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   9251篇
  免费   520篇
  国内免费   26篇
耳鼻咽喉   59篇
儿科学   148篇
妇产科学   234篇
基础医学   1220篇
口腔科学   235篇
临床医学   805篇
内科学   2331篇
皮肤病学   98篇
神经病学   1076篇
特种医学   312篇
外科学   972篇
综合类   104篇
一般理论   10篇
预防医学   803篇
眼科学   305篇
药学   654篇
  3篇
中国医学   8篇
肿瘤学   420篇
  2023年   66篇
  2022年   84篇
  2021年   191篇
  2020年   119篇
  2019年   173篇
  2018年   183篇
  2017年   111篇
  2016年   159篇
  2015年   149篇
  2014年   200篇
  2013年   386篇
  2012年   466篇
  2011年   530篇
  2010年   307篇
  2009年   308篇
  2008年   472篇
  2007年   516篇
  2006年   493篇
  2005年   541篇
  2004年   445篇
  2003年   411篇
  2002年   419篇
  2001年   203篇
  2000年   193篇
  1999年   183篇
  1998年   127篇
  1997年   91篇
  1996年   76篇
  1995年   72篇
  1994年   58篇
  1993年   64篇
  1992年   126篇
  1991年   116篇
  1990年   110篇
  1989年   90篇
  1988年   78篇
  1987年   71篇
  1986年   72篇
  1985年   70篇
  1984年   51篇
  1983年   65篇
  1982年   64篇
  1981年   67篇
  1980年   54篇
  1979年   53篇
  1978年   59篇
  1977年   56篇
  1975年   50篇
  1973年   46篇
  1970年   48篇
排序方式: 共有9797条查询结果,搜索用时 0 毫秒
71.
72.
73.
PurposeThe purpose of this study was to determine whether accommodation-induced changes in ciliary muscle dimensions vary between emmetropes and myopes, and the effect of the image analysis method.MethodsSeventy adults aged 18 to 27 years consisted of 25 people with emmetropia (spherical equivalent refraction [SER] +0.21 ± 0.36 diopters [D]) and 45 people with myopia (−2.84 ± 1.72 D). There were 23 people with low myopia (>−3 D) and 22 people with moderate myopia (−3 to −6 D). Right eye ciliary muscles were imaged (Visante OCT; Carl Zeiss Meditec) at 0 D and 6 D demands. Measures included ciliary muscle length (CML), ciliary muscle curved length (CMLarc), maximum ciliary muscle thickness (CMTmax), CMT1, CMT2, and CMT3 (fixed distances 1–3 mm from the scleral spur), CM25, CM50, and CM75 (proportional distances 25%–75%). Linear mixed model analysis determined effects of refractive groups, race, and demand on dimensions. Significance was set at P < 0.05.ResultsMyopic eyes had greater CML and CMLarc nasally than emmetropic eyes. Myopic eyes had thicker muscles than emmetropic eyes at nasal positions, except CM25 and CMT3, and at CM75 temporally. During accommodation and only nasally, CML reduced in emmetropic and myopic eyes, and CMLarc reduced in myopic eyes only. During accommodation, both nasally and temporally, muscles thickened anteriorly (CMT1 and CM25) and thinned posteriorly (CMT3 and CM75) except for temporal CM75. Moderate myopic eyes had greater temporal CMLarc than low myopic eyes, and the moderate myopes had thicker muscles both nasally and temporally using fixed and proportional distances.ConclusionsPeople with myopia had longer and thicker ciliary muscles than people with emmetropia. During accommodation, the anterior muscle thickened and the curved nasal muscle length shortened, more in myopic than in emmetropic eyes. The fixed distance method is recommended for repeat measures in the same individual. The proportional distance method is recommended for comparisons between refractive groups.  相似文献   
74.
The avidity of antibodies to DNA in the sera of 8 patients with SLE was determined by saturation analysis and Scatchard plots. Five of the patients had severe lupus nephritis; the other 3 had relatively mild or no kidney disease. The Scatchard plots revealed components with high relative avidity in the patients with severe nephritis (K values 4.4–10.4 x 105 M−1 for nDNA), compared with the patients who had mild or no kidney disease (K values 0.3–1.8 x 105 M−1 for nDNA). Avidity measurements may be helpful in the evaluation and treatment of patients with SLE.  相似文献   
75.
Thirty-one patients with 46 digital mucinous pseudocysts are reviewed. The pseudocysts are usually soft, fluctuant, dome-shaped, dimpled, smooth lesions located near and often associated with a linear defect of the fingernail. Transillumination confirms the diagnosis. Treatment is conservative, usually consisting of intralesional injections. If surgery is necessary, distal interphalangeal joint injection of methylene blue aids in complete removal by identifying the mesothelial-lined pedicle leading from the distal joint to the pseudocyst.  相似文献   
76.
77.
By decreasing plaque burden, atherectomy provides an alternative to angioplasty and stenting as a means of revascularizing patients with peripheral arterial disease. A new atherectomy device (SilverHawk) has recently been approved by the Food and Drug Administration, but the results with its use are unclear. We analyzed a series of consecutive patients undergoing atherectomy. We retrospectively reviewed the charts of 35 patients undergoing infrainguinal (IF) atherectomy in 38 limbs. The Trans-Atlantic Inter-Society Consensus (TASC) classification and Society of Vascular Surgery runoff scores were calculated. Time to event analysis was performed using Kaplan-Meier estimates. Risk factors affecting patency were analyzed with a multivariate Cox model. Mean patient age was 70 +/- 9.6 years. Indications for intervention were claudication (26%), rest pain (21%), and tissue loss (53%). Femoropopliteal (FP) atherectomy was performed in 68% and tibial atherectomy in 32%. For FP lesions, the TASC distribution was A, 42%; B, 23%; C, 4%; and D, 15%. The average lesion treatment length was 9.4 +/- 10.6 cm (range 1-40), and the runoff score was 5.1 +/- 3.5. For tibial lesions, the TASC distribution was A, 0%; B, 17%; C, 8%; and D, 75%. The average lesion treatment length was 9.2 +/- 6.0 cm (range 2-20), with a runoff score of 5.4 +/- 2.4. A total of 39% of patients had prior IF interventions. Adjunctive angioplasty of the atherectomized lesion was performed in 55% of cases, stenting in 0%, and adjunctive therapy for tandem lesions in 39%. The postoperative ankle-brachial index increased by 0.30 +/- 0.14 and toe pressures increased by 40 +/- 32.4 mm Hg. Mean follow-up was 10 +/- 8 months (range 0.3-23). During the studied period, seven patients required major limb amputation and five open surgical revascularization. Total primary and secondary patency rates were 66% and 70% at 1 year, respectively. Primary and secondary patency rates for FP atherectomy were 68% and 73% at 1 year, respectively. The limb salvage rate was 74% at 6 months. Patients with prior interventions in the atherectomized segment had an almost 10-fold decrease in primary patency. Atherectomy produces acceptable results, similar to those in reported series of conventional balloon angioplasty/stenting. Patients with prior IF interventions had a nearly 10-fold decrease in primary patency. A greater than sixfold decrease in patency rates was noted in patients who underwent simultaneous inflow or outflow procedures, but this finding did not reach statistical significance (p = 0.082). Future studies should focus on cost comparisons with other treatments such as angioplasty and stenting, and prospective randomized trials should be performed to compare these treatment alternatives.  相似文献   
78.
Computerized lung-sound analysis is a sensitive and quantitative method to identify wheezing by its typical pattern on spectral analysis. We evaluated the accuracy of the VRI, a multi-sensor, computer-based device with an automated technique of wheeze detection. The method was validated in 100 sound files from seven subjects with asthma or chronic obstructive pulmonary disease and seven healthy subjects by comparison of auscultation findings, examination of audio files, and computer detection of wheezes. Three blinded physicians identified 40 sound files with wheezes and 60 sound files without wheezes. Sensitivity and specificity were 83% and 85%, respectively. Negative predictive value and positive predictive value were 89% and 79%, respectively. Overall inter-rater agreement was 84%. False positive cases were found to contain sounds that simulate wheezes, such as background noises with high frequencies or strong noises from the throat that could be heard and identified without a stethoscope. The present findings demonstrate that the wheeze detection algorithm has good accuracy, sensitivity, specificity, negative predictive value and positive predictive value for wheeze detection in regional analyses with a single sensor and multiple sensors. Results are similar to those reported in the literature. The device is user-friendly, requires minimal patient effort, and, distinct from other devices, it provides a dynamic image of breath sound distribution with wheeze detection output in less than 1 minute.  相似文献   
79.
80.
Epidemiologic Survillance of Cardiovascular Disease Mollar G, Cavalieri L, Galarza C, Waisman G, Beratarrechea A, Petrlik E, Langlois E, Soriano F, Marchetti M, and Gonzalez B de Quirós F Programas Médicos de Plan de Salud del Hospital Italiano de Buenos Aires

To enhance efficacy of health care, surveillance activities are required, especially with chronic prevalent diseases. Epidemiologic surveillance allows US to quantify and qualify health problems, settle priorities, identify high risk groups, manage and monitor health care systems, detect frequency changes in events, and assess performance of prevention and disease management programs. We have developed a surveillance system that identifies and reports daily on patients having cardiovascular disease (CVD) who are uncontrolled.

Objective: To evaluate the accomplishment of blood pressure (BP) measurement in people with CVD belonging to a health care system included in an epidemiological surveillance list.

Design: Cohort study between 1/1/2004 and 9/1/2004.

Methods: Patients 60 years old or older identified by surveillance system during the first term of 2004, were followed up. Patients were identified as having CVD through electronic medical record using international classification for primary attention (ICPA).

Patients are reported by the software system when presenting any of the following criteria: no blood pressure record during the past 6 months, blood pressure above 140/90 in the last record, and if diabetic A1C above 7.5%.

The connection with the appointment system allowed us to detect previously the patient’s attendance and, 15 min before his or her medical appointment, send the patient to be examined by the executors of a chronic disease program, according to the JNC VII guidelines.

The BP measurement is a common intervention to most chronic diseases because it increases cardiovascular risk, hence it is considered a process indicator of the surveillance system.

Results: Of the 24,411 patients having CVD, 5506 (26%) were listed during the first term, mean age was 74 years and 65% were female. By the end of 2004, 4660 (85%) patients had blood pressure recorded with an average values of 136.76 mmHg for systolic and 77.51 for diastolic blood pressure. Blood pressure was assessed three times in average.

Conclusion: Surveillance system allowed identifying of and intervening in a high proportion of patients.  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