全文获取类型
收费全文 | 930篇 |
免费 | 126篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 85篇 |
妇产科学 | 12篇 |
基础医学 | 137篇 |
口腔科学 | 10篇 |
临床医学 | 97篇 |
内科学 | 236篇 |
皮肤病学 | 20篇 |
神经病学 | 54篇 |
特种医学 | 112篇 |
外科学 | 83篇 |
综合类 | 46篇 |
预防医学 | 59篇 |
眼科学 | 8篇 |
药学 | 61篇 |
肿瘤学 | 43篇 |
出版年
2021年 | 8篇 |
2019年 | 11篇 |
2018年 | 10篇 |
2017年 | 12篇 |
2016年 | 10篇 |
2015年 | 9篇 |
2014年 | 18篇 |
2013年 | 18篇 |
2012年 | 22篇 |
2011年 | 26篇 |
2010年 | 43篇 |
2009年 | 35篇 |
2008年 | 52篇 |
2007年 | 44篇 |
2006年 | 47篇 |
2005年 | 40篇 |
2004年 | 32篇 |
2003年 | 27篇 |
2002年 | 18篇 |
2001年 | 22篇 |
2000年 | 21篇 |
1999年 | 26篇 |
1998年 | 24篇 |
1997年 | 25篇 |
1996年 | 15篇 |
1995年 | 21篇 |
1994年 | 20篇 |
1993年 | 19篇 |
1992年 | 17篇 |
1991年 | 23篇 |
1990年 | 17篇 |
1989年 | 25篇 |
1988年 | 20篇 |
1987年 | 19篇 |
1986年 | 26篇 |
1985年 | 21篇 |
1984年 | 13篇 |
1983年 | 13篇 |
1982年 | 17篇 |
1981年 | 16篇 |
1980年 | 20篇 |
1979年 | 13篇 |
1978年 | 13篇 |
1977年 | 17篇 |
1976年 | 15篇 |
1975年 | 15篇 |
1972年 | 8篇 |
1971年 | 8篇 |
1969年 | 6篇 |
1968年 | 8篇 |
排序方式: 共有1065条查询结果,搜索用时 15 毫秒
1.
2.
ALBERTO Q FARIAS LUCIANA L GONÇALVES EDUARDO LR CANÇADO ANTONIO C SEGURO SILVIA B CAMPOS CLARICE P ABRANTES-LEMOS FLAIR J CARRILHO 《Journal of gastroenterology and hepatology》2006,20(1):147-152
Background and Aims: Primary biliary cirrhosis (PBC) might be complicated by osteoporosis, whose etiology remains unknown but seems to be multifactorial. Prevalence rates of 30% to 60% for distal renal tubular acidosis (DRTA) have been reported in PBC patients, generally as incomplete DRTA. Although it is undisputed that a reduced bone mineral density (BMD) is the expected outcome among patients who have been suffering from longstanding chronic metabolic acidosis, it is unclear if incomplete DRTA is also associated with metabolic bone disease in PBC patients. The present study was undertaken to compare the BMD of PBC patients with and without DRTA.
Methods: The BMD of 23 PBC patients (11 with DRTA and 12 without), all with normal clearance of creatinine, was assessed by dual energy radiograph absorptiometry. The diagnosis of DRTA was made if the urine pH was above 5.4 in all samples after the oral acid overload, showing tubular inability to acidify urine in the presence of test-induced systemic metabolic acidosis.
Results: Densitometric signs of osteoporosis were found in 82% of DRTA cases and in 83% of patients without DRTA (difference not significant). There were no significant differences in BMD measurement, T and Z scores of patients with and without DRTA.
Conclusions: The present study could not support a correlation between the presence of DRTA and the bone loss observed in PBC patients. 相似文献
Methods: The BMD of 23 PBC patients (11 with DRTA and 12 without), all with normal clearance of creatinine, was assessed by dual energy radiograph absorptiometry. The diagnosis of DRTA was made if the urine pH was above 5.4 in all samples after the oral acid overload, showing tubular inability to acidify urine in the presence of test-induced systemic metabolic acidosis.
Results: Densitometric signs of osteoporosis were found in 82% of DRTA cases and in 83% of patients without DRTA (difference not significant). There were no significant differences in BMD measurement, T and Z scores of patients with and without DRTA.
Conclusions: The present study could not support a correlation between the presence of DRTA and the bone loss observed in PBC patients. 相似文献
3.
B G Campling A C Haworth H M Baker D L Greer J J Holden E C Bradley J Pym D F Dexter 《Cancer》1992,69(8):2064-2074
The establishment and characterization of 11 human lung cancer cell lines are described in this article. Nine of these cell lines were established over a 5-year period, from 1983 to 1988, from patients treated at the Kingston Regional Cancer Centre. These include eight definite or probable small cell lung cancer (SCLC) lines and one adenocarcinoma line. In addition, two other SCLC cell lines were characterized. All of the lines have been in continuous culture for more than 2 years. The clinical histories of the patients from whom the cell lines were derived are outlined here. Several features of the cell lines are presented, including the following: (1) a comparison of the histologic features of the cell lines with the original biopsy specimens; (2) the expression of various markers, including cytokeratin, carcinoembryonic antigen, calcitonin, and neuron-specific enolase; (3) activities of the enzymes l-dopa decarboxylase and the brain isoenzyme of creatine kinase; (4) growth characteristics; (5) cloning efficiency in soft agar; (6) tumorigenicity in nude mice; and (7) cytogenetic studies. These cell lines, obtained directly from patients with a spectrum of drug-sensitive and drug-resistant tumors, will be valuable in vitro models of sensitivity and resistance to chemotherapy in lung cancer. 相似文献
4.
5.
6.
S J Fowler J French N J Screaton J Foweraker A Condliffe C S Haworth A R Exley D Bilton 《The European respiratory journal》2006,28(6):1204-1210
The aim of the current study was to investigate the prevalence and clinical associations of nontuberculous mycobacteria (NTM) in a well-characterised cohort of patients with adult-onset bronchiectasis. The sputum of all patients attending a tertiary referral bronchiectasis clinic between April 2002 and August 2003 was examined for mycobacteria as part of an extensive diagnostic work-up. NTM-positive patients subsequently had further sputa examined. A modified bronchiectasis scoring system was applied to all high-resolution computed tomography (HRCT) scans from NTM-positive patients, and a matched cohort without NTM. Out of 98 patients attending the clinic, 10 had NTM in their sputum on first culture; of those, eight provided multiple positive cultures. Three patients were treated for NTM infection. A higher proportion of NTM-positive than -negative patients were subsequently diagnosed with cystic fibrosis (two out of nine versus two out of 75). On HRCT scoring, more patients in the NTM-positive group had peripheral mucus plugging than in the NTM-negative group. In the current prospective study of a large cohort of patients with bronchiectasis, 10% cultured positive for nontuberculous mycobacteria in a random clinic sputum sample. Few clinical parameters were helpful in discriminating between groups, except for a higher prevalence of previously undiagnosed cystic fibrosis and of peripheral mucus plugging on high-resolution computed tomography in the nontuberculous mycobacteria group. 相似文献
7.
Prior studies have shown that pneumothorax is one of the more difficult entities to diagnose with digitized radiography. This study was designed to test whether increasing resolution from 1.25 to 2.5 line pairs per millimeter (lp/mm) and image processing (edge enhancement from unsharp masking) would increase accuracy and confidence in the diagnosis of pneumothorax, as well as normal cases and other forms of lung disease. Conventional radiographs were digitized with use of a laser reader and then reformatted as film hard copy. Eleven observers read 35 cases reformatted in three different ways (1.25 lp/mm, 2.5 lp/mm, 1.25 lp/mm unsharp mask). The images with finer resolution (2.5 lp/mm) and unsharp mask images were superior to those with coarser resolution (1.25 lp/mm) for the diagnosis of pneumothorax. There was no difference in diagnostic accuracy for normal patients. For abnormalities other than pneumothorax, the unsharp mask images were significantly worse. Confidence in the diagnosis of pneumothorax and other abnormalities was highest with the finest resolution (2.5 lp/mm). 相似文献
8.
Stab wounds to the temporal fossa 总被引:1,自引:0,他引:1
Stab wounds to the temporal fossa appear as a characteristic clinical entity. Patients admitted with stab wounds to the head during the period 1970 to 1986 were reviewed retrospectively. Of these, 10 met the criteria of having suffered a stab wound that penetrated the skull and dura mater of the temporal fossa. Injury to the internal carotid artery-cavernous sinus complex (3 patients) or to the basilar artery-pons region (5 patients) was frequent. Two other patients experienced injury to the trigeminal nerve and the petrous ridge. The mechanical, neurological, radiological, and prognostic features of knife wounds to this region are discussed. 相似文献
9.
MGC Hendriks P Dogterom JT Ebels B Oosterhuis LR Geertsema T Hulot G Bianchetti and JHG Jonkman 《Fundamental & clinical pharmacology》1998,12(5):559-565
Summary— In the present study we have compared the steady state biopharmaceutic characteristics of four diltiazem once daily controlled release capsules: Mono-Tildiem LP 300® (300 mg), Adizem® XL (300 mg)1, Cardizem® (300 mg) and Dilacor® (240 mg). Sixteen healthy male volunteers (aged 22.9 ± 3.3 years, range 19–31 years) completed an open label, multiple oral dose, randomized, four-period crossover study without a washout period in between. The volunteers received each diltiazem formulation once daily for four days. Trough diltiazem and metabolites plasma concentrations were determined on days 3 and 4. The 24-h plasma concentration-time profiles were assessed after the dose on day 4 of each period. The following steady state pharmacokinetic parameters for diltiazem were calculated: the minimum plasma concentration (cmin), the maximum plasma concentration (cmax), the time to reach that concentration (tmax), the time interval during which the plasma concentration exceeds 50% of cmax (t50), the area under the plasma concentration-time curve (AUC72–96) and the peak-to-trough fluctuation (PTF). For the metabolites of diltiazem, N-mono-desmethyl-diltiazem (NDM) and desacetyldiltiazem (DAD), AUC72–96 (AUCNDM and AUCDAD) and the ratio metabolite/parent compound were calculated. Steady state was achieved on day 3. Except one, all controlled release formulations have satisfactory controlled release properties allowing once daily administration. However, significant (P < 0.05) differences were found between the pharmacokinetic characteristics which do not allow exchange of the various formulations. Concentrations well below 50 ng·mL-1 in the morning hours were observed for Dilacor® (240 mg) and Adizem® XL (300 mg), which could be a disadvantage of these formulations as it is well-known that ischaemic events occur at a higher rate during that part of the day. The plasma concentration profiles of NDM and DAD, the major circulating metabolites, parallel the plasma concentration profiles for the parent compound. From a clinical point of view, all treatments were well tolerated. 相似文献
10.
Assessment of the common bile duct before cholecystectomy using ultrasound and biochemical measurements: validation based on follow-up.
下载免费PDF全文
![点击此处可从《Annals of the Royal College of Surgeons of England》网站下载免费的PDF全文](/ch/ext_images/free.gif)
D. S. Watkin J. M. Haworth D. J. Leaper M. H. Thompson 《Annals of the Royal College of Surgeons of England》1994,76(5):317-319
The selective use of operative cholangiography with cholecystectomy is controversial. We have combined measurement of the serum bilirubin, alkaline phosphatase and alanine aminotransferase with ultrasound measurement of the bile duct diameter to assess the common bile duct before cholecystectomy. Direct contrast cholangiography was not performed if the results of these measurements were normal on the day before operation. There were 253 patients assessed in this way before laparoscopic cholecystectomy. Patients with known bile duct stones were excluded, but those with a previous history of jaundice, pancreatitis or abnormal liver function tests were included. In 47 cases abnormalities were found and X-ray cholangiograms were performed; only six patients were found to have bile duct stones. Follow-up of all 253 patients, including repeating the preoperative measurements after 12 months in 93, found only two patients with evidence that common duct stones had been missed and these two stones passed spontaneously. No bile duct injuries have occurred. We conclude that preoperative assessment of the bile duct using ultrasound and liver function tests safely obviates the need for 'routine' operative cholangiography. 相似文献