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   2221篇
  免费   162篇
  国内免费   10篇
耳鼻咽喉   19篇
儿科学   130篇
妇产科学   31篇
基础医学   261篇
口腔科学   27篇
临床医学   159篇
内科学   465篇
皮肤病学   28篇
神经病学   179篇
特种医学   118篇
外科学   384篇
综合类   25篇
预防医学   86篇
眼科学   63篇
药学   209篇
中国医学   1篇
肿瘤学   208篇
  2023年   14篇
  2022年   55篇
  2021年   91篇
  2020年   44篇
  2019年   81篇
  2018年   86篇
  2017年   55篇
  2016年   46篇
  2015年   74篇
  2014年   94篇
  2013年   145篇
  2012年   166篇
  2011年   144篇
  2010年   100篇
  2009年   67篇
  2008年   74篇
  2007年   91篇
  2006年   101篇
  2005年   60篇
  2004年   69篇
  2003年   58篇
  2002年   65篇
  2001年   54篇
  2000年   53篇
  1999年   36篇
  1998年   31篇
  1997年   14篇
  1996年   16篇
  1995年   15篇
  1993年   11篇
  1992年   27篇
  1991年   38篇
  1990年   34篇
  1989年   29篇
  1988年   23篇
  1987年   19篇
  1986年   21篇
  1985年   18篇
  1984年   14篇
  1983年   10篇
  1982年   10篇
  1981年   8篇
  1980年   9篇
  1979年   10篇
  1977年   10篇
  1975年   9篇
  1974年   9篇
  1973年   11篇
  1972年   9篇
  1971年   7篇
排序方式: 共有2393条查询结果,搜索用时 0 毫秒
61.

Background

Tissue factor (TF), the physiologic initiator of coagulation, is over-expressed in pancreatic cancer, and is associated with a pro-coagulant and pro-angiogenic state. We hypothesized that in patients with pancreaticobiliary cancers (PBC), elevated circulating microparticle-associated TF (MP-TF) activity would be associated with thrombosis and worsened survival.

Patients and Methods

Clinical data and plasma were obtained for consecutive patients with PBC seen at Roswell Park Cancer Institute from 2005-08. MP-TF activity levels were measured using a TF-dependent FXa generation assay.

Results

The study population comprised 117 patients, including pancreatic (n = 80), biliary (n = 34) or unknown primary histologically consistent with PBC (n = 3). Of these, 52 patients (44.5%) experienced thromboembolism, including pulmonary embolism (n = 15), deep venous thrombosis (n = 21) and other arterial or venous events (n = 32). Mean TF was 2.15 (range 0.17- 31.01) pg/mL. Median survival was 98.5 days for MP-TF activity ≥ 2.5 pg/mL versus 231 days for MP-TF activity < 2.5 pg/mL (p < 0.0001). In multivariate analysis, elevated MP-TF activity was associated with both VTE (OR 1.4, 95% CI 1.1-1.6) and mortality (HR 2.5, 95% CI 1.4-4.5).

Conclusions

Elevated circulating MP-TF activity is associated with thrombosis and worsened survival in patients with PBC. MP-TF activity as a prognostic biomarker warrants further prospective evaluation.  相似文献   
62.

Background:

Therapeutic relevance of computed tomography (CT) in children with partial seizures is reported to be remarkably low (1-2%). However, in the developing countries where infections involving the nervous system are common, routine CT scan of brain may help in finding treatable causes of seizures.

Objective:

Aim of this study was to evaluate the significance of CT scan of brain in the management of children with partial seizures.

Materials and Methods:

Children with partial epilepsy, whose predominant seizure type was focal motor seizures, were included in the study. CT scan of brain was done in all children aged between 1 month and 12 years with partial seizures of unknown etiology prospectively. The clinical findings of these children were noted along with the CT findings.

Results:

Between August 2001 and July 2002, of the 200 children with seizure disorder 50 children who satisfied the inclusion criteria were included in the study. CT scan of brain was normal in 16 children (32%) and was abnormal in 34 children (68%). Twenty children (~60% of abnormal scan) had potentially correctable lesions: Tuberculoma (n = 13), neurocysticercosis (n = 3), and brain abscess (n = 4). Five children had changes representing static pathology that did not influence patient management. The clinical features correlated with CT findings in 78% children.

Conclusion:

Children with partial motor seizures have high probability of having abnormal findings on CT scan of brain, especially, neuro-infections which are potentially treatable. Therefore, CT scan brain should be carried out in all children with partial motor seizures especially, in developing countries.  相似文献   
63.
The growing fraction (GF) of tumor has been reported as one of the predictive markers of the efficacy of chemotherapeutics. Therefore, a semi-mechanistic model has been developed that describes tumor growth on the basis of cell cycle, allowing the incorporation of the GF of a tumor in pharmacokinetic/pharmacodynamic (PK/PD) modeling. Efficacy data of anti-glypican 3 (GPC3) antibody drug conjugate (ADC) in a hepatocellular carcinoma (HCC) patient derived xenograft (PDX) model was used for evaluation of this proposed model. Our model was able to describe the kinetics of growth inhibition of HCC PDX models following treatment with anti-GPC3 ADC remarkably well. The estimated tumurostatic concentrations were used in tandem with human PKs translated from cynomolgus monkey for prediction of the efficacious dose. The projected efficacious human dose of anti-GPC3 ADC was in the range 0.20–0.63 mg/kg for the Q3W dosing regimen, with a median dose of 0.50 mg/kg. This publication is the first step in evaluating the applicability of GF in PK/PD modeling of ADCs. The authors are hopeful that incorporation of GF will result in an improved translation of the preclinical efficacy of ADCs to clinical settings and thereby better prediction of the efficacious human dose.  相似文献   
64.
65.
Identifying pathogen and host-related laboratory parameters are essential for the early diagnosis of leprosy reactions. The present study aimed to clarify the validity of measuring the profiles of serum cytokines [interleukin (IL)-4, IL-6, IL-10, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha], the soluble IL-6 receptor (sIL-6R), soluble T cell (sCD27) and macrophage (neopterin) activation markers and Mycobacterium leprae-specific anti-PGL-I IgM antibodies in relation to the leprosy spectrum and reactions. Serum samples from 131 Indonesian leprosy patients (82 non-reactional leprosy patients and 49 reactional) and 112 healthy controls (HC) from the same endemic region were investigated. Forty-four (89.8%) of the reactional patients had erythema nodosum leprosum (ENL) while only five (10.2%) had reversal reaction (RR). Follow-up serum samples after corticosteroid treatment were also obtained from 17 of the patients with ENL and one with RR. A wide variability in cytokine levels was observed in the patient groups. However, IFN-gamma and sIL-6R were elevated significantly in ENL compared to non-ENL patients. Levels of IFN-gamma, TNF-alpha and sIL-6R declined significantly upon corticosteroid treatment of ENL. Thus, although the present study suggests limited applicability of serial measurement of IFN-gamma, TNF-alpha and sIL-6R in monitoring treatment efficacy of ENL, reactions it recommends a search for a wider panel of more disease-specific markers in future studies.  相似文献   
66.
Based on a multi-method study conducted with middle-class young people (aged 15–17) in three secondary schools in New Delhi, India, this paper focuses on heterosocial dynamics within school peer cultures as an important site of learning about gender and sexuality. Findings indicate that young people negotiate and adapt rakhi (brother-sister) relationships to form less strictly platonic heterosocial friendships, which leave open the possibility of romance. Students’ preferences for certain heterosocial relationships are considered within the context of wider cultural narratives. For example, students often rejected rakhi relationships, tied to traditional, conservative values, in favour of heterosocial friendships associated with more modern and desirable social patterns. Moreover, students’ own definitions of acceptable heterosocial interactions within peer cultures suggest that they are adept at negotiating norms of gender segregation that are enforced in co-educational schools. In contrast to other formal and informal sources of sexual learning available to them, experiences and stories of romances circulating in schools seemed to offer students alternative, more positive ways of understanding teenage intimacy and sexuality.  相似文献   
67.
The aim of this study was to describe a novel device that has been designed to facilitate anterior segment and novice surgeons to perform extraocular needle-guided haptic insertion technique (X-NIT) for scleral fixation intraocular lens surgery (SFIOL). We performed SFIOL surgery using X-NIT device in 21 eyes of 21 patients. The mean preoperative best-corrected visual acuity (BCVA) was 0.5 ± 0.2 logarithm of minimum angle of resolution (log MAR), which improved by one or more lines postoperatively in all eyes. There were no intraoperative complications. Postoperatively, we noted minimal corneal edema in one patient and dispersed vitreous hemorrhage in one patient. The sharpness and angulation of the needle and the haptic holding ability of silicone stopper were found to be satisfactory. The X-NIT device may potentially improve the safety of SFIOL procedures by minimizing intraocular maneuvers.  相似文献   
68.
HSS Journal ® - Few studies have analyzed differences in radiographic parameters and patient-reported outcomes (PROs) between expandable and static interbody devices in patients undergoing...  相似文献   
69.
Katsuura  Yoshihiro  Shafi  Karim  Jacques  Chelsie  Virk  Sohrab  Iyer  Sravisht  Cunningham  Matthew 《HSS journal》2020,16(2):177-182
HSS Journal ® - The biologic steps involved in creating a bony fusion between adjacent segments of the spine are a complex and highly coordinated series of events. There have been significant...  相似文献   
70.
CXCL12 is abundantly expressed in reticular cells associated with the perivascular niches of the bone marrow (BM) and is indispensable for B lymphopoiesis. Cxcl12 promotes osteoclastogenesis and has been implicated in pathologic bone resorption. We had shown earlier that estrogen receptor α deletion in osteoprogenitors and estrogen deficiency in mice increase Cxcl12 mRNA and protein levels in the BM plasma, respectively. We have now generated female and male mice with conditional deletion of a Cxcl12 allele in Prrx1 targeted cells (Cxcl12∆Prrx1) and show herein that they have a 90% decrease in B lymphocytes but increased erythrocytes and adipocytes in the marrow. Ovariectomy increased the expression of Cxcl12 and B-cell number in the Cxcl12f/f control mice, but these effects were abrogated in the Cxcl12∆Prrx1 mice. Cortical bone mass was not affected in Cxcl12∆Prrx1 mice. Albeit, the cortical bone loss caused by ovariectomy was greatly attenuated. Most unexpectedly, the rate of bone turnover in sex steroid–sufficient female or male Cxcl12∆Prrx1 mice was dramatically increased, as evidenced by a more than twofold increase in several osteoblast- and osteoclast-specific mRNAs, as well as increased mineral apposition and bone formation rate and increased osteoclast number in the endosteal surface. The magnitude of the Cxcl12∆Prrx1-induced changes were much greater than those caused by ovariectomy or orchidectomy in the Cxcl12f/f mice. These results strengthen the evidence that CXCL12 contributes to the loss of cortical bone mass caused by estrogen deficiency. Moreover, they reveal for the first time that in addition to its effects on hematopoiesis, CXCL12 restrains bone turnover—without changing the balance between resorption and formation—by suppressing osteoblastogenesis and the osteoclastogenesis support provided by cells of the osteoblast lineage. © 2020 American Society for Bone and Mineral Research.  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