全文获取类型
收费全文 | 194183篇 |
免费 | 2075篇 |
国内免费 | 37篇 |
专业分类
耳鼻咽喉 | 1365篇 |
儿科学 | 7122篇 |
妇产科学 | 3274篇 |
基础医学 | 18939篇 |
口腔科学 | 2226篇 |
临床医学 | 13974篇 |
内科学 | 34290篇 |
皮肤病学 | 1034篇 |
神经病学 | 18511篇 |
特种医学 | 10227篇 |
外国民族医学 | 1篇 |
外科学 | 31623篇 |
综合类 | 2470篇 |
一般理论 | 4篇 |
预防医学 | 19749篇 |
眼科学 | 3142篇 |
药学 | 10354篇 |
中国医学 | 638篇 |
肿瘤学 | 17352篇 |
出版年
2021年 | 281篇 |
2020年 | 196篇 |
2019年 | 242篇 |
2018年 | 22194篇 |
2017年 | 17577篇 |
2016年 | 19747篇 |
2015年 | 1260篇 |
2014年 | 1280篇 |
2013年 | 1352篇 |
2012年 | 7820篇 |
2011年 | 21861篇 |
2010年 | 19365篇 |
2009年 | 11994篇 |
2008年 | 20293篇 |
2007年 | 22569篇 |
2006年 | 1392篇 |
2005年 | 3014篇 |
2004年 | 4194篇 |
2003年 | 5099篇 |
2002年 | 3224篇 |
2001年 | 940篇 |
2000年 | 1045篇 |
1999年 | 700篇 |
1998年 | 443篇 |
1997年 | 359篇 |
1996年 | 224篇 |
1995年 | 268篇 |
1994年 | 243篇 |
1993年 | 183篇 |
1992年 | 420篇 |
1991年 | 479篇 |
1990年 | 456篇 |
1989年 | 405篇 |
1988年 | 347篇 |
1987年 | 298篇 |
1986年 | 308篇 |
1985年 | 301篇 |
1984年 | 242篇 |
1983年 | 217篇 |
1982年 | 164篇 |
1981年 | 132篇 |
1980年 | 165篇 |
1979年 | 261篇 |
1978年 | 170篇 |
1977年 | 159篇 |
1975年 | 162篇 |
1974年 | 158篇 |
1973年 | 143篇 |
1972年 | 152篇 |
1970年 | 140篇 |
排序方式: 共有10000条查询结果,搜索用时 831 毫秒
151.
Dittmar Böckler Hardy Schumacher Klaus Klemm Marcel Riemensperger Philipp Geisbüsch Drosos Kotelis Harry Rotert Jens-Rainer Allenberg 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》2007,392(6):715-723
OBJECTIVES: to report our experience with hybrid vascular procedures in patients with pararenal and thoracoabdominal aortic pathologies. METHODS: 68 patients were treated for thoracoabdominal aortic pathologies between October 1999 and February 2004; 19 patients (16 men; mean age 68, range 40-79) with high risk for open thoracoabdominal repair were considered to be candidates for combined endovascular and open repair. Aortic pathologies included five thoracoabdominal Crawford I aneurysms, one postdissection expanding aneurysm, three symptomatic plaque ruptures (Crawford IV), five combined thoracic descending and infrarenal aneurysms with a healthy visceral segment, three juxtarenal or para-anastomotic aneurysms, and two patients with simultaneous open aortic arch replacement and a rendezvous maneuver for thoracic endografting. Commercially available endografts were implanted with standardized endovascular techniques after revascularization of visceral and renal arteries. RESULTS: Technical success was 95%. One patient developed a proximal type I endoleak after chronic expanding type B dissection and currently is waiting conversion. Nine patients underwent elective, five emergency and five urgent (within 24 h) repair. 17 operations were performed simultaneously, and 2 as a staged procedure. Postoperative complications include two retroperitoneal hemorrhages, and one patient required long-term ventilation with preexisting subglottic tracheal stenosis. Thirty-day mortality was 17% (one multiple organ failure, one secondary rupture after open aortic arch repair, one myocardial infarction). Paraplegia or acute renal failure were not observed. Total survival rate was to 83% with a mean follow-up of 30 months. CONCLUSIONS: Midterm results of combined endovascular and open procedures in the thoracoabdominal aorta are encouraging in selected high risk patients. Staged interventions may reduce morbidity. 相似文献
152.
Background
Hip dislocation in children with cerebral palsy (CP) is a common and severe problem. The dislocation can be avoided, by screening and preventive treatment of children with hips at risk. The aim of this study was to analyse the characteristics of children with CP who develop hip displacement, in order to optimise a hip surveillance programme. 相似文献153.
Steven Z George John D Childs Deydre S Teyhen Samuel S Wu Alison C Wright Jessica L Dugan Michael E Robinson 《BMC musculoskeletal disorders》2007,8(1):92
Background
There are few effective strategies reported for the primary prevention of low back pain (LBP). Core stabilization exercises targeting the deep abdominal and trunk musculature and psychosocial education programs addressing patient beliefs and coping styles represent the current best evidence for secondary prevention of low back pain. However, these programs have not been widely tested to determine if they are effective at preventing the primary onset and/or severity of LBP. The purpose of this cluster randomized clinical trial is to determine if a combined core stabilization exercise and education program is effective in preventing the onset and/or severity of LBP. The effect of the combined program will be compared to three other standard programs. 相似文献154.
Philippe Béchard Pierre Dolbec Julie Germain Gino Perron 《Journal canadien d'anesthésie》2004,51(4):398-399
155.
156.
157.
Relaxin down-regulates renal fibroblast function and promotes matrix remodelling in vitro. 总被引:1,自引:0,他引:1
Rosemary Masterson Tim D Hewitson Kristen Kelynack Marina Martic Laura Parry Ross Bathgate Ian Darby Gavin Becker 《Nephrology, dialysis, transplantation》2004,19(3):544-552
BACKGROUND: Renal fibroblasts are important effector cells in tubulointerstitial fibrosis, with experimental antifibrotic strategies focusing on the functional down-regulation of these cells. Several experimental models of fibrosis have provided evidence for the effectiveness of the polypeptide hormone relaxin as a potential antifibrotic agent. This study was conducted to further elucidate the antifibrotic mechanisms of relaxin on renal fibroblasts in vitro. METHODS: Rat cortical fibroblasts were obtained from outgrowth culture of renal tissue isolated from kidneys 3 days post-unilateral ureteric obstruction and constituted 100% of cells studied. A relaxin radio-receptor assay was used to establish binding of relaxin to renal fibroblasts in vitro. Functional studies then examined the effects of H2 relaxin (0, 1, 10 and 100 ng/ml) on fibroblast kinetics, expression of alpha-smooth muscle actin (alpha-SMA), total collagen synthesis, collagenase production and collagen-I lattice contraction. CTGF mRNA expression was also measured by northern analysis. RESULTS: H2 relaxin bound with high affinity to rat renal fibroblasts, but receptor numbers were low. Consistent with its previously reported bimodal effect, transforming growth factor (TGF-beta 1) reduced fibroblast proliferation, an effect abrogated by H2 relaxin. Fibroblasts exposed to H2 relaxin (100 ng/ml) for 24 h demonstrated decreased immunostaining for alpha-SMA and reduced alpha-SMA protein expression compared with controls. There was a trend for a relaxin-mediated reduction in total collagen synthesis and alpha 1(I) mRNA expression with large dose-related increases in collagenase protein expression being observed. TGF-beta 1-stimulated collagen-I lattice contraction was significantly inhibited following co-incubation with 100 ng/ml relaxin. Incremental doses of H2 relaxin had no significant effect on CTGF mRNA expression. CONCLUSIONS: The findings of this study suggest that the antifibrotic effects of relaxin involve down-regulation of fibroblast activity, increase in collagenase synthesis and restructuring of collagen-I lattices, which are consistent with its known physiological role of matrix remodelling. Although there appears to be an interaction between TGF-beta 1 and H2 relaxin, this does not appear to involve a reduction in CTGF mRNA expression. 相似文献
158.
Ung-il Chung Hiroshi Kawaguchi Tsuyoshi Takato Kozo Nakamura 《Journal of orthopaedic science》2004,9(4):410-414
Mammalian bones have three distinct origins (paraxial mesoderm, lateral plate mesoderm, and neural crest) and undergo two different modes of formation (intra-membranous and endochondral). Bones derived from the paraxial mesoderm and lateral plate mesoderm mainly form through the endochondral process. During this process, hypertrophic chondrocytes play a vital role in inducing both osteogenesis and angiogenesis. One of the essential osteogenic factors secreted from hypertrophic chondrocytes is Indian hedgehog (Ihh). In contrast, bones derived from the neural crest mainly form through the intramembranous pro-cess and do not require Ihh. Thus, depending on their origin, bones have distinct signaling properties, which need to be considered in the research and application of bone biology.Presented at the 18th Annual Research Meeting of the Japanese Orthopaedic Association, Kitakyushu, Japan, October 17, 2003 相似文献
159.
160.
Fady K. Balaa T. Clark Gamblin Allan Tsung J. Wallis Marsh David A. Geller 《Journal of gastrointestinal surgery》2008,12(2):338-343
Background Application of linear stapling devices for extrahepatic vascular control in liver surgery has been well-established. However,
the technique for use of stapling devices in hepatic parenchymal transection is not well defined.
Purpose To describe the safety and efficacy of our technique for use of vascular stapling devices in hepatic parenchymal transection
during open right hepatic lobectomy is the purpose of this study.
Methodology We reviewed our experience with 101 consecutive open right hepatic lobectomies performed by a single surgeon between January
2003 and July 2006, in which vascular staplers were utilized for the parenchymal transection phase.
Results Of the 101 patients who underwent resection, 53 (52%) were female. The mean age was 58 years. Malignant disease was the indication
for resection in the majority of patients (88%). Of those with cancer, 78% (69 of 89) had metastatic colorectal cancer, 6%
(5 of 89) had metastatic neuroendocrine tumor, 4% (4 of 89) had hepatocellular carcinoma, 4% (4 of 89) had cholangiocarcinoma,
and the remaining 8% were other metastatic cancers. Twelve patients (12%) underwent resection for hepatic adenoma or symptomatic
benign disease (FNH or hemangioma). Forty-eight patients (48%) underwent a major ancillary procedure at the time of hepatic
resection. Thirty-nine patients (39%) had a nonanatomic wedge resection of a left lobe lesion, 27 patients (27%) had one or
more lesions treated with radiofrequency ablation (RFA), and 6 patients (6%) were treated with a synchronous bowel resection.
The median total operative time was 336 min (range 155–620 min). A Pringle maneuver for temporary vascular inflow occlusion
was utilized in all cases, with a median time of 9 min (range 4–17 min). Ten patients (10%) required blood transfusion during
surgery or in the postoperative period. The maximum transfusion was 2 U of packed red blood cells (PRBC) in seven patients
and 1 U of PRBC in three patients. The mean nadir postoperative hematocrit was 28.2. All patients with malignant disease had
tumor-free margins at the completion of the procedure. The average hospital length of stay was 6.0 days. One patient (1%)
developed a clinically significant bile leak requiring a postoperative endoscopic retrograde cholangiography (ERCP). No patient
required reoperation. The 30 and 60-day postoperative survival was 100%.
Conclusion These findings indicate that application of vascular stapling devices for parenchymal transection in major hepatic resection
is a safe technique, with low transfusion requirements and minimal postoperative bile leak. The technique allows for rapid
transection of the entire right hepatic lobe in under 10 min. Short video clips of the technique will be demonstrated.
Presented at the 2007 American Hepato–Pancreato–Biliary Association, Las Vegas, Nevada, April 19–22, 2007 (oral presentation/video
presentation). 相似文献