clinical evaluation of various cardiovascular diseases. Currently, this evaluation is often performed manually which is tedious and time consuming and suffers from significant interobserver and intraobserver variability. This paper introduces a new automatic method, based on nonlinear dimensionality reduction (NLDR) for extracting the curve of the LV volume changes over a cardiac cycle from two-dimensional (2-D) echocardiography images. Isometric feature mapping (Isomap) is one of the most popular NLDR algorithms. In this study, a modified version of Isomap algorithm, where image to image distance metric is computed using nonrigid registration, is applied on 2-D echocardiography images of one cycle of heart. Using this approach, the nonlinear information of these images is embedded in a 2-D manifold and each image is characterized by a symbol on the constructed manifold. This new representation visualizes the relationship between these images based on LV volume changes and allows extracting the curve of the LV volume changes automatically. Our method in comparison to the traditional segmentation algorithms does not need any LV myocardial segmentation and tracking, particularly difficult in the echocardiography images. Moreover, a large data set under various diseases for training is not required. The results obtained by our method are quantitatively evaluated to those obtained manually by the highly experienced echocardiographer on ten healthy volunteers and six patients which depict the usefulness of the presented method.  相似文献   
14.
15.
BackgroundDiagnosis of human papillomavirus (HPV) disease remains a challenge due to several factors related to the cost, the workload of available commercial assays to detect and genotype HPV, and to the low prevalence of infected patients.ObjectiveOur study aimed to develop a real-time PCR, based on SPF10 primers, in order to combine HPV-DNA detection and genotype identification avoiding the negative samples.Study designValidation of SYBR-green based SPF10 real-time PCR on HPV-DNA plasmids followed by the investigation of the viral status in 92 samples from oropharyngeal (94%) cutaneous biopsies (3%) and anal smears (3%) which had previously been HPV-genotyped by LiPA hybridization. In-house HPV viral loads were performed to evaluate the SPF10 real-time PCR sensitivity.ResultsData showed that 100% of HPV plasmids, assessable by LiPA hybridization, were detected and genotyped appropriately after SPF10 real-time PCR assays. These results defined a range of melting temperature peaks for HPV positivity by real-time PCR. The efficient determination of the presence of HPV-DNA by SPF10 real-time PCR was validated for 98% of clinical samples compared to commercial method. Discordant results were due to a low HPV-DNA amount and to a supplementary HPV genotype identified. The SPF10 real-time PCR sensitivity was evaluated between 1 and 10 copies/103 cells using in-house HPV (6, 11 and 16) viral load assays.ConclusionThe real-time PCR method was efficient in combining screening and genotyping of HPV-DNA. Cost and workload reduction by SPF10 real-time PCR approach may facilitate earlier diagnosis and clinical management of HPV infected patients.  相似文献   
16.
17.
18.
19.
The purpose of the study was to evaluate the qualitative aspect and global impact of surgery in a district hospital (DH) since the launching of the surgery at the district level. Surgical care was provided by general practitioners (GP) who received 12-month training in surgery, certified by a “Capacity of District Surgery” (CDS) diploma. It was a prospective study during 4 years from 2007 to 2010. Of the 34 DHs, only 21 were functional and included in this study. Most of the DHs had two or more CDS (n?=?15). The majority of the DHs had one nurse surgical aid (n?=?16) and one nurse anesthetist (n?=?17). The total number of surgical operations was 18,441 cases; emergency cases represented 51.8 % and elective surgery 48.2 %. Regarding emergency surgery, cesarean sections revealed the most common surgical procedure (37.21 %), followed by wound debridement (19.42 %). In elective surgery, hernia repair and hydrocelectomy were the most common surgical procedures (69.60 %), followed by gynecologic procedures in 12.74 % of the cases. The global complication rate was 4.34 %. The global mortality rate was 1.04 % (n?=?192), 102 deaths following cesarean section (2.87 %). No death was encountered in elective surgery. Nine hundred and fifty-five patients (5.17 %) were transferred to a higher-level facility of whom 598 patients (62.61 %) were admitted for fracture treatment. The concept of district surgery has proven to be an effective tool to counter skilled medical manpower shortage to perform emergency and elective basic surgery at the rural level and could be adopted by developing countries facing similar health challenges.  相似文献   
20.
Malignant neoplasms are associated with a wide variety of paraneoplastic rheumatological syndromes. The paraneoplastic nature should be based on specific criteria. We report a series of eight cases of paraneoplastic rheumatic syndromes revealing an underlying neoplasia. Our series consists of six men and two women, with a mean age of 46.1 (20-69?years). The first case is a hypertrophic osteoarthropathy of Pierre Marie that occurred in a 20-year-old man 1?month after treatment for his nasopharyngeal carcinoma; the paraclinical examinations showed lung and bone metastasis. The second case is that of a bilateral shoulder-hand syndrome revealing an invasive squamous cell carcinoma of the cervix in a 63-year-old woman. The third case involved a 69-year-old patient who had surgery 2?years ago for prostate adenocarcinoma and presented with polymyalgia rheumatica revealing bone metastasis. We also report two cases of leukemia in adults revealed by polyarthritis. The sixth observation is that of a paraneoplastic scleroderma that occurred concomitantly with prostate cancer. The seventh case of an acute arthritis showed a B lymphoma. The eighth case is that of a 52-year-old patient who presented with inflammatory arthralgias, and digital clubbing revealing a squamous cell carcinoma of the skin. Paraneoplastic rheumatism remains a rare event, but knowledge of it is essential for early diagnosis of underlying cancer.  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