全文获取类型
收费全文 | 4052篇 |
免费 | 228篇 |
国内免费 | 50篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 117篇 |
妇产科学 | 27篇 |
基础医学 | 580篇 |
口腔科学 | 86篇 |
临床医学 | 256篇 |
内科学 | 1153篇 |
皮肤病学 | 23篇 |
神经病学 | 253篇 |
特种医学 | 180篇 |
外科学 | 758篇 |
综合类 | 19篇 |
预防医学 | 78篇 |
眼科学 | 22篇 |
药学 | 212篇 |
中国医学 | 6篇 |
肿瘤学 | 552篇 |
出版年
2024年 | 1篇 |
2023年 | 37篇 |
2022年 | 66篇 |
2021年 | 132篇 |
2020年 | 62篇 |
2019年 | 75篇 |
2018年 | 135篇 |
2017年 | 88篇 |
2016年 | 118篇 |
2015年 | 133篇 |
2014年 | 160篇 |
2013年 | 179篇 |
2012年 | 353篇 |
2011年 | 351篇 |
2010年 | 173篇 |
2009年 | 155篇 |
2008年 | 254篇 |
2007年 | 289篇 |
2006年 | 270篇 |
2005年 | 214篇 |
2004年 | 225篇 |
2003年 | 238篇 |
2002年 | 195篇 |
2001年 | 37篇 |
2000年 | 41篇 |
1999年 | 46篇 |
1998年 | 52篇 |
1997年 | 35篇 |
1996年 | 34篇 |
1995年 | 31篇 |
1994年 | 20篇 |
1993年 | 26篇 |
1992年 | 34篇 |
1991年 | 9篇 |
1990年 | 8篇 |
1989年 | 7篇 |
1988年 | 13篇 |
1987年 | 9篇 |
1986年 | 2篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1970年 | 2篇 |
1967年 | 1篇 |
排序方式: 共有4330条查询结果,搜索用时 0 毫秒
41.
Colloidal crystals (CCs) are periodic arrays of monodisperse microparticles. Such CCs are very attractive as they can be potentially applicable as versatile photonic devices such as reflective displays, sensors, lasers, and so forth. In this article, we describe a promising methodology for synthesizing monodisperse magnetite microparticles whose diameters are controllable in the range of 100–200 nm only by adjusting the base concentration of the reaction solution. Moreover, monodisperse magnetite microparticles in aqueous suspensions spontaneously form the CC structures under an external magnetic field, leading to the appearance of Bragg reflection colors. The reflection peak can be blue-shifted from 730 nm to 570 nm by the increase in the external magnetic field from 28 mT to 220 mT. Moreover, the reflection properties of CCs in suspension depend on the microparticle concentration in suspension and the diameter of the magnetite microparticles. Both fine-control of microparticle diameter and investigation of magneto-optical properties of CCs would contribute to the technological developments in full-color reflective displays and sensors by utilizing these monodisperse magnetite microparticles. 相似文献
42.
Shin Kobayashi Naoto Gotohda Toshio Nakagohri Shinichiro Takahashi Masaru Konishi Taira Kinoshita 《World journal of surgery》2009,33(2):312-317
Background Risk factors of surgical site infection (SSI) after hepatectomy under the guideline of Centers for Disease Control and Prevention
(CDC) are not well examined.
Methods Hospital records of consecutive patients who underwent hepatectomy without biliary reconstruction for liver cancers were reviewed
retrospectively. Prophylactic antibiotics were given to patients just before skin incision and every 3 hours during the operations.
Clinicopathological factors were compared between patients who developed SSI and those without it.
Results There were 405 patients identified, and the incidence of SSI was 23 cases (5.8%). In multivariate analysis, intraoperative
bowel injury, blood loss >2000 ml, and age older than 65 years were significant risk factors of SSI after hepatectomy.
Conclusions Prophylactic antibiotics were necessary only during the operation for most patients who underwent hepatectomy without biliary
reconstruction. However, patients with intraoperative bowel injury, blood loss >2000 ml, and age older than 65 years are at
risk to develop SSI and might need additional administration of prophylactic antibiotics after surgery. 相似文献
43.
Chikara Kunisaki Hirochika Makino Ryo Takagawa Kei Sato Mayumi Kawamata Amane Kanazawa Naoto Yamamoto Yasuhiko Nagano Shoichi Fujii Hidetaka A. Ono Hirotoshi Akiyama Hiroshi Shimada 《Surgical endoscopy》2009,23(9):2085-2093
Background Some studies have found high incidences of intraoperative and postoperative complications for patients with gastric cancer.
To determine the predictive factors for the surgical complications of laparoscopic gastric surgery, surgical outcomes were
evaluated.
Methods Between April 2002 and December 2007, 152 patients with preoperatively diagnosed early gastric cancer who underwent laparoscopy-assisted
distal gastrectomy (LADG) were enrolled. Visceral (VFA) and subcutaneous fat areas (SFA) were assessed by Fat Scan software.
The predictive factors for surgical complications of LADG were evaluated by univariate and logistic regression analyses.
Results Of 152 patients, conversion to open surgery due to uncontrollable bleeding was observed in nine male patients, and postoperative
complications were detected in seven male and one female patient (four anastomotic leakage, two intraabdominal abscess, one
pancreatic fistula, and one lymphorrhea). High body mass index (BMI) and high VFA independently predicted conversion to open
surgery and postoperative complications. VFA was significantly higher, operation time was longer, blood loss was greater,
and SFA was lower in male than in female patients, whereas no significant difference was observed in BMI between male and
female patients.
Conclusions High BMI and high VFA can predict technical difficulties during laparoscopic gastric surgery and postoperative complications.
Particularly, LADG should be performed cautiously to prevent surgical complications for male patients with high VFA. Predictive
impact of VFA should be further determined in a larger set of patients. 相似文献
44.
45.
Fukuda N Wada J Niki M Sugiyama Y Mushiake H 《World journal of emergency surgery : WJES》2012,7(1):12-6
ABSTRACT: OBJECTIVE: This study aimed to investigate clinical features of abdominal emergency surgery in elderly patients, and to determine factors predicting mortality in these patients. METHODS: The study population included 94 patients aged 80 years or older who underwent emergency surgery for acute abdominal diseases between 2000 and 2010. Thirty-six patients (38.3%) were male and fifty-eight patients (61.7%) were female (mean age, 85.6 years). Main outcome measures included background of the patient's physical condition (concomitant medical disease, and performance status), cause of disease, morbidity and mortality, and disease scoring system (APACHE II, and POSSUM). Prognostic factors affecting mortality of the patient were also evaluated by univariate analysis using Fisher's exact test and Mann- Whitney U-test, and by multivariate analysis using multiple logistic regression analysis. RESULTS: Of the 94 patients, 71 (75.5%) had a co-existing medical disease; most patients had hypertension (46.8%). The most frequent surgical indications were acute cholecystitis in 23 patients (24.5%), followed by intestinal obstruction in 18 patients (19.1%). Forty-one patients (43.6%) had complications during hospital stay; the most frequent were surgical site infection (SSI) in 21 patients (22.3%) and pneumonia in 12 patients (12.8%). Fifteen patients died (overall mortality, 16%) within 1 month after operation. The most common causes of death were sepsis related to pan-peritonitis in 5 patients (5.3%), and pneumonia in 4 patients (4.3%). Multiple logistic regression analysis showed that time from onset of symptoms to hospital admission and the POSSUM scoring system could be prognostic factors for mortality. CONCLUSIONS: Mortality in elderly patients who underwent emergency surgery for acute abdominal disease can be predicted using the disease scoring system (POSSUM) and on the basis of delay in hospital admission. Keywords. 相似文献
46.
Yukiko Hasuike Naoto Kakita Makoto Aichi Satoko Masachika Mari Kantou Shoko Ikeda Takahashi Masayoshi Nanami Yasuyuki Nagasawa Takahiro Kuragano Takeshi Nakanishi 《Journal of vascular surgery》2019,69(1):174-180.e2
Objective
For patients with end-stage renal disease on hemodialysis, the durability of vascular access (VA) is still far from optimal, and access survival after intervention for access failure is an important aspect. Procoagulant status is a leading cause of access failure. Coagulation-fibrinolysis imbalance can occur in hemodialyzed patients, but the influence of the imbalance has not been fully elucidated.Methods
We prospectively examined coagulation-fibrinolysis balance to assess the risk of access failure after the intervention of revascularization in a cohort of 462 hemodialysis patients. Thrombin-antithrombin complex (TAT) and plasmin-α2-plasmin inhibitor complex (PIC) are markers for coagulation and fibrinolysis. Median follow-up was 243 days. The end point was clinical access failure: revascularization or access revision. The survival curve for VA patency was assessed using the Kaplan-Meier method and compared using the log-rank test. Cox proportional hazards regression models that allowed adjustment for baseline differences in age, sex, dialysis vintage, diabetes mellitus, and various factors (quantity of blood flow, prothrombin time-international normalized ratio, fibrin degradation products, C-reactive protein, interleukin-6, tumor necrosis factor-α, and pentraxin-3) were used.Results
The 162 patients who reached an end point had smaller access flow volume and smaller percentage of arteriovenous fistula and higher TAT/PIC ratio. Kaplan-Meier analysis indicated that the patients with elevated TAT/PIC ratio showed poorer outcome (P < .001). On Cox regression modeling, elevated TAT/PIC was an independent risk factor for access failure (hazard ratio, 1.58; P = .03).Conclusions
Our results suggest that coagulation-fibrinolysis imbalance is a significant risk factor for access failure and may predict VA failure in hemodialyzed patients after access intervention. 相似文献47.
48.
Yoshiyuki Nakatsuji Kendo Kiyosawa Eiji Tanaka Takeshi Sodeyama Naoto Horigome Shoji Kajikawa Shigeko Naito Yoshihiro Akahane 《Liver international》1991,11(3):176-184
ABSTRACT— To clarify the discrepancy in hepatitis B surface antigen (HBsAg) subtypes present in the serum and liver, as well as among hepatocytes, liver specimens which were resected from 37 HBsAg-positive patients with hepatocellular carcinoma (HCC) were examined. We evaluated HBsAg and the subtypic determinants of HBsAg and hepatitis B core antigen (HBcAg) using the peroxidase-antiperoxidase (PAP) staining method. Hepatitis B antigens were more frequently detected in small tumors (HBsAg in 67%, HBcAg in 40%) than in large ones (HBsAg in 36%, HBcAg in 14%). The prevalence of each subtypic determinant in the HBsAg positive non-tumorous vs. tumorous areas was 100% vs. 67% in a, 100% vs. 57% in d, 100% vs. not tested in y, 100% vs. 53% in r and 25% vs. 0% in w (a, d, y, r and w represent subtypic determinants). There was virtually no difference in a set of subtypic determinants between the serum and liver. However, there were some variations in a set of subtypic determinants among the hepatocytes. On the other hand, liver tissue of compound subtype adyr in serum contained both cells with a,d,r and with a,y,r as well as a few cells with a,d,y,r. These findings suggest that HBV genomes in hepatocytes of type B chronic liver disease may differ genetically among cells even in the same liver tissue. 相似文献
49.
Cho A Arita S Koike N Isaka N Kusume K Okazumi S Makino H Tohma T Matsubara K Gunji H Ochiai T 《Hepato-gastroenterology》2005,52(66):1886-1888
Two-staged pancreatoduodenectomy, including exteriorization of the pancreatic juice and second-look pancreaticojejunostomy, has been recommended for high-risk patients to avoid pancreatic leakage, which often causes intra-abdominal hemorrhage. We present a new technique of interventional pancreaticojejunostomy under both fluoroscopy and endoscopy without second-look laparotomy. A 77-year-old woman with local recurrence and liver metastasis from colon cancer underwent hepato-pancreatoduodenectomy with the external drainage of pancreatic juice via the pancreatic duct tube without pancreaticojejunostomy. Two months later, the jejunum was punctured with the insertion of a 5-F needle-knife into the pancreatic fistula during endoscopic observation of jejunal lumen, followed by the insertion of two 0.35-inch guidewires into the jejunum and the pancreatic fistula. Finally, a 10-Fr stenting tube was placed between the jejunum and the pancreatic fistula. No complications developed. 相似文献
50.
Saito Y Guo YM Hirokawa M Saito K Komatsuda A Takahashi N Fujishima M Fujishima N Yamashita J Sawada K 《International journal of hematology》2008,88(1):64-72
Tumor necrosis factor-alpha (TNF-alpha) has been shown to induce the differentiation of CD34(+) cells toward dendritic cells (DCs). We have previously shown that DCs are co-generated from human CD34(+) cells during erythroid or megakaryocytic differentiation in the presence of TNF-alpha, and those DCs are able to stimulate autologous T cell proliferation. The aim of this study was to learn whether the co-stimulation of granulocyte colony-stimulating factor (G-CSF) and TNF-alpha would generate neutrophil progenitors and DCs together from human CD34(+) cells, and if this was the case, to clarify the phenotypic and functional characteristics of these DCs. When highly purified human CD34(+) cells were cultured for 7 days with G-CSF alone, the generated cells predominantly expressed a granulocyte marker, CD15, and then differentiated into neutrophils after 14 days of culture. The addition of TNF-alpha with G-CSF markedly decreased the number of CD15(+) cells without affecting the total number of cells during 7 days of culture. Almost one third of the generated cells were positive for CD11c and CD123. Furthermore, CD11c(+) cells were found to phagocytose CD15(+) cells and were able to induce allogeneic, but not autologous, T cell proliferation in the mixed lymphocyte reaction (MLR). On the other hand, the CD11c(+) cells generated by TNF-alpha and cytokines capable of inducing erythroid differentiation were able to stimulate autologous T cells. There was a difference in the expression of CD80, CD83 and CD86 among CD11c(+) cells induced by G-CSF plus TNF-alpha and those generated by interleukin-3, stem cell factor, and erythropoietin plus TNF-alpha. These results indicate that the co-stimulation of human CD34(+) cells with G-CSF and TNF-alpha induces the phagocytosis of co-developing neutrophil progenitors by DCs, and the stimulatory effects of these DCs on autologous T cells is different from that of DCs generated from CD34(+) cells during erythroid differentiation. 相似文献