全文获取类型
收费全文 | 37821篇 |
免费 | 2581篇 |
国内免费 | 1378篇 |
专业分类
耳鼻咽喉 | 705篇 |
儿科学 | 788篇 |
妇产科学 | 1508篇 |
基础医学 | 2269篇 |
口腔科学 | 742篇 |
临床医学 | 3622篇 |
内科学 | 6580篇 |
皮肤病学 | 307篇 |
神经病学 | 1585篇 |
特种医学 | 1316篇 |
外国民族医学 | 2篇 |
外科学 | 10382篇 |
综合类 | 4583篇 |
现状与发展 | 2篇 |
预防医学 | 1301篇 |
眼科学 | 1018篇 |
药学 | 2096篇 |
100篇 | |
中国医学 | 1005篇 |
肿瘤学 | 1869篇 |
出版年
2024年 | 94篇 |
2023年 | 636篇 |
2022年 | 1208篇 |
2021年 | 1594篇 |
2020年 | 1525篇 |
2019年 | 1367篇 |
2018年 | 1460篇 |
2017年 | 1326篇 |
2016年 | 1217篇 |
2015年 | 1261篇 |
2014年 | 2442篇 |
2013年 | 2328篇 |
2012年 | 2059篇 |
2011年 | 2394篇 |
2010年 | 2039篇 |
2009年 | 1993篇 |
2008年 | 2112篇 |
2007年 | 2073篇 |
2006年 | 1797篇 |
2005年 | 1636篇 |
2004年 | 1346篇 |
2003年 | 1191篇 |
2002年 | 966篇 |
2001年 | 810篇 |
2000年 | 565篇 |
1999年 | 492篇 |
1998年 | 406篇 |
1997年 | 378篇 |
1996年 | 320篇 |
1995年 | 278篇 |
1994年 | 279篇 |
1993年 | 249篇 |
1992年 | 235篇 |
1991年 | 193篇 |
1990年 | 147篇 |
1989年 | 135篇 |
1988年 | 138篇 |
1987年 | 108篇 |
1986年 | 91篇 |
1985年 | 136篇 |
1984年 | 127篇 |
1983年 | 72篇 |
1982年 | 96篇 |
1981年 | 84篇 |
1980年 | 75篇 |
1979年 | 61篇 |
1978年 | 44篇 |
1977年 | 53篇 |
1976年 | 38篇 |
1975年 | 29篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
121.
目的通过检测子宫内膜异位症(EMs)患者血清及腹腔液中血小板衍生生长因子(PDGF)、血管细胞粘附分子-(VCAM-1)浓度,探讨PDGF和VCAM-1在EMs发病中的作用。方法选取手术后病理证实为EMs的40例患者为EMs组,其中I~II期17例,III~IV23例;非EMs组20例作为对照组。应用酶联免疫吸附法(ELISA)检测血清及腹腔液中PDGF和VCAM-1水平。结果EMs组血清及腹腔液中PDGF、VCAM-1水平均明显高于对照组(P<0.01)。随EMs期别的增加,其血清和腹腔液中PDGF、VCAM-1含量呈上升趋势;EMsIII~IV期水平显著高于I~II期(P<0.05)。EMs患者PDGF与VCAM-1呈正相关性(P<0.05)。结论EMs患者PDGF、VCAM-1表达水平升高,在EMs的发生发展中具有重要作用。 相似文献
122.
W. E. Uber S. E. Self A. B. Van Bakel N. L. Pereira 《American journal of transplantation》2007,7(9):2064-2074
Acute antibody-mediated rejection (AMR) in heart transplantation is often associated with hemodynamic compromise, and is associated with increased mortality and development of accelerated transplant coronary artery disease (TCAD). The diagnosis of AMR has historically been controversial and outcomes with aggressive immunosuppressive therapy including plasmapheresis and cyclophosphamide are poor. Advances in diagnostic techniques like the demonstration of immunopathologic evidence for antibody-mediated rejection by deposition of the complement split product C4d in tissue and detection of anti-HLA antibodies by flow cytometry will assist in further characterizing AMR. Immunosuppression targeting B-lymphocytes and use of m-TOR inhibitors to alter the predilection to develop TCAD and improve survival in AMR remains to be proven. 相似文献
123.
124.
目的研究重组人生长激素(rhGH)对生长激素受体(GHR)不同表达状态裸鼠人胃癌移植瘤生长及血管内皮生长因子(VEGF)表达的影响。方法采用免疫细胞化学染色法筛选出GHR阳性和阴性表达的细胞株各1株,分别接种于24只裸鼠皮下。将两种细胞接种裸鼠均随机分为对照组(0.9%NaCl,0.2ml/d)、低剂量rhGH组(0.5U·kg^-1·d^-1,0.2ml/d)和高剂量rhGH组(2.5U·kg^-1·d^-1,0.2mL/d)3组,每组8只,各组均连续给药14d,观察并记录裸鼠体重和肿瘤体积变化;采用酶联免疫吸附法测定各组裸鼠血清VEGF含量,免疫组织化学方法检测胃癌组织中VEGF蛋白表达,RT-PCR方法检测胃癌组织VEGFmRNA水平变化。结果筛选出GHR阳性表达的人胃癌细胞株SGC-7901和阴性表达的MKN-45。对于GHR^+SGC-7901接种裸鼠,rhGH给药组皮下移植瘤体积较对照组增大(P〈0.05),且高剂量rhGH组促增长效应最为显著(P〈0.05),3组间体重差异无统计学意义(P〉0.05);高剂量rhGH组的血清VEGF浓度为(252.94±15.32)ng/L,明显高于对照组的(49.94±5.73)ng/L和低剂量rhGH组的(167.60±9.54)ng/L(P〈0.05);对照组VEGF表达为中度阳性,rhGH给药组呈强阳性;高剂量rhGH组肿瘤组织中VEGFmRNA相对表达量为0.6470±0.0447,明显高于对照组的0.3230±0.0258和低剂量rhGH组的0.4120±0.0351(P〈0.05)。对于GHR—MKN-45接种裸鼠,rhGH给药组体重明显大于对照组(P〈0.05);肿瘤体积大小、血清VEGF水平、肿瘤组织VEGF蛋白及mRNA表达,3组间差异均无统计学意义(P〉0.05)。结论rhGH能促进GHR阳性表达的SGC-7901移植瘤生长,并促进VEGF表达增高;对于GHR阴性的MKN-45移植瘤,则没有表现出明显的促肿瘤生长及促VEGF表达效应。GHR存在可能是rhGH影响VEGF分泌的关键靶点。 相似文献
125.
126.
Summary Human fibrin glue (Tissucol) is a plasma-derived compound endowed with adhesive and hemostatic properties and possessing a specific local anti-infection function mediated through activation of nonspecific immunity elements. The aim of this study is to show that in patients who have undergone prolonged reconstructive plastic surgery following cancer resection, Tissucol decreases infectious complications as compared to a control group. Between June 1985 and February 1988, 51 subjects were treated with fibrin glue during reconstruction operations. Analysis of the results showed that Tissucol produced a statistically significant reduction both of immediate complications, such as inflammation and partial separation of the surgical wound, and of delayed complications, such as scar hypertrophy and cutaneous fistulae. In conclusion, patients treated with Tissucol showed a better quality of surgical wound, a more rapid postoperative functional recovery and consequently a decrease in the duration of hospitalization. 相似文献
127.
Expression and distribution of vascular endothelial growth factor protein in human brain tumors 总被引:9,自引:0,他引:9
T. Pietsch Markus M. Valter Helmut K. Wolf A. von Deimling H.-J. Su Huang Webster K. Cavenee Otmar D. Wiestler 《Acta neuropathologica》1997,93(2):109-117
Marked neovascularization is a hallmark of many neoplasms in the nervous system. Recent reports indicate that the endothelial
mitogen vascular endothelial growth factor (VEGF) may play a critical role in the regulation of vascular endothelial proliferation
in malignant gliomas. Using novel monoclonal antibodies to the VEGF polypeptide we have determined the expression and cellular
distribution of VEGF protein in a representative series of 171 human central nervous system (CNS) tumors by immunohistochemistry
and immunoblotting. In agreement with previous in situ hybridization data, 19 out of 20 glioblastomas (95%) showed immunoreactivity
for VEGF, whereas both the percentage of immunoreactive tumors and the extent of immunoreactivity for VEGF were significantly
lower in astrocytomas. Of the pilocytic astrocytomas (WHO grade I) 44% were immunoreactive for VEGF, but we observed several
cases with pronounced vascular proliferates in the absence of VEGF. In ependymomas, meningiomas, hemangioblastomas, and primitive
neuroectodermal tumors, there was no correlation between VEGF expression, vascular endothelial proliferation and the grade
of malignancy. Oligodendrogliomas and the oligodendroglial component of mixed gliomas lacked immunoreactive VEGF, indicating
that endothelial growth factors other than VEGF may regulate tumor angiogenesis in these neoplasms. Western blot analysis
showed a predominant VEGF protein species of 23 kDa and confirmed the immunohistochemical data in all cases. Our findings
demonstrate that VEGF is expressed in a wide spectrum of brain tumors in which it may induce neovascularization. However,
other angiogenic factors also appear to contribute to the vascularization of CNS neoplasms.
Received: 18 April 1996 / Revised, accepted: 20 August 1996 相似文献
128.
Abstract: Adequate venous access is an essential component of therapeutic plasma exchange (TPEX). The simplest kind of venous access is venipuncture of antecubital veins, but this technique may be limited by venous size or scarring following the procedure, requiring the placement of a specialized vascular access device (VAD). VADs provide reliable central venous access and may remain in place for several weeks or months, depending on the VAD and the venous site chosen. Their use, however, is potentially limited by the risk of complications. We discuss indications for insertion, choice of catheter and access site, and complications of VAD placement for TPEX. 相似文献
129.
130.
The quality of acute stroke units on a nation-wide level: the Austrian Stroke Registry for acute stroke units 总被引:1,自引:0,他引:1
M. M. Steiner M. Brainin for the participants in the Austrian Stroke Registry for Acute Stroke Units 《European journal of neurology》2003,10(4):353-360
Concepts for stroke units that cover the acute phase vary. Therefore, the network of acute stroke units that is being set up in Austria in a uniform way is of general interest. This nationwide network has been established in accordance to evidence-based recommendations and prespecified criteria for available resources. The location for such a unit follows a maximum of 90-min isochrones (transport time) to the hospital. The quality of the network is currently documented and the results are reported. A nationwide stroke registry was prospectively performed on 15 stroke units that were already functional in this network. The aim was to document the quality performance of Austrian stroke units, focusing on rapid admissions, ready availability of investigations and therapies performed. Outcome measures were Barthel scale, Rankin score and percentages of complications. Between August 1998 and December 2000, 2,313 patients with ischemic stroke or with primary intracerebral hemorrhage admitted to an Austrian stroke unit within 24 h after onset of symptoms were prospectively included. Forty-three percent of the patients had a moderate or severe stroke. Fifty-seven percent of all patients were admitted to the stroke unit within 3 h after the onset of symptoms. Twenty-seven percent of these patients were brought in by ambulance accompanied by an emergency physician. Two percent of patients were admitted by helicopter. Fifty-four percent of patients had their first brain imaging within 30 min after admission, another 26% within 3 h. Intravenous thrombolysis was performed in 4.1% of patients. The overall stroke-unit mortality was about 6.8% and mortality at 3 months was 12.9%. The outcome at 3 months showed a modified Rankin Scale score of 0 or 1 in 47% of patients, denoting none or mild impairment. This network of acute stroke units is highly efficient in terms of rapid admissions, short intrahospital delays, as well as rapid use of readily available investigations. Stroke units seem to be well accepted by the general public and the medical community because our data show that all types of strokes are treated in Austrian stroke units, including severe strokes. The total number of concurrently treated acute strokes in other institutions across Austria is not known and no formal comparison with other systems of hospitalized care was undertaken, therefore further research is necessary. 相似文献