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   5802篇
  免费   631篇
  国内免费   169篇
耳鼻咽喉   60篇
儿科学   244篇
妇产科学   163篇
基础医学   151篇
口腔科学   94篇
临床医学   1274篇
内科学   1322篇
皮肤病学   135篇
神经病学   330篇
特种医学   193篇
外科学   1630篇
综合类   15篇
预防医学   361篇
眼科学   327篇
药学   52篇
肿瘤学   251篇
  2023年   107篇
  2021年   70篇
  2020年   98篇
  2019年   47篇
  2018年   127篇
  2017年   176篇
  2016年   191篇
  2015年   142篇
  2014年   226篇
  2013年   310篇
  2012年   105篇
  2011年   127篇
  2010年   237篇
  2009年   345篇
  2008年   140篇
  2007年   75篇
  2006年   116篇
  2005年   87篇
  2004年   43篇
  2003年   54篇
  2002年   56篇
  2001年   114篇
  2000年   87篇
  1999年   149篇
  1998年   188篇
  1997年   209篇
  1996年   305篇
  1995年   258篇
  1994年   201篇
  1993年   119篇
  1992年   132篇
  1991年   145篇
  1990年   76篇
  1989年   139篇
  1988年   115篇
  1987年   92篇
  1986年   113篇
  1985年   92篇
  1984年   93篇
  1983年   78篇
  1982年   69篇
  1981年   64篇
  1980年   82篇
  1979年   48篇
  1978年   66篇
  1977年   43篇
  1976年   47篇
  1975年   46篇
  1964年   49篇
  1963年   47篇
排序方式: 共有6602条查询结果,搜索用时 15 毫秒
61.
A retrospective study of all ileogastrostomy procedures (n=26) performed in 1993 by one surgeon (IGMC) was carried out to investigate the hypothesis that Helicobacter pylori may be implicated in certain severe cases of postoperation nausea and diarrhea. Ten of 26 persons (38.5%) displayed nausea and notable diarrhea (greater than or equal to ten bowel movements per day), seven of which warranted upper GI investigation. One hundred per cent (seven of seven) of these persons were found to possess H. pylori upon C-14 breath test. In four of six cases eradication therapy (1 g amoxicillin b.i.d./20 mg omeprazole b.i.d. for 2 weeks) corresponded with a resolution of severe nausea and diarrhea (one additional case involved omeprazole use only), suggesting that H. pylori should be considered as a possible cause of these symptoms post-ileogastrostomy. Additionally, in four of seven cases persons were re-tested (C-14 breath analysis) at least 1 month post-therapy and in this group three persons were found to be free of the organism. All three cases of notable diarrhea and nausea resolved with treatment, providing the strongest evidence for a possible association between infection and these symptoms.  相似文献   
62.
Public involvement in health care priority setting: an economic perspective   总被引:1,自引:1,他引:0  
Background  Public involvement in health care decision making and priority setting in the UK is being promoted by recent policy initiatives. In 1993, the British Medical Association called for public consultation where rationing of services was to be undertaken. The approach to priority setting advocated by many health economists is the maximization of quality adjusted life years (QALYs). Typically, for a particular health care programme, the QALY calculation takes account of four features: (1) the number of patients receiving the programme, (2) the survival gain, (3) the gain in quality of life and, (4) the probability of treatment success. Only one feature, that relating to quality of life, is based upon public preferences. If the QALY is to be used as a tool for health care resource allocation at a societal level then it should incorporate broader societal preferences.
Methods  This study used an interview-based survey of 91 members of the general public to explore whether the traditional QALY maximization model is a good predictor of public responses to health care priority setting choices.
Results and conclusions  Many respondents did not choose consistently in line with a QALY maximization objective and were most influenced by quality of life concerns. There was little support for health care programmes that provided a prognostic improvement but left patients in relatively poor states of health. The level of respondent engagement in the survey exercise was not sensitive to the provision of supporting clinical information.  相似文献   
63.
Our aim was to examine the feasibility of a totally laparoscopic insertion of a bifurcated aortofemoral bypass graft in a canine model and to compare the surgical results with those in control animals undergoing standard grafting and laparoscopic-assisted bypass procedures. Using a six-port approach, we exposed and cross clamped the aorta, tunneled a bifurcated Dacron graft, and performed an end-to-end aortic anastomosis while maintaining pneumoperitoneum by means of CO2. Proximal anastomoses were performed with 4/0 double-ended continuous Prolene sutures and distal anastomoses were performed through standard groin incisions. Total operating and aortic cross-clamp times were measured as was the total blood loss for each procedure. Clinical outcome was also documented. Eight female laboratory-bred hounds underwent successful totally laparoscopic aortobifemoral bypass grafting, eight underwent open grafting, and eight underwent laparoscopic-assisted bypass. Mean operating time was 193 minutes in the animals undergoing totally laparoscopic insertion vs. 156 minutes in the open group and 180 minutes in the laparoscopic-assisted group. Aortic cross-clamping time was also significantly longer at 87 minutes vs. 43 minutes (p < 0.001)=" in=" the=" totally=" laparoscopic=" group,=" but=" blood=" loss=" was=" less.=" all=" eight=" laparotomy=" and=" laparoscopic-assisted=" dogs=" were=" still=" alive=" with=" no=" complications=" at=" 28=" days,=" whereas=" three=" of=" the=" eight=" in=" the=" totally=" laparoscopic=" group=" showed=" evidence=" of=" temporary=" paraplegia.=" this=" experimental=" study=" demonstrates=" that=" a=" totally=" laparoscopic=" approach=" can=" be=" used=" to=" insert=" a=" bifurcated=" aortofemoral=" bypass=" with=" a=" proximal=" end-to-end=" anastomosis=" but=" currently=" does=" not=" save=" time=" and=" may=" increase=" the=" risk=" of=" neurologic=">Presented at the Twentieth Annual Meeting of the Peripheral Vascular Surgery Society, New Orleans, La., June 10, 1995.  相似文献   
64.
The success of vertical gastroplasty may be jeopardized by gastric leakage or ulceration due to failure of the technique. Reports of band erosion and staple-line leakage have led us to seek technical improvements to reduce technical failures. We describe a modification to the technique of band placement and a manoeuvre to aid the placement of staples when the TA90 staple gun is used.  相似文献   
65.
Many forms of gastric banding have been described and high reoperation rates reported. These can be mainly attributed to excess vomiting associated both with and without stenosis. Reflux oesophagitis and the ‘sump’ effect may be other causes. This paper examines the problems associated with banding leading to revisional surgery and introduces a new technique, ‘fundal supporting suture’, to correct these problems. Preliminary results on 126 bandings without the modification and 22 with the modification are presented.  相似文献   
66.
Increased placental apoptosis in intrauterine growth restriction   总被引:2,自引:0,他引:2  
OBJECTIVES: Our purpose was to investigate a possible role for apoptosis in the pathophysiologic mechanisms of intrauterine growth restriction. STUDY DESIGN: Placental samples were obtained from 43 uncomplicated third-trimester pregnancies and from 26 pregnancies complicated by intrauterine growth restriction. The definition used to identify cases of intrauterine growth restriction depended on three criteria: clinical evidence of suboptimal growth, ultrasonographic evidence of deviation from an appropriate growth percentile, and individualized birth weight ratios <10th percentile. Light microscopy was used to quantify the incidence of apoptosis. Electron microscopy and TUNEL (terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick end labeling) staining were used to confirm the occurrence of apoptosis. RESULTS: Quantification of apoptosis (medians and interquartile ranges) resulted in the following values: normal third trimester (n = 43) 0.14% of cells (0.08% to 0.20%) and intrauterine growth restriction third trimester (n  = 26) 0.24% of cells (0.16% to 0.29%). The incidence of apoptosis was significantly higher in placentas from pregnancies with intrauterine growth restriction compared with normal third-trimester placentas (p < 0.01, Mann Whitney U test). CONCLUSIONS: These results suggest that apoptosis may play a role in the pathophysiologic mechanisms of intrauterine growth restriction.(Am J Obstet Gynecol 1997;177:401)  相似文献   
67.
CONTEXT: Despite advances in early detection and prevention of cervical cancer, women living in rural areas, and particularly in Appalachia, the rural South, the Texas/Mexico border, and the central valley of California, have had consistently higher rates of cervical cancer mortality than their counterparts in other areas during the past several decades. METHODS: This paper reviews the published literature from 1966 to July 2002 to assess three potential pathways underlying this excess mortality--high human papilloma virus (HPV) prevalence, lack of or infrequent screening and advanced disease at diagnosis, and under-use of recommended treatment and shorter survival. FINDINGS: Living in rural areas may impose barriers to cervical cancer control, including lack of transportation and medical care infrastructures. Population characteristics that place women at greater risk for developing and dying from cervical cancer, such as low income, lack of health insurance, and physician availability, are concentrated in rural areas. Published data, however, are insufficient to identify the key reasons for the observed mortality patterns. CONCLUSIONS: At this time, given the lack of definitive evidence in the published literature, decisions about priorities in areas with high rates of cervical cancer mortality will depend on knowledge of current levels of screening, incidence, and stage distribution; and service delivery infrastructures, resources, and acceptability of interventions to the target population.  相似文献   
68.
69.
A TEN-YEAR HOSPITAL SURVEY OF EYELID CANCER   总被引:1,自引:0,他引:1  
Two hundred and four cases of malignant eyelid tumours, managed at the Concord Hospital, were reviewed. These cases spanned a ten-year period between 1973 and 1982 and all were treated surgically. The nature of each tumour was confirmed by histopathological examination. Included in this review were the site of the tumour, the tumour pathology, the surgical management, the type of surgeon involved, the ocular complications, the management of recurrences and any mortality. The importance of preventing recurrences by adequate initial surgery with frozen section control is emphasized.  相似文献   
70.
Exophthalmometry, the quantitative assessment of the position of the globe in the orbit, is a clinically useful measurement. The purpose of this study was to examine the performance of a simple exophthal-mometer that would lend itself to accurate and convenient use in clinical practice. In this study, two observers independently performed exophthalmometry on 100 eyes using the Hertel and Luedde instruments. The results were compared between instruments and between observers. There was no statistically or clinically significant difference between measurements taken with the Luedde as compared with the Hertel instrument. The Luedde exophthal-mometer has a number of advantages over the Hertel exophthalmometer, and represents a simple, inexpensive and equally reliable means of evaluating clinically the anteroposterior position of the eye in the orbit.  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