全文获取类型
收费全文 | 11472篇 |
免费 | 885篇 |
国内免费 | 55篇 |
专业分类
耳鼻咽喉 | 63篇 |
儿科学 | 253篇 |
妇产科学 | 238篇 |
基础医学 | 1883篇 |
口腔科学 | 123篇 |
临床医学 | 1286篇 |
内科学 | 2468篇 |
皮肤病学 | 223篇 |
神经病学 | 969篇 |
特种医学 | 437篇 |
外科学 | 1775篇 |
综合类 | 137篇 |
一般理论 | 3篇 |
预防医学 | 935篇 |
眼科学 | 153篇 |
药学 | 785篇 |
中国医学 | 17篇 |
肿瘤学 | 664篇 |
出版年
2022年 | 77篇 |
2021年 | 133篇 |
2020年 | 105篇 |
2019年 | 192篇 |
2018年 | 189篇 |
2017年 | 148篇 |
2016年 | 174篇 |
2015年 | 213篇 |
2014年 | 277篇 |
2013年 | 444篇 |
2012年 | 570篇 |
2011年 | 658篇 |
2010年 | 392篇 |
2009年 | 373篇 |
2008年 | 644篇 |
2007年 | 646篇 |
2006年 | 661篇 |
2005年 | 740篇 |
2004年 | 705篇 |
2003年 | 789篇 |
2002年 | 769篇 |
2001年 | 164篇 |
2000年 | 161篇 |
1999年 | 167篇 |
1998年 | 193篇 |
1997年 | 168篇 |
1996年 | 138篇 |
1995年 | 122篇 |
1994年 | 129篇 |
1993年 | 91篇 |
1992年 | 110篇 |
1991年 | 123篇 |
1990年 | 145篇 |
1989年 | 111篇 |
1988年 | 122篇 |
1987年 | 104篇 |
1986年 | 114篇 |
1985年 | 95篇 |
1984年 | 91篇 |
1983年 | 92篇 |
1982年 | 81篇 |
1981年 | 91篇 |
1980年 | 81篇 |
1979年 | 61篇 |
1978年 | 63篇 |
1977年 | 58篇 |
1976年 | 66篇 |
1974年 | 59篇 |
1973年 | 42篇 |
1972年 | 45篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Anal dilatation is still used in the treatment of anal fissure and haemorrhoids. Using anorectal physiology and anal endosonography we have studied 12 men presenting with faecal incontinence following anal dilatation. Resting anal pressures were low, pudendal nerve latencies were normal; 11 men had a disrupted internal anal sphincter and in ten this was extensively fragmented. Three also had defects of the external anal sphincter. These findings demonstrate for the first time the nature of the structural injury which may be caused by anal dilatation. 相似文献
3.
Characterization of gp 50, a major glycoprotein present in rat brain synaptic membranes, with a monoclonal antibody 总被引:4,自引:0,他引:4
Philip W. Beesley Toni Paladino Claude Gravel Richard A. Hawkes James W. Gurd 《Brain research》1987,408(1-2):65-78
Several cell lines secreting monoclonal antibodies (Mabs) against a major forebrain synaptic membrane (SM) glycoprotein, gp 50, have been raised. Western blots show that the Mabs react with a polypeptide doublet of Mrs 49 and 45 kDa. These polypeptides exist solely in a concanavalin A (Con A) binding form. Removal of the Con A receptors by digestion with endo-beta-N-acetylglucosaminidase H (endo H) lowers the Mrs of the glycoprotein doublet to 36.5 and 34 kDa. Western blots of 2D polyacrylamide gels indicate that gp 50 exists in several isoforms. Solid phase radioimmunoassay (RIA) and Western blots of brain subcellular fractions show the antigenic material to be concentrated in the SM fraction, but to be present in much lower amounts in synaptic junctions and postsynaptic densities. Gp 50 appears to be brain specific. Regional distribution studies show that it is present in all brain regions but is two-fold concentrated in cerebellum, brainstem and midbrain compared to forebrain. Immunocytochemical studies of several brain regions show that gp 50-like immunoreactivity is neuron specific and is concentrated in selected neuronal species, particularly granule cells. In both cerebellar and hippocampal granule cells gp 50-like immunoreactivity is localized in the perikarya and primary dendrites. Though immunocytochemistry did not show staining of synaptic regions this may be due to masking of the reactive epitope. The results are discussed in terms of the molecular properties of gp 50 and its subcellular localization in brain tissue. 相似文献
4.
A. Beamonte F. Goldfain-Blanc N. Casadevall D. Bazot H. Bertheux N. Claude 《Comparative clinical pathology》2005,14(1):61-65
As part of the early preclinical development of a new antipsychotic compound, Wistar rats of both sexes were dosed orally for upto 7 days. At high doses, expected changes in appearance and behavior, decreases in bodyweight gain and feed intake but also a fluid and pale bone marrow (BM) were observed. Blood cell counts were normal as were clinical chemical values. BM sections showed a red cell hypoplasia. Circulating reticulocytes and erythroblasts on BM smears were decreased suggesting that the compound might have a selective toxicity for the erythroid lineage. In a mechanistic experiment, rats were dosed for 9 days and phlebotomized after 7 days of exposure to stimulate erythroid regeneration. Red-blood cell mass, reticulocytes and erythropoietin (EPO) levels were monitored before and upto 48 h after bleeding. Results showed that an EPO-mediated pathogenesis could be excluded. The effect of the drug on the formation of Colony-forming units (CFU)-E and CFU-GM was then quantitatively measured in vitro after direct exposure to the compound. In two successive assays, rat or human BM cells were incubated with the drug dissolved in the collection medium at final concentrations of 0.3×10–7 –3×10–5 M. In the presence of adequate growth factors, CFU-E and CFU-GM were cultured and cell proliferation was compared between treated and control groups. Our results showed an expected inhibition by the drug of the growth of erythroid progenitors associated to a similar effect on myeloid progenitors. The CFU-E and CFU-GM of both human and rat sources were totally inhibited from the concentration of 3×10–5 M. The IC50 values were consistent with rat peak plasma levels reached in vivo by the drug. Therefore, the short-term cloning assays performed on rat BM cells were sensitive indicators of the hematotoxicity of the compound and were considered as predictive for human toxicity. 相似文献
5.
6.
7.
We present a new simple approach for automated, non-destructive measurement of the alpha-emitting radium isotopes ((223)Ra, (224)Ra, and (226)Ra) in water based on the emanation of their respective radon daughters ((219)Rn, (220)Rn, and (222)Rn). The method combines the high adsorption uptake of MnO(2) Resin for radium (K(d)=2.4 x 10(4)ml/g) over a wide pH range with the simplicity of the activity registration using a commercial radon-in-air analyzer (RAD7, DURRIDGE Company, Inc). Radium is first adsorbed onto the MnO(2) Resin by passing a water sample through the resin packed in a gas-tight glass cartridge. The same cartridge is then connected to the radon analyzer via a simple tubing system to circulate air through the resin and a drying system. The efficiency of the proposed system is determined by running standards prepared in the same manner. Our results indicate that the efficiency for (226)Ra is >22% if both (218)Po and (214)Po counts are collected. This is comparable with typical efficiencies for alpha spectrometry but with much less sample preparation. We estimate that an MDA of 0.8 pCi/L for (226)Ra may be obtained with this new approach using a 1L water sample and less than 4h of counting. 相似文献
8.
Robert M. Levy Roman Saikovsky Evgeniya Shmidt Alexander Khokhlov Bruce P. Burnett 《Nutrition Research》2009
Flavocoxid (Limbrel), a proprietary mixture of flavonoid molecules (baicalin and catechin), was tested against a traditional nonsteroidal anti-inflammatory drug, naproxen, for the management of the signs and symptoms of moderate osteoarthritis (OA) in humans. Discomfort and global disease activity were used as the primary end points, and safety assessments were also taken for both treatments as a secondary endpoint. In this double-blind study, 103 subjects were randomly assigned to receive either flavocoxid [500 mg twice daily (BID)] or naproxen (500 mg BID) in a 1-month onset of action trial. Outcome measures included the short Western Ontario and McMaster University Osteoarthritis Index, subject Visual Analogue Scale for discomfort and global response, and investigator Visual Analogue Scale for global response and fecal occult blood. Both flavocoxid and naproxen showed significant reduction in the signs and symptoms of knee OA (P ≤ .001). There were no statistically detectable differences between the flavocoxid and naproxen groups with respect to any of the outcome variables. Similarly, there were no statistically detectable differences between the groups with respect to any adverse event, although there was a trend toward a higher incidence of edema and nonspecific musculoskeletal discomfort in the naproxen group. In this short-term pilot study, flavocoxid was as effective as naproxen in controlling the signs and symptoms of OA of the knee and would present a safe and effective option for those individuals on traditional nonsteroidal anti-inflammatory drugs or cyclooxygenase-2 inhibitors. A low incidence of adverse events was reported for both groups. 相似文献
9.
The authors obtained 82% good results by using rigid ureteroscopy to treat a total of 55 calculi in a series of 51 patients and they propose the following therapeutic approach: calculi in the lumbar ureter are frequently difficult to reach (54% failures). There is no harm in gently trying to remove the stone by ureteroscopy which, in the event of failure, can be followed by percutaneous surgery or posterolumbar incision. Rigid ureteroscopy is easier and more reliable in the case of calculi in the iliac or pelvic ureter (7% failures) and the indications can be extended. 相似文献
10.
Vasonatrin peptide: a unique synthetic natriuretic and vasorelaxing peptide. 总被引:11,自引:1,他引:10 下载免费PDF全文
C M Wei C H Kim V M Miller J C Burnett Jr 《The Journal of clinical investigation》1993,92(4):2048-2052
This study reports the cardiovascular and renal actions of a novel and newly synthesized 27-amino acid peptide termed vasonatrin peptide (VNP). VNP is a chimera of atrial natriuretic peptide (ANP) and C-type natriuretic peptide (CNP). This synthetic peptide possesses the 22-amino acid structure of CNP, which is a cardiovascular selective peptide of endothelial origin and is structurally related to ANP. VNP also possesses the five-amino acid COOH terminus of ANP. The current study demonstrates both in vitro and in vivo that VNP possesses the venodilating actions of CNP, the natriuretic actions of ANP, and unique arterial vasodilating actions not associated with either ANP or CNP. 相似文献