全文获取类型
收费全文 | 177912篇 |
免费 | 50431篇 |
国内免费 | 3133篇 |
专业分类
耳鼻咽喉 | 3044篇 |
儿科学 | 5459篇 |
妇产科学 | 2158篇 |
基础医学 | 31161篇 |
口腔科学 | 6890篇 |
临床医学 | 22252篇 |
内科学 | 41323篇 |
皮肤病学 | 10147篇 |
神经病学 | 19979篇 |
特种医学 | 7564篇 |
外国民族医学 | 7篇 |
外科学 | 26574篇 |
综合类 | 5851篇 |
现状与发展 | 5篇 |
一般理论 | 55篇 |
预防医学 | 9739篇 |
眼科学 | 3913篇 |
药学 | 15803篇 |
18篇 | |
中国医学 | 4045篇 |
肿瘤学 | 15489篇 |
出版年
2024年 | 201篇 |
2023年 | 1001篇 |
2022年 | 2476篇 |
2021年 | 5538篇 |
2020年 | 7189篇 |
2019年 | 13137篇 |
2018年 | 13006篇 |
2017年 | 13600篇 |
2016年 | 14878篇 |
2015年 | 16147篇 |
2014年 | 16880篇 |
2013年 | 17922篇 |
2012年 | 13199篇 |
2011年 | 12837篇 |
2010年 | 13830篇 |
2009年 | 9530篇 |
2008年 | 8212篇 |
2007年 | 6689篇 |
2006年 | 6148篇 |
2005年 | 5580篇 |
2004年 | 4694篇 |
2003年 | 4513篇 |
2002年 | 4097篇 |
2001年 | 3671篇 |
2000年 | 3237篇 |
1999年 | 2300篇 |
1998年 | 954篇 |
1997年 | 807篇 |
1996年 | 656篇 |
1995年 | 552篇 |
1994年 | 492篇 |
1993年 | 363篇 |
1992年 | 772篇 |
1991年 | 680篇 |
1990年 | 670篇 |
1989年 | 614篇 |
1988年 | 568篇 |
1987年 | 509篇 |
1986年 | 416篇 |
1985年 | 365篇 |
1984年 | 281篇 |
1983年 | 229篇 |
1982年 | 145篇 |
1981年 | 150篇 |
1980年 | 123篇 |
1979年 | 221篇 |
1978年 | 156篇 |
1977年 | 108篇 |
1975年 | 112篇 |
1974年 | 118篇 |
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
991.
Alanna M. Kongkriangkai Christopher King Lisa J. Martin Emily Wakefield Carlos E. Prada Geraldine Kelly‐Mancuso Elizabeth K. Schorry 《American journal of medical genetics. Part A》2019,179(4):602-607
Tumor growths, migraine headaches, and other health‐related complications reported in patients with neurofibromatosis type 1 (NF1) are often associated with pain. Thus, this study sought to describe and quantify the pain experience in children and young adults with NF1. Surveys were administered to 49 participants (28 children and 21 adults), ages 8 through 40 years. The survey included the Numeric Rating Scale 11 (NRS11) to assess pain intensity and the Patient Reported Outcomes Measurement Information System (PROMIS) to assess pain interference. A supplemental survey was created to measure pain frequency, chronicity, quality, and location. Results suggest pain is not only present in 55% of the cohort, but that it can begin at early ages. Pain was chronic in 35% of participants, with 41% reporting the use of medication to manage pain symptoms. Common sources of pain included migraine headaches and NF‐related tumors. Pain was described as having neuropathic features (i.e., burning, tingling, numbness, or itching), and was localized to the head, back, and extremities. Further, subsets of participants reported moderate‐to‐severe pain intensity, high frequency of pain, and interference of pain in daily activities. Continued investigation of the pain experience in a multisystem disorder, such as NF1, remains essential to providing guidance in the setting of complex pain management. 相似文献
992.
Daphné Lehalle Roberto Colombo Michael O'Grady Bénédicte Héron Nada Houcinat Paul Kuentz Sebastien Moutton Arthur Sorlin Julien Thevenon Julian Delanne Sebastien Gay Caroline Racine Aurore Garde Frédéric Tran Mau‐Them Christophe Philippe Antonio Vitobello Sophie Nambot Frédéric Huet Yannis Duffourd François Feillet Christel Thauvin‐Robinet Sandrine Marlin Laurence Faivre 《American journal of medical genetics. Part A》2019,179(9):1756-1763
Alpha‐mannosidosis (AM) is a very rare (prevalence: 1/500000 births) autosomal recessive lysosomal storage disorder. It is characterized by multi‐systemic involvement associated with progressive intellectual disability, hearing loss, skeletal anomalies, and coarse facial features. The spectrum is wide, from very severe and lethal to a milder phenotype that usually progresses slowly. AM is caused by a deficiency of lysosomal alpha‐mannosidase. A diagnosis can be established by measuring the activity of lysosomal alpha‐mannosidase in leucocytes and screening for abnormal urinary excretion of mannose‐rich oligosaccharides. Genetic confirmation is obtained with the identification of MAN2B1 mutations. Enzyme replacement therapy (LAMZEDER) was approved for use in Europe in August 2018. Here, we describe seven individuals from four families, diagnosed at 3–23 years of age, and who were referred to a clinical geneticist for etiologic exploration of syndromic hearing loss, associated with moderate learning disabilities. Exome sequencing had been used to establish the molecular diagnosis in five cases, including a two‐sibling pair. In the remaining two patients, the diagnosis was obtained with screening of urinary oligosaccharides excretion and the association of deafness and hypotonia. These observations emphasize that the clinical diagnosis of AM can be challenging, and that it is likely an underdiagnosed rare cause of syndromic hearing loss. Exome sequencing can contribute significantly to the early diagnosis of these nonspecific mild phenotypes, with advantages for treatment and management. 相似文献
993.
Wataru Yasui Zhong-Qiang Ji Hiroki Kuniyasu Ayse Ayhan Hiroshi Yokozaki Hisao Ito Eiichi Tahara 《Virchows Archiv : an international journal of pathology》1992,421(6):513-519
Summary The expression of transforming growth factor alpha (TGF-) was examined in various human tissues and the fetus, using immunohistochemistry and Northern blot analysis. TGF- immunoreactivity was detected mainly in the epithelial cells of the digestive tract, liver, pancreas, kidney, thyroid, adrenal, skin, mammary gland and genital organs. In the digestive tract, epithelial cells with regenerative change or hyperplastic change showed strong immunoreactivity to TGF-. Peripheral nerve, vessels, megakaryocytes and macrophages in the lung and spleen were also positive for TGF-. By Northern blot analysis the expression of TGF- mRNA was confirmed in the digestive tract, salivary gland, thyroid, kidney and mammary gland. In the human fetus, the nerve tissues, liver, adrenal and kidney were positive for TGF-. Strong immunoreactivity to TGF- was observed in the hepatocytes of the fetus. These findings indicate that TGF- is produced by a variety of nonneoplastic cells in both adult and fetal tissues. 相似文献
994.
Inhibition of Ehrlichia risticii infection in murine peritoneal macrophages by gamma interferon, a calcium ionophore, and concanavalin A 总被引:2,自引:8,他引:2
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Ehrlichia risticii incubated with mouse peritoneal macrophages elicited with thioglycolate broth survived and replicated, thereby allowing examination of the effects of several immunopotentiating agents. Treatment of the macrophages with recombinant murine gamma interferon (rMuIFN-gamma) in vitro at 1 day before or 3 h after infection made the macrophages resistant to infection with E. risticii, and macrophages treated with rMuIFN-gamma at 1 to 3 days after infection developed the capacity to eradicate intracellular E. risticii. Similar effects were seen with macrophages treated with the Ca2+ ionophore A23187 before or after E. risticii infection in vitro. Concanavalin A treatment before or 3 h after infection caused the macrophages to become resistant to infection with E. risticii but could confer neither ehrlichiacidal nor ehrlichiastic activity to them once infection had been established for more than 1 day. Bacterial products such as lipopolysaccharide and muramyl dipeptide were less or not at all effective, respectively, in conferring antiehrlichial activity to macrophages. Finally, protein kinase C activator, phorbol myristate acetate, and recombinant tumor necrosis factor did not induce any antiehrlichial activity in macrophages when the macrophages were treated either before or after infection. 相似文献
995.
Summary The complete nucleotide sequence of the genomic RNA of odontoglossum ringspot tobamovirus (ORSV) was determined. The RNA genome of ORSV is 6618 nucleotides long and contains five open reading frames (ORFs 1 to 5) coding for proteins of Mr 126 K, 181 K, 34 K, 18 K and 52 K, respectively. This is the longest RNA of the known viruses of theTobamovirus genus. The sequences of the ORSV RNA encoded proteins exhibit high homology to the proteins of the members of theTobamovirus genus. The genomic organization and sequence analysis showed that ORSV is more closely related to tobacco mild green mosaic virus (TMGMV), pepper mild mottle virus (PMMV), tomato mosaic virus (ToMV) and TMV than to cucumber green mottle mosaic virus (CGMMV) and sunn-hemp mosaic virus (SHMV).The nucleotide sequence reported in this paper will appear in the EMBL, GenBank and DDBJ nucleotide sequence databases under the accession number X82130. 相似文献
996.
997.
Sang-Hyun Cho Dong Gyu Kim Dae-Shik Kim Yun-Hee Kim Chu-Hee Lee Sung Ho Jang 《Neuroscience letters》2007
Diffusion tensor tractography (DTT) is useful for exploring the state of the corticospinal tract (CST). An accurate estimation of the integrity of the CST in the early stage of a cerebral infarct would enable a determination of motor recovery. DTT was performed to classify CST integrity following a corona radiata infarct to evaluate if the procedure could characterize the motor outcome of the affected hand. Fifty-five patients with completely paralyzed hands due to a corona radiata infarct were recruited for the study, and DTT images were obtained within 7–30 days after a stroke. The DTI findings for the patients were classified into four groups. In type A, the CST was preserved around the infarct; in type B, the CST originated from a cortex other than the primary motor cortex; in type C, the CST was interrupted at the infarct; in type D, the CST failed to reach the infarct due to degeneration. Six months after a stroke, the motor function of the affected hand was evaluated with the motricity index (MI) for the hand, the Medical Research Council score (MRC) for finger extensors and the modified Brunnstrom classification (MBC). These indices were significantly influenced by the DTT type (p < 0.05). The highest MI, MRC and MBC were seen in the DTT type A patients; the lowest MI, MRC and MBC were seen in the DTT type D patients (p < 0.05). The integrity of the corticospinal tract determined by DTT obtained during the early stage of a corona radiata infarct seems to be helpful in predicting the motor outcome of the affected hand. 相似文献
998.
Gunilla Caisander Hannah Park Katarina Frej Jenny Lindqvist Christina Bergh Kersti Lundin Charles Hanson 《Chromosome research》2006,14(2):131-137
There have been recent reports of human embryonic stem cell (hESC) lines developing chromosomal aberrations after long-term
culture, indicating an unstable genomic status due to the in vitro milieu. This raises concern, since it would limit their use in therapeutics. In this study the chromosomal status of five
well-characterized hESC lines, SA002, SA002.5, AS034.1.1, SA121 and SA461, was monitored during long-term in vitro culture. The criteria of defined hESCs were met by all of the five hESC lines (four diploid and one trisomic for chromosome
13). The genomes were screened for chromosomal aberrations and rearrangements using comparative genomic hybridization (CGH),
interphase fluorescence in situ hybridization (FISH) and traditional karyotyping on several occasions while in culture. The genomic integrity was shown to
be maintained after repeated freeze-thaw procedures and continuous culture in vitro for up to 22 months (148 passages). We discuss the most common de novo chromosomal aberrations reported in hESCs, as well as their possible origin. 相似文献
999.
Hepatocytes are anchorage-dependent cells sensitive to microenvironment; the control of the physicochemical properties of the extra-cellular matrices may be useful to the maintenance of hepatocyte functions in vitro for various applications. In a microcapsule-based 3-D hepatocyte culture microenvironment, we could control the physical properties of the collagen nano-fibres by fine-tuning the complex-coacervation reaction between methylated collagen and terpolymer of hydroxylethyl methacrylate-methyl methacrylate-methylacrylic acid. The physical properties of the nano-fibres were quantitatively characterized using back-scattering confocal microscopy to help optimize the physical support for hepatocyte functions. We further enhanced the chemical properties of the collagen nano-fibres by incorporating galactose onto collagen, which can specifically interact with the asialoglycoprotein receptor on hepatocytes. By correlating a range of collagen nano-fibres of different physicochemical properties with hepatocyte functions, we have identified a specific combination of methylated and galactosylated collagen nano-fibres optimal for maintaining hepatocyte functions in vitro. A model of how the physical and chemical supports interplay to maintain hepatocyte functions is discussed. 相似文献
1000.
Platelet interactions with calcium-phosphate-coated surfaces 总被引:1,自引:0,他引:1
Many studies have shown that calcium-phosphate (CaP)-coated endosseous implants exhibit more peri-implant bone formation and bone contact at early healing times than uncoated implants. Since the rate of healing is influenced by blood/implant interactions and possibly the degree of blood platelet activation, the aim of this study was to determine whether the topography, microtopography, or the presence of calcium (Ca) and phosphate (PO(4)) ions in the implant surface plays a predominant role in platelet activation. We define the threshold between topography and microtopography as the limit of the scale range of platelets themselves; thus, a microtopographic surface is defined by one which exhibits features 3mum. With the help of four international collaborating laboratories, we prepared 11 titanium and CaP-modified titanium surfaces each with different (micro)topographies and interrogated these surfaces with both platelet adhesion (lactate dehydrogenase activity) and platelet activation (microparticle formation and P-selectin expression) assays. Our results show that: calcium (Ca)- and phosphate (PO(4))-containing surfaces of increasing surface microtopographical complexity exhibit increasing platelet activation; surfaces with similar surface microtopographies show similar levels of platelet activation regardless of the presence of Ca and PO(4) in the surface; and that surface microtopography is responsible for platelet activation rather than the presence of Ca and PO(4) in the surface. 相似文献