全文获取类型
收费全文 | 12070篇 |
免费 | 1014篇 |
国内免费 | 31篇 |
专业分类
耳鼻咽喉 | 138篇 |
儿科学 | 520篇 |
妇产科学 | 324篇 |
基础医学 | 1608篇 |
口腔科学 | 140篇 |
临床医学 | 1975篇 |
内科学 | 2217篇 |
皮肤病学 | 165篇 |
神经病学 | 1202篇 |
特种医学 | 202篇 |
外国民族医学 | 2篇 |
外科学 | 900篇 |
综合类 | 149篇 |
一般理论 | 19篇 |
预防医学 | 1897篇 |
眼科学 | 177篇 |
药学 | 617篇 |
中国医学 | 9篇 |
肿瘤学 | 854篇 |
出版年
2024年 | 27篇 |
2023年 | 156篇 |
2022年 | 200篇 |
2021年 | 375篇 |
2020年 | 282篇 |
2019年 | 430篇 |
2018年 | 437篇 |
2017年 | 371篇 |
2016年 | 340篇 |
2015年 | 379篇 |
2014年 | 485篇 |
2013年 | 723篇 |
2012年 | 975篇 |
2011年 | 965篇 |
2010年 | 544篇 |
2009年 | 450篇 |
2008年 | 759篇 |
2007年 | 821篇 |
2006年 | 733篇 |
2005年 | 654篇 |
2004年 | 626篇 |
2003年 | 564篇 |
2002年 | 540篇 |
2001年 | 91篇 |
2000年 | 49篇 |
1999年 | 67篇 |
1998年 | 108篇 |
1997年 | 78篇 |
1996年 | 78篇 |
1995年 | 61篇 |
1994年 | 61篇 |
1993年 | 37篇 |
1992年 | 37篇 |
1991年 | 43篇 |
1990年 | 27篇 |
1989年 | 35篇 |
1988年 | 28篇 |
1987年 | 29篇 |
1986年 | 21篇 |
1985年 | 21篇 |
1984年 | 27篇 |
1983年 | 19篇 |
1982年 | 26篇 |
1981年 | 23篇 |
1980年 | 30篇 |
1979年 | 12篇 |
1978年 | 12篇 |
1977年 | 14篇 |
1976年 | 21篇 |
1974年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
61.
Taylor S Thordarson DS Maxfield L Fedoroff IC Lovell K Ogrodniczuk J 《Journal of consulting and clinical psychology》2003,71(2):330-338
The authors examined the efficacy, speed, and incidence of symptom worsening for 3 treatments of posttraumatic stress disorder (PTSD): prolonged exposure, relaxation training, or eye movement desensitization and reprocessing (EMDR; N = 60). Treaments did not differ in attrition, in the incidence of symptom worsening, or in their effects on numbing and hyperarousal symptoms. Compared with EMDR and relaxation training, exposure therapy (a) produced significantly larger reductions in avoidance and reexperiencing symptoms, (b) tended to be faster at reducing avoidance, and (c) tended to yield a greater proportion of participants who no longer met criteria for PTSD after treatment. EMDR and relaxation did not differ from one another in speed or efficacy. 相似文献
62.
Nora Franceschini Kari E North Jeffrey B Kopp Louise McKenzie Cheryl Winkler 《Genetics in medicine》2006,8(2):63-75
Nephrotic syndrome, characterized by edema, proteinuria, hyperlipidemia and low serum albumin, is a manifestation of kidney disease involving the glomeruli. Nephrotic syndrome may be caused by primary kidney disease such as focal segmental glomerulosclerosis. Mutations in the podocin gene, NPHS2, have been shown in familial and sporadic forms of steroid-resistant nephrotic syndrome, including focal segmental glomerulosclerosis. Podocin is an integral membrane protein located at the slit diaphragm of the glomerular permeability barrier. Complete information is lacking for the population frequency of some NPHS2 variants for all racial and ethnic groups. The most frequently reported variant, R229Q, is more common among European-derived populations than African-derived populations. We calculated crude odds ratios and 95% confidence intervals of childhood nephrotic syndrome and focal segmental glomerulosclerosis associated with R229Q heterozygosity using data from five studies. The R229Q variant is not associated with focal segmental glomerulosclerosis in the US population of African descent. In contrast, the R229Q variant is associated with a trend toward increased focal segmental glomerulosclerosis risk in European-derived populations, with an estimated increased risk of 20-40%. Our insight into the association between NPHS2 variants and nephrotic disease is hampered by the limitations of the existing studies, including small numbers of affected individuals and suboptimal control groups. Nevertheless, the available data suggest that large epidemiological case-control studies to examine the association between NPHS2 variants and nephrotic syndrome are warranted. 相似文献
63.
The RAD6 gene of Saccharomyces cerevisiae is required for post-replication repair of UV-damaged DNA, UV mutagenesis, and sporulation. Here, we show that the radiation sensitivity of a MAT
a
rad6 strain can be suppressed by the MAT2 gene carried on a multicopy plasmid. The a1-2 suppression is specific to the RAD6 pathway, as mutations in genes required for nucleotide excision repair or for recombinational repair do not show such mating-type suppression. The a1-2 suppression of the rad6 mutation requires the activity of the RAD52 group of genes, suggesting that suppression occurs by channelling of post-replication gaps present in the rad6 mutant into the RAD52 recombinational repair pathway. The a1-2 repressor could mediate this suppression via an enhancement in the expression, or the activity, of recombination genes. 相似文献
64.
Differential activities of the RET tyrosine kinase receptor isoforms during mammalian embryogenesis 下载免费PDF全文
de Graaff E Srinivas S Kilkenny C D'Agati V Mankoo BS Costantini F Pachnis V 《Genes & development》2001,15(18):2433-2444
The RET receptor tyrosine kinase has a critical role in kidney organogenesis and the development of the enteric nervous system. Two major isoforms, RET9 and RET51, differ in the amino acid sequence of the C-terminal tail as a result of alternative splicing. To determine the roles of these isoforms in vivo, we used targeted mutagenesis to generate mice that express either RET9 or RET51. Monoisoformic RET9 mice, which lack RET51, are viable and appear normal. In contrast, monoisoformic RET51 animals, which lack RET9, have kidney hypodysplasia and lack enteric ganglia from the colon. To study the differential activities of the two RET isoforms further, we generated transgenic mice expressing ligand-dependent and constitutively active forms of RET9 or RET51 under the control of the Hoxb7 regulatory sequences. Such RET9 transgenes are capable of rescuing the kidney agenesis in RET-deficient mice or causing kidney hypodysplasia in wild-type animals. In contrast, similar RET51 transgenes fail to rescue the kidney agenesis or cause hypodysplasia. Our findings show that RET9 and RET51 have different signaling properties in vivo and define specific temporal and spatial requirements of c-Ret function during renal development and histogenesis of the enteric nervous system. 相似文献
65.
Sarah Curran Lindsey Kent Alison Gould Louise Huckett Sandra Richards Eric Taylor Philip Asherson 《American journal of medical genetics. Part A》2002,114(3):269-271
Several lines of evidence implicate synaptosomal‐associated protein of 25 kDa (SNAP‐25) in the etiology of attention deficit hyperactivity disorder (ADHD). Most notably, the coloboma mouse mutant, considered to be a good animal model of hyperactivity, has a deletion spanning this gene. Introducing a SNAP‐25 transgene into these animals alleviates hyperlocomotion. We have identified a novel microsatellite repeat in SNAP‐25 located between the 5′UTR and the first coding exon, and tested for association with ADHD. Case‐control analyses suggest there may be a role of this polymorphism in ADHD, with one allele over‐represented in controls and another over‐represented in probands. Within‐family tests of linkage and association confirmed these findings. Further work is needed to ascertain the role of SNAP‐25 in ADHD and assess the functional significance of this polymorphism. © 2002 Wiley‐Liss, Inc. 相似文献
66.
Breast cancer risk associated with ovulation-stimulating drugs 总被引:4,自引:0,他引:4
Brinton LA Scoccia B Moghissi KS Westhoff CL Althuis MD Mabie JE Lamb EJ 《Human reproduction (Oxford, England)》2004,19(9):2005-2013
BACKGROUND: Despite the recognized role of hormones in the aetiology of breast cancer, there has been little evaluation of hormonal preparations used to treat infertility. METHODS: A retrospective cohort study of 12,193 women evaluated for infertility between 1965 and 1988 at five clinical sites identified 292 in situ and invasive breast cancers in follow-up through 1999. Standardized incidence ratios (SIRs) compared breast cancer risks with those of the general population. Analyses within the cohort estimated rate ratios (RRs) associated with medications after adjustment for other breast cancer predictors. RESULTS: Infertile patients had a significantly higher breast cancer risk than the general population [SIR = 1.29, 95% confidence interval (CI) 1.1-1.4]. Analyses within the cohort showed adjusted RRs of 1.02 for clomiphene citrate and 1.07 for gonadotrophins, and no substantial relationships to dosage or cycles of use. Slight and non-significant elevations in risk were seen for both drugs after > or = 20 years of follow-up (RRs = 1.39 for clomiphene and 1.54 for gonadotrophins). However, the risk associated with clomiphene for invasive breast cancers was statistically significant (RR = 1.60, 95% CI 1.0-2.5). CONCLUSIONS: Although there was no overall increase in breast cancer risk associated with use of ovulation-stimulating drugs, long-term effects should continue to be monitored. 相似文献
67.
Louise R Rodino-Klapac Paul ML Janssen Chrystal L Montgomery Brian D Coley Louis G Chicoine K Reed Clark Jerry R Mendell 《Journal of translational medicine》2007,5(1):45-11
Background
Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder with monogenic mutations setting the stage for successful gene therapy treatment. We have completed a study that directly deals with the following key issues that can be directly adapted to a gene therapy clinical trial using rAAV considering the following criteria: 1) A regional vascular delivery approach that will protect the patient from widespread dissemination of virus; 2) an approach to potentially facilitate safe passage of the virus for efficient skeletal muscle transduction; 3) the use of viral doses to accommodate current limitations imposed by vector production methods; 4) and at the same time, achieve a clinically meaningful outcome by transducing multiple muscles in the lower limb to prolong ambulation. 相似文献68.
Metabolic and Functional Characteristics of Alveolar Macrophages Recovered from Rats Exposed to Marijuana Smoke 下载免费PDF全文
David B. Drath Jeannette M. Shorey Louise Price Gary L. Huber 《Infection and immunity》1979,25(1):268-272
Pulmonary alveolar macrophages were obtained by bronchopulmonary lavage from male rats after 30 consecutive days of in vivo exposure to marijuana and tobacco smoke. No significant differences were found between either group of experimental animals and controls in the number of cells recovered, the protein content per 10(6) cells, or the percentage of cells that adhered to plastic surfaces. The ability of macrophages to phagocytize viable bacteria was not affected by exposure to either marijuana or tobacco smoke in that both treatment groups ingested Staphylococcus aureus over a 60-min period as well as did control cells. Differences were found between the groups, however, with respect to cellular metabolism. Marijuana smoke inhalation caused a small decrease in the amount of oxygen consumed by macrophages during phagocytosis, as compared with control cells. This may have been reflected in the even greater decrease in superoxide formation observed during particle engulfment by these treated cells. Tobacco smoke, on the other hand, increased oxygen consumption and was without effect on superoxide release. Neither tobacco nor marijuana smoke treatment had an effect on the direct oxidation of glucose via the hexose monophosphate shunt. Our results indicate that, despite several metabolic alterations in response to marijuana and tobacco smoke, alveolar macrophages were not compromised with respect to their ability to ingest a particulate challenge. 相似文献
69.
Richard Cooper Ivan Soltero Jeremiah Stamler Louise Mojonnier Yolanda Hall Dorothy Moss David M. Berkson Tom Tokich 《Journal of the National Medical Association》1982,74(4):349-355
Quit-rates for cigarette smokers in a lifestyle intervention program aimed at reducing coronary risk were 24 percent for all participants and 34 percent for non-dropouts. Recidivism remained very low during participation in the program. Half of the smokers who quit did so after being in the program more than two years. These data suggest that while engaging in an effort to make other changes in lifestyle, many smokers can be helped to quit. Sustained antismoking efforts in the clinical practice of medicine can be expected to share these same positive aspects. While mass public health programs to eliminate smoking and prevent young people from taking up the habit are being developed, health practitioners can make a significant contribution by including vigorous efforts at smoking cessation as part of routine practice. 相似文献
70.
Use of bacteriophage Ba1 to identify properties associated with Bordetella avium virulence 下载免费PDF全文
Bordetella avium causes bordetellosis, an upper respiratory disease of birds. Commercially raised turkeys are particularly susceptible. We report here on the use of a recently described B. avium bacteriophage, Ba1, as a tool for investigating the effects of lysogeny and phage resistance on virulence. We found that lysogeny had no effect on any of the in vivo or in vitro measurements of virulence we employed. However, two-thirds (six of nine) spontaneous phage-resistant mutants of our virulent laboratory strain, 197N, were attenuated. Phage resistance was associated, in all cases, with an inability of the mutants to bind phage. Further tests of the mutants revealed that all had increased sensitivities to surfactants, and increased amounts of incomplete (O-antigen-deficient) lipopolysaccharide (LPS) compared to 197N. Hot phenol-water-extracted 197N LPS inactivated phage in a specific and dose-dependent manner. Acid hydrolysis and removal of lipid A had little effect upon the ability of isolated LPS to inactivate Ba1, suggesting that the core region and possibly the O antigen were required for phage binding. All of the mutants, with one exception, were significantly more sensitive to naive turkey serum and, without exception, significantly less able to bind to tracheal rings in vitro than 197N. Interestingly, the three phage-resistant mutants that remained virulent appeared to be O antigen deficient and were among the mutants that were the most serum sensitive and least able to bind turkey tracheal rings in vitro. This observation allowed us to conclude that even severe defects in tracheal ring binding and serum resistance manifested in vitro were not necessarily indicative of attenuation and that complete LPS may not be required for virulence. 相似文献