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   17382篇
  免费   808篇
  国内免费   94篇
耳鼻咽喉   177篇
儿科学   372篇
妇产科学   358篇
基础医学   1979篇
口腔科学   1453篇
临床医学   1160篇
内科学   4549篇
皮肤病学   433篇
神经病学   1411篇
特种医学   299篇
外科学   2514篇
综合类   90篇
一般理论   4篇
预防医学   1241篇
眼科学   372篇
药学   757篇
中国医学   81篇
肿瘤学   1034篇
  2024年   11篇
  2023年   132篇
  2022年   275篇
  2021年   584篇
  2020年   332篇
  2019年   530篇
  2018年   616篇
  2017年   408篇
  2016年   423篇
  2015年   523篇
  2014年   739篇
  2013年   898篇
  2012年   1459篇
  2011年   1584篇
  2010年   896篇
  2009年   733篇
  2008年   1201篇
  2007年   1367篇
  2006年   1154篇
  2005年   1015篇
  2004年   895篇
  2003年   742篇
  2002年   757篇
  2001年   88篇
  2000年   60篇
  1999年   72篇
  1998年   113篇
  1997年   96篇
  1996年   82篇
  1995年   53篇
  1994年   55篇
  1993年   44篇
  1992年   25篇
  1991年   22篇
  1990年   23篇
  1989年   11篇
  1988年   16篇
  1987年   12篇
  1986年   11篇
  1985年   12篇
  1984年   26篇
  1983年   19篇
  1982年   11篇
  1981年   24篇
  1980年   20篇
  1979年   10篇
  1978年   8篇
  1977年   18篇
  1976年   13篇
  1974年   6篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
BackgroundNetwork analysis has been used to explore the interplay between psychopathology and functioning in psychosis, but no study has used dedicated statistical techniques to focus on the bridge symptoms connecting these domains. The current study aims to estimate the network of depressive, negative, and positive symptoms, general psychopathology, and real-world functioning in people with first-episode schizophrenia or schizophreniform disorder, focusing on bridge nodes.MethodsBaseline data from the OPTiMiSE trial were analyzed. The sample included 446 participants (age 40.0 ± 10.9 years, 70% males). The network was estimated with a Gaussian graphical model, using scores on individual items of the positive and negative syndrome scale (PANSS), the Calgary depression scale for schizophrenia, and the personal and social performance scale. Stability, strength centrality, expected influence (EI), predictability, and bridge centrality statistics were computed. The top 20% scoring nodes on bridge strength were selected as bridge nodes.ResultsNodes from different rating scales assessing similar psychopathological and functioning constructs tended to cluster together in the estimated network. The most central nodes (EI) were Delusions, Emotional Withdrawal, Depression, and Depressed Mood. Bridge nodes included Depression, Conceptual Disorganization, Active Social Avoidance, Delusions, Stereotyped Thinking, Poor Impulse Control, Guilty Feelings, Unusual Thought Content, and Hostility. Most of the bridge nodes belonged to the general psychopathology subscale of the PANSS. Depression (G6) was the bridge node with the highest value.ConclusionsThe current study provides novel insights for understanding the complex phenotype of psychotic disorders and the mechanisms underlying the development and maintenance of comorbidity and functional impairment after psychosis onset.  相似文献   
82.
BackgroundThe New York Heart Association (NYHA) functional classification is the most commonly used classification system for heart failure (HF), whereas cardiopulmonary exercise testing (CPET) is the gold standard for functional status evaluation in HF.ObjectiveThis study aimed to analyze correlation and concordance between NYHA classes and CPET variables.MethodsHF patients with clinical indication for CPET and ejection fraction (EF) < 50% were selected. Correlation (Spearman coefficient) and concordance (kappa) between NYHA classification and CPET-based classifications were analyzed. A p < 0.05 was accepted as significant.ResultsIn total, 244 patients were included. Mean age was 56 ± 14 years, and mean EF was 35.5% ± 10%. Distribution of patients according to NYHA classification was 31.2%% class I, 48.3% class II, 19.2% class III, and 1.3% class IV. Correlation (r) between NYHA and Weber classes was 0.489 (p < 0.001), and concordance was 0.231 (p < 0.001). Correlation (r) between NYHA and ventilatory classes (minute ventilation/carbon dioxide production [VE/VCO2] slope) was 0.218 (p < 0.001), and concordance was 0.002 (p = 0.959). Spearman correlation between NYHA and CPET score classes was 0.223 (p = 0.004), and kappa concordance was 0.027 (p = 0.606).ConclusionThere was a moderate association between NYHA and Weber classes, although concordance was low. Ventilatory (VE/VCO2slope) and CPET score classes had a weak association and a low concordance with NYHA classes.  相似文献   
83.
BackgroundAdequate treatment of arterial hypertension and achieving arterial hypertension goals in are important in reducing cardiovascular outcomes.ObjectivesTo describe angiotensin receptor blockers in monotherapy or double combination therapy and the rate of arterial hypertension control.MethodsThis cross-sectional study evaluated patients who were using angiotensin receptor blockers between 2017 and 2020. Those using three or more antihypertensive drugs were excluded. The analyzed variables included sex, age, body mass index, valid home blood pressure monitoring (HBPM) measurements, casual and HBPM systolic and diastolic blood pressure measurements, blood pressure variability, and antihypertensive and angiotensin receptor blocker class. Paired t, chi-square, and Fisher’s exact tests were used, as well as overlapping 95% confidence intervals and a significance level of 5% (p < 0.05).ResultsOf 17,013 patients, 12,813 met the inclusion criteria, 62.1% of whom were female. The mean number of valid measurements was 23.3 (SD, 2.0). The mean HBPM and casual measurements for systolic blood pressure were 126.8 (SD, 15.8) mmHg and 133.5 (SD, 20.1) mmHg (p <0.001), respectively, while those for diastolic blood pressure were 79.1 (SD, 9.7 mmHg) and 83.6 (SD, 11.9) mmHg (p <0.001), respectively. Losartan was the most common angiotensin receptor blocker and resulted in the highest blood pressure values. Combinations of angiotensin receptor blockers with diuretics or calcium channel antagonists resulted in lower blood pressure values.ConclusionsMore than half of the patients used losartan, although it was the least efficient drug for reducing and controlling blood pressure.  相似文献   
84.
85.
The advent of minimally invasive surgery and the advances in endoluminal flexible endoscopy have converged to generate a new concept in digestive surgery, whose acronym natural orifice transluminal endoscopic surgery (NOTES), has become a familiar term in the surgical community. NOTES has been performed through the mouth, the bladder, the rectum and the vagina. Of these four approaches, the vagina has gained most popularity for several reasons. It is not only readily accessible and easy to decontaminate but it also provides safe entry and simple closure. The transvaginal approach has been described in the experimental and the clinical setting as an option for cholecystectomy, nephrectomy, splenectomy, segmental gastrectomy, retroperitoneal exploration and bariatric surgery. However, larger series are needed to delineate the exact risks of this approach, and to transcend cultural barriers that impede its wider introduction. Prospective randomized trials will shed light on the definitive role of the vaginal approach in minimal invasive surgery of the future.  相似文献   
86.
ObjectiveTo determine how many dispensary drugs should be in the safety stock in a tertiary hospital in accordance with the risk level and the number of days that the hospital is able to withstand a stockout.MethodsWe statistically analysed the infliximab order recorded over a period of 120 days. This drug is relevant for this study as it is costly and is immediately supplied to the clinic. Using the data records for purchasing and dispensing in our department, we created a table to compare the level of risk assumed with the number of units in stock and the number of days that the safety stock should last. In addition, we calculated how much stock there should be in accordance with different heuristic rules used by pharmacy departments.ResultsIn the period being studied, the daily order was 11.4 ± 14.8 units of infliximab. Using the methodology proposed, we discovered that there should be 79 units in the safety stock. Other hospital rules determine values of 47 and 119 units.ConclusionsThe method proposed allows us to discover the risk level that is assumed when selecting the safety stock. Therefore, we are able to design a safety stock policy consistent with the risk level adopted. Under certain assumptions the safety stock quota provided by this method could be reduced. Lastly, there is a notable difference between the safety stock values suggested by different rules, as it has been shown in this article.  相似文献   
87.
88.

Objective  

This study aims to compare the manual correction of the automatic analysis of ApneaLink™ between a skilled observer in the interpretation of sleep studies and a subject trained only in the scoring of ApneaLink™ device.  相似文献   
89.
90.
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