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   665篇
  免费   52篇
  国内免费   3篇
耳鼻咽喉   17篇
儿科学   27篇
妇产科学   23篇
基础医学   45篇
口腔科学   34篇
临床医学   55篇
内科学   155篇
皮肤病学   2篇
神经病学   43篇
特种医学   19篇
外科学   101篇
综合类   33篇
预防医学   26篇
眼科学   7篇
药学   113篇
中国医学   2篇
肿瘤学   18篇
  2023年   15篇
  2022年   57篇
  2021年   85篇
  2020年   42篇
  2019年   53篇
  2018年   35篇
  2017年   23篇
  2016年   18篇
  2015年   22篇
  2014年   22篇
  2013年   19篇
  2012年   31篇
  2011年   31篇
  2010年   16篇
  2009年   11篇
  2008年   19篇
  2007年   29篇
  2006年   20篇
  2005年   16篇
  2004年   22篇
  2003年   8篇
  2002年   11篇
  2001年   6篇
  2000年   6篇
  1999年   5篇
  1997年   2篇
  1996年   4篇
  1995年   2篇
  1992年   3篇
  1991年   5篇
  1990年   2篇
  1989年   3篇
  1988年   6篇
  1987年   8篇
  1986年   3篇
  1985年   2篇
  1982年   3篇
  1979年   2篇
  1975年   3篇
  1974年   7篇
  1973年   5篇
  1972年   3篇
  1971年   8篇
  1968年   3篇
  1965年   2篇
  1964年   2篇
  1960年   1篇
  1959年   1篇
  1957年   2篇
  1956年   1篇
排序方式: 共有720条查询结果,搜索用时 11 毫秒
1.
A retrospective study was carried out on 40 children from Saudi Arabia with Henoch-Sch?nlein syndrome to delineate its clinical pattern. More than 50 per cent of the cases occurred in winter. There was no apparent causal relationship with B-haemolytic streptococcal infection. All patients had skin rash. Fifty-eight per cent had gastrointestinal manifestations, 58 per cent had joint manifestations and 38 per cent had renal manifestations. The main clinical features of Henoch-Sch?nlein syndrome in Saudi children are comparable to those reported elsewhere.  相似文献   
2.
3.
Increasing epidemiological evidence suggests that optimal diet quality helps to improve preservation of lung function and to reduce chronic obstructive pulmonary disease (COPD) risk, but no study has investigated the association of food insecurity (FI) and lung health in the general population. Using data from a representative sample of US adults who participated in the National Health and Nutrition Examination Survey (NHANES) 2007–2012 cycles, we investigated the association between FI with lung function and spirometrically defined COPD in 12,469 individuals aged ≥ 18 years of age. FI (high vs. low) was defined using the US Department of Agriculture’s Food Security Scale). Population-weighted adjusted regression models were used to investigate associations between FI, and forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), their ratio, and spirometrically defined restriction (FVC below the lower limit of normal) and airflow obstruction (COPD). The prevalence of household FI was 13.2%. High household FI was associated with lower FVC (adjusted β-coefficient −70.9 mL, 95% CI −116.6, −25.3), and with higher odds (OR) of spirometric restriction (1.02, 95% CI 1.00, 1.03). Stratified analyses showed similar effect sizes within specific ethnic groups. High FI was associated with worse lung health in a nationally representative sample of adults in the US.  相似文献   
4.
Kidney transplant (KT) outcomes for HIV-infected (HIV+) persons are excellent, yet acute rejection (AR) is common and optimal immunosuppressive regimens remain unclear. Early steroid withdrawal (ESW) is associated with AR in other populations, but its utilization and impact are unknown in HIV+ KT. Using SRTR, we identified 1225 HIV+ KT recipients between January 1, 2000, and December 31, 2017, without AR, graft failure, or mortality during KT admission, and compared those with ESW with those with steroid continuation (SC). We quantified associations between ESW and AR using multivariable logistic regression and interval-censored survival analysis, as well as with graft failure and mortality using Cox regression, adjusting for donor, recipient, and immunologic factors. ESW utilization was 20.4%, with more zero HLA mismatch (8% vs 4%), living donors (26% vs 20%), and lymphodepleting induction (64% vs 46%) compared to the SC group. ESW utilization varied widely across 129 centers, with less use at high- versus moderate-volume centers (6% vs 21%, P < .001). AR was more common with ESW by 1 year (18.4% vs 12.3%; aOR: 1.081.612.41, P = .04) and over the study period (aHR: 1.021.391.90, P = .03), without difference in death-censored graft failure (aHR 0.600.911.36, P = .33) or mortality (aHR: 0.751.151.77, P = .45). To reduce AR after HIV+ KT, tailoring of ESW utilization is reasonable.  相似文献   
5.
In the liver, the immunostaining of cytokeratins (CK) 7 and 20 has been used to distinguish usual peripheral cholangiocarcinomas (CC) and colorectal carcinoma metastasis (CRM). However, other subtypes of CC are not infrequent and may be particularly difficult to distinguish from CRM by histology and even immunohistochemistry. Therefore, 48 CC from different locations, either peripheral (n = 19), or nonperipheral, that is, from the large intrahepatic bile ducts, the hilum, and the extrahepatic bile ducts (n = 29), and with different cytoarchitectural patterns were tested for CK7 and CK20 and compared with 31 CRM. CC were positive for CK7 and CK20 in 96% and 70%, respectively, whatever the architecture and differentiation of the tumor. The labeling index (LI) of CK7 in CC was always high, whereas it was low or moderate for CK20. CK20-positive phenotype was significantly more frequent in nonperipheral than in peripheral CC (82% vs 47%; p = 0.007). CRM were all positive for CK20 with a high LI, and mostly negative (81%) for CK7. In conclusion, (1) the CK immunoprofile of CC varies according to the location of the tumor in the biliary tract, peripheral CC being more often CK7+/CK20-, and nonperipheral ones CK7+/CK20+; and (2) a decision tree based on CK20 LI and CK7 positivity allows the distinction of CRM and CC, even for the nonperipheral type.  相似文献   
6.
Between January 1993 and December 2000, an unrelated donor search (UDS) was initiated for 97 consecutive patients [46 acute lymphoblastic leukemia (ALL) and 51 acute myeloid leukemia (AML)]. Leukemia was considered to be of poor prognosis in cases of refractory disease (n=70), unfavourable karyotype (n=22) or miscellaneous (n=5). All patients had previously received various chemotherapies and 9 had undergone an autologous stem cell transplantation (SCT). The median age at UDS initiation was 25 (range 2.7-55) years. The median time to identify a suitable living donor or cord blood (CB) was 60 days. Eventually, 33 patients received unrelated allo-SCT (including 9 CB), 12 auto-SCT, 39 chemotherapy and 13 palliative treatment. At a median of 54 months, 18 patients were alive, including 15 in remission. The 4-year overall survival rates were 32%, 37%, 15% and 0% for allo-SCT, auto-SCT, chemotherapy or palliative treatment, respectively. Patients who received either allo- or auto-SCT had better survival than those who did not (P<0.0001). For ALL, only allo-SCT significantly improved survival (P<0.007). Finally, patients who received allo-SCT died less often of relapse than patients who did not (P<0.0001). Unrelated allo-SCT gives a substantial long-term survival and cure in patients with high-risk acute leukemia. For patients who achieve remission and for whom UDS fails, auto-SCT may prove to be a good approach. For patients who fail to enter into remission, intensive salvage chemotherapy has a very limited effect.  相似文献   
7.
Herein, zinc oxide nanoparticles (ZnO NPs) were greenly synthesized from Tridax procumbens aqueous leaf extract (TPE) and characterized physically (e.g., Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM)) and biologically (test of their anti-diabetic activity). Anti-diabetic activities of TPE and TPE-derived ZnO NPs have been carried out in a streptozotocin (STZ)—induced diabetic rat model. Diabetes mellitus (DM) was induced with a single intraperitoneal dosage of the glucose analogue STZ (55 mg/Kg) known to be particularly toxic to pancreatic insulin-producing beta-cells. TPE and TPE-derived ZnO NPs were administered orally, once every day for 21 days in diabetic rats, at 100 and 200 mg/Kg, respectively. The standard antidiabetic medication, glibenclamide, was used as a control at a dose of 10 mg/Kg. Various parameters were investigated, including bodyweight (bw) variations, glycemia, lipidaemia, glycated hemoglobin (HbA1c), and histopathological alterations in the rat’s liver and pancreas. The TPE-mediated NPs were small, spherical, stable, and uniform. Compared to TPE and, to a lesser extent, glibenclamide, TPE-derived ZnO NPs lowered blood glucose levels considerably (p < 0.05) and in a dose-dependent manner while preventing body weight loss. Further, positive benefits for both the lipid profile and glycated hemoglobin were also noticed with TPE-derived ZnO NPs. The histopathological assessment revealed that synthesized TPE-derived ZnO NPs are safe, non-toxic, and biocompatible. At 200 mg/Kg/day, TPE-derived ZnO NPs had a more substantial hypoglycemic response than at 100 mg/Kg/day. Thus, in this first reported experimental setting, ZnO NPs biosynthesized from the leaf extract of Tridax procumbens exert more potent anti-diabetic activity than TPE and glibenclamide. We conclude that such a greenly prepared nanomaterial may be a promising alternative or complementary (adjuvant) therapy, at least to the current Indian’s traditional medicine system. Translational findings are prompted in human populations to determine the efficacy of these NPs.  相似文献   
8.
(1) Background: The management of gastrointestinal stromal tumors (GIST) has significantly evolved over the last two decades, with the introduction of tyrosine kinase inhibitors (TKI). We aim to report 10 years of experience of GIST management at a regional cancer center in Canada. (2) Methods: We retrospectively analyzed the records of 248 consecutive patients diagnosed with GIST between 2011 and 2021. We describe the clinical and pathological data, management, and outcome, including survival. (3) Results: The most common GIST sites were the stomach 63% (156), followed by the small bowel 29% (73). At diagnosis, 83% (206) of patients had localized disease (stage I–III). According to the modified National Institutes of Health consensus criteria (NIH) for GIST, around 45% (90) had intermediate or high-risk disease. Most patients, 86% (213), underwent curative surgical resection. Forty-nine patients received adjuvant imatinib, while forty-three patients had advanced disease and received at least one line of TKI. With a median follow-up of 47 months, the 5-year recurrence-free survival (RFS) rates for very low and low risk were 100% and 94%, respectively, while those for intermediate and high risk were 84% and 51%, respectively. The 5-year overall survival (OS) rates for very low and low risk were 100% and 94%, while intermediate, high risk, and advanced were 91%, 88%, and 65%, respectively. Using the Kaplan–Meier method, there were statistically significant differences in RFS and OS between NIH risk groups, p < 0.0005. In univariate analysis, ECOG, site, mitosis, secondary malignancy, and size were predictors for OS. High mitosis and large size (>5 cm) were associated with worse RFS. (4) Conclusions: Curative surgical resection remains the gold standard management of GIST. Our results are comparable to the reported literature. Further research is needed to explore histology’s role in risk stratification and initiating adjuvant TKI.  相似文献   
9.
10.
The COVID-19 pandemic has the tendency to affect various organizational paradigm alterations, which civilization hasyet to fully comprehend. Personal to professional, individual to corporate, and across most industries, the spectrum of transformations is vast. Economically, the globe has never been more intertwined, and it has never been subjected to such widespread disruption. While many people have felt and acknowledged the pandemic’s short-term repercussions, the resultant paradigm alterations will certainly have long-term consequences with an unknown range and severity. This review paper aims at acknowledging various approaches for the prevention, detection, and diagnosis of the SARS-CoV-2 virus using nanomaterials as a base material. A nanostructure is a material classification based on dimensionality, in proportion to the characteristic diameter and surface area. Nanoparticles, quantum dots, nanowires (NW), carbon nanotubes (CNT), thin films, and nanocomposites are some examples of various dimensions, each acting as a single unit, in terms of transport capacities. Top-down and bottom-up techniques are used to fabricate nanomaterials. The large surface-to-volume ratio of nanomaterials allows one to create extremely sensitive charge or field sensors (electrical sensors, chemical sensors, explosives detection, optical sensors, and gas sensing applications). Nanowires have potential applications in information and communication technologies, low-energy lightning, and medical sensors. Carbon nanotubes have the best environmental stability, electrical characteristics, and surface-to-volume ratio of any nanomaterial, making them ideal for bio-sensing applications. Traditional commercially available techniques have focused on clinical manifestations, as well as molecular and serological detection equipment that can identify the SARS-CoV-2 virus. Scientists are expressing a lot of interest in developing a portable and easy-to-use COVID-19 detection tool. Several unique methodologies and approaches are being investigated as feasible advanced systems capable of meeting the demands. This review article attempts to emphasize the pandemic’s aftereffects, utilising the notion of the bullwhip phenomenon’s short-term and long-term effects, and it specifies the use of nanomaterials and nanosensors for detection, prevention, diagnosis, and therapy in connection to the SARS-CoV-2.  相似文献   
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