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981.
Maximilian
Krämer Christoph Rösmann Frank Hoffmann Torsten Bertram 《Optimal control applications & methods.》2020,41(4):1211-1232
Collaborative robots have to adapt its motion plan to a dynamic environment and variation of task constraints. Currently, they detect collisions and interrupt or postpone their motion plan to prevent harm to humans or objects. The more advanced strategy proposed in this article uses online trajectory optimization to anticipate potential collisions, task variations, and to adapt the motion plan accordingly. The online trajectory planner pursues a model predictive control approach to account for dynamic motion objectives and constraints during task execution. The prediction model relates reference joint velocities to actual joint positions as an approximation of built-in robot tracking controllers. The optimal control problem is solved with direct collocation based on a hypergraph structure, which represents the nonlinear program and allows to efficiently adapt to structural changes in the optimization problem caused by moving obstacles. To demonstrate the effectiveness of the approach, the robot imitates pick-and-place tasks while avoiding self-collisions, semistatic, and dynamic obstacles, including a person. The analysis of the approach concerns computation time, constraint violations, and smoothness. It shows that after model identification, order reduction, and validation on the real robot, parallel integrators with compensation for input delays exhibit the best compromise between accuracy and computational complexity. The model predictive controller can successfully approach a moving target configuration without prior knowledge of the reference motion. The results show that pure hard constraints are not sufficient and lead to nonsmooth controls. In combination with soft constraints, which evaluate the proximity of obstacles, smooth and safe trajectories are planned. 相似文献
982.
983.
Joseph K. Kendal Arvind Singla Asmaa Affan Kurt Hildebrand Abdullah Al-Ani Mark Ungrin Douglas J. Mahoney Doha Itani Frank R. Jirik Michael J. Monument 《Clinical orthopaedics and related research》2020,478(12):2921
BackgroundThe putative benefit of rhBMP-2 is in the setting of limb reconstruction using structural allografts, whether it be allograft-prosthetic composites, osteoarticular allografts, or intercalary segmental grafts. There are also potential advantages in augmenting osseointegration of uncemented endoprosthetics and in reducing infection. Recombinant human BMP-2 might mitigate nonunion in structural allograft augmented osteosarcoma limb salvage surgery; however, its use is limited because of concerns about the prooncogenic effects of the agent.Questions/purposes(1) To assess if BMP-2 signaling influences osteosarcoma cell line growth. (2) To characterize degree of osteosarcoma cell line osteoblastic differentiation in response to BMP-2. (3) To assess if BMP-2 signaling has a consistent effect on local or systemic tumor burden in various orthotopic murine models of osteosarcoma.MethodsIn this study, 143b, SaOS-2 and DLM8-M1 osteosarcoma cell lines were transfected with BMP-2 cDNA controlled by a constitutive promoter (experimental) or an empty vector (control) using a PiggyBac transposon system. Cellular proliferation was assessed using a quantitative MTT colorimetric assay. Osteoblastic differentiation was compared between control and experimental cell lines using quantitative real-time polymerase chain reaction of the osteoblastic markers connective tissue growth factor, Runx-2, Osterix, alkaline phosphatase and osteocalcin. Experimental and control cell lines were injected into the proximal tibia of either NOD-SCID (143b and SaOS-2 xenograft model), or C3H (DLM8-M1 syngeneic model) mice. Local tumor burden was quantitatively assessed using tumor volume caliper measurements and bioluminescence, and qualitatively assessed using post-mortem ex vivo microCT. Lung metastasis was qualitatively assessed by the presence of bioluminescence, and incidence was confirmed using histology. rhBMP-2 soaked absorbable collagen sponges (experimental) and sterile-H2O soaked absorbable collagen sponges (control) were implanted adjacent to 143b proximal tibial cell line injections to compare the effects of exogenous BMP-2 application with endogenous upregulation.ResultsConstitutive expression of BMP-2 increased the in vitro proliferation of 143b cells (absorbance values 1.2 ± 0.1 versus 0.89 ± 0.1, mean difference 0.36 [95% CI 0.12 to 0.6]; p = 0.01), but had no effect on SaOS-2 and DLM8-M1 cell proliferation. In response to constitutive BMP-2 expression, 143b cells had no differences in osteoblastic differentiation, while DLM8-M1 cells downregulated the early marker connective tissue growth factor (mean ΔCt 0.2 ± 0.1 versus 0.6 ± 0.1; p = 0.002) and upregulated the early-mid range marker Runx-2 (mean ΔCt -0.8 ± 0.1 versus -1.1 ± 0.1; p = 0.002), and SaOS-2 cells upregulated the mid-range marker Osterix (mean ΔCt -2.1 ± 0.6 versus -3.9 ± 0.6; p = 0.002). Constitutive expression of BMP-2 resulted in greater 143b and DLM8-M1 local tumor volume (143b: 307.2 ± 106.8 mm3 versus 1316 ± 387.4 mm3, mean difference 1009 mm3 [95% CI 674.5 to 1343]; p < 0.001, DLM8-M1 week four: 0 mm3 versus 326.1 ± 72.8 mm3, mean difference 326.1 mm3 [95% CI 121.2 to 531]; p = 0.009), but modestly reduced local tumor growth in SaOS-2 (9.5 x 108 ± 8.3x108 photons/s versus 9.3 x 107 ± 1.5 x 108 photons/s, mean difference 8.6 x 108 photons/s [95% CI 5.1 x 108 to 1.2 x 109]; p < 0.001). Application of exogenous rhBMP-2 also increased 143b local tumor volume (495 ± 91.9 mm3 versus 1335 ± 102.7 mm3, mean difference 840.3 mm3 [95% CI 671.7 to 1009]; p < 0.001). Incidence of lung metastases was not different between experimental or control groups for all experimental conditions.ConclusionsAs demonstrated by others, ectopic BMP-2 signaling has unpredictable effects on local tumor proliferation in murine models of osteosarcoma and does not consistently result in osteosarcoma cell line differentiation. Further investigations into other methods of safe bone and soft tissue healing augmentation and the use of differentiation therapies is warranted.Clinical RelevanceOur results indicate that BMP-2 has the potential to stimulate the growth of osteosarcoma cells that are poorly responsive to BMP-2 mediated osteoblastic differentiation. As this differentiation potential is unpredictable in the clinical setting, BMP-2 may promote the growth of microscopic residual tumor burden after resection. Our study provides further support for the recommendation to avoid the use of BMP-2 after limb-salvage surgery in patients with osteosarcoma. 相似文献
984.
Mannion Anne F. Mariaux Francine Reitmeir Raluca Fekete Tamas F. Haschtmann Daniel Loibl Markus Jeszenszky Dezsö Kleinstück Frank S. Porchet François Elfering Achim 《European spine journal》2020,29(8):1935-1952
European Spine Journal - Depression, anxiety, catastrophising, and fear-avoidance beliefs are key "yellow flags" (YFs) that predict a poor outcome in back patients. Most surgeons... 相似文献
985.
Oleg Rummo Mario Carmellini Nassim Kamar Antoine Durrbach Christiane Mousson Flavia Caputo Zoltan Mathe Maarten H. L. Christiaans Dirk R. J. Kuypers Jürgen Klempnauer Swapneel Anaokar Martin Hurst Gbenga Kazeem Nasrullah Undre Frank Lehner 《Transplant international》2020,33(2):161-173
The objectives of this study were to assess long-term graft survival, patient survival, renal function, and acute rejections in de novo kidney transplant recipients, treated with once-daily prolonged-release tacrolimus-based therapy. The study was a 5-year non-interventional prospective follow-up of patients from the ADHERE study, a Phase IV 12-month open-label assessment of patients randomized to receive prolonged-release tacrolimus in combination with mycophenolate mofetil (MMF) (Arm 1) or sirolimus (Arm 2). From 838 patients in the randomized study, 587 were included in the long-term follow-up, of whom 510 completed the study at year 5. At 1 year post-transplant, graft and patient survival rates were 93.0% and 97.8%, respectively, and at 5 years were 84.0% and 90.8%, respectively. Cox proportional hazards analysis showed no association between graft loss, initial randomized treatment arm, donor age, donor type, or sex. The 5-year acute rejection-free survival rate was 77.4%, and biopsy-confirmed acute rejection-free survival rate was 86.0%. Renal function remained stable over the follow-up period: mean ± SD eGFR 4-variable modification diet in renal disease formula (MDRD4) was 52.3 ± 21.6 ml/min/1.73 m2 at 6 months and 52.5 ± 23.0 ml/min/1.73 m2 at 5 years post-transplant. These findings support the role of long-term once-daily prolonged-release tacrolimus-based immunosuppression, in combination with sirolimus or MMF, for renal transplant recipients in routine clinical practice. 相似文献
986.
Jacqueline M. Smits Jens Gottlieb Erik Verschuuren Patrick Evrard Rogier Hoek Christiane Knoop György Lang Johanna M. Kwakkel-van Erp Robin Vos Geert Verleden Benoit Rondelet Daniel Hoefer Frank Langer Rene Schramm Konrad Hoetzenecker Diana van Kessel Bart Luijk Leonard Seghers Tobias Deuse Roland Buhl Christian Witt Agita Strelniece Dave Green Erwin de Vries Guenter Laufer Dirk Van Raemdonck 《Transplant international》2020,33(5):544-554
The aim of this study was to investigate whether there is an impact of donation rates on the quality of lungs used for transplantation and whether donor lung quality affects post-transplant outcome in the current Lung Allocation Score era. All consecutive adult LTx performed in Eurotransplant (ET) between January 2012 and December 2016 were included (N = 3053). Donors used for LTx in countries with high donation rate were younger (42% vs. 33% ≤45 years, P < 0.0001), were less often smokers (35% vs. 46%, P < 0.0001), had more often clear chest X-rays (82% vs. 72%, P < 0.0001), had better donor oxygenation ratios (20% vs. 26% with PaO2/FiO2 ≤ 300 mmHg, P < 0.0001), and had better lung donor score values (LDS; 28% vs. 17% with LDS = 6, P < 0.0001) compared with donors used for LTx in countries with low donation rate. Survival rates for the groups LDS = 6 and ≥7 at 5 years were 69.7% and 60.9% (P = 0.007). Lung donor quality significantly impacts on long-term patient survival. Countries with a low donation rate are more oriented to using donor lungs with a lesser quality compared to countries with a high donation rate. Instead of further stretching donor eligibility criteria, the full potential of the donor pool should be realized. 相似文献
987.
Perschel FH Schemer R Seiler L Reincke M Deinum J Maser-Gluth C Mechelhoff D Tauber R Diederich S 《Clinical chemistry》2004,50(9):1650-1655
BACKGROUND: The ratio of plasma aldosterone concentration to plasma renin activity (PAC/PRA) is the most common screening test for primary hyperaldosteronism (PHA), but it is not standardized among laboratories. We evaluated new automated assays for the simultaneous measurement of PAC and plasma renin concentration (PRC). METHODS: We studied 76 healthy normotensive volunteers and 28 patients with confirmed PHA. PAC and PRC were measured immunochemically in EDTA plasma on the Nichols Advantage chemiluminescence analyzer, and PRA was determined by an activity assay. RESULTS: In volunteers, PAC varied from 33.3 to 1930 pmol/L, PRA from 1.13 to 19.7 ng.mL(-1).h(-1) (0.215 ng.mL(-1).h(-1) = 1 pmol.L(-1).s(-1)), and PRC from 5.70 to 116 mU/L. PAC/PRA ratios ranged from 4.35 to 494 (pmol/L)/(ng.mL(-1).h(-1)) and PAC/PRC ratios from 0.69 to 71.0 pmol/mU. In PHA patients, PAC ranged from 158 to 5012 pmol/L, PRA from 0.40 to 1.70 ng.mL(-1).h(-1), and PRC from 0.80 to 11.7 mU/L. PAC/PRA ratios were between 298 and 6756 (pmol/L)/(ng.mL(-1).h(-1)) and PAC/PRC ratios between 105 and 2328 pmol/mU. Whereas PAC or PRC showed broad overlap between PHA patients and volunteers, the PAC/PRC ratio indicated distinct discrimination of these two groups at a cutoff of 71 pmol/mU. CONCLUSION: The PAC/PRC ratio offers several practical advantages compared with the PAC/PRA screening method. The present study offers preliminary evidence that it may be a useful screening test for PHA. Further studies are required to validate these results, especially in hypertensive cohorts. 相似文献
988.
Charlotte Haug John Hoey Richard Horton Sheldon Kotzin Christine Laine Ana Marusic Harold C.Sox 刁骧 《中国循证医学杂志》2006,6(3):231-232
无私和信任是人体试验研究的核心。自愿参加研究的受试者是无私的,因为他们相信自己的参与将为他人健康的改善做出贡献,也相信研究者会尽最大努力减少受试者的风险。由于受试者的无私和信任,临床研究才成为可能,因此研究机构有义务使临床研究的实施符合伦理学要求,并诚实地报道研究结果。而诚实的报道首先需要知道所有现存的临床研究,即使其结果对赞助方不利。 相似文献
989.
990.
Mark Christopher Snoddy Maximilian Frank Lang Thomas J. An Phillip Michael Mitchell William Jeffrey Grantham Benjamin Scoot Hooe Harrison Ford Kay Ritwik Bhatia Rachel V. Thakore Jason Michael Evans William Todd Obremskey Manish Kumar Sethi 《International orthopaedics》2014,38(8):1711-1716