全文获取类型
收费全文 | 2630269篇 |
免费 | 213912篇 |
国内免费 | 4900篇 |
专业分类
耳鼻咽喉 | 35865篇 |
儿科学 | 87621篇 |
妇产科学 | 74903篇 |
基础医学 | 374299篇 |
口腔科学 | 75615篇 |
临床医学 | 236329篇 |
内科学 | 515349篇 |
皮肤病学 | 58610篇 |
神经病学 | 216035篇 |
特种医学 | 103143篇 |
外国民族医学 | 897篇 |
外科学 | 395594篇 |
综合类 | 64782篇 |
现状与发展 | 6篇 |
一般理论 | 972篇 |
预防医学 | 207139篇 |
眼科学 | 60853篇 |
药学 | 192609篇 |
2篇 | |
中国医学 | 5477篇 |
肿瘤学 | 142981篇 |
出版年
2018年 | 27460篇 |
2017年 | 21101篇 |
2016年 | 23784篇 |
2015年 | 27035篇 |
2014年 | 37972篇 |
2013年 | 57338篇 |
2012年 | 77499篇 |
2011年 | 81906篇 |
2010年 | 48358篇 |
2009年 | 46238篇 |
2008年 | 77033篇 |
2007年 | 81425篇 |
2006年 | 82685篇 |
2005年 | 80242篇 |
2004年 | 77813篇 |
2003年 | 74440篇 |
2002年 | 72349篇 |
2001年 | 125914篇 |
2000年 | 129540篇 |
1999年 | 108860篇 |
1998年 | 30527篇 |
1997年 | 27640篇 |
1996年 | 27569篇 |
1995年 | 26509篇 |
1994年 | 24522篇 |
1993年 | 23170篇 |
1992年 | 86279篇 |
1991年 | 83169篇 |
1990年 | 80639篇 |
1989年 | 77523篇 |
1988年 | 71833篇 |
1987年 | 70506篇 |
1986年 | 66654篇 |
1985年 | 63920篇 |
1984年 | 48314篇 |
1983年 | 41338篇 |
1982年 | 24735篇 |
1981年 | 22056篇 |
1979年 | 44759篇 |
1978年 | 31287篇 |
1977年 | 26324篇 |
1976年 | 24792篇 |
1975年 | 25746篇 |
1974年 | 31477篇 |
1973年 | 30390篇 |
1972年 | 28069篇 |
1971年 | 26135篇 |
1970年 | 24429篇 |
1969年 | 22761篇 |
1968年 | 21057篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
Victoria L. Parker Matthew C. Winter John A. Tidy Barry W. Hancock Julia E. Palmer Naveed Sarwar Baljeet Kaur Katie McDonald Xianne Aguiar Kamaljit Singh Nick Unsworth Imran Jabbar Allan A. Pacey Robert F. Harrison Michael J. Seckl 《International journal of cancer. Journal international du cancer》2023,152(5):986-997
Gestational trophoblastic neoplasia (GTN) patients are treated according to the eight-variable International Federation of Gynaecology and Obstetrics (FIGO) scoring system, that aims to predict first-line single-agent chemotherapy resistance. FIGO is imperfect with one-third of low-risk patients developing disease resistance to first-line single-agent chemotherapy. We aimed to generate simplified models that improve upon FIGO. Logistic regression (LR) and multilayer perceptron (MLP) modelling (n = 4191) generated six models (M1-6). M1, all eight FIGO variables (scored data); M2, all eight FIGO variables (scored and raw data); M3, nonimaging variables (scored data); M4, nonimaging variables (scored and raw data); M5, imaging variables (scored data); and M6, pretreatment hCG (raw data) + imaging variables (scored data). Performance was compared to FIGO using true and false positive rates, positive and negative predictive values, diagnostic odds ratio, receiver operating characteristic (ROC) curves, Bland-Altman calibration plots, decision curve analysis and contingency tables. M1-6 were calibrated and outperformed FIGO on true positive rate and positive predictive value. Using LR and MLP, M1, M2 and M4 generated small improvements to the ROC curve and decision curve analysis. M3, M5 and M6 matched FIGO or performed less well. Compared to FIGO, most (excluding LR M4 and MLP M5) had significant discordance in patient classification (McNemar's test P < .05); 55-112 undertreated, 46-206 overtreated. Statistical modelling yielded only small gains over FIGO performance, arising through recategorisation of treatment-resistant patients, with a significant proportion of under/overtreatment as the available data have been used a priori to allocate primary chemotherapy. Streamlining FIGO should now be the focus. 相似文献
22.
Triposkiadis Filippos Xanthopoulos Andrew Skoularigis John Starling Randall C. 《Heart failure reviews》2022,27(6):1991-2003
Heart Failure Reviews - The nitric oxide (NO)–guanylate cyclase (GC)–cyclic guanosine monophosphate (cGMP) pathway plays an important role in cardiovascular, pulmonary and renal... 相似文献
23.
Comprehensive evidence regarding the treatment of non-anaemic iron deficiency in patients undergoing valvular heart surgery is lacking. This study aimed to investigate the association between non-anaemic iron deficiency and postoperative outcomes in these patients. We retrospectively analysed 321 patients of which 180 (56%) had iron deficiency (defined as serum ferritin < 100 ng.ml-1 or < 300 ng.ml-1 with transferrin saturation < 20%). While the iron-deficient group had lower pre-operative haemoglobin levels than the non-iron deficient group (median (IQR [range]) 134 (127–141 [120–172]) g.l-1, 143 (133–150 [120–179]) g.l-1, p = 0.001), there was no between-group difference in allogeneic red blood cell transfusion. Median (IQR [range]) days alive and out of hospital at postoperative day 90 was 1 day shorter in the iron-deficient group (80 (77–82 [9–85]) days vs. 81 (79–83 [0–85]) days, p = 0.026). In multivariable analysis, only cardiopulmonary bypass duration (p = 0.032) and intra-operative allogeneic red blood cell transfusion (p = 0.011) were significantly associated with reduced days alive and out of hospital at postoperative day 90. Iron deficiency did not exert any adverse influence on secondary outcomes except length of hospital stay. Our findings indicate that non-anaemic iron deficiency alone is not associated with adverse effects in patients undergoing valvular heart surgery when it does not translate into an increased risk of allogeneic transfusion. 相似文献
24.
Post-induction hypotension is common and associated with postoperative complications. We hypothesised that pneumatic leg compression reduces post-induction hypotension in elderly patients undergoing robot-assisted laparoscopic prostatectomy. In this double-blind randomised study, patients were allocated randomly to the pneumatic leg compression group (n = 50) or control (n = 50). In the intervention group, pneumatic leg compression was initiated before induction of anaesthesia. In the control group, pneumatic leg compression was initiated 20 min after anaesthesia induction. The primary outcome was the incidence of post-induction hypotension in these groups. Post-induction hypotension was defined as systolic blood pressure < 90 mmHg during the first 20 min after induction. Haemodynamic variables and area under the curve of post-induction systolic blood pressure over time were assessed. Complications associated with pneumatic leg compression were recorded, including: peripheral neuropathy; compartment syndrome; extensive bullae beneath the leg sleeves; and pulmonary thromboembolism. The incidence of post-induction hypotension decreased in the pneumatic leg compression group compared with that in the control group; 5 (10%) vs. 29 (58%), respectively, p < 0.001. In the pneumatic leg compression group, the lowest systolic, diastolic and mean blood pressures 20 min after induction of anaesthesia were significantly greater than the control group. Pneumatic leg compression resulted in an increased area under the curve of systolic blood pressure in the first 20 min after induction, p = 0.001. There were no pneumatic leg compression-related complications. Pneumatic leg compression reduced post-induction hypotension in elderly patients undergoing robot-assisted laparoscopic prostatectomy, suggesting that it is an effective and safe intervention to prevent post-induction hypotension among elderly patients undergoing general anaesthesia. 相似文献
25.
26.
27.
28.
Tengzhi Liu Kathrine Røe Redalen Morten Karlsen 《Journal of labelled compounds & radiopharmaceuticals》2022,65(7):191-202
Cyclotron-produced copper-64 radioisotope tracers offer the possibility to perform both diagnostic investigation by positron emission tomography (PET) and radiotherapy by a theranostic approach with bifunctional chelators. The versatile chemical properties of copper add to the importance of this isotope in medicinal investigation. [64Cu][Cu (ATSM)] has shown to be a viable candidate for imaging of tumor hypoxia; a critical tumor microenvironment characteristic that typically signifies tumor progression and resistance to chemo-radiotherapy. Various production and radiosynthesis methods of [64Cu][Cu (ATSM)] exist in labs, but usually involved non-standardized equipment with varying production qualities and may not be easily implemented in wider hospital settings. [64Cu][Cu (ATSM)] was synthesized on a modified GE TRACERlab FXN automated synthesis module. End-of-synthesis (EOS) molar activity of [64Cu][Cu (ATSM)] was 2.2–5.5 Ci/μmol (HPLC), 2.2–2.6 Ci/μmol (ATSM-titration), and 3.0–4.4 Ci/μmol (ICP-MS). Radiochemical purity was determined to be >99% based on radio-HPLC. The final product maintained radiochemical purity after 20 h. We demonstrated a simple and feasible process development and quality control protocols for automated cyclotron production and synthesis of [64Cu][Cu (ATSM)] based on commercially distributed standardized synthesis modules suitable for PET imaging and theranostic studies. 相似文献
29.
30.
Xiumei Jiang Xiaowei Zhang Patrick Gray Jiwen Zheng Timothy R. Croley Peter P. Fu 《journal of environmental science and health part c-environmental carcinogenesis & ecotoxicology reviews》2019,37(2):116-131
Gold nanoparticles (Au NPs) hold great promise in food, industrial and biomedical applications due to their unique physicochemical properties. However, influences of the gastrointestinal tract (GIT), a likely route for Au NPs administration, on the physicochemical properties of Au NPs has been rarely evaluated. Here, we investigated the influence of GIT fluids on the physicochemical properties of Au NPs (5, 50, and 100?nm) and their implications on intestinal epithelial permeability in vitro. Au NPs aggregated in fasted gastric fluids and generated hydroxyl radicals in the presence of H2O2. Cell studies showed that GIT fluids incubation of Au NPs affected the cellular uptake of Au NPs but did not induce cytotoxicity or disturb the intestinal epithelial permeability. 相似文献