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   9893篇
  免费   678篇
  国内免费   19篇
耳鼻咽喉   209篇
儿科学   255篇
妇产科学   166篇
基础医学   1409篇
口腔科学   140篇
临床医学   998篇
内科学   2010篇
皮肤病学   95篇
神经病学   968篇
特种医学   312篇
外国民族医学   2篇
外科学   1319篇
综合类   90篇
一般理论   7篇
预防医学   915篇
眼科学   242篇
药学   679篇
中国医学   10篇
肿瘤学   764篇
  2022年   39篇
  2021年   149篇
  2020年   59篇
  2019年   126篇
  2018年   154篇
  2017年   118篇
  2016年   131篇
  2015年   160篇
  2014年   238篇
  2013年   390篇
  2012年   545篇
  2011年   550篇
  2010年   332篇
  2009年   351篇
  2008年   606篇
  2007年   589篇
  2006年   626篇
  2005年   656篇
  2004年   627篇
  2003年   605篇
  2002年   704篇
  2001年   121篇
  2000年   98篇
  1999年   133篇
  1998年   159篇
  1997年   129篇
  1996年   103篇
  1995年   102篇
  1994年   87篇
  1993年   83篇
  1992年   63篇
  1991年   72篇
  1990年   49篇
  1989年   45篇
  1988年   48篇
  1987年   51篇
  1986年   50篇
  1985年   75篇
  1984年   80篇
  1983年   97篇
  1982年   91篇
  1981年   99篇
  1980年   103篇
  1979年   41篇
  1978年   51篇
  1977年   67篇
  1976年   41篇
  1975年   42篇
  1974年   39篇
  1973年   31篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
122.
BackgroundIt is unknown, whether metastatic prostate cancer (CaP) patients with intermediate life expectancy (5–10 years) should be considered for external beam radiation therapy (EBRT) to the prostate. We addressed this void.MethodsWithin the Surveillance, Epidemiology, and End Results database (2004–2016), we identified 835 M1a or M1b CaP substaged patients with prostate-specific antigen (PSA) < 20 ng/ml and with intermediate life expectancy (LE) 5 to 10 years, treated with EBRT or no EBRT. Inverse probability of treatment-weighting (IPTW), Kaplan-Meier plots and Cox-regression models (CRMs) were used.ResultsOverall, 179 (21.4%) patients received EBRT and 656 (78.6%) did not. EBRT rates increased from 13.9 to 23.8% (2004–2016; P= 0.04). After IPTW-adjustment, median OS was 45 vs. 35 months, in EBRT vs. no EBRT patients (P < 0.001). In IPTW-adjusted Cox-regression models, EBRT independently predicted lower overall mortality (hazard ratio [HR]: 0.7, CI 0.61–0.89; P= 0.001). After stratification according to M1 substages, EBRT was associated with lower overall mortality in M1a (HR: 0.2, CI 0.05–0.91; P= 0.03) and M1b (HR: 0.7, CI 0.55–0.88; P = 0.003) substages.ConclusionEBRT was associated with lower mortality in metastatic CaP patients with low PSA and intermediate LE (5–10 years). In consequence, greater consideration for EBRT should be given in those patients. However, it is important to consider study limitations until clinical trials confirm the proposed benefit.  相似文献   
123.
BackgroundThe NCCN guidelines recommend active surveillance (AS) as an option for the initial management of cT1a 0-2 cm renal lesions. However, data about comparison between renal cell carcinoma (RCC) 0-2 cm vs. 2.1-4 cm are scarce.MethodsWithin the Surveillance, Epidemiology, and End Results database (2002–2016), 46,630 T1a NanyMany stage patients treated with nephrectomy were identified. Data were tabulated according to histological subtype, tumor grade (low [LG] vs. high [HG]), as well as age category and gender. Additionally, rates of synchronous metastases were quantified.ResultsOverall, 69.3 vs. 74.1% clear cell, 21.4 vs. 17.6% papillary, 6.9 vs. 6.8% chromophobe, 2.0 vs. 1.1% sarcomatoid dedifferentiation, 0.2 vs. 0.2% collecting duct histological subtype were identified for respectively 0-2 cm and 2.1-4 cm RCCs. In both groups, advanced age was associated with higher rate of HG clear cell and HG papillary histological subtype. In 0-2 cm vs. 2.1-4 cm RCCs, 13.8% vs. 20.2% individuals operated on harbored HG tumors and were more prevalent in males. Lower synchronous metastases rates were recorded in 0-2 cm RCC and ranged from 0 in respectively multilocular cystic to 0.9% in HG papillary histological subtype. The highest synchronous metastases rates were recorded in sarcomatoid dedifferentiation histological subtype (13.8% and 9.7%) in both groups.ConclusionsRelative to 2.1-4 cm RCCs, 0-2 cm RCCs harbored lower rates of HG tumors, lower rates of aggressive variant histology and lower rates of synchronous metastases. The indications and demographics of patients selected for AS may be expanded in the future to include younger and healthier patients.  相似文献   
124.
125.
126.
Multifocal cystic oncocytosis (MCO) is a rare, benign process accounting for approximately 0.1% of salivary gland lesions. Salivary oncocytosis is characterized by multiple unencapsulated solid nodules of oncocytic cells derived from transformed striated ducts. MCO is a variant of salivary oncocytosis which manifests as cystically dilated striated ducts. It is difficult to obtain a definitive preoperative diagnosis of MCO; therefore, these lesions are commonly treated with surgery. We report the unique case of a 66-year-old male who previously underwent a superficial left parotidectomy for a pleomorphic adenoma. Four years later, he presented with clinical and radiographic suspicion of a multifocal recurrent pleomorphic adenoma. The patient subsequently underwent a revision parotidectomy. However, final pathology confirmed a diagnosis of MCO. Although MCO is commonly treated with surgery due to lack of a definitive preoperative diagnosis, surgery is unnecessary outside of diagnostic, functional or cosmetic considerations. Thus, if a patient with parotid oncocytosis treated by superficial parotidectomy develops disease re-manifestation in the residual deep lobe, further surgery is not indicated. There is no risk of malignant progression in this process. We report on this unusual entity as it may mimic salivary malignancy or, as in this case, recurrence of benign disease.  相似文献   
127.
128.
Foxp3 and natural regulatory T cells: key to a cell lineage?   总被引:22,自引:0,他引:22  
Ramsdell F 《Immunity》2003,19(2):165-168
  相似文献   
129.
Studies with murine models demonstrate 2 pathways of systemic anaphylaxis: one mediated by IgE, Fc epsilonRI, mast cells, histamine, and platelet-activating factor (PAF), and the other mediated by IgG, Fc gammaRIII, macrophages, and PAF. The former pathway requires much less antibody and antigen than the latter. As a result, IgG antibody can block IgE-mediated anaphylaxis induced by small quantities of antigen without mediating Fc gammaRIII-dependent anaphylaxis. The IgE pathway is most likely responsible for most human anaphylaxis, which generally involves small amounts of antibody and antigen; similarities in the murine and human immune systems suggest that the IgG pathway might mediate disease in persons repeatedly exposed to large quantities of antigen. Mice, like human subjects, can experience IgE/Fc epsilonRI/mast cell-mediated gastrointestinal and systemic anaphylaxis in response to ingested antigen. Gastrointestinal symptoms depend on serotonin and PAF; mediator dependence of systemic symptoms has not been determined. Both local and systemic anaphylaxis induced by ingested antigens might be blocked by IgA and IgG antibodies. IL-4 and IL-13 signaling through the IL-4 receptor alpha chain, in addition to promoting the mastocytosis and IgE antibody production that mediate most human anaphylaxis, exacerbates the effector phase of anaphylaxis by increasing target cell responsiveness to vasoactive mediators. As a result, IL-4 receptor alpha chain antagonists might be particularly effective suppressors of anaphylaxis.  相似文献   
130.
Summary For several years now, substantial efforts have been devoted to the development and the implementation of a screening program for breast cancer in the Canton of Vaud. A four-year pilot phase is now starting, involving two regional hospitals with their catchment areas; women over 50 and under 70 years old will be invited to participate in the program. A double view mammography will be made, with a double reading made by the hospital radiologists; a third reading will be made in case of discrepancy between the two first radiologists. Patients classified as positive for screening (e.g., with a suspect radiological image) will be referred to their practitioner for further diagnosis and treatment. The medical and public health background of this program is discussed, more specifically the reasons for developing a screening program, the choice of mammography rather than other tools, and the need to implement screening as an organized program.
Zusammenfassung Vertreter verschiedener medizinischer Fachgebiete bemühen sich seit einigen Jahren darum, für den Kanton Waadt ein Früherfassungsprogramm für den Brustkrebs auf die Beine zu stellen. In zwei Regionen des Kantons wird nun ein Pilotprojekt gestartet, das sich an die 50 bis 70jährigen Frauen richtet und vier Jahre dauern soll. Angeboten wird eine Mammographie in zwei Ebenen, die von zwei Röntgenologen unabhängig voneinander beurteilt werden wird (kommen die beiden Experten zu unterschiedlichen Beurteilungen, wird eine dritte Meinung eingeholt). Bei einem positiven Befund wird die betroffene Frau dem Hausarzt überwiesen, der die diagnostischen Abklärungen und nötigenfalls die Behandlung einleiten wird. Die medizinischen Grundlagen und der epidemiologische Hintergrund werden dargestellt; speziell erwähnt werden die Gründe für die Entwicklung eines Früherfassungsprogrammes und für die Wahl der Mammographie als Screeningmethode.

Résumé Depuis plusieurs années, un groupe réunissant les compétences de plusieurs disciplines médicales examine les possibilités d'implanter le dépistage du cancer du sein dans le Canton de Vaud. Un projet-pilote d'une durée de 4 ans va démarrer dans deux zones sanitaires du canton, adressé aux femmes âgées entre 50 et 70 ans: il s'agira d'une mammographie à double incidence et double lecture (avec une troisième lecture en cas de discordance entre les radiologues hospitaliers). Les femmes classées positives après l'examen de dépistage seront transférées à leur médecin traitant pour le diagnostic et, le cas échéant, le traitement. Le contexte médical et sanitaire de ce programme est discuté, en particulier les raisons spécifiques qui ont poussé les promoteurs à développer un programme organisé de dépistage par mammographie.


Paper presented at a symposium on The Public Health Perspective of Social and Preventive Medicine, in celebration of the 20th anniversary of the Department of Social and Preventive Medicine, University of Berne, 25 June 1992 in Berne.  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