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   22534篇
  免费   1547篇
  国内免费   52篇
耳鼻咽喉   181篇
儿科学   664篇
妇产科学   645篇
基础医学   3427篇
口腔科学   723篇
临床医学   2771篇
内科学   3961篇
皮肤病学   561篇
神经病学   2131篇
特种医学   480篇
外国民族医学   2篇
外科学   2265篇
综合类   150篇
一般理论   41篇
预防医学   2313篇
眼科学   321篇
药学   1725篇
中国医学   47篇
肿瘤学   1725篇
  2023年   186篇
  2022年   398篇
  2021年   665篇
  2020年   371篇
  2019年   633篇
  2018年   664篇
  2017年   481篇
  2016年   582篇
  2015年   550篇
  2014年   805篇
  2013年   1085篇
  2012年   1509篇
  2011年   1581篇
  2010年   859篇
  2009年   748篇
  2008年   1256篇
  2007年   1247篇
  2006年   1250篇
  2005年   1184篇
  2004年   1024篇
  2003年   894篇
  2002年   887篇
  2001年   330篇
  2000年   349篇
  1999年   335篇
  1998年   193篇
  1997年   167篇
  1996年   131篇
  1995年   139篇
  1994年   135篇
  1993年   117篇
  1992年   231篇
  1991年   253篇
  1990年   223篇
  1989年   217篇
  1988年   217篇
  1987年   206篇
  1986年   207篇
  1985年   209篇
  1984年   136篇
  1983年   146篇
  1982年   106篇
  1981年   111篇
  1980年   91篇
  1979年   123篇
  1978年   109篇
  1977年   104篇
  1976年   73篇
  1975年   68篇
  1974年   75篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
We present an adenoid cystic carcinoma of the base of tongue in a 48-year-old male with a restricted chromosomal alteration by cytogenetic and spectral karyotypic analysis (SKY). SKY and G-banding analyses identified the t(6;14)(q25;q13) as the sole structural aberration in all metaphases analyzed. This finding supports a critical role for this event in the development of this tumor. The implications of chromosome 6q translocation in this case and in previously reported adenoid cystic carcinomas are highlighted and discussed.  相似文献   
72.
73.

Objective

Participation in evidenced‐based arthritis self‐management programs (SMPs) has not been well documented. The purpose of this study was to investigate the participation rate and participant characteristics in a closed cohort of subjects in a geographic region where arthritis SMPs have been offered multiple times and continuously for 2 decades.

Methods

Data were from osteoarthritis (OA) and rheumatoid arthritis subjects participating in the Arthritis, Rheumatism, and Aging Medical Information System (ARAMIS) who resided in the San Francisco (SF) Bay area who had responded to questions about ever participating in an SMP. Differences between participants and nonparticipants were examined by t‐tests and chi‐square tests.

Results

Questions added to the Health Assessment Questionnaire were returned by 1,176 patients; 618 resided in the SF Bay area. Of the SF Bay area sample, 41.9% had participated in an SMP. Small group SMPs, which had been offered multiple times, in diverse settings, continuously over the past 2 decades, were attended by the highest proportion (28%) of participants. Characteristics of participants and nonparticipants in the SF Bay area were similar (~70 years old, 15 years of education, and the majority had OA [~72%]). However, a higher proportion of participants were white (88% versus 82%; P = 0.046) and female (82% versus 73%; P < 0.05).

Conclusion

When arthritis SMPs were offered multiple times in diverse settings and continuously over many years, >40% of the cohort was reached. More research is needed with larger samples and different geographic regions to identify participation rates in more diverse populations.  相似文献   
74.
In this ongoing study, patients with an estimated prostate size of no more than 20 gm are randomized to undergo either transurethral resection of the prostate (TURP) or transurethral incision (TUIP) at the 6 o'clock position. To date, 93 patients have been included, and 3 months postoperatively, 80 to 90 per cent of the patients in each group reported improvement. There was also a significant decrease in symptom scores and a significant increase in maximum urinary flow rate, with great variation within each group but without difference between the groups. In both groups, there appears to be some deterioration over time. Operating time, estimated blood loss, time to catheter removal postoperatively, and duration of postoperative hospital stay were all significantly in favor of TUIP. Loss of ejaculation was reported by 37 per cent of patients after TURP and by 13 per cent after TUIP (not statistically significant). There was no difference between the groups in the need for further surgery. Therefore, TUIP is recommended as an alternative to TURP in patients with small prostates.  相似文献   
75.
We studied 14 eyes of 14 patients undergoing argon laser peripheral iridotomy for occludable (narrow) anterior chamber angles. Preoperative and postoperative pachymetry and corneal endothelial cell counts by specular microscopy were obtained centrally and in both the treated and nontreated superior quadrants. No significant differences were found between preoperative and postoperative measurements of corneal thickness and endothelial cell counts in any area.  相似文献   
76.
Efficacy of Intraoperative Cooling Methods   总被引:3,自引:0,他引:3  
Background: Patients may require perioperative cooling for a variety of reasons including treatment of a malignant hyperthermia crisis and induction of therapeutic hypothermia for neurosurgery. The authors compared heat transfer and core cooling rates with five cooling methods.

Methods: Six healthy volunteers were anesthetized with desflurane and nitrous oxide. The cooling methods were 1) circulating water (5 [degree sign] Celsius, full-length mattress and cover), 2) forced air (10 [degree sign] Celsius, full-length cover), 3) gastric lavage (500 ml iced water every 10 min), 4) bladder lavage (300 ml iced Ringer's solution every 10 min), and 5) ice-water immersion. Each method was applied for 40 min or until the volunteers' core temperatures approached 34 [degree sign] Celsius. The volunteers were rewarmed to normothermia between treatments. Core cooling rates were evaluated using linear regression.

Results: The first volunteer developed abdominal cramping and diarrhea after gastric lavage. Consequently, the technique was not again attempted. Bladder lavage increased heat loss 10 [nearly =] 10 W and decreased core temperature 0.8 +/- 0.3 [degree sign] Celsius/h (r2 = 0.99 +/- 0.002; means +/- SD). Forced-air and circulating-water cooling comparably increased heat flux, [nearly =] 170 W. Consequently, core cooling rates were similar during the two treatments at 1.7 +/- 0.5 [degree sign] Celsius/h (r2 = 0.99 +/- 0.001) and 1.6 +/- 1.1 [degree sign] Celsius/h (r2 = 0.98 +/- 0.02), respectively. Immersion in an ice water slurry increased heat loss [nearly =] 600-800 W and decreased core temperature 9.7 +/- 4.4 [degree sign] Celsius/h (r sup 2 = 0.98 +/- 0.01). Immersion cooling was associated with an afterdrop of [nearly =] 2 [degree sign] Celsius.  相似文献   

77.
OBJECTIVE: The purpose of this study was to compare the preparation costs of two common methods used for neonatal red blood cell transfusion aliquots. METHODS: Three months of data from a Level 2 and Level 3 neonatal intensive care unit (NICU) were used to determine the comparative cost for red cell aliquot transfusions using an eight bag aliquot/transfer system or the syringe set system. Using leuko-poor red blood cell blood collected in Adsol and containing approximately 320 ml of red blood cells and supernatant solution, the average cost of neonatal transfusion aliquots was determined using the Charter Medical syringe set and the Charter Medical eight bag aliquot/transfer system. RESULTS: A total of 126 red blood cell transfusion aliquots were used over the three month period. The amount transfused with each aliquot ranged from 5.0 ml - 55.0 ml with an average of 24.0 ml per aliquot. The cost per aliquot using the eight aliquot/transfer set was calculated as $36.25 and the cost per aliquot using the syringe set cost was calculated as $30.71. Additional benefits observed with the syringe set included decreased blood waste. CONCLUSION: When comparing Charter Medical multiple aliquot bag sets and the Charter Medical syringe aliquot system to provide neonatal transfusions, the use of the syringe system decreased blood waste and proved more cost effective.  相似文献   
78.
Binding of [3H]Ro 5-4864 to mitochondrial membrane preparations of rat cerebral cortex was measured after repeated (5 days) IV administration of diazepam (10 mg/kg daily) and clonazepam (2.5 mg/kg daily). The B(max) value for [3H]Ro 5-4864 was significantly reduced in rats treated with diazepam (-49%) but not in those treated with clonazepam. These findings suggest the involvement of peripheral-type binding sites in the development of rapid tolerance to the sedative effects of benzodiazepines. A downregulation of [3H]Ro 5-4864 (-65%) was also observed after repeated administration of Ro 5-4864 (4 mg/kg daily), thus confirming that this compound behaves as an agonist at its own recognition sites.  相似文献   
79.
The circulating concentration of 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] is a physiologic index of enzymatic activity of the renal 1-hydroxylase of 25-hydroxychole-calciferol (25-OH-D3). Hydroxylation of 25-OH-D3 and circulating 1,25-(OH)2D3 are decreased in the streptozotocin diabetic rat. We previously found that activity of another redox enzyme system, cytosolic superoxide dismutase, also decreased in streptozotocin diabetes, can be restored by treatment with glutathione. In the present experiment we tested the effect of glutathione treatment on vitamin D metabolism in control and diabetic rats. Enteral glutathione increased circulating 1,25-(OH)2D3 and decreased 25-OH-D3 in both control and diabetic animals. These results suggest that exogenous glutathione increases 25-OH-D3 1-hydroxylation both under basal conditions in the normal animal and in diabetes-induced depression.  相似文献   
80.
Lambs harbouring an 8-week-old infection with Fasciola hepatica, together with fluke-free animals, were dosed orally with 2 g per kg body weight of sawfly larvae (Arge pullata). Fluke-free, non-dosed lambs and lambs infected only with F. hepatica served as controls. Clinico-pathological observations on sawfly-dosed, fluke-free lambs revealed the characteristic picture of sawfly poisoning. Four of six animals had to be killed in extremis. In contrast, sawfly-dosed, fluke-infected lambs exhibited only moderate clinico-pathological signs of sawfly poisoning and no deaths occurred. A reduction in the sawfly-induced liver pathology as a consequence of the concurrent F. hepatica infection was also noted. Possible factors responsible for the antagonistic effect of F. hepatica infection on sawfly poisoning in lambs are discussed.  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