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   268篇
  国内免费   16篇
耳鼻咽喉   28篇
儿科学   46篇
妇产科学   51篇
基础医学   408篇
口腔科学   71篇
临床医学   359篇
内科学   530篇
皮肤病学   39篇
神经病学   243篇
特种医学   147篇
外科学   314篇
综合类   69篇
一般理论   1篇
预防医学   251篇
眼科学   72篇
药学   190篇
中国医学   1篇
肿瘤学   188篇
  2022年   19篇
  2021年   42篇
  2020年   18篇
  2019年   40篇
  2018年   61篇
  2017年   37篇
  2016年   30篇
  2015年   54篇
  2014年   50篇
  2013年   79篇
  2012年   124篇
  2011年   103篇
  2010年   75篇
  2009年   91篇
  2008年   122篇
  2007年   100篇
  2006年   97篇
  2005年   106篇
  2004年   113篇
  2003年   91篇
  2002年   82篇
  2001年   91篇
  2000年   81篇
  1999年   81篇
  1998年   53篇
  1997年   56篇
  1996年   42篇
  1995年   47篇
  1994年   24篇
  1993年   27篇
  1992年   64篇
  1991年   67篇
  1990年   60篇
  1989年   74篇
  1988年   56篇
  1987年   45篇
  1986年   59篇
  1985年   67篇
  1984年   47篇
  1983年   44篇
  1982年   34篇
  1981年   18篇
  1980年   25篇
  1979年   34篇
  1978年   28篇
  1976年   18篇
  1975年   28篇
  1973年   24篇
  1971年   17篇
  1969年   21篇
排序方式: 共有3008条查询结果,搜索用时 15 毫秒
111.
BackgroundIntercostal nerve blockade (INB) for thoracic surgery analgesia has gained popularity in practice, but evidence demonstrating its efficacy remains sparse and inconsistent. We investigated the effect of INB with standard bupivacaine (SB) with epinephrine versus liposomal bupivacaine (LB) versus a mixed solution of the two on postoperative pain control and outcomes in video assisted thoracoscopic lobectomy patients.MethodsSince 2014, our practice has shifted from using INBs with SB with epinephrine, to LB, to a mix of the two as the central component of multimodal analgesia after video assisted thoracoscopic surgery. The blocks are performed in a standardized fashion under thoracoscopic visualization consecutively from two rib spaces above to two below the outermost incisions. We retrospectively compared all minimally invasive lobectomies performed at our institution between January 2014 and July 2018 by type of local anesthetic used for INB. We examined median length of stay (LOS), opioid utilization, and subjective pain scores [0–10].ResultsOut of 302 minimally invasive lobectomy patients, 34 received SB with epinephrine, 222 received LB alone, and 46 received the mixed solution. LOS was almost a full day shorter in the LB group than in the SB group (34.8 vs. 56.5 hours, P=0.01). There was nearly 25% lower median total morphine equivalent utilization in the mixed solution cohort compared to the LB cohort (−7.1 mg, P=0.02). Additionally, IV morphine equivalent utilization was over 50% lower in the mixed solution group than in the SB with epinephrine group (−10.0 mg, P=0.03).ConclusionsOur study is by far the largest (N=302) to compare types of local anesthetic used for INB within a uniform case population. The reductions in LOS and opiate utilization observed in our study among patients receiving LB-based formulations were both statistically and clinically significant.  相似文献   
112.
113.
The efficacy of the non-steroidal anti-inflammatory analgesic, ketorolac (Toradol), was investigated in 52 day case patients undergoing removal of impacted third molar teeth under intravenous sedation and local analgesia. The study was double-blind, randomized and placebo-controlled. A single 30 mg dose of ketorolac was administered intravenously just prior to induction of sedation with midazolam. Ketorolac was well tolerated and provided good postoperative analgesia. It is suggested that ketorolac is a useful addition to the analgesic armamentarium and appropriately prescribed, provides good pain relief following day case oral surgery.  相似文献   
114.
Serotonin can induce analgesia when injected directly into the brain, but analgesia after peripheral administration has been more difficult to show. The pentobarbital anesthetized mouse (PAM) model, developed to alleviate some of the problems involved in the measurement of tail flick latency, was used to assess the action of peripherally administered serotonin. Mice were anesthetized with about 65 mg/kg of sodium pentobarbital IP and their tail flick latencies measured while they were in stage III anesthesia. In these anesthetized mice, IP serotonin induced a significant analgesia that was much more robust than that found in awake mice. The analgesic effect was dose-dependent from 0.25 mg/kg to 10 mg/kg but was not blocked by the antiopiate naltrexone. Of several psychotropic agents tested, only amitriptyline, mianserin, and trazodone had significant effects on analgesia in the PAM model. The analgesic effect of serotonin was reproduced by the 5HT2 agonist DOI and totally blocked by the 5HT2 antagonist NPP. These results show the utility of the PAM model in studying nonopiate analgesia and suggest that the analgesic action of serotonin is mediated primarily through the 5HT2 receptor.  相似文献   
115.
116.
Predators must ignore unhelpful background “noise” within information-rich environments and focus on useful cues of prey activity to forage efficiently. Learning to disregard unrewarding cues should happen quickly, weakening future interest in the cue. Prey odor, which is rapidly investigated by predators, may be particularly appropriate for testing whether consistently unrewarded cues are ignored, and whether such behavior can be exploited to benefit prey. Using wild free-ranging populations of black rats, Rattus rattus, an alien predator of global concern, we tested whether the application of bird-nesting odors before the introduction of artificial nests (odor preexposure), enhanced the survival of birds eggs (prey) compared with areas where prey and nesting odors were introduced concurrently. In areas where predators had encountered prey odor before prey being available, the subsequently introduced eggs showed 62% greater survival than in areas where prey and odor were introduced together. We suggest that black rats preexposed to prey odor learned to ignore the unrewarding cue, leading to a significant improvement in prey survival that held for the 7-d monitoring period. Exploiting rapid learning that underpins foraging decisions by manipulating sensory contexts offers a nonlethal, but effective approach to reducing undesirable predatory impacts. Techniques based on olfactory preexposure may provide prey with protection during critical periods of vulnerability, such as immediately following a prey reintroduction. These results also highlight the potential benefits to species conservation to be gained from a greater understanding of the cognitive mechanisms driving alien predator behavior within ecological contexts.  相似文献   
117.
BackgroundIt has been hypothesised that elderly orthopaedic trauma patients may be malnourished when compared to the general population. We conducted an observational study to identify if this was the case.MethodsThirty elderly trauma patients (≥ 65 years) admitted to the orthopaedic unit were recruited. Serum markers (albumin, urea, creatinine, sodium, potassium, haemoglobin, white cell count, platelets, lymphocytes, C-reactive protein, magnesium, calcium) anthropometric measurements (triceps skin-fold thickness, mid-arm circumference, body mass index) and short form mini-nutritional assessment (MNA-SF®) were carried out at presentation and at 3 months postoperation. Serum markers were also repeated at day 1 and day 3 postoperation.ResultsSixty percent had an initial mini-nutritional assessment (MNA-SF®) score of less or equal to 11 points indicating that they were at risk from possible malnutrition. However, median BMI at presentation was normal at 22.79 kg/m2 (WHO guidelines) (Interquartile range [IQR] 19.8–28). Interestingly, a higher proportion of the group (67%) were below the 50th centile for age related BMI centiles. At follow-up (15 patients), there was no significant difference in anthropometric measures. The mean MNA-SF® had increased, but not significantly (P = 0.121).ConclusionsIt could be extrapolated from this study that elderly trauma patients may be at risk of malnutrition regardless of their BMI at presentation and should be screened using validated nutrition screening tools and monitored. The use of age specific centiles is also recommended. Further research is needed using larger sample sizes to confirm these findings.  相似文献   
118.
BackgroundNational Institute for Health and Clinical Excellence guidelines (CG87) recommend neutral protamine hagedorn (NPH) insulin for the provision of basal insulin in type 2 diabetes, but use of analogue insulin is as much as 40%. Where residual endogenous insulin secretory capacity is present there is no evidence that analogue insulins provide any additional benefit over human insulins, and they come at an expensive premium. Anecdotally, however, there is a reluctance to switch people back to NPH insulin, partly because of a perceived risk of pancreatic failure and potential ketosis. Urinary C-peptide creatinine ratio (UCPCR) has been validated as a method for evaluating residual endogenous insulin secretion in type 1 and type 2 diabetes, with a UCPCR of no more than 0·2 nmol/mmol suggestive of absolute insulin deficiency. We aimed to evaluate the prevalence of true insulin deficiency among patients with type 2 diabetes with UCPCR, and confirm findings with the gold standard mixed meal tolerance test (MMTT).Methods191 insulin-treated patients with a clinical diagnosis of type 2 diabetes (diagnosed at or after age 45 years and who did not start insulin within the first year of diagnosis) collected a 2-h post-prandial urine sample for UCPCR measurement. Nine patients from two subgroups (UCPCR ≤0·2 nmol/mmol and UCPCR >0·2) completed a standard MMTT.Findings11 (5·8%) of 191 patients had two consistent UCPCRs of less than or equal to 0·2 nmol/mmol. Nine were able to do the MMTT, of whom five were confirmed to have absolute insulin deficiency (stimulated serum c-peptide <0·2 nmol/L). Three of these five patients were glutamic acid decarboxylase antibody-negative. Nine of nine patients with UCPCR of more than 0·2 nmol/L had confirmed endogenous insulin secretion in their MMTT. Those with insulin deficiency had a shorter time to starting insulin (median 2·5 years [IQR 1·5–3·0] vs 6·0 [3·0–10·75], p=0·005) and lower body-mass index (25 kg/m2 vs 29, p=0·04) but no other significant differences in clinical characteristics.InterpretationWe have demonstrated a very low prevalence of true pancreatic failure in this population of insulin-treated patients with type 2 diabetes. This requires further exploration by comparison of a population being treated with NPH insulin with one on analogue insulin, and then determining whether UCPCR could act as a clinical decision support tool to safely switch from analogue insulin to NPH insulin.FundingNational Institute for Health Research.  相似文献   
119.
120.
(Headache 2010;50:600‐612) Objective.— The objective of this study was to evaluate the effectiveness of the Mercy Migraine Management Program (MMMP), an educational program for physicians and patients. The primary outcome was change in headache days from baseline at 3, 6, and 12 months. Secondary outcomes were changes in migraine‐related disability and quality of life, worry about headaches, self‐efficacy for managing migraines, emergency room (ER) visits for headache, and satisfaction with headache care. Background.— Despite progress in the understanding of the pathophysiology of migraine and development of effective therapeutic agents, many practitioners and patients continue to lack the knowledge and skills to effectively manage migraine. Educational efforts have been helpful in improving the quality of care and quality of life for migraine sufferers. However, little work has been performed to evaluate these changes over a longer period of time. Also, there is a paucity of published research evaluating the influence of education about migraine management on cognitive and emotional factors (for example, self‐efficacy for managing headaches, worry about headaches). Methods.— In this open‐label, prospective study, 284 individuals with migraine (92% female, mean age = 41.6) participated in the MMMP, an educational and skills‐based program. Of the 284 who participated in the program, 228 (80%) provided data about their headache frequency, headache‐related disability (as measured by the Headache Impact Test‐6 (HIT‐6), migraine‐specific quality of life (MSQ), worry about headaches, self‐efficacy for managing headaches, ER visits for headaches, and satisfaction with care at 4 time points over 12 months (baseline, 3 months, 6 months, 12 months). Results.— Overall, 46% (106) of subjects reported a 50% or greater reduction in headache frequency. Over 12 months, patients reported fewer headaches and improvement on the HIT‐6 and MSQ (all P < .001). The improvement in headache impact and quality of life was greater among those who had more worry about their headaches at baseline. There were also significant improvements in “worry about headaches,”“self‐efficacy for managing headaches,” and “satisfaction with headache care.” Conclusion.— The findings demonstrate that patients participating in the MMMP reported improvements in their headache frequency as well as the cognitive and emotional aspects of headache management. This program was especially helpful among those with high amounts of worry about their headaches at the beginning of the program. The findings from this study are impetus for further research that will more clearly evaluate the effects of education and skill development on headache characteristics and the emotional and cognitive factors that influence headache.  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