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   8207篇
  免费   354篇
  国内免费   71篇
耳鼻咽喉   103篇
儿科学   109篇
妇产科学   48篇
基础医学   891篇
口腔科学   89篇
临床医学   477篇
内科学   2213篇
皮肤病学   419篇
神经病学   509篇
特种医学   358篇
外科学   1890篇
综合类   29篇
预防医学   202篇
眼科学   55篇
药学   331篇
中国医学   11篇
肿瘤学   898篇
  2024年   5篇
  2023年   66篇
  2022年   111篇
  2021年   191篇
  2020年   117篇
  2019年   152篇
  2018年   208篇
  2017年   164篇
  2016年   181篇
  2015年   215篇
  2014年   274篇
  2013年   359篇
  2012年   532篇
  2011年   585篇
  2010年   306篇
  2009年   256篇
  2008年   477篇
  2007年   559篇
  2006年   538篇
  2005年   540篇
  2004年   533篇
  2003年   525篇
  2002年   531篇
  2001年   100篇
  2000年   83篇
  1999年   114篇
  1998年   126篇
  1997年   93篇
  1996年   92篇
  1995年   87篇
  1994年   63篇
  1993年   43篇
  1992年   37篇
  1991年   40篇
  1990年   35篇
  1989年   47篇
  1988年   35篇
  1987年   29篇
  1986年   26篇
  1985年   22篇
  1984年   19篇
  1983年   17篇
  1982年   11篇
  1981年   11篇
  1980年   10篇
  1979年   10篇
  1978年   15篇
  1976年   5篇
  1975年   11篇
  1974年   5篇
排序方式: 共有8632条查询结果,搜索用时 15 毫秒
91.
Neurokinin 2 receptor (NK2R), a G protein‐coupled receptor for neurokinin A (NKA), a tachykinin family member, regulates various physiological functions including pain response, relaxation of smooth muscle, dilation of blood vessels, and vascular permeability. However, the precise role and regulation of NK2R expression in cancer cells have not been fully elucidated. In this study, we found that high NK2R gene expression was correlated with the poor survival of colorectal cancer patients, and Interferon (IFN‐α/β) stimulation significantly enhanced NK2R gene expression level of colon cancer cells in a Janus kinas 1/2 (JAK 1/2)‐dependent manner. NKA stimulation augmented viability/proliferation and phosphorylation of Extracellular‐signal‐regulated kinase 1/2 (ERK1/2) levels of IFN‐α/β‐treated colon cancer cells and NK2R blockade by using a selective antagonist reduced the proliferation in vitro. Administration of an NK2R antagonist alone or combined with polyinosinic‐polycytidylic acid, a synthetic analog of double‐stranded RNA, to CT26‐bearing mice significantly suppressed tumorigenesis. NK2R‐overexpressing CT26 cells showed enhanced tumorigenesis and metastatic colonization in both lung and liver after the inoculation into mice. These findings indicate that IFN‐α/β‐mediated NK2R expression is related to the malignancy of colon cancer cells, suggesting that NK2R blockade may be a promising strategy for colon cancers.  相似文献   
92.
Background We conducted a multiinstitutional analysis to clarify the clinical significance of perioperative chemotherapy, in invasive bladder cancers in Japan, and to identify the patient subpopulations who could benefit from perioperative chemotherapy.Methods A total of 913 consecutive patients aged less than 80 years who underwent radical cystectomy for invasive bladder cancer from 1990 to 2000 at 32 Japanese hospitals were retrospectively analyzed. Median follow-up was 3.8 years (range, 0.1 to 11.8 years).Results In total, 341 patients (37.3%) were treated with perioperative chemotherapy, including neoadjuvant chemotherapy (n = 174), adjuvant chemotherapy (n = 114), or a combination of both chemotherapies (n = 53). With cisplatin-based combination chemotherapy, the MVAC (methotrexate, vinblastine, doxorubicin, and cisplatin) regimen was the one most frequently used for perioperative chemotherapy, but the average number of cycles was distinctly less than that in reported randomized trials. MEC (methotrexate, epirubicin, and cisplatin) chemotherapy had efficacy similar to that of the MVAC regimen. On analysis of patients stratified by stage, the overall survival of patients with adjuvant chemotherapy was significantly better than that of those without adjuvant chemotherapy, in patients with pT2b, pN0 or pT3, pN0 (P = 0.016 or 0.020, respectively), but adjuvant chemotherapy had no, or the opposite, effect on patients with pT2a, pN0, pT4, pN0, or pTany, pN+. On the other hand, neoadjuvant chemotherapy provided a statistically significant survival benefit only for patients with clinical T3N0 (P = 0.015). Of note, in the high-risk subgroup, the overall survival rate for patients with complete response (CR) after neoadjuvant chemotherapy was significantly better than that of patients with partial response (PR) or no change (NC)/progressive disease (PD) (P = 0.043).Conclusion In Japan, cisplatin-based combination chemotherapy has been the main modality adopted perioperatively for high-risk patients with radical cystectomy. This studys clinical results indicated that perioperative chemotherapy may improve survival in patients with T3N0 or pT2b/pT3, pN0 bladder cancer.  相似文献   
93.
94.
STUDY OBJECTIVE: To analyze variables for successful 1-step hysteroscopic myomectomies of sessile submucous myomas. DESIGN: Retrospective case-control study. (Canadian Task Force classification II-2). SETTING: Single operator's practice in a university hospital and its related hospitals. PATIENTS: Twenty-eight patients with sessile submucous myomas and menorrhagia, infertility, or both. INTERVENTIONS: Our strategy for hysteroscopic myomectomy is as follows. First, we scraped and/or vaporized intrauterine dome of myoma until top of myoma was even with level of wall of cavity. Next, the remnant intramural node was squeezed by uterine contractions induced by prostaglandin F2alpha injection. Finally, the newly raised myoma dome was sectioned or vaporized electrosurgically only within the space of the intrauterine cavity and/or was separated mechanically from healthy myometrium without electrosurgery. MEASUREMENTS AND MAIN RESULTS: Submucous myomas in 16 (57.1%) patients were completely removed after 1 surgery. By logistic regression analysis, thickness of outer myometrial layer of myoma node (OR 3.06, p = .02), myoma size (OR 0.86, p = .04), and intramural extension degree (OR 0.91, p = .03) were significantly associated with outcome of complete resection. CONCLUSION: Thickness of outer myometrial layer of myoma node, myoma size, and intramural extension degree predicted outcome of 1-step hysteroscopic myomectomy. The chance of performing successful surgery increased with increased thickness of outer myometrial layer of myoma, and decreased with larger myomas and greater degrees of intramural extension.  相似文献   
95.
96.
The purple-flesh potato (Solanum tuberosum L.) cultivar “Shadow Queen” (SQ) naturally contains anthocyanins. This randomized, double-blind, placebo-controlled study determines whether ingesting purple potatoes increases the number of mesenchymal stem cells (MSC) and improves stress response, a minor health complaint in healthy adults (registration number: UMIN000038876). A total of 15 healthy subjects (ages: 50–70 years) with minor health complaints were randomly assigned to one of two groups. For 8 weeks, the placebo group received placebo potatoes cv. “Haruka” and the test group received test potato cv. SQ containing 45 mg anthocyanin. The MSC count and several stress responses were analyzed at weeks 0 and 8 of the intake periods. The ingestion of a SQ potato did not affect the MSC count but markedly improved psychological stress response, irritability, and depression as minor health complaints compared with “Haruka”. No adverse effects were noted. Hence, an 8-week intake of SQ could improve stress responses.  相似文献   
97.
European Archives of Psychiatry and Clinical Neuroscience - Significant evidence links white matter (WM) microstructural abnormalities to cognitive impairment in schizophrenia (SZ), but the...  相似文献   
98.
MR imaging of primary malignant lymphoma of the pancreas   总被引:2,自引:0,他引:2  
Pancreatic lymphoma is rare and is usually found as a large pancreatic mass. We report the case of a small 2-cm pancreatic lymphoma in a 54-year-old woman that had its histological origin in the pancreatic parenchyma. The mass showed homogeneously high signal-intensity on T2-weighted images and low signal-intensity on T1-weighted images. The infiltrative nature and hypovascularity in early-phase dynamic contrast study without encasement of arteries and veins were well demonstrated by MR imaging and were consistent with malignant lymphoma.  相似文献   
99.
OBJECTIVES: The aim of this study is to evaluate the usefulness of gastroesophageal reflux (GER) scintigraphy using the knee-chest (KC) position for the diagnosis of gastroesophageal reflux disease (GERD). METHODS: The study subjects were 37 patients with GERD and 8 healthy volunteers (control group). Endoscopically observed esophageal mucosal breaks were evaluated with the Los Angeles classification. For GER scintigraphy, the subjects ingested liquid yogurt labeled with 99mTc-diethylene triamine pentaacetic acid (99mTc-DTPA) and water. Imaging was performed in the supine and KC position, and GER was graded as 1-4 according to the extent of GER assessed by scintigraphy. RESULTS: GER scintigraphy revealed no reflux in the control group (specificity: 100%). In the supine position, gastroesophageal reflux was observed in 49% of the patients with GERD, compared to 76% in the KC position. 21 of 23 (91%) patients with erosive esophagitis were shown to have GER with scintigraphy. GER scintigraphy revealed severe reflux (grade 3 or 4) (83%, 10/12) in the patients who had severe mucosal breaks (LA grade C or D). GER scintigraphy detected grade 1 or 2 reflux in 7 of the 14 patients who were endoscopically negative. There was a correlation between the endoscopically determined severity of mucosa and the reflux grade which was determined with GER scintigraphy. CONCLUSION: GER scintigraphy can detect gastroesophageal reflux with a high sensitivity in the KC position and might be a useful method in the screening and assessment of the severity of this disease. This method would be useful for the diagnosis of GERD in endoscopically negative patients.  相似文献   
100.
We conducted a questionnaire survey about radiation-safety management condition in Japanese nuclear medicine facilities to make materials of proposition for more reasonable management of medical radioactive waste. We distributed a questionnaire to institutions equipped with Nuclear Medicine facilities. Of 1,125 institutions, 642 institutes (52.8%) returned effective answers. The questionnaire covered the following areas: 1) scale of an institution, 2) presence of enforcement of radiotherapy, 3) system of a tank, 4) size and number of each tank, 5) a form of draining-water system, 6) a displacement in a radioactive rays management area, 7) a measurement method of the concentration of medical radioactive waste in draining water system, 8) planned and used quantity of radioisotopes for medical examination and treatment, 9) an average displacement of hospital for one month. In most institutions, a ratio of dose limitation of radioisotope in draining-water system was less than 1.0, defined as an upper limitation in ordinance. In 499 hospitals without facilities of hospitalization for unsealed radioisotope therapy, 473 hospitals reported that sum of ratios of dose limits in a draining-water system was less than 1.0. It was calculated by used dose of radioisotope and monthly displacement from hospital, on the premise that all used radioisotope entered in the general draining-water system. When a drainage including radioactivity from a controlled area join with that from other area before it flows out of a institution, it may be diluted and its radioactive concentration should be less than its upper limitation defined in the rule. Especially, in all institutions with a monthly displacement of more than 25,000 m3, the sum of ratio of the concentration of each radionuclide to the concentration limit dose calculated by used dose of radioisotope, indicated less than 1.0.  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