全文获取类型
收费全文 | 27879篇 |
免费 | 2811篇 |
国内免费 | 469篇 |
专业分类
耳鼻咽喉 | 193篇 |
儿科学 | 589篇 |
妇产科学 | 273篇 |
基础医学 | 2508篇 |
口腔科学 | 892篇 |
临床医学 | 6428篇 |
内科学 | 4032篇 |
皮肤病学 | 399篇 |
神经病学 | 2280篇 |
特种医学 | 472篇 |
外国民族医学 | 11篇 |
外科学 | 2097篇 |
综合类 | 2702篇 |
现状与发展 | 4篇 |
预防医学 | 2717篇 |
眼科学 | 1272篇 |
药学 | 1264篇 |
11篇 | |
中国医学 | 972篇 |
肿瘤学 | 2043篇 |
出版年
2024年 | 70篇 |
2023年 | 613篇 |
2022年 | 857篇 |
2021年 | 1387篇 |
2020年 | 1221篇 |
2019年 | 1193篇 |
2018年 | 1094篇 |
2017年 | 1168篇 |
2016年 | 1159篇 |
2015年 | 1136篇 |
2014年 | 1720篇 |
2013年 | 2015篇 |
2012年 | 1414篇 |
2011年 | 1472篇 |
2010年 | 1227篇 |
2009年 | 1251篇 |
2008年 | 1239篇 |
2007年 | 1224篇 |
2006年 | 1135篇 |
2005年 | 1056篇 |
2004年 | 870篇 |
2003年 | 780篇 |
2002年 | 719篇 |
2001年 | 582篇 |
2000年 | 507篇 |
1999年 | 438篇 |
1998年 | 402篇 |
1997年 | 334篇 |
1996年 | 333篇 |
1995年 | 296篇 |
1994年 | 295篇 |
1993年 | 272篇 |
1992年 | 234篇 |
1991年 | 216篇 |
1990年 | 156篇 |
1989年 | 125篇 |
1988年 | 119篇 |
1987年 | 101篇 |
1986年 | 94篇 |
1985年 | 145篇 |
1984年 | 102篇 |
1983年 | 78篇 |
1982年 | 90篇 |
1981年 | 65篇 |
1980年 | 50篇 |
1979年 | 29篇 |
1978年 | 29篇 |
1977年 | 17篇 |
1976年 | 12篇 |
1975年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Nobuo Tsuda Paritosh Roy Chowdhury Tomayoshi Hayashi Masanobu Anami Masachika Iseki Shigehiko Koga Fukuzo Matsuya Hiroshi Kanetake Yutaka Saito Yoshio Horita 《Pathology international》1997,47(11):778-783
Primary renal angiosarcoma is very rare. To our knowledge, only 15 cases have been reported to date. A 77-year-old Japanese man with a unilateral kidney presented with massive hematuria followed by renal failure. A renal tumor was suspected and a left nephrectomy was performed. The histopathological diagnosis was angiosarcoma of the kidney. A hemorrhagic tumor measuring 10 × 5 cm and clotted blood was found in the modularly area. The atypical tumor cells had a sinusoidal and solid appearance, and showed Immunohistochemically positive reactions for some of the endothelial markers. The patient died about 21 months after the nephrectomy and the autopsy revealed massive metastases to the liver and retroperitoneum. One of the differential diagnoses of the case was anglomyolipoma, because the tumor cells were relatively bland in their histological appearance with entrapped fat cells in the pelvic area. Fifteen case reports with titles that included the term 'hemangiosarcoma/anglosarcoma', 'hemangioendothelloma/endothelloma' or 'vascular sarcoma' of the kidney were reviewed and compared to the present case. 相似文献
82.
Carolyn A Chew-Graham Karina Lovell Chris Roberts Robert Baldwin Michael Morley Alistair Burns David Richards Heather Burroughs 《The British journal of general practice》2007,57(538):364-370
BACKGROUND: Depression is the most common mental health disorder in people aged over 65 years. Late-life depression is associated with chronic illness and disability. AIM: To investigate the feasibility of a collaborative care model for depression in older people in a primary care setting. DESIGN OF STUDY: Randomised controlled trial with 16-weeks follow up. SETTING: A primary care trust in Manchester. METHOD: Participants were 105 people aged 60 years or older who scored 5 or more on the Geriatric Depression Scale; 53 were randomly allocated to an intervention group and 52 to a usual care group. The intervention group received care managed by a community psychiatric nurse who delivered an intervention comprising a facilitated self-help programme with close liaison with primary care professionals and old-age psychiatry according to a defined protocol. The usual care group received usual GP care. A nested qualitative study explored the views of the health professionals and patients regarding the acceptability and effectiveness of the intervention. RESULTS: The main outcome measure was recovery from depression. Patients in the intervention group were less likely to suffer from major depressive disorder at follow up compared with usual care (0.32, 95% confidence = interval = 0.11 to 0.93, P = 0.036). The qualitative component of the study demonstrated the acceptability of the intervention to patients. CONCLUSION: A model of collaborative care for older people with depression, used in a primary care setting with a facilitated self-help intervention is more effective than usual GP care. This study demonstrates that the implementation of a collaborative care model is feasible in UK primary care and that the intervention is effective and acceptable to patients. 相似文献
83.
Cloning and characterization of the cDNA encoding the HA protein of a hemagglutination-defective measles virus strain 总被引:3,自引:0,他引:3
Hiroyuki Saito Hiroyasu Sato Mariko Abe Seizaburo Harata Ken-Ichi Amano Tsunehisa Suto Morihiro Morita 《Virus genes》1994,8(1):107-113
cDNA clones corresponding to the mRNA for the hemagglutinin of the hemagglutination-defective strain AK-1 of measles virus were isolated and characterized. Compared with the prototype Edmonstron strain, 60 nucleotide substitutions that resulted in 18 amino acid changes were detected. An additional potential N-linked glycosylation site was added by point mutation, which was supported by the observation that the hemagglutinin of the AK-1 strain was stained more heavily after NaDodSO4PAGE and periodic acid-Schiff (PAS) staining than the Edmonston strain. Computer-assisted analysis revealed that three reverse turns in the secondary structure had disappeared in the hemagglutinin of the AK-1 strain. Moreover, one of these structural changes occurred in the closely glycosylated region at amino acid residues 168–240, which appeared to be a biologically important functional domain. The isoelectric point calculated from the predicted amino acid sequence became about 1 pH unit more basic in the AK-1 strain than the Edmonston strain. This present study is the first sequence analysis of the hemagglutinin gene in a hemagglutination-defective strain of the measles virus. 相似文献
84.
Espinosa M Noé G Troncoso C Ho SB Villalón M 《Human reproduction (Oxford, England)》2002,17(8):1964-1972
BACKGROUND: Cervical mucus is a heterogeneous mixture of water, ions and mucins that form a hydrophilic polymer gel. Mucins, the main components of mucus, are condensed inside secretory granules and swell to become a hydrogel after exocytosis. Using human cervical secretory cell primary cultures, the effect of [Ca(2+)] and [H(+)] on the swelling velocity of mucin granules was investigated in vitro. METHODS and RESULTS: Immunocytochemistry demonstrated that estrogen and progesterone receptors were expressed in cultured secretory cells along with mucins type 1, 4, 5AC and 5B. Exocytosis of secretory cells, recorded by videomicroscopy, showed that during swelling, the radius of the secretory granule matrix followed first-order kinetics. An increase in extracellular [Ca(2+)] from 1 to 4 mmol/l or a reduction in pH from 7.4 to 6.5 was seen to produce a significant decrease in the velocity of swelling of the secretory granule matrix. CONCLUSIONS: The inverse relationship observed between the diffusion of the granular matrix and the extracellular [Ca(2+)] or [H(+)] suggested that changes in cation concentration might drastically affect the swelling characteristics of mucins and provide a control mechanism for the observed viscoelastic properties of mucus. 相似文献
85.
Nishioji K Okanoue T Itoh Y Narumi S Sakamoto M Nakamura H Morita A Kashima K 《Clinical and experimental immunology》2001,123(2):271-279
To clarify the role of IP-10 in autoimmune liver diseases, we studied the serum levels of IP-10 in 14 patients with autoimmune hepatitis (AIH), 23 patients with primary biliary cirrhosis (PBC), and 65 patients with chronic viral hepatitis (20 type B and 45 type C). The hepatic expression of IP-10 mRNA and the correlation between the serum levels of IP-10 and clinical parameters were also evaluated. In addition to 20 healthy controls, 16 rheumatoid arthritis (RA) patients were included as an extrahepatic inflammatory disease. The serum level of IP-10 was significantly (P < 0.02) higher in patients with AIH, PBC, and chronic hepatitis B and C than in healthy controls, and it was significantly correlated (P < 0.05) with the serum levels of aspartate aminotransferase and alanine aminotransferase in patients with AIH, PBC, and chronic hepatitis B and C. The serum level of IP-10 was not elevated in RA patients. After successful treatment of AIH and chronic hepatitis C, the serum level of IP-10 decreased to the same level as in healthy volunteers. As we previously showed in cases with chronic hepatitis B or C, in situ hybridization in both AIH and PBC cases demonstrated the expression of IP-10 mRNA in hepatocytes around focal or lobular necrosis surrounded by infiltrating mononuclear cells, whereas IP-10 mRNA was not expressed in areas around the damaged bile ducts in PBC cases. The present results suggest that IP-10 is specifically produced by hepatocytes in inflammatory areas irrespective of the aetiology of hepatitis, and that IP-10 may help to recruit T cells to the hepatic lesions in autoimmune liver diseases as well as in chronic viral hepatitis. 相似文献
86.
Isolation of human immunodeficiency virus (HIV) from plasma during primary HIV infection 总被引:13,自引:0,他引:13
Jan Albert Hans Gaines Anders Snnerborg Gunnel Nystrm Pehr Olov Pehrson Francesca Chiodi Madeleine von Sydow Lars Moberg Knut Lidman Bertil Christensson Birgitta sj Eva Maria Feny 《Journal of medical virology》1987,23(1):67-73
Human immunodeficiency virus (HIV) has been isolated from plasma in 6 of 7 patients showing clinical symptoms of a primary HIV infection. Parallel cultures from peripheral blood mononuclear cells (PBMC) yielded virus in 5 patients. In one case, virus could only be isolated from the cerebrospinal fluid but not from peripheral blood. Detectable viremia was transient and preceded the appearance of HIV specific antibodies. After cessation of acute symptoms, the frequency of HIV isolations was similar to that of asymptomatic carriers (23 and 26%, respectively). The role of the immune response in terminating detectable viremia remains to be established. 相似文献
87.
Fourteen women with primary dysmenorrhea were administered four sessions of systematic desensitization (SD) by either a male or a female therapist. The following measures were taken during the flow periods before and after treatment and at a 6-month follow-up: menstrual symptom checklist, medication usage, invalid hours, and menstrual attitudes. At pretreatment, menstrually distressed women had significantly higher scores on all measures compared to a normative group and an explicitly nondistressed group. At posttreatment, treated women's scores on the dependent variables were significantly reduced. All indices were reduced to a nondistressed level at posttreatment and at 6-month follow-up. Type of dysmenorrhea (congestive vs. spasmodic), trait anxiety level, and therapist sex did not predict differential responsiveness to SD. SD did not affect frontalis EMG, peripheral blood flow, or pain threshold. A Retrospective Symptom Scale of menstrual distress was found to be highly reliable, valid, and sensitive. 相似文献
88.
Primary biliary cirrhosis and coronary atherosclerosis: Protective antioxidant effect of bilirubin 总被引:1,自引:0,他引:1
L. B. Dudnik O. A. Azyzova N. P. Solovyova A. P. Savchenkova M. A. Pokrovskaya 《Bulletin of experimental biology and medicine》2008,145(1):18-22
Increased concentration of lipid peroxidation products in patients with primary biliary cirrhosis is related to elevation
of serum lipid content, but not to activation of lipid peroxidation. Hyperbilirubinemia in patients with primary biliary cirrhosis
is accompanied by a decrease in the concentration of lipid peroxidation products and increase in antioxidant activity of blood
serum. Antioxidants play a major role in the prevention of atherosclerosis. We hypothesized that the absence of increased
risk of atherosclerosis in patients with primary biliary cirrhosis is due to inhibition of lipid peroxidation in blood serum
by antioxidant compound bilirubin.
__________
Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 145, No. 1, pp. 23–28, January, 2008 相似文献
89.
目的:通过对食管和贲门癌原发病灶和淋巴结转移病灶肿瘤抑制基因p53变化规律的研究,加深对食管和贲门癌转移发生的分子学基础的了解。方法:采用组织病理学和免疫组织化学(ABC)方法,对31例手术切除的食管和贲门癌原发病灶和转移病灶肿瘤抑制基因p53蛋白聚集进行比较研究。结果:31例手术标本中,病理检查发现24例食管鳞状细胞癌,7例为贲门腺癌。研究表明:24例食管原发和转移鳞癌中,11例原发和转移病灶中均出现p53蛋白聚集的变化,原发和转移病灶的一致性变化发生率为61%(11/18);在6例原发病灶p53免疫组化阴性患者中,其淋巴结转移病灶也同时出现免疫阴性反应。在7例胃贲门腺癌中,3例原发和转移病灶同时出现p53免疫阳性表达的一致率为50%(3/6);1例原发病灶p53免疫组化阴性患者,其淋巴结转移病灶也出现阴性反应。结论:肿瘤抑制基因p53在食管和贲门癌癌变和转移中起一定的作用。可能是食管和贲门癌侵袭与转移过程中值得重视的生物学指标之一。 相似文献
90.
Autoimmune polyendocrinopathy – candidosis – ectodermal dystrophy (APECED): autosomal recessive inheritance 总被引:9,自引:0,他引:9
A genetic analysis was made of 58 patients and their 42 families with APECED (autoimmune polyendocrinopathy--candidosis--ectodermal dystrophy). APECED is characterized by hypoparathyroidism, primary adrenocortical failure and chronic mucocutaneous candidosis, but none of its components is constant. Other endocrine deficiencies can occur as well and also dystrophy of dental enamel and nails. The proportion of affected siblings was 0.147 +/- 0.034 (S.D.) when corrected for truncate single ascertainment, 0.246 +/- 0.019 when corrected for a priori truncate complete ascertainment and 0.240 +/- 0.047 when corrected for a posteriori truncate complete ascertainment. The male/female ratio was 1.04. The results are compatible with autosomal recessive transmission. No heterozygous manifestations of the gene were found. The gene is enriched in isolated subpopulations in central and eastern Finland. APECED is part of the "Finnish heritage of disease". 相似文献