全文获取类型
收费全文 | 23729篇 |
免费 | 1267篇 |
国内免费 | 137篇 |
专业分类
耳鼻咽喉 | 163篇 |
儿科学 | 612篇 |
妇产科学 | 386篇 |
基础医学 | 2942篇 |
口腔科学 | 662篇 |
临床医学 | 1637篇 |
内科学 | 6038篇 |
皮肤病学 | 456篇 |
神经病学 | 2112篇 |
特种医学 | 807篇 |
外科学 | 3719篇 |
综合类 | 139篇 |
一般理论 | 1篇 |
预防医学 | 631篇 |
眼科学 | 377篇 |
药学 | 1716篇 |
中国医学 | 33篇 |
肿瘤学 | 2702篇 |
出版年
2023年 | 136篇 |
2022年 | 264篇 |
2021年 | 443篇 |
2020年 | 245篇 |
2019年 | 331篇 |
2018年 | 464篇 |
2017年 | 323篇 |
2016年 | 389篇 |
2015年 | 465篇 |
2014年 | 557篇 |
2013年 | 675篇 |
2012年 | 1004篇 |
2011年 | 1106篇 |
2010年 | 649篇 |
2009年 | 547篇 |
2008年 | 968篇 |
2007年 | 1100篇 |
2006年 | 1047篇 |
2005年 | 1092篇 |
2004年 | 1006篇 |
2003年 | 941篇 |
2002年 | 1001篇 |
2001年 | 946篇 |
2000年 | 922篇 |
1999年 | 866篇 |
1998年 | 307篇 |
1997年 | 233篇 |
1996年 | 273篇 |
1995年 | 162篇 |
1994年 | 161篇 |
1993年 | 155篇 |
1992年 | 542篇 |
1991年 | 493篇 |
1990年 | 510篇 |
1989年 | 460篇 |
1988年 | 435篇 |
1987年 | 434篇 |
1986年 | 377篇 |
1985年 | 392篇 |
1984年 | 283篇 |
1983年 | 193篇 |
1979年 | 214篇 |
1978年 | 145篇 |
1977年 | 140篇 |
1974年 | 132篇 |
1971年 | 138篇 |
1970年 | 132篇 |
1969年 | 133篇 |
1968年 | 140篇 |
1967年 | 141篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
A synthesis of psychological interventions for the bereaved 总被引:1,自引:0,他引:1
Several interventions have been implemented to address the adverse psychological and physical consequences associated with bereavement. In this review, we summarize four major theories of bereavement, present a qualitative review of bereavement intervention studies, and assess the overall effectiveness of bereavement intervention studies in a quantitative meta-analysis. Summaries of the theories are drawn from published theoretical works. The qualitative and quantitative reviews were based on searches of Medline, PsychINFO, and Dissertation Abstracts International databases using the keywords "bereaved" and "bereavement." Overall, the interventions were largely methodologically flawed, rarely specified what theory of bereavement they were testing, and slowed surprisingly weak effect sizes. Possible interpretations for the small effect sizes are discussed, and future directions are outlined. 相似文献
102.
Hirata T Iida A Shiraki-Iida T Kitazato K Kato A Nagai Y Hasegawa M 《Journal of virological methods》2002,104(2):125-133
An improved system is described to recover non-transmissible Sendai virus that lack the envelope fusion (F) gene from cloned cDNA. The system (1) used plasmids that expressed the F and the HN viral envelope proteins, as well as the plasmids that expressed the viral NP, P, and L proteins as helper plasmids for recovery, and (2) overlaid packaging cells that expressed the F protein. With this improved system, we have succeeded in recovery of F-defective Sendai virus expressing two foreign proteins, and expression vectors that do not contain the EGFP reporter gene. This system may provide the basis for constructing recombinant F-defective Sendai virus for preventing and treating human diseases in the form of vaccines and vectors for gene therapy. 相似文献
103.
Nishimura H Tokuyama K Arakawa H Ohki Y Sato A Kato M Mochizuki H Morikawa A 《International archives of allergy and immunology》2002,129(4):320-326
BACKGROUND: Chronic exposure to fenoterol (FEN), a beta(2)-adrenergic receptor (beta(2)-AR) agonist, was shown to induce both airway hyperresponsiveness and airway remodeling in experimental animals. OBJECTIVE: We wanted to know the effects of chronic exposure to procaterol (PRO), a beta(2)-AR agonist, on airway function and structure, because this agent is widely used as a bronchodilator in Japan. For comparison, the effects of FEN were also examined. METHODS: Aerosolized PRO (0.1 or 1 mg/ml), FEN (1 mg/ml) or vehicle (0.9% NaCl) was given to guinea pigs 3 times a day for 6 weeks. Sublaryngeal deposition of these agents was calculated using radioisotopes. At 72 h after the last inhalation of PRO, FEN or vehicle, the dose-response relationship between lung resistance (R(L)) and intravenously administered acetylcholine (ACh) was measured. After measuring R(L), histological changes in noncartilaginous airway dimensions were evaluated. RESULTS: The amount of sublaryngeal deposition of 0.1 mg/ml PRO in the present study was speculated to be 100 times larger than that of therapeutic dose. ACh concentrations causing 2-fold, 10-fold and maximal increases in R(L) were not different in 4 groups tested. In the smaller membranous airways (<0.4 mm in diameter), but not the larger ones, thickening of adventitial areas was significantly greater in animals treated with beta(2)-AR agonists than in control animals (23 and 25, and 96% higher in animals treated with 0.1 and 1 mg/ml PRO or 1 mg/ml FEN, respectively). The degree of the increase was significantly less in PRO-treated animals than in FEN-treated animals (p < 0.01). CONCLUSION: Our results did not provide any evidence that regular inhalation of PRO at the therapeutic dose might induce bronchial hyperresponsiveness. In addition, huge amounts of PRO only caused a mild thickening of the adventitial areas, suggesting that PRO may be a weak inducer of airway remodeling compared with FEN. 相似文献
104.
Atsuo Murata Hitoshi Toda Ken -Ichi Uda Hirohito Hayashida Takeshi Kato Hidewaki Nakagawa Shigekazu Yokoyama Hideaki Morishita Toru Yamakawa Jiro Hirose Takesada Mori Nariaki Matsuura 《Inflammation》1994,18(4):337-347
Severe inflammatory responses after major surgeries, trauma, and infection develop multiple organ dysfunction. In the mechanisms of the pathogenesis of these responses, activated neutrophils are thought to be important in terms of their ability to produce various kinds of proteinases, which can degrade various proteins constructing human tissues. Among their proteinases, neutrophil elastase is the strongest serine proteinase secreted from activated neutrophils. Thus, we examined in this study the inhibitory effect and therapeutic efficacy of newly produced recombinant human Kunitz-type proteinase inhibitor (R-020), which coded the second domain of human urinary trypsin inhibitor. R-020 was effective in significantly improving the survival rate after induction of the rat lethal peritonitis model (cecal ligation and punctureinduced septic shock model). We suggest that various serine proteinases are implicated in the pathogenesis of neutrophil-related multiple organ failure and that recombinant human Kunitz-type proteinase inhibitor might be effective in the treatment of these kinds of organ dysfunction. 相似文献
105.
Monocarboxylate transporter 1 (MCT1) plays a direct role in short-chain fatty acids absorption in caprine rumen 总被引:2,自引:0,他引:2
Doaa Kirat Junji Masuoka Hideaki Hayashi Hidetomo Iwano Hiroshi Yokota Hiroyuki Taniyama Seiyu Kato 《The Journal of physiology》2006,576(2):635-647
Despite the importance of short-chain fatty acids (SCFA) in maintaining the ruminant physiology, the mechanism of SCFA absorption is still not fully studied. The goal of this study was to elucidate the possible involvement of monocarboxylate transporter 1 (MCT1) in the mechanism of SCFA transport in the caprine rumen, and to delineate the precise cellular localization and the level of MCT1 protein along the entire caprine gastrointestinal tract. RT-PCR revealed the presence of mRNA encoding for MCT1 in all regions of the caprine gastrointestinal tract. Quantitative Western blot analysis showed that the level of MCT1 protein was in the order of rumen ≥ reticulum > omasum > caecum > proximal colon > distal colon > abomasum > small intestine. Immunohistochemistry and immunofluorescence confocal analyses revealed widespread immunoreactive positivities for MCT1 in the caprine stomach and large intestine. Amongst the stratified squamous epithelial cells of the forestomach, MCT1 was predominantly expressed on the cell boundaries of the stratum basale and stratum spinosum. Double-immunofluorescence confocal laser-scanning microscopy confirmed the co-localization of MCT1 with its ancillary protein, CD147 in the caprine gastrointestinal tract. In vivo and in vitro functional studies, under the influence of the MCT1 inhibitors, p -chloromercuribenzoate (pCMB) and p -chloromercuribenzoic acid (pCMBA), demonstrated significant inhibitory effect on acetate and propionate transport in the rumen. This study provides evidence, for the first time in ruminants, that MCT1 has a direct role in the transepithelial transport and efflux of the SCFA across the stratum spinosum and stratum basale of the forestomach toward the blood side. 相似文献
106.
Kenichi Ohashi Yo Kato Jun Kanno Tsutomu Kasuga 《Virchows Archiv : an international journal of pathology》1990,417(2):137-143
Summary Normal oesophagus specimens taken from 65 autopsy cases and surgical specimens from 127 oesophageal carcinoma cases were examined
histopathologically to determine melanocyte incidence and distribution. Melanocytes were found in the epithelio-stromal junction
in 7.7% of normal oesophagus specimens examined at autopsy, and in 29.9% of surgical cases with oesophageal carcinoma. Positive
specimens in the latter groups, especially from pre-operatively irradiated individuals, showed a more remarkable increase
of melanocytes than was evident in any of the normal oesophageal samples. There were no significant differences in incidence
between males and females, or between age groups. In cases where the cancer invaded into deeper stroma, the melanocytes were
mainly observed in the normal epithelium around the carcinomas. Epithelial and stromal elements of the melanotic mucosa commonly
showed hyperplastic changes such as acanthosis or basal cell hyperplasia, and chronic oesophagitis. Melanocytes were observed
most commonly in the lower part of the oesophagus, the site where malignant melanoma of the oesophagus, most often originates.
These results strongly suggest that the melanocyte increase observed in areas of hyperplastic epithelium and chronic oesophagitis
may play an important role as a precursor lesion for malignant melanoma in the oesophagus. 相似文献
107.
108.
Li N Nakamura K Jiang Y Tsurui H Matsuoka S Abe M Ohtsuji M Nishimura H Kato K Kawai T Atsumi T Koike T Shirai T Ueno H Hirose S 《Human molecular genetics》2004,13(2):171-179
Systemic lupus erythematosus (SLE), a complex multigenic disease, is a typical antibody-mediated autoimmune disease characterized by production of autoantibodies against a variety of autoantigens and immune complex-type tissue inflammation, most prominently in the kidney. Evidence suggests that genetic factors predisposing to aberrant proliferation/maturation of self-reactive B cells initiate and propagate the disease. In SLE-prone New Zealand Black (NZB) mice and their F1 cross with New Zealand White (NZW) mice, B cell abnormalities can be ascribed mainly to self-reactive CD5+ B1 cells. Our genome-wide scans to search for susceptibility genes for aberrant activation of B1 cells in these mice showed evidence that the gene, Ltk, encoding leukocyte tyrosine kinase (LTK), is a possible candidate. LTK is a receptor-type protein tyrosine kinase, belonging to the insulin receptor superfamily, and is mainly expressed in B lymphocyte precursors and neuronal tissues. Sequence and functional analyses of the gene revealed that NZB has a gain-of-function polymorphism in the LTK kinase domain near YXXM, a binding motif of the p85 subunit of phosphatidylinositol 3-kinase (PI3K). SLE patients also had this type of Ltk polymorphism with a significantly higher frequency compared with the healthy controls. Our findings suggest that these polymorphic LTKs cause up-regulation of the PI3K pathway and possibly form one genetic component of susceptibility to abnormal proliferation of self-reactive B cells in SLE. 相似文献
109.
Ijiri R Tanaka Y Kato K Misugi K Ohama Y Shinkai M Nishi T Aida N Kondo F 《Pathology international》2001,51(1):16-19
With the application of liver transplantation for patients with biliary atresia (BA), we have had the opportunity to review the clinicopathologic features of the native livers from 10 transplanted BA patients. A single large nodule at porta hepatis (hilar nodule) was noted in three of 10 patients, and an ill-defined nodule-like lesion at porta hepatis was present in two other patients. The three BA patients with hilar nodules were long-term survivors, compared to the patients with nodule-like and those without nodules. The hilar nodules measured between 5.0 cm and 8.0 cm and histologically, they were partly surrounded by fibrous septa with relatively well-preserved liver architectures and fewer inflammatory cells at the portal triads when compared to the surrounding cirrhotic lesions. No nuclear or cellular atypia was observed. Proliferating cell nuclear antigen labeling index was higher in the surrounding cirrhotic lesions than the hilar nodules. The nodule-like lesions at porta hepatis also showed similar light microscopic and immunohistochemical features as the hilar nodules. These hilar nodules did not seem to contain any malignant potential. The benign histology with relatively well-preserved liver architecture and the preferential site of occurrence at porta hepatis where bile seemed to flow more smoothly, suggested possible residues of less-affected hepatic tissues. 相似文献
110.