全文获取类型
收费全文 | 9096篇 |
免费 | 582篇 |
国内免费 | 46篇 |
专业分类
耳鼻咽喉 | 48篇 |
儿科学 | 143篇 |
妇产科学 | 159篇 |
基础医学 | 1298篇 |
口腔科学 | 321篇 |
临床医学 | 846篇 |
内科学 | 2039篇 |
皮肤病学 | 404篇 |
神经病学 | 1006篇 |
特种医学 | 570篇 |
外科学 | 1251篇 |
综合类 | 44篇 |
一般理论 | 1篇 |
预防医学 | 357篇 |
眼科学 | 140篇 |
药学 | 538篇 |
中国医学 | 3篇 |
肿瘤学 | 556篇 |
出版年
2023年 | 42篇 |
2022年 | 90篇 |
2021年 | 197篇 |
2020年 | 160篇 |
2019年 | 155篇 |
2018年 | 172篇 |
2017年 | 156篇 |
2016年 | 240篇 |
2015年 | 256篇 |
2014年 | 316篇 |
2013年 | 406篇 |
2012年 | 702篇 |
2011年 | 684篇 |
2010年 | 431篇 |
2009年 | 387篇 |
2008年 | 668篇 |
2007年 | 665篇 |
2006年 | 659篇 |
2005年 | 632篇 |
2004年 | 534篇 |
2003年 | 472篇 |
2002年 | 481篇 |
2001年 | 126篇 |
2000年 | 73篇 |
1999年 | 124篇 |
1998年 | 112篇 |
1997年 | 83篇 |
1996年 | 55篇 |
1995年 | 48篇 |
1994年 | 31篇 |
1993年 | 36篇 |
1992年 | 63篇 |
1991年 | 56篇 |
1990年 | 33篇 |
1989年 | 30篇 |
1988年 | 34篇 |
1987年 | 27篇 |
1986年 | 27篇 |
1985年 | 15篇 |
1984年 | 17篇 |
1983年 | 13篇 |
1982年 | 10篇 |
1980年 | 14篇 |
1979年 | 18篇 |
1978年 | 10篇 |
1975年 | 10篇 |
1972年 | 11篇 |
1971年 | 12篇 |
1969年 | 13篇 |
1934年 | 13篇 |
排序方式: 共有9724条查询结果,搜索用时 15 毫秒
1.
Familial risk and heritability of intellectual disability: a population-based cohort study in Sweden
2.
Erika Cecon Anna Ivanova Marine Luka Florence Gbahou Anne Friederich Jean‐Luc Guillaume Patrick Keller Klaus Knoch Raise Ahmad Philippe Delagrange Michele Solimena Ralf Jockers 《Journal of pineal research》2019,66(2)
Melatonin receptors play important roles in the regulation of circadian and seasonal rhythms, sleep, retinal functions, the immune system, depression, and type 2 diabetes development. Melatonin receptors are approved drug targets for insomnia, non‐24‐hour sleep‐wake disorders, and major depressive disorders. In mammals, two melatonin receptors (MTRs) exist, MT1 and MT2, belonging to the G protein‐coupled receptor (GPCR) superfamily. Similar to most other GPCRs, reliable antibodies recognizing melatonin receptors proved to be difficult to obtain. Here, we describe the development of the first monoclonal antibodies (mABs) for mouse MT1 and MT2. Purified antibodies were extensively characterized for specific reactivity with mouse, rat, and human MT1 and MT2 by Western blot, immunoprecipitation, immunofluorescence, and proximity ligation assay. Several mABs were specific for either mouse MT1 or MT2. None of the mABs cross‐reacted with rat MTRs, and some were able to react with human MTRs. The specificity of the selected mABs was validated by immunofluorescence microscopy in three established locations (retina, suprachiasmatic nuclei, pituitary gland) for MTR expression in mice using MTR‐KO mice as control. MT2 expression was not detected in mouse insulinoma MIN6 cells or pancreatic beta‐cells. Collectively, we report the first monoclonal antibodies recognizing recombinant and native mouse melatonin receptors that will be valuable tools for future studies. 相似文献
3.
4.
5.
Kerstin Schmidt Johannes Hoffend Annette Altmann Ludwig G Strauss Antonia Dimitrakopoulou-Strauss Britta Engelhardt Dirk Koczan J?rg Peter Thomas J Dengler Walter Mier Michael Eisenhut Uwe Haberkorn Ralf Kinscherf 《Journal of nuclear medicine》2006,47(3):543-551
Growth of malignant tumors is dependent on sufficient blood supply. Thus, inhibition of tumor angiogenesis is emerging as a promising target in the treatment of malignancies. Human angiostatin (hANG) is one of the most potent inhibitors of endothelial cell proliferation, angiogenesis, and tumor growth in vivo. However, its mechanisms operating in vivo are not well understood. METHODS: To obtain more information about functional changes in the angiogenic process, we established Morris hepatoma (MH3924A) cell lines expressing hANG (hANG-MH3924A). The effects of hANG expression on proliferation and apoptosis of human umbilical vein endothelial cells (HUVECs) were measured in coculture experiments in vitro. To evaluate changes in tumor perfusion and blood volume, H2 15O and 68Ga-DOTA-albumin (DOTA is 1,4,7,10-tetraazacyclododecane-N,N',N',N'-tetraacetic acid) were used for PET studies in vivo. Additionally, immunohistologic quantification of vascularization, apoptosis, and proliferation as well as gene array analyses were performed. RESULTS: Our in vitro experiments demonstrate reduced proliferation and increased apoptosis in HUVECs when being cocultured with hANG-MH3924A. In support, tumor growth of hANG-MH3924A is diminished by 95% in vivo. However, tumor perfusion and blood volume are increased in hANG-MH3924A corresponding to an increased microvessel density. Furthermore, hANG-transfected tumors show changes in expression of genes related to apoptosis, stress, signal transduction, and metabolism. CONCLUSION: hANG expression leads to inhibition of tumor growth, increased apoptosis, and changes in the expression of multiple genes involved in stress reactions, signal transduction, and apoptosis, which indicates a multifactorial reaction of tumors. An enhanced microvessel density is seen as part of these reactions and is associated with increased perfusion as measured by PET. 相似文献
6.
D J Brooks J S Gibbs P Sharp S Herold D R Turton S K Luthra E M Kohner S R Bloom T Jones 《Journal of cerebral blood flow and metabolism》1986,6(2):240-244
Regional cerebral [11C]3-O-methyl-D-glucose ([11C]MeG) uptake kinetics have been measured in five insulin-dependent diabetic patients and four normal controls using positron emission tomography (PET). Concomitant measurement of regional cerebral blood volume and CBF enabled corrections for the presence of intravascular [11C]MeG signal in cerebral regions of interest to be carried out, and regional cerebral [11C]MeG unidirectional extraction fractions to be computed. Four of the five diabetic subjects were studied with their fasting plasma glucose level clamped at a normoglycaemic level (4 mM), and four were studied at hyperglycaemic plasma glucose levels (mean 13 mM). The four diabetic subjects whose fasting plasma glucose levels were clamped at a normoglycaemic level of 4 mM had mean fasting whole-brain, cortical, and white matter [11C]MeG extraction fractions of 15, 15, and 16%, respectively, values similar to those found for the four normal controls (whole brain, 14%; cortex, 13%; white matter, 17%). Mean regional cerebral [11C]MeG extraction fractions were significantly reduced in diabetic subjects during hyperglycaemia whether their plasma insulin levels were undetectable or whether they were raised by continuous intravenous insulin infusion. Such a reduction in [11C]MeG extraction under hyperglycaemic conditions can be explained entirely in terms of increased competition between [11C]MeG and D-glucose for the passive facilitated transport carrier system for hexoses across the blood-brain barrier (BBB). It is concluded that the number and affinity of D-glucose carriers present in the BBB are within normal limits in treated insulin-dependent diabetic subjects. In addition, insulin appears to have no effect on the transport of D-glucose across the BBB. 相似文献
7.
8.
A Herold 《Der Chirurg》2006,77(8):737-47; quiz 748
Hemorrhoidal disease is one of the most frequent disorders in western countries. The aim of individual therapy is freedom from symptoms achieved by normalisation of anatomy and physiology. Treatment is orientated to the stage of disease: haemorrhoids 1 are treated conservatively. In addition to high-fibre diet, sclerotherapy is used. Haemorrhoids 2 prolapse during defecation and return spontaneously. First-line treatment is rubber band ligation. Haemorrhoids 3 that prolapse during defecation have to be digitally reduced, and the majority need surgery. For segmental disorders, haemorrhoidectomy according to Milligan-Morgan or Ferguson is recommended. In circular disease, Stapler hemorrhoidopexy is now the procedure of choice. Using a therapeutic regime according to the hemorrhoidal disease classification offers high healing rates and low rates of complications and recurrence. 相似文献
9.
10.
I. Kaare Tesdal Werner Jaschke Mathias Bühler Ralf Adamus Thomas Filser Eggert Holm Max Georgi 《Cardiovascular and interventional radiology》1997,20(1):29-37
Purpose To evaluate prospectively our experience with transjugular intrahepatic portosystemic shunt (TIPS) using four different metallic
stents.
Methods Between November 1991 and April 1995, 57 patients (41 men and 16 women; age 35–72 years, mean 54 years) underwent the TIPS
procedure. Techniques for portal vein localization before and during TIPS were fluoroscopy, computed tomography (CT) studies,
wedged hepatic venography, arterial portography, and ultrasound. After predilation we deployed balloon-expandable (n=48) and self-expanding (n=45) metallic stents. Fifteen patients underwent variceal embolization. Initial follow-up angiograms (mean 6.9 months, range
3–24 months) were obtained in 39 of these patients.
Results Fifty-three patients (93%) had successful TIPS placement. The mean decrease in portal pressure was 42.7%. Besides fluoroscopy,
the most helpful techniques for portal vein localization were venography and CT. Residual stenosis (n=1) and late shortening (n=4) of Wallstents resulted in shunt dysfunction. The technical problems encountered with the Palmaz stent resulted from its
lack of flexibility. We combined balloon-expandable and self-expanding stents in 12 patients. The 30-day and late follow-up
(mean 11.9 months) percutaneous reintervention rates were 11.3% and 64.2%, respectively. There were no clinically significant
complications related to the TIPS insertions.
Conclusion An ideal stent does not exist for TIPS, and the authors recommend combining a Palmaz stent with a flexible self-expanding
stent. 相似文献