全文获取类型
收费全文 | 21505篇 |
免费 | 1711篇 |
国内免费 | 49篇 |
专业分类
耳鼻咽喉 | 111篇 |
儿科学 | 852篇 |
妇产科学 | 713篇 |
基础医学 | 2990篇 |
口腔科学 | 320篇 |
临床医学 | 2916篇 |
内科学 | 3823篇 |
皮肤病学 | 286篇 |
神经病学 | 2610篇 |
特种医学 | 317篇 |
外科学 | 1749篇 |
综合类 | 259篇 |
一般理论 | 46篇 |
预防医学 | 2926篇 |
眼科学 | 389篇 |
药学 | 1463篇 |
中国医学 | 28篇 |
肿瘤学 | 1467篇 |
出版年
2023年 | 214篇 |
2022年 | 243篇 |
2021年 | 473篇 |
2020年 | 350篇 |
2019年 | 544篇 |
2018年 | 592篇 |
2017年 | 465篇 |
2016年 | 472篇 |
2015年 | 539篇 |
2014年 | 785篇 |
2013年 | 1115篇 |
2012年 | 1602篇 |
2011年 | 1657篇 |
2010年 | 889篇 |
2009年 | 852篇 |
2008年 | 1357篇 |
2007年 | 1498篇 |
2006年 | 1484篇 |
2005年 | 1386篇 |
2004年 | 1358篇 |
2003年 | 1238篇 |
2002年 | 1153篇 |
2001年 | 170篇 |
2000年 | 126篇 |
1999年 | 156篇 |
1998年 | 228篇 |
1997年 | 194篇 |
1996年 | 145篇 |
1995年 | 137篇 |
1994年 | 106篇 |
1993年 | 128篇 |
1992年 | 83篇 |
1991年 | 77篇 |
1990年 | 64篇 |
1989年 | 64篇 |
1988年 | 54篇 |
1987年 | 51篇 |
1986年 | 43篇 |
1985年 | 51篇 |
1984年 | 53篇 |
1983年 | 69篇 |
1982年 | 75篇 |
1981年 | 65篇 |
1980年 | 70篇 |
1979年 | 44篇 |
1978年 | 41篇 |
1977年 | 39篇 |
1976年 | 45篇 |
1974年 | 39篇 |
1973年 | 44篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Herbal remedies generate more than 1.8 billion dollars in annual sales in the United States. Herbal products have been associated with a wide spectrum of hepatic toxicities. With the recent Women's Health Initiative Study demonstrating increased risk of breast cancer and cardiovascular events associated with hormone therapy, many women may resort to herbal remedies for persistent menopause symptoms. We report a case of autoimmune hepatitis likely triggered by the use of black cohosh (Actaea racemosa), an agent marketed to treat menopause symptoms. Given this case report, we recommend close monitoring of women using this herbal preparation. 相似文献
102.
Human TLR-7-, -8-, and -9-mediated induction of IFN-alpha/beta and -lambda Is IRAK-4 dependent and redundant for protective immunity to viruses 总被引:12,自引:0,他引:12
Yang K Puel A Zhang S Eidenschenk C Ku CL Casrouge A Picard C von Bernuth H Senechal B Plancoulaine S Al-Hajjar S Al-Ghonaium A Maródi L Davidson D Speert D Roifman C Garty BZ Ozinsky A Barrat FJ Coffman RL Miller RL Li X Lebon P Rodriguez-Gallego C Chapel H Geissmann F Jouanguy E Casanova JL 《Immunity》2005,23(5):465-478
Five TLRs are thought to play an important role in antiviral immunity, sensing viral products and inducing IFN-alpha/beta and -lambda. Surprisingly, patients with a defect of IRAK-4, a critical kinase downstream from TLRs, are resistant to common viruses. We show here that IFN-alpha/beta and -lambda induction via TLR-7, TLR-8, and TLR-9 was abolished in IRAK-4-deficient blood cells. In contrast, IFN-alpha/beta and -lambda were induced normally by TLR-3 and TLR-4 agonists. Moreover, IFN-beta and -lambda were normally induced by TLR-3 agonists and viruses in IRAK-4-deficient fibroblasts. We further show that IFN-alpha/beta and -lambda production in response to 9 of 11 viruses tested was normal or weakly affected in IRAK-4-deficient blood cells. Thus, IRAK-4-deficient patients may control viral infections by TLR-3- and TLR-4-dependent and/or TLR-independent production of IFNs. The TLR-7-, TLR-8-, and TLR-9-dependent induction of IFN-alpha/beta and -lambda is strictly IRAK-4 dependent and paradoxically redundant for protective immunity to most viruses in humans. 相似文献
103.
Rajpar MH Koch MJ Davies RM Mellody KT Kielty CM Dixon MJ 《Human molecular genetics》2002,11(21):2559-2565
Dentine dysplasia type II is an autosomal dominant disorder in which mineralization of the dentine of the primary teeth is abnormal. On the basis of the phenotypic overlap between, and shared chromosomal location with, dentinogenesis imperfecta type II, a second disorder of dentine mineralization, it has been proposed that the two conditions are allelic. As recent studies have shown that dentinogenesis imperfecta type II results from mutation of the bicistronic dentine sialophosphoprotein gene (DSPP ), we have tested this hypothesis by sequencing DSPP in a family with a history of dentine dysplasia type II. Our results have shown that a missense change, which causes the substitution of a tyrosine for an aspartic acid in the hydrophobic signal peptide domain of the protein, underlies the phenotype in this family. Biochemical analysis has further demonstrated that this mutation causes a failure of translocation of the encoded proteins into the endoplasmic reticulum, and is therefore likely to lead to a loss of function of both dentine sialoprotein and dentine phosphoprotein. 相似文献
104.
Helen Elden Hans-Christian Ostgaard Monika Fagevik-Olsen Lars Ladfors Henrik Hagberg 《BMC complementary and alternative medicine》2008,8(1):34
Background
Previous publications indicate that acupuncture is efficient for the treatment of pelvic girdle pain, PGP, in pregnant women. However, the use of acupuncture for PGP is rare due to insufficient documentation of adverse effects of this treatment in this specific condition. The aim of the present work was to assess adverse effects of acupuncture on the pregnancy, mother, delivery and the fetus/neonate in comparison with women that received stabilising exercises as adjunct to standard treatment or standard treatment alone. 相似文献105.
BACKGROUND: Surveys of the public in several countries have found that negative attitudes towards antidepressants are common. However, there has been little research into the factors associated with these attitudes. METHODS: A national survey of 999 Australian adults assessed beliefs about the helpfulness or harmfulness of antidepressants for a person with depression and suicidal thoughts. Associated factors investigated were as follows: sociodemographic characteristics, exposure to depression, ability to recognize depression, beliefs about other depression interventions, beliefs about long-term outcomes with and without treatment, beliefs about causes, and stigmatizing attitudes. RESULTS: Around a quarter of Australian adults believe that antidepressants would be harmful for a person who is depressed and suicidal. This group was less educated, had less exposure to depression, showed poorer recognition of depression, was less favorable about other standard interventions including psychological ones, was less pessimistic about the long-term outcome if the person did not have treatment, and was more likely to see depression as due to weakness and to be under the individual's control. LIMITATIONS: The survey did not directly ask about reasons for believing that antidepressants would be harmful. CONCLUSIONS: Belief in the harmfulness of antidepressants is associated with a general lack of exposure to depression, leading to an underestimation of its seriousness and of the necessity for intervention. 相似文献
106.
Lovering Ruth; Middleton-Price Helen R.; O'Reilly Marie-Anne J.; Genet Sally A.; Parkar Mohammed; Sweatman Angela K.; Bradley Linda D.; Alterman Lesley A.; Malcolm Sue; Morgan Gareth; Levinsky Roland J.; Kinnon Christine 《Human molecular genetics》1993,2(2):139-141
Genetic linkage analysis has been instrumental in mapping thegene for X-linked agammaglobulinemia (XLA) to the proximal longarm of the human X chromosome, to Xq22. Due to the relativerarity of this disease the localization of the gene within Xq22has remained imprecise. We have investigated twenty-nine familiesaffected by XLA and have found no recombinants with the DXS178locus in over 30 informative meioses. DXS178 is now the mostreliable and informative locus for use in pre-natal diagnosisand carrier detection of XLA. In addition, we have identifiednew closely linked proximal and distal flanking markers forXLA, DXS442 and DXS101, respectively. These loci are separatedby 2cM, considerably reducing the extent of DNA within whichthe XLA locus can be contained. This will open up the way formore directed positional cloning efforts for the isolation ofthe XLA gene. 相似文献
107.
Johnson H Haggard P 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2003,150(4):490-496
Attending to a cued location in space leads to faster reaction times when a stimulus is presented there. The reasons for this
attentional effect, and its specific locus in the information-processing chain between stimulus and response, remain unclear.
One suggestion is that attention speeds the conscious detection of stimuli. Surprisingly, this possibility appears not to
have been tested directly. To resolve this question, we asked subjects to make simple responses to lateralised targets that
followed either a valid, invalid or neutral cue, and to judge the perceived time of the target onset, or of their response,
by delayed report of the position of a clock hand. Our results showed that only a small and non-significant part of the attentional
effect is due to delayed conscious awareness of the stimulus. The greater part of the attentional effect is localised either
subsequent to conscious detection of stimuli or occurs in a separate, parallel processing stream from that which generates
the motor response.
Electronic Publication 相似文献
108.
Helen J. Cooke John Atherton Young 《Pflügers Archiv : European journal of physiology》1970,318(4):315-324
Summary Techniques have been developed for collection of urine in embryonic and newly hatched chickens for the purpose of studying the development of renal function.The reliability of EDTA-51Cr as a substitute for inulin-14C in the determination of GFR was studied. Since inulin and EDTA-51Cr clearances in the hatched chicken averaged 1.61±0.23 (S.E.) ml/min per kg body weight and 1.58±0.27 ml/min per kg body weight, respectively, EDTA-51Cr clearance was considered a suitable measure of GFR.GFR increased significantly in the first few days after hatching. Filtration rate was 0.068±0.008 (S.E.) ml/min per g kidney weight in the embryo and increased to 0.148±0.008 ml/min per g shortly after hatching. By nine days after hatching GFR had risen to 0.290±0.015 ml/min per g, a value comparable to that reported for the adult.Clearances of sodium, potassium, chloride and total osmolyte also increased with age. When these clearances were corrected for changing glomerular filtration rates the embryonic chicks were found to excrete a greater percentage of the filtered load. These results show that adult levels of glomerulo-tubular balance are not attained until after hatching.A preliminary report of this work has already been published [3]. 相似文献
109.
Induced genomic instability in the human B lymphoblastoid cell line TK6 manifests itself as increases in end-to-end chromosome fusions and non-reciprocal chromosome translocations. It is not associated with elevated frequencies of specific locus mutations or other cytogenetic alterations. Previous studies on a limited number of cells and end-points suggested that induced instability in TK6 mirrors spontaneous instability in terms of the types of alterations observed. In the present study we expanded on our previous analysis to include more cells and more end-points in order to derive a more precise measure of spontaneous instability in TK6 cells. The frequency of normal growth rate thymidine kinase mutants (TK(-/-)), measured in 44 independently isolated clones, was 2.73 +/- 0.78 x 10(-6)/cell, while that for slow growth mutants was 2.39 +/- 0.52 x 10(-6)/cell. These are similar to the frequencies observed for HPRT mutants in primary human cells. There was wide variation in chromatid break frequencies, but the average break frequency, at 0.04+/-0.01 breaks/cell, was only slightly higher than that reported for primary human cells. In contrast, the dicentric frequency of 0.006/cell was more than 10-fold higher for TK6 cells than that reported for normal primary human cells. Furthermore, the dicentrics in TK6 cells are unusual in that they are the result of end-to-end chromosome fusions. TK6 cells also show much higher levels of non-reciprocal chromosome translocations than are usually observed in primary human cells. The results suggest an inherent instability in TK6 cells that differs from what is observed in primary cells in that it affects the frequency of end-to-end chromosome fusions and non-reciprocal chromosome translocations, but not TK gene mutations or other cytogenetic alterations. 相似文献
110.
Computerized family practitioner committee records — a data base for general practitioners 下载免费PDF全文
Linda Hargrave Allen Hutchinson Alan Cavill Leonard A. Goldstone Helen Watson 《The British journal of general practice》1988,38(306):22-23
In the primary care environment the role of preventive medicine is assuming increasing importance and general practitioners need accurate and up-to-date information about their practice population. Computerization of family practitioner committee registers should provide a readily accessible data base from which data about groups of patients within the practice area can easily be extracted. This paper describes a study carried out in Northumberland, which set out to establish the type of information which would be of interest to general practitioners and how it could be produced.
It was found that a data base holding only registration data was of limited value to general practitioners, although useful for identifying target groups for screening programmes and showing demographic trends within the practice. The doctors felt that the inclusion of medical data would make the register a far more effective resource.
相似文献