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   2724篇
  免费   224篇
  国内免费   16篇
耳鼻咽喉   13篇
儿科学   87篇
妇产科学   66篇
基础医学   351篇
口腔科学   35篇
临床医学   250篇
内科学   406篇
皮肤病学   40篇
神经病学   209篇
特种医学   255篇
外科学   422篇
综合类   126篇
一般理论   14篇
预防医学   429篇
眼科学   31篇
药学   91篇
中国医学   1篇
肿瘤学   138篇
  2022年   26篇
  2021年   54篇
  2020年   29篇
  2019年   46篇
  2018年   65篇
  2017年   41篇
  2016年   50篇
  2015年   66篇
  2014年   75篇
  2013年   105篇
  2012年   123篇
  2011年   132篇
  2010年   91篇
  2009年   94篇
  2008年   103篇
  2007年   110篇
  2006年   92篇
  2005年   89篇
  2004年   72篇
  2003年   77篇
  2002年   91篇
  2001年   64篇
  2000年   90篇
  1999年   55篇
  1998年   61篇
  1997年   60篇
  1996年   52篇
  1995年   41篇
  1994年   32篇
  1993年   25篇
  1992年   85篇
  1991年   65篇
  1990年   64篇
  1989年   65篇
  1988年   61篇
  1987年   55篇
  1986年   56篇
  1985年   40篇
  1984年   35篇
  1983年   38篇
  1982年   19篇
  1981年   23篇
  1978年   22篇
  1977年   17篇
  1976年   16篇
  1975年   19篇
  1974年   19篇
  1973年   17篇
  1972年   21篇
  1970年   15篇
排序方式: 共有2964条查询结果,搜索用时 15 毫秒
1.
Our objective was to determine the inter-examiner agreement of a simplified pelvic organ prolapse quantification (POPQ) exam and to assess its correlation with the standard POPQ exam. This study consists of two parts; both were preformed in a prospective, randomized, blinded fashion on women presenting with complaints attributed to pelvic organ support defects. The first study was done to determine the inter-examiner reliability of a simplified POPQ exam. The simplified POPQ exam is based on the POPQ with similar ordinal staging but with only four points measured instead of nine. Forty-eight women underwent exams by five different investigators. The order of exams was randomized and the examiners were blinded to the results of each other’s findings. The results of these two exams were compared using weighted kappa statistics. The second part of the study was done to determine the inter-system agreement between the simplified vs standard POPQ exam. A group of 49 women were examined by four different investigators: one using the simplified and the other using standard POPQ exams. The order of the exams was randomized and the examiners were blinded to the results of each other’s exam. Kendall’s tau-b statistics were used to determine the inter-system agreement. For the inter-examiner reliability of the POPQ exam, the average age was 60±13 years. The weighted kappa statistics for the inter-examiner reliability of the simplified prolapse classification system were 0.86 for the overall stage, 0.89 and 0.86 for the anterior and posterior vaginal walls, respectively, 0.82 for the apex/cuff, and 0.72 for the cervix. All demonstrate significant agreement. For the inter-system association between the simplified POPQ and standard POPQ, the average age was 61±15 year. The Kendall’s tau-b value for overall stage was 0.90, 0.83, and 0.87 for the anterior and posterior walls respectively, and 0.78 for the cuff/apex and 0.98 for the cervix. There is good inter-examiner agreement of a simplified POPQ classification system and it appears to have good inter-system association with the POPQ.IUGA Standardization of Terminology Committee members: Robert Freeman MD (chairman), Steven Swift, Eckhard Petri MD, Richard J. Scotti MD, and Peter Dwyer MD.  相似文献   
2.
The clinical and histological findings in an animal model of ocular cell mediated immune responses are described. These were evoked in sensitised guinea-pigs by dropping tuberculin into the conjunctival sac or injecting it under the palpebral conjunctiva. When tuberculin was dropped into the conjunctival sac, higher doses were required to evoke a strong response than when it was injected subconjunctivally. When high doses of antigen were used for challenge, a mild response was observed in unchallenged contralateral eyes. The cellular response at low doses of tuberculin consisted predominantly of mononuclear cells. At higher doses the cellular infiltrate was more pronounced, and polymorphonuclear cells tended to predominate 24 hours after challenge, while at 48 hours mononuclear cells predominated.  相似文献   
3.
4.
Breast pumps are medical devices used to express milk and maintain the milk supply. The purpose of this study was to characterize adverse events reported to the United States Food and Drug Administration (FDA) on breast pumps. Thirty-seven adverse event reports on breast pumps were identified from the Manufacturer and User Facility Device Experience database between 1992 and 2003. Four additional reports were found in the Device Experience Network database from 1992 to 1996. The most commonly reported adverse events for electric breast pumps were pain, soreness, or discomfort; the need for medical intervention; and breast tissue damage. Most frequently reported problems for manual breast pumps were breast tissue damage and infection. Contamination of breast milk during pumping was also reported. Breast pump adverse events are likely underreported to the FDA. Reporting adverse events is important for improving the design and manufacture of breast pumps and subsequently decreasing adverse events.  相似文献   
5.
The successful use of guided percutaneous needle aspiration in the management of four patients with solitary splenic abscess is described. Two patients had needle aspiration alone and two patients, with large splenic abscesses, had drainage tubes inserted. The procedures were well tolerated and allowed rapid microbiological diagnosis with selection of appropriate antibiotic therapy. The techniques were useful in patients felt to be poor anaesthetic risks, and the complications of splenectomy were avoided.  相似文献   
6.
Exercise is associated with a reduced risk of coronary heart disease, has beneficial effects on cardiovascular risk factors, and has other health benefits. No more than 10 per cent to 20 per cent of adults in Australia and other developed countries participate in regular vigorous physical activity, while over 65 per cent of Australian adults are almost totally sedentary. Survey data from the U.S.A. suggest that levels of participation in jogging and walking have increased in the past 10 years but that the proportion of people who take no deliberate exercise has also increased. Large-scale community interventions to promote exercising have not been subject to rigorous evaluation and it is difficult to reach any firm conclusions about the effects of exercise promotion. However, it is possible to identify some of the factors which may influence exercise participation, and there is information from trials of large-scale, multifactorial interventions to reduce cardiovascular risk which provides some helpful guidelines about how it may be useful to proceed. Approaches to increasing levels of exercise participation should emphasise community-based efforts which provide appropriate settings and social support for exercising, making exercise a more appealing and accessible option for large numbers of people; the use of mass media for community education about exercising should be co-ordinated carefully with specific community activities. Personalized fitness instruction, groups and classes should place more emphasis on exercise as a pattern of behaviour to be integrated into a person's way of life and maintained over time; and there is the potential for more widespread and systematic use of self-instructional exercise materials to assist people who wish to exercise independently. Because there exist only limited local research findings and work in other countries does not yet provide conclusive information, research and development priorities for these areas are suggested.  相似文献   
7.
Subacute (daily) administration of diisopropylfluorophosphate (DFP) to male swine (Yorkshire white) resulted in a 97% inhibition of cholinesterase and a decrease of [3H]quinuclidinyl benzilate [( 3H]QNB) binding sites in homogenates of striata by approximately 50% after 14 days. The maximal density of receptors (Bmax) decreased from 2.1 +/- 0.3 to 1.0 +/- 0.2 pmole/mg protein. There was no significant change in the dissociation constant (Kd) for [3H]QNB binding (control: 52.6 +/- 10.7 pM; 7-day: 57 +/- 2.8 pM). Carbachol displacement of [3H]QNB binding yielded data best fit by a two-binding site model. The dissociation constants were KiL = 115 +/- 62 microM (55 +/- 3%) and KiH = 1.8 +/- 0.7 microM (45 +/- 3%), respectively, for the low- and high-affinity states. Seven-Day treatment with DFP reduced the percentage of high-affinity receptors to 22 +/- 8.6%, but affected neither the low- nor the high-affinity Kd (100 +/- 20 and 2 +/- 0.6 microM). With the addition of Mg2+, striatal homogenates had low- and high-affinity receptors in the proportion of approximately 1 to 1. In the presence of Gpp(NH)p + Mg2+ the ratio of high- to low-affinity receptors was 3:1 in homogenates of control tissue (to 26 +/- 5%). This treatment had no effect on this ratio in homogenates of tissue from 7-day DFP-treated swine (3:1) since it was already 3:1. Pirenzepine displacement of [3H]QNB binding was best described by a two-binding site model, with Ki values of 38 +/- 14 and 201 +/- 78 nM, which represent 74 and 26% of the binding sites, respectively. The high affinity Kd value was unchanged following 7 days of DFP treatment (24 +/- 5 nM). There appears to be little change in the displacement curves for pirenzepine inhibition of [3H]QNB binding. This suggests that about 75% of the receptors are of the M1 subtype. Thus, subacute administration of DFP causes not only a decrease in the number of receptors, but also a change in the proportion of agonist affinity states which is related to the interaction of the guanine nucleotide binding protein and the muscarinic receptor.  相似文献   
8.
Background: Ventral abdominal wall hernias are a common cause of morbidity and mortality. Opinion varies as to appropriate management. A recent consensus meeting on incisional hernia identified the need to standardise repair. On this background, a survey of current practice was performed. Method: A questionnaire was sent to 101 practicing general surgeons within the West of Scotland. Incisional, epigastric and para-umbilical defects were subdivided into defect size <2, 2–5 and >5 cm. The surgeons were asked to indicate the most appropriate repair (suture, mayo or mesh) for each. The influence of reducibility on the decision to repair was also assessed. Results: Sixty-one of 101 questionnaires were returned valid giving a response rate of 60%. Suture repair was significantly more likely to be used in all defects <2 cm (P<0.001). Mesh repair was significantly more likely to be recommended in all defects >5 cm (P<0.001). Of defects >5-cm, mesh was recommended for 90% of incisional hernia compared with 81% of epigastric and 76% of para-umbilical hernia (P<0.001). There was no significant difference in choice of repair for defect size 2–5 cm with opinion divided between suture and mesh. Irreducibility increased the likelihood of recommendation for repair. Conclusion: This survey shows a lack of consensus on the appropriate repair of ventral abdominal wall hernia amonge practicing consultant general surgeons. This reflects the contrasting views within the current literature.  相似文献   
9.
There are few options now available to treat patients with severe genuine stress incontinence caused by urethral failure. These patients usually have a low maximum urethral closure pressure (less than 20 cm of water) and anterior vaginal wall scarring caused by previous surgery. In 32 such patients we used the Martius fat pad insertion procedure, in addition to the Stamey procedure, and achieved a 91% symptomatic success rate over a mean 13-month follow-up period. Because of its simplicity, reliability and low morbidity, we recommend this procedure in this difficult group of patients before performing a sling procedure or insertion of an artificial urinary sphincter.  相似文献   
10.
Questionable dietary remedies for cancer decreased quality of life and did nothing to improve cancer outcomes in patients with extensive disease.  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