全文获取类型
收费全文 | 2504篇 |
免费 | 181篇 |
国内免费 | 10篇 |
学科分类
医药卫生 | 2695篇 |
出版年
2023年 | 29篇 |
2022年 | 22篇 |
2021年 | 67篇 |
2020年 | 48篇 |
2019年 | 79篇 |
2018年 | 122篇 |
2017年 | 121篇 |
2016年 | 127篇 |
2015年 | 93篇 |
2014年 | 152篇 |
2013年 | 218篇 |
2012年 | 265篇 |
2011年 | 277篇 |
2010年 | 158篇 |
2009年 | 101篇 |
2008年 | 83篇 |
2007年 | 57篇 |
2006年 | 63篇 |
2005年 | 35篇 |
2004年 | 37篇 |
2003年 | 29篇 |
2002年 | 36篇 |
2001年 | 51篇 |
2000年 | 32篇 |
1999年 | 36篇 |
1998年 | 24篇 |
1997年 | 18篇 |
1996年 | 22篇 |
1995年 | 16篇 |
1994年 | 14篇 |
1993年 | 14篇 |
1992年 | 14篇 |
1991年 | 11篇 |
1990年 | 12篇 |
1989年 | 13篇 |
1988年 | 6篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 8篇 |
1984年 | 12篇 |
1983年 | 7篇 |
1982年 | 11篇 |
1981年 | 13篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1978年 | 7篇 |
1977年 | 10篇 |
1975年 | 6篇 |
1972年 | 7篇 |
1971年 | 6篇 |
排序方式: 共有2695条查询结果,搜索用时 31 毫秒
1.
2.
3.
O. Trejo J. A. Girón E. Pérez-Guzmán E. Segura C. Fernández-Gutiérrez A. García-Tapia A. J. Clavo A. Bascuñana 《European journal of clinical microbiology & infectious diseases》1997,16(11):807-815
In order to analyze the etiology, cytological and biochemical characteristics, and outcome of pleural disease in patients infected with HIV, the medical records of 86 HIV-positive patients with pleural effusion were reviewed. Controls were 106 HIV-negative patients with parapneumonic or tuberculous effusion. Most HIV-positive patients were intravenous drug abusers (95.3%). Pleural effusions in HIV-positive patients were caused by infections in 76 (89.4%) cases. Parapneumonic effusion was diagnosed in 59 patients and tuberculous pleuritis in 15 patients.Staphylococcus aureus was the most frequently isolated bacteria. Parameters for differentiating complicated cases of parapneumonic exudate from uncomplicated cases, such as pleural fluid pH<7.20 (sensitivity 80% vs. 84.3%), pleural fluid glucose<35 mg/dl (sensitivity 45% vs. 56.25%) pleural fluid LDH > 1600 Ul/l (sensitivity 85% vs. 62.50%), showed similar sensitivity in HIV-positive and HIV-negative patients. Monocytes in pleural fluid were significantly decreased in tuberculous pleuritis in HIV-positive patients (506±425 vs. 1014±1196 monocytes/ml, p<0.05). No significant differences were detected in the outcome of HIV-positive and HIV-negative patients with pleural disease. It can be concluded that the pleural effusion was of predominantly infectious etiology in HIV-positive patients from populations with a high prevalence of intravenous drug abuse. Neither the biochemical parameters in pleural fluid nor the outcome differed significantly between HIV-positive and HIV-negative patients. 相似文献
4.
Bošnjaković Petar Ivković Tomislav Ilić Miodrag Aracki Snežana 《Cardiovascular and interventional radiology》1992,15(4):217-220
Flexible tantalum stents (Strecker) were used as an adjunct to percutaneous transluminal angioplasty (PTA) in the treatment
of stenotic arterial or venous limbs of Brescia-Cimino hemodialysis fistulas. The diagnostic procedure was performed using
retrograde fistulography. After PTA with unsatisfactory results, stents were placed in 5 patients with significant residual
stenoses and poor fistula function. Within the mean follow-up period of 6.4 months (range 3–10 months) all fistulas were functioning.
We conclude that Strecker stent is useful in the treatment of stenotic hemodialysis arteriovenous fistulas as an adjunct to
PTA. 相似文献
5.
6.
牛磺酸与大脑发育关系的初步探讨——牛磺酸与行为 总被引:6,自引:0,他引:6
本实验将断乳大鼠随机分成三组。补充0.6%牛磺酸组(ST组);未补充牛磺酸组(TF组);及5703大鼠常备膳组(5703组)。用水迷宫及食物偏爱性试验观察补充牛磺酸对大鼠学习、记忆能力的影响。结果表明,三组大鼠在水迷宫试验总潜伏期,总错误次数,无误率及持续时间四项指标上均存在高度显著差异。ST:TF P<0.01;ST:5703 P<0.01;5703:TF P<0.05。ST与TF在食物偏爱性试验上存在显著差异(P<0.05)。上述结果表明:牛磺酸与大脑发育有关,表现为补充了牛磺酸的大鼠在学习、记忆等方面的提高。而牛磺酸缺乏对幼鼠大脑及智力发育有不利影响,表现为学习、记忆能力的不足。 相似文献
7.
Marija Čarman-Kržan 《Inflammation research》1983,13(2-3):162-166
The antagonist-sensitive binding of [3H]mepyramine to beef aortic membranes was as expected for binding to histamine H1-receptors. [3H]mepyramine binds rapidly and in saturable fashion to the specific receptor sites, specific binding reaching equilibrium in 3 min at 37°CScatchard's analysis of the binding data gave a dissociation constant of 3.0 nM for the radioligand-receptor complex and maximal number of binding sites: 31 fmol/mg protein. In the competition studies histamine H1-antagonists are more potent inhibitors of radioligand binding than H2-antagonist. They inhibit [3H]mepyramine binding in the following order: mepyramine >triprolidine 相似文献
8.
Development of flow cytogenetics and physical genome mapping in chickpea (Cicer arietinum L.) 总被引:2,自引:0,他引:2
K. Vláčilová D. Ohri J. Vrána J. Číhalíková M. Kubaláková G. Kahl J. Doležel 《Chromosome research》2002,10(8):695-706
Procedures for flow cytometric analysis and sorting of mitotic chromosomes (flow cytogenetics) have been developed for chickpea (Cicer arietinum). Suspensions of intact chromosomes were prepared from root tips treated to achieve a high degree of metaphase synchrony. The optimal protocol consisted of a treatment of roots with 2mmol/L hydroxyurea for 18h, a 4.5-h recovery in hydroxyurea-free medium, 2h incubation with 10µmol/L oryzalin, and ice-water treatment overnight. This procedure resulted in an average metaphase index of 47%. Synchronized root tips were fixed in 2% formaldehyde for 20min, and chromosome suspensions prepared by mechanical homogenization of fixed root tips. More than 4×105 morphologically intact chromosomes could be isolated from 15 root tips. Flow cytometric analysis of DAPI-stained chromosomes resulted in histograms of relative fluorescence intensity (flow karyotypes) containing eight peaks, representing individual chromosomes and/or groups of chromosomes with a similar relative DNA content. Five peaks could be assigned to individual chromosomes (A, B, C, G, H). The purity of sorted chromosome fractions was high, and chromosomes B and H could be sorted with 100% purity. PCR on flow-sorted chromosome fractions with primers for sequence-tagged microsatellite site (STMS) markers permitted assignment of the genetic linkage group LG8 to the smallest chickpea chromosome H. This study extends the number of legume species for which flow cytogenetics is available, and demonstrates the potential of flow cytogenetics for genome mapping in chickpea. 相似文献
9.
Xavier AC Siqueira SA Costa LJ Mauad T Nascimento Saldiva PH 《Virchows Archiv : an international journal of pathology》2005,446(3):225-231
Autopsy findings of missed diagnoses that would probably have changed management or prognosis occur in up to 29% of cases in general hospitals. Such proportions may be higher in subsets of patients with complex diseases. We reviewed 2908 consecutive autopsies performed over a period of 29 months in a large-volume hospital, analyzing 118 autopsies of patients with hematological malignancies or severe aplastic anemia. A review of macroscopic reports as well as microscopic examination of tissue samples was performed. Medical records were reviewed for clinical diagnoses. Discordances between clinical and autopsy diagnoses were classified using Goldmans criteria. Additionally, we searched for clinical parameters correlated with occurrence of class-I discrepancy using a multivariate method. Median age was 46.5 years, and 25.4% had received a hematopoietic stem-cell transplant. Overall, 11.9% (6.6–19.1%) of patients died before conclusion of the hematological diagnosis and 33% (24.6–42.3%) died with no active hematological disease. We found class-I discrepancy in 31.3% (23.1–40.5 %) of cases. The most common among these diagnoses were hematological disease, pneumonia and gastrointestinal bleeding. In a univariate analysis, being elderly (P=0.04) was positively correlated with the finding of class-I discrepancies; while, having received previous specific hematological treatment (P=0.0005) or hematopoietic stem-cell transplants (P=0.013), or being admitted to a specialized hematology unit (P=0.0006) were negatively correlated to the occurrence of such discrepancies. Multivariate analysis showed that care in a specialized hematology unit (OR 0.34, 0.12–0.93) was independently associated with lower occurrence of discrepancies. We concluded that critical diagnoses are often missed in highly complex hematological patients especially in the absence of admission to specialized hematology units. 相似文献
10.
Vladimíra Džugasová Margita Obernauerová Katarína Horváthová Mariana Vachová Martina Žáková Július Šubík 《Current genetics》1998,34(4):297-302
The PEL1/PGS1 gene of the yeast Saccharomyces cerevisiae is essential for the viability of rho
–/rho° mutants and the normal cardiolipin content of cells. The PEL1-GFP fusion gene has been found to complement the pel1/pgs1 mutation and its fluorescent protein was localized to mitochondria similarly to the β-galactosidase activity of a protein encoded by the PEL1-lacZ fusion gene. The expression of the PEL1-lacZ reporter gene was repressed in cells grown in the presence of inositol and choline, reduced in the ino2 and ino4 strains, but constitutive in the opi1 null-mutant strain. The results demonstrate that Pel1p, playing a vital role in cells impaired in the mitochondrial DNA,
is localized in the mitochondria and expressed in response to inositol and choline.
Received: 15 June / 15 July 1998 相似文献