全文获取类型
收费全文 | 8598篇 |
免费 | 540篇 |
国内免费 | 50篇 |
专业分类
耳鼻咽喉 | 222篇 |
儿科学 | 476篇 |
妇产科学 | 83篇 |
基础医学 | 797篇 |
口腔科学 | 252篇 |
临床医学 | 727篇 |
内科学 | 2096篇 |
皮肤病学 | 96篇 |
神经病学 | 618篇 |
特种医学 | 241篇 |
外科学 | 1562篇 |
综合类 | 229篇 |
一般理论 | 2篇 |
预防医学 | 330篇 |
眼科学 | 373篇 |
药学 | 517篇 |
中国医学 | 29篇 |
肿瘤学 | 538篇 |
出版年
2023年 | 102篇 |
2022年 | 207篇 |
2021年 | 395篇 |
2020年 | 242篇 |
2019年 | 258篇 |
2018年 | 348篇 |
2017年 | 244篇 |
2016年 | 278篇 |
2015年 | 296篇 |
2014年 | 441篇 |
2013年 | 505篇 |
2012年 | 691篇 |
2011年 | 650篇 |
2010年 | 388篇 |
2009年 | 326篇 |
2008年 | 500篇 |
2007年 | 499篇 |
2006年 | 387篇 |
2005年 | 324篇 |
2004年 | 303篇 |
2003年 | 268篇 |
2002年 | 230篇 |
2001年 | 123篇 |
2000年 | 92篇 |
1999年 | 94篇 |
1998年 | 68篇 |
1997年 | 48篇 |
1996年 | 33篇 |
1995年 | 28篇 |
1994年 | 33篇 |
1993年 | 30篇 |
1992年 | 57篇 |
1991年 | 69篇 |
1990年 | 60篇 |
1989年 | 55篇 |
1988年 | 53篇 |
1987年 | 46篇 |
1986年 | 41篇 |
1985年 | 45篇 |
1984年 | 17篇 |
1983年 | 28篇 |
1982年 | 15篇 |
1979年 | 31篇 |
1978年 | 20篇 |
1975年 | 22篇 |
1973年 | 14篇 |
1972年 | 21篇 |
1971年 | 14篇 |
1970年 | 15篇 |
1965年 | 13篇 |
排序方式: 共有9188条查询结果,搜索用时 15 毫秒
61.
Diagnostic impact of core-needle biopsy on fine-needle aspiration of non-Hodgkin lymphoma 总被引:1,自引:0,他引:1
Gong JZ Snyder MJ Lagoo AS Vollmer RT Dash RR Madden JF Buckley PJ Jones CK 《Diagnostic cytopathology》2004,31(1):23-30
We retrospectively reviewed 74 fine-needle aspiration (FNA) cases of presumptive non-Hodgkin lymphoma (NHL). All the cases had cytology and core-needle biopsy and 53 cases had concurrent flow cytometric analysis. FNA (cytology and flow cytometry) and core-needle biopsy were evaluated independently. FNA was diagnostic of diffuse large B-cell lymphoma (DLBL) in 25% (13/53) of cases and small B-cell NHL in 15% (8/53) of cases, whereas core-needle biopsy was diagnostic of DLBL in 37% (27/74) of cases and small B-cell NHL in 8% (6/74) of cases. Subclassification of small B-cell NHL was reached in 3/6 cases by core-needle biopsy. Insufficient cases were observed in both FNA (47%; 25/53) and core-needle biopsy (28%; 21/74) groups. With the combination of FNA and core-needle biopsy, diagnostic cases of DLBL increased to 43% (32/74) and insufficient samples were reduced to 16% (12/74). There was no clear advantage in the diagnosis and classification of small B-cell NHL by adding core-needle biopsy to FNA (14%; 10/74). We conclude that core-needle biopsy is a useful adjunct to FNA in the diagnosis of DLBL and shall be encouraged. In small B-cell NHL, core-needle biopsy does not add to the diagnostic ability of FNA. Cases insufficient for diagnosis may be seen in both core-needle biopsy and FNA. A combined approach reduces the number of insufficient cases and is recommended in routine FNA practice. 相似文献
62.
Jacobson SG Sumaroka A Aleman TS Cideciyan AV Schwartz SB Roman AJ McInnes RR Sheffield VC Stone EM Swaroop A Wright AF 《Human molecular genetics》2004,13(17):1893-1902
Mutations in the nuclear receptor gene, NR2E3, cause a disorder of human retinal photoreceptor development characterized by hyperfunction and excess of the minority S (short wavelength or blue) cone photoreceptor type, but near absence of function of the majority rod receptor. NR2E3 disease can also progress to blindness. How the human retina accommodates mis-specified types and numbers of neurons and advances to retinal degeneration are unknown. We studied the retinal organization in vivo of patients with NR2E3 mutations. Early human NR2E3 disease with S cone hyperfunction showed thickened retinal layers within an otherwise normally structured retina. With visual loss, however, lamination was coarse and there was a strikingly thick and bulging appearance to the retina, localized to an annulus encircling the central fovea. This pattern was not found in other retinal degenerations. The abnormal laminar retinal architecture of early NR2E3 disease may be due in part to larger cells with an S cone phenotype in place of rods that failed to differentiate. The later-stage dysplastic appearance suggests a previously unrecognized proliferative response in human retinal degeneration. 相似文献
63.
We have studied quantitatively the levels of substance P and calcitonin gene-related peptide in nerves innervating skin and muscle of rats, and examined the effects of cross-anastomosing these nerves so that they regenerate to an inappropriate target. We have also compared the ability of nerves to induce neurogenic extravasation with their peptide content. Peptide was measured by radioimmunoassay in the proximal section of ligated peripheral nerves, and neurogenic oedema was measured by determination of Evans Blue extravasation induced by either systemic capsaicin treatment or topical mustard oil application. The levels of these peptides are higher in cutaneous nerves than muscle nerves. This cannot be explained by differences in the number of fibres in the nerves studied. The levels of peptides fall when cutaneous afferents reinnervate muscle, and rise when muscle afferents reinnervate skin. We suggest that these changes occur because of some tissue-specific trophic influence arising from the tissue innervated. The ability to produce extravasation in skin is highly correlated with the substance P and calcitonin gene-related peptide levels of its innervation, even when this occurs in inappropriate nerves which do not normally produce extravasation. 相似文献
64.
Optimum dosage of ispaghula husk in patients with irritable bowel syndrome: correlation of symptom relief with whole gut transit time and stool weight. 总被引:4,自引:1,他引:3 下载免费PDF全文
To determine the optimum dose of ispaghula husk in patients with irritable bowel syndrome (IBS) and to assess the correlation, if any between the relief in patients' symptoms and the whole gut transit time, and the increase in stool weight, a two part study was carried out. In part 1, 14 male patients were given ispaghula husk in increasing doses of 10 g, 20 g, and 30 g a day for a duration of 17 days each (14 days of study period + three days of stool collection). Ten patients completed the trial. The symptom score improved significantly with all the three doses of ispaghula. Both 20 g and 30 g doses of ispaghula were superior to the 10 g dose but there was no significant difference between the 20 g and 30 g doses. There was a significant (p less than 0.001) increase in the daily stool weight with 10 g dose of fibre with further significant increases with the 20 g and 30 g doses. A positive correlation was seen between the improvement in the symptom score and the increase in stool weight with the 10 g dose of ispaghula but not with the 20 g and 30 g doses. Whole gut transit time remained fairly constant throughout the study period and there was no relationship with either the dose of ispaghula, the alteration in stool weight, or the improvement in the patients symptoms. Ten patients completed part 2 of the study in which ispaghula husk was given in the same dose (10 g, 20 g, and 30 g) but in a random order and with a "washout" period of one week between individual doses. Again all the three doses of ispaghula produced a significant improvement in the symptoms; 20 g and 30 g doses were equally effective and both were significantly superior to the 10 g dose. Assessed individually, all the three symptoms improved significantly; improvement in constipation and pain abdomen was more pronounced than diarrhoea. It is concluded that the optimum dose of ispaghula husk in irritable bowel syndrome is 20 g per day. There is some correlation between the increase in stool weight and the improvement in symptom score but the whole gut transit time remains unchanged despite alterations in stool weight and patients' symptoms. 相似文献
65.
66.
Christian Klemt Paul Walker Anand Padmanabha Venkatsaiakhil Tirumala Liang Xiong Young-Min Kwon 《The Journal of arthroplasty》2021,36(4):1393-1400
BackgroundRacial and ethnic disparities in access to hip and knee total joint arthroplasty (TJA) and postoperative outcomes have wide-reaching implications for patients and the health care system. The aim of this study is to evaluate the effect of ethnicity on clinical outcomes and complications following revision hip and knee TJA.MethodsA single-institution, retrospective analysis of a consecutive series of 4424 revision hip and knee TJA patients was evaluated. Student’s t-test and chi-squared analysis were used to identify significant differences in patient demographics and clinical outcomes between Caucasians and various ethnic minorities, including African Americans, Hispanics, and Asians.ResultsWhen compared with white patients, African American patients demonstrated a significantly higher BMI (P = .04), ASA score (P = .04), length of hospital stay (P = .06), and postoperative infection rates (P = .04). Hispanics demonstrated a significantly higher BMI (P = .04), when compared with white patients, alongside a significantly higher risk for postoperative infection (P < .01). African American demonstrated a significantly higher ASA score (P = .02; P = .03), when compared with Hispanics and Asians, alongside a significantly increased length of stay (P = .01) and higher risk for postoperative infection (P = .02).ConclusionThe study findings demonstrate an underutilization of revision TJA by ethnic minority groups, suggesting that disparities in access to orthopedic surgery increase from primary to revision surgery despite higher failure rates of minority ethnic groups reported after primary TJA surgery. In addition, inferior postoperative outcomes were associated with African Americans and Hispanics, when compared to white patients, with African Americans demonstrating the highest risk of postoperative complications. 相似文献
67.
68.
Sandeep K. Jha Imtiakum Jamir Kshitij Sisodia Niteen Kumar Gaurav Sood Nitin Shanker Sachin Anand Gaurav Dubey Vinod Choudhary Pankaj Lohia Amit Singhal Manav Wadhawan Ajay Kumar Abhideep Chaudhary 《Transplantation proceedings》2021,53(4):1118-1125
IntroductionLiving-donor liver transplantation (LDLT) has been mostly suspended and deceased-donor living transplantation activity has been considerably reduced because of coronavirus disease 2019 (COVID-19). We modified our protocols and procedures in line with COVID-19 guidelines. Since the restructuring, we have performed 20 LDLTs. Our study reports the outcomes of these cases and demonstrates the feasibility of LDLT during this pandemic.Materials and MethodsThe changes were influenced by experiences and communications from across the globe. A month-long self-imposed moratorium was spent in restructuring the program and implementing new protocols. Twenty LDLTs were performed between April 18 and September 15 using the new protocols. Our experience includes 2 simultaneous liver-kidney transplants, 1 ABO-incompatible LDLT, and 1 pediatric case (age 11 months).ResultsNineteen patients recovered and 1 patient died. We maintained our postoperative immunosuppression protocol without many changes. Major complications were observed in 30% of recipients but none of the donors. One recipient was infected with COVID-19 during the postoperative period. A donor-recipient couple contracted COVID-19 after discharge from the hospital. All patients recovered from COVID-19 and liver enzymes were unaffected.ConclusionThis study represents a microcosm of experience in LDLT during the COVID-19 era. Outcomes of LDLT are not affected by COVID-19 per se, provided that we make necessary changes. 相似文献
69.
Rania El Fekih James Hurley Vasisht Tadigotla Areej Alghamdi Anand Srivastava Christine Coticchia John Choi Hazim Allos Karim Yatim Juliano Alhaddad Siawosh Eskandari Philip Chu Albana B. Mihali Isadora T. Lape Mauricio P. Lima Filho Bruno T. Aoyama Anil Chandraker Kassem Safa James F. Markmann Leonardo V. Riella Richard N. Formica Johan Skog Jamil R. Azzi 《Journal of the American Society of Nephrology : JASN》2021,32(4):994
BackgroundDeveloping a noninvasive clinical test to accurately diagnose kidney allograft rejection is critical to improve allograft outcomes. Urinary exosomes, tiny vesicles released into the urine that carry parent cells’ proteins and nucleic acids, reflect the biologic function of the parent cells within the kidney, including immune cells. Their stability in urine makes them a potentially powerful tool for liquid biopsy and a noninvasive diagnostic biomarker for kidney-transplant rejection.MethodsUsing 192 of 220 urine samples with matched biopsy samples from 175 patients who underwent a clinically indicated kidney-transplant biopsy, we isolated urinary exosomal mRNAs and developed rejection signatures on the basis of differential gene expression. We used crossvalidation to assess the performance of the signatures on multiple data subsets.ResultsAn exosomal mRNA signature discriminated between biopsy samples from patients with all-cause rejection and those with no rejection, yielding an area under the curve (AUC) of 0.93 (95% CI, 0.87 to 0.98), which is significantly better than the current standard of care (increase in eGFR AUC of 0.57; 95% CI, 0.49 to 0.65). The exosome-based signature’s negative predictive value was 93.3% and its positive predictive value was 86.2%. Using the same approach, we identified an additional gene signature that discriminated patients with T cell–mediated rejection from those with antibody-mediated rejection (with an AUC of 0.87; 95% CI, 0.76 to 0.97). This signature’s negative predictive value was 90.6% and its positive predictive value was 77.8%.ConclusionsOur findings show that mRNA signatures derived from urinary exosomes represent a powerful and noninvasive tool to screen for kidney allograft rejection. This finding has the potential to assist clinicians in therapeutic decision making. 相似文献