全文获取类型
收费全文 | 24677篇 |
免费 | 1539篇 |
国内免费 | 57篇 |
专业分类
耳鼻咽喉 | 678篇 |
儿科学 | 1799篇 |
妇产科学 | 798篇 |
基础医学 | 2123篇 |
口腔科学 | 1540篇 |
临床医学 | 1991篇 |
内科学 | 4285篇 |
皮肤病学 | 703篇 |
神经病学 | 1820篇 |
特种医学 | 1063篇 |
外科学 | 5143篇 |
综合类 | 225篇 |
一般理论 | 10篇 |
预防医学 | 1152篇 |
眼科学 | 702篇 |
药学 | 1461篇 |
中国医学 | 86篇 |
肿瘤学 | 694篇 |
出版年
2023年 | 311篇 |
2022年 | 197篇 |
2021年 | 465篇 |
2020年 | 408篇 |
2019年 | 517篇 |
2018年 | 940篇 |
2017年 | 779篇 |
2016年 | 1001篇 |
2015年 | 868篇 |
2014年 | 1109篇 |
2013年 | 1868篇 |
2012年 | 1499篇 |
2011年 | 1630篇 |
2010年 | 1164篇 |
2009年 | 714篇 |
2008年 | 1097篇 |
2007年 | 1091篇 |
2006年 | 1241篇 |
2005年 | 1142篇 |
2004年 | 1115篇 |
2003年 | 1060篇 |
2002年 | 1032篇 |
2001年 | 715篇 |
2000年 | 807篇 |
1999年 | 591篇 |
1998年 | 311篇 |
1997年 | 274篇 |
1996年 | 246篇 |
1995年 | 178篇 |
1994年 | 166篇 |
1993年 | 135篇 |
1992年 | 138篇 |
1991年 | 115篇 |
1990年 | 116篇 |
1989年 | 95篇 |
1988年 | 84篇 |
1987年 | 54篇 |
1986年 | 65篇 |
1985年 | 60篇 |
1984年 | 61篇 |
1983年 | 60篇 |
1982年 | 57篇 |
1981年 | 51篇 |
1980年 | 48篇 |
1979年 | 45篇 |
1978年 | 48篇 |
1977年 | 43篇 |
1976年 | 32篇 |
1975年 | 34篇 |
1974年 | 33篇 |
排序方式: 共有10000条查询结果,搜索用时 281 毫秒
121.
The past decade has been marked by significant advances in the application of gene transfer into living cells of animals and humans, with the resulting catapulting of preclinical and basic scientific concepts into therapeutic trials. A variety of virus-mediated gene delivery techniques have proved to be superior to other methodologies. This article concisely reviews the current status of gene and tumor therapy, focusing on virus-based technologies, describes the molecular biology of neurotropic herpesviruses and the application of herpes simplex virus, a relative of pseudorabies virus (PRV) in gene transfer and cancer therapy protocols. Finally, it addresses the issue of whether PRV, a nonhuman pathogen, could serve as a suitable research and therapeutic tool as concerns genetic and tumor therapy. 相似文献
122.
P M Ellerbroek M Oudkerk Pool B U Ridwan K M Dolman B M von Blomberg A E von dem Borne S G Meuwissen R Goldschmeding 《Journal of clinical pathology》1994,47(3):257-262
AIMS--To study ulcerative colitis associated neutrophil cytoplasmic antibodies (p-ANCA) in respect of class and subclass distribution, antigen specificity, and (sub)cellular localisation of the antigen(s) to which these antibodies are directed. METHODS--p-ANCA positivity was determined using the standard indirect immunofluorescence test (IIFT). The immunoglobulin (Ig) subclass distribution of p-ANCA was investigated using monoclonal antibodies directed against IgG1, IgG2, IgG3, and IgG4. Intracellular antigen localisation studies were performed on (fractionated) neutrophils using antigen-specific antibodies. RESULTS--In contrast to vasculitis associated ANCA, ulcerative colitis p-ANCA are mainly of IgG1 and IgG3 subclass and lack IgG4. Ulcerative colitis p-ANCA are myeloid specific. IIFT data indicate that the related antigen(s) seem(s) to be located not in the cytosol, but in the granules (most likely the azurophil granules) of the neutrophil. CONCLUSIONS--p-ANCA in ulcerative colitis have a different immunoglobulin subclass distribution than the ANCA of systemic necrotising vasculitis and necrotising and crescentic glomerulonephritis. This may point to differences in immune regulation between these diseases. Both cathepsin G and lactoferrin are recognised by a subpopulation of ulcerative colitis p-ANCA. In our series, eight out of 36 (22%) of ulcerative colitis associated p-ANCA react with lactoferrin and seven (19.5%) other sera with cathepsin G. None of them recognised both antigens. The main target antigen(s) of ulcerative colitis p-ANCA still remain(s) to be identified. 相似文献
123.
Gürpinar OA Tuzlakoğlu K Onur MA Tümer A Serdar MA Unal N Pişkin E 《Journal of biomaterials science. Polymer edition》2003,14(6):589-600
In this study, attachment and growth of Baby Hamster Kidney (BHK) cells on ethylene diamine (EDA)-plasma-treated poly(L-lactide/epsilon-caprolactone) biodegradable copolymer films were investigated. The co-polymer (Mw: 58000; Mn: 35000 and PI 1.60) was synthesised by ring-opening polymerization of the respective dimers with using stannous octoate as the catalyst. The final ratio of L-lactide to epsilon-caprolactone obtained by 1H-NMR was 87:13. The co-polymer films were treated with the EDA-plasma in a glow-discharge apparatus. The BHK-30 cell line was cultured on plain and EDA-plasma-treated films and their pre-wetted forms (with ethanol and/or cell culture medium before use). Cell attachment and growth were followed. Alkaline phosphatase (ALP) activity and glucose uptake in cell culture medium were also investigated. There was no attachment in the first 12 h. Glow-discharge treatment increased significantly the attachment and growth. Pre-wetting with ethanol and cell culture medium was also increase significantly both the attachment and growth. 相似文献
124.
125.
Janać B Pesić V Peković S Rakić L Stojiljković M 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2005,165(3):402-406
The time-course of changes of basal and amphetamine (AMPH)-induced locomotor and stereotypic activities in adult male Wistar rats after a single ribavirin injection was studied. In the first set of experiments, 10, 20 or 30 mg ribavirin/kg body weight (b.w.) were injected i.p. to rats and their basal motor activities were recorded every 10 min for 2 h and compared with those of saline-treated controls. In the second set of experiments, the animals were pretreated with ribavirin and 20 min later i.p. injected with AMPH (1.5 mg/kg b.w.). The controls received AMPH 20 min after the saline injection. Motor activity was recorded after the first injection and until 120 min after AMPH administration. Ribavirin did not significantly affect the time-course of either basal locomotor or stereotypic activities. Pretreatment with any of the applied ribavirin doses decreased the AMPH-induced hyperlocomotor response. However, the most pronounced effect was observed with ribavirin doses of 20 mg/kg and 30 mg/kg when administered during the first 10 min and 30 min after the AMPH injection respectively. In contrast, the stereotypic activities of these animals were only slightly changed. These results indicate a different susceptibility of regions in the basal ganglia to ribavirin. 相似文献
126.
Biochemical profile of blood serum of siraz <Emphasis Type="Italic">Capoeta capoeta umbla</Emphasis>
Abdulkadir Bayir A. Necdet Sirkecioğlu Harun Polat N. Mevlüt Aras 《Comparative clinical pathology》2007,16(2):119-126
Seasonal changes in blood plasma biochemistry of siraz Capoeta capoeta umbla were determined throughout 1 year. In the present study, while the highest values for glucose and globulin were found in
winter, the values for increased activities of total protein, albumin, calcium, sodium levels, albumin/globulin ratio, lactate
dehydrogenase, and alkaline phosphatase were determined in summer. We determined that blood biochemistry values of siraz,
which were positively affected by water temperature and pH, except glucose and globulin. Glucose and globulin were negatively
affected by water temperature and pH. Consequently, it was concluded that the seasons are key factors when blood parameters
are used as biomarkers for environmental alterations. It is difficult to define the most important factors affecting seasonal
changes of blood biochemistry in fish. 相似文献
127.
A. G. Fahrenkamp C. Wibbeke W. Böcker K. W. Schmid G. Winde D. Öfner R. Fischer-Colbrie 《Virchows Archiv : an international journal of pathology》1995,426(4):361-367
The aim of the present study was to investigate immunohistochemically the distribution of chromogranin A, chromogranin B, and secretogranin II in a series of 152 neuroendocrine tumours of the gastrointestinal tract. Tumour tissues from 25 argyrophil gastric carcinoids, 18 gastrin and 5 somatostatin-producing tumours, 4 gangliocytic paragangliomas, 49 classical argentaffin and 2 L cell appendiceal carcinoids, 27 classical ileal carcinoids, 17 rectal carcinoids, and 5 poorly differentiated neuroendocrine tumours of the stomach and rectum were immunostained with antibodies against chromogranin A, chromogranin B, and secretogranin II. Chromogranin A was the major granin expressed in gastric carcinoids and in serotonin-producing carcinoids of the appendix and the ileum. In contrast, strong chromogranin B and secretogranin II immunoreactivity was found in rectal carcinoids, in which chromogranin A was rarely expressed. Since chromogranin A is a widely used marker for neuroendocrine differentiation, it is of diagnostic importance that some gastrin-producing tumours, gangliocytic paragangliomas, poorly differentiated neuroendocrine carcinomas, and appendiceal L cell carcinoids completely lacked chromogranin A positivity. It is concluded that the various neuroendocrine tumours of the gastrointestinal tract show distinctly different patterns of granin expression, probably reflecting their histogenetical origin. 相似文献
128.
Sönmez AS Yasar L Savan K Koç S Ozcan J Toklar A Yazicioğu F Akgün A Sut N 《Human reproduction (Oxford, England)》2005,20(1):175-179
BACKGROUND: The aim of this study was to evaluate the effects of metformin and acarbose on insulin resistance, hormone profiles and ovulation rates in patients with clomiphene citrate-resistant polycystic ovary syndrome (PCOS). METHODS: Thirty clomiphene citrate-resistant patients were selected randomly and divided into two groups. Group I was treated with 100 mg/day clomiphene citrate and 300 mg/day acarbose 100 mg/day orally, for 3 months. Group II was treated with clomiphene citrate 100 mg/day and metformin 1700 mg/day orally, for 3 months. Serum fasting insulin and glucose, FSH, LH, estradiol, progesterone, prolactin and total testosterone levels plus body mass index (BMI) were measured before and after treatment. Follicle growth was followed by transvaginal ultrasonography. RESULTS: LH:FSH ratio and total testosterone concentrations decreased (P<0.05) and ovulation rates increased in both groups. Reduction in weight and BMI was only significant in the acarbose group. CONCLUSIONS: Both treatment modalities were effective in the treatment of insulin resistance and improving ovulation rates. Increase in the number of eumenorrhoeic and normoinsulinaemic cases and decrease in the number of insulin-resistant cases were significant in both groups (P<0.05). Ovulation rate was greater in the metformin group in the second month of therapy (P<0.05). Acarbose was found to be a safe and effective agent that could be used in cases with clomiphene-resistant PCOS. 相似文献
129.
Somatic mosaicism for a MECP2 mutation associated with classic Rett syndrome in a boy 总被引:4,自引:0,他引:4
Topçu M Akyerli C Sayi A Törüner GA Koçoğlu SR Cimbiş M Ozçelik T 《European journal of human genetics : EJHG》2002,10(1):77-81
Rett syndrome is a severe neurodevelopmental disorder that arises from mutations in the X-linked MECP2 gene. It is almost exclusively seen in girls due to the predominant occurrence of the mutations on the paternal X-chromosome, and also the early postnatal lethal effect of the disease causing mutations in hemizygous boys. We identified a boy with features of classic Rett syndrome who is mosaic for the truncating MECP2 mutation R270X. Chromosome analysis showed normal karyotype. These results indicate that a MECP2 mutation associated with Rett syndrome in females could lead to a similar phenotype in males as a result of somatic mosaicism. 相似文献
130.
Cadavers remain a principal teaching tool for anatomists and medical educators teaching gross anatomy. Infectious pathogens in cadavers that present particular risks include Mycobacterium tuberculosis, hepatitis B and C, the AIDS virus HIV, and prions that cause transmissible spongiform encephalopathies such as Creutzfeldt-Jakob disease (CJD) and Gerstmann-Straussler-Scheinker syndrome (GSS). It is often claimed that fixatives are effective in inactivation of these agents. Unfortunately cadavers, even though they are fixed, may still pose infection hazards to those who handle them. Specific safety precautions are necessary to avoid accidental disease transmission from cadavers before and during dissection and to decontaminate the local environment afterward. In this brief review, we describe the infectious pathogens that can be detected in cadavers and suggest safety guidelines for the protection of all who handle cadavers against infectious hazards. 相似文献