全文获取类型
收费全文 | 5827篇 |
免费 | 363篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 49篇 |
儿科学 | 461篇 |
妇产科学 | 65篇 |
基础医学 | 745篇 |
口腔科学 | 77篇 |
临床医学 | 411篇 |
内科学 | 978篇 |
皮肤病学 | 133篇 |
神经病学 | 282篇 |
特种医学 | 234篇 |
外科学 | 732篇 |
综合类 | 167篇 |
一般理论 | 1篇 |
预防医学 | 414篇 |
眼科学 | 173篇 |
药学 | 682篇 |
中国医学 | 34篇 |
肿瘤学 | 557篇 |
出版年
2023年 | 33篇 |
2022年 | 55篇 |
2021年 | 129篇 |
2020年 | 85篇 |
2019年 | 85篇 |
2018年 | 129篇 |
2017年 | 99篇 |
2016年 | 128篇 |
2015年 | 129篇 |
2014年 | 192篇 |
2013年 | 235篇 |
2012年 | 349篇 |
2011年 | 358篇 |
2010年 | 220篇 |
2009年 | 149篇 |
2008年 | 273篇 |
2007年 | 256篇 |
2006年 | 229篇 |
2005年 | 219篇 |
2004年 | 218篇 |
2003年 | 208篇 |
2002年 | 154篇 |
2001年 | 187篇 |
2000年 | 145篇 |
1999年 | 146篇 |
1998年 | 56篇 |
1997年 | 53篇 |
1996年 | 46篇 |
1995年 | 45篇 |
1994年 | 39篇 |
1992年 | 102篇 |
1991年 | 76篇 |
1990年 | 88篇 |
1989年 | 97篇 |
1988年 | 76篇 |
1987年 | 74篇 |
1986年 | 76篇 |
1985年 | 92篇 |
1984年 | 67篇 |
1983年 | 61篇 |
1980年 | 45篇 |
1979年 | 71篇 |
1978年 | 42篇 |
1977年 | 39篇 |
1976年 | 51篇 |
1975年 | 68篇 |
1974年 | 38篇 |
1973年 | 61篇 |
1971年 | 41篇 |
1969年 | 39篇 |
排序方式: 共有6195条查询结果,搜索用时 15 毫秒
41.
Reproductive performances of female hamsters were investigated during Ancylostoma ceylanicum (hookworm) infection. Animals having the highest levels of infection (34.96 +/- 1.11 worms) showed degenerative changes in the reproductive system. Ovaries of infected animals contained a few primary or secondary follicles. On cocaging with males of proven fertility, only 7-8% (80% in controls) of the infected females mated but did not conceive as evidenced by the absence of corpora lutea or implantation sites on day 10 postcoitum. Animals with low worm burdens (5.94 +/- 0.65 worms), however, showed almost normal fertility. The uterine weight bioassay and compensatory ovarian hypertrophy suggest strong suppression of pituitary gonadotrophin contents in infected females. Resorptive effects on the pregnancy outcome of infected female hamsters were also recorded. 相似文献
42.
Expression of c-myc and c-fms oncogenes in trophoblastic cells in hydatidiform mole and normal human placenta. 总被引:3,自引:0,他引:3
下载免费PDF全文
![点击此处可从《Journal of clinical pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A N Cheung G Srivastava S Pittaluga T K Man H Ngan R J Collins 《Journal of clinical pathology》1993,46(3):204-207
AIMS: To compare the expression of c-myc and c-fms proto-oncogenes in the placenta and hydatidiform mole. METHODS: Twelve hydatidiform moles and six induced abortion cases were collected. c-myc and c-fms proto-oncogene expression was analysed by northern blot hybridisation and immunohistochemical staining. RESULTS: The results of northern blot hybridisation analysis showed that c-fms was expressed more strongly in hydatidiform moles compared with normal placenta of similar gestational age. Moreover, c-fms mRNA concentrations increased with more advanced gestational age in moles but not in normal placentas. c-myc expression was very low in hydatidiform moles and normal placentas. Both oncogenes, however, had no direct correlation with the clinical course of the molar pregnancies. CONCLUSION: The difference in c-fms expression between hydatidiform moles and normal placentas suggests that c-fms may have a role in the development of molar pregnancies. 相似文献
43.
Thirty seven cases of oesophageal squamous cell carcinoma were studied by applying DNA slot blot analysis and in situ hybridisation using type specific probes for HPV 6, 11, 16 and 18. Cases of condyloma accuminata, cervical carcinoma, and laryngeal papilloma were used as controls. Blocks including areas of invasive carcinoma, intraepithelial neoplasia, and normal epithelium were studied in each case. No HPV genome was detectable in any of the oesophageal cases. It is concluded that these types of HPV do not have an association with oesophageal squamous cell carcinoma. 相似文献
44.
45.
Pelin Sahlén Rapolas Spalinskas Samina Asad Kunal Das Mahapatra Pontus Höjer Anandashankar Anil Jesper Eisfeldt Ankit Srivastava Pernilla Nikamo Anaya Mukherjee Kyu-Han Kim Otto Bergman Mona Ståhle Enikö Sonkoly Andor Pivarcsi Carl-Fredrik Wahlgren Magnus Nordenskjöld Fulya Taylan Isabel Tapia-Páez 《The Journal of allergy and clinical immunology》2021,147(5):1742-1752
- Download : Download high-res image (202KB)
- Download : Download full-size image
46.
Mishra A Singhal A Chauhan DS Katoch VM Srivastava K Thakral SS Bharadwaj SS Sreenivas V Prasad HK 《Journal of clinical microbiology》2005,43(11):5670-5678
Mycobacterium tuberculosis and M. bovis infect animals and humans. Their epidemiologies in developed and developing countries differ, owing to differences in the implementation of preventive measures (World Health Organization, 1999). Identification and differentiation of these closely related mycobacterial species would help to determine the source, reservoirs of infection, and disease burden due to diverse mycobacterial pathogens. The utility of the hupB gene (Rv2986c in M.tuberculosis, or Mb3010c in M.bovis) to differentiate M. tuberculosis and M. bovis was evaluated by a PCR-restriction fragment length polymorphism (RFLP) assay with 56 characterized bovine isolates (S. Prabhakar et al., J. Clin. Microbiol. 42:2724-2732, 2004). The degree of concordance between the PCR-RFLP assay and the microbiological characterization was 99.0% (P < 0.001). A nested PCR (N-PCR) assay was developed, replacing the PCR-RFLP assay for direct detection of M. tuberculosis and M. bovis in bovine samples. The N-PCR products of M. tuberculosis and M. bovis corresponded to 116 and 89 bp, respectively. The detection limit of mycobacterial DNA by N-PCR was 50 fg, equivalent to five tubercle bacilli. M. tuberculosis and/or M. bovis was detected in 55.5% (105/189) of the samples by N-PCR, compared to 9.4% (18/189) by culture. The sensitivities of N-PCR and culture were 97.3 and 29.7, respectively, and their specificities were 22.2 and 77.7%, respectively. The percentages of animals or samples identified as infected with M.tuberculosis or M. bovis by N-PCR and culture reflected the clinical categorizations of the cattle (P of <0.05 to <0.01). Mixed infection by N-PCR was detected in 22 animals, whereas by culture mixed infection was detected in 1 animal. 相似文献
47.
Buckner C Gines LG Saunders CJ Vojtech L Srivastava I Gettie A Bohm R Blanchard J Barnett SW Safrit JT Stamatatos L 《Virology》2004,320(1):167-180
The potential of vaccine-elicited anti-HIV envelope antibodies to control HIV-infection was evaluated by immunizing macaques with the HIV envelope protein and transiently depleting them of their CD8+ cells before intravenous challenge with the pathogenic CCR5-tropic SIV/HIV chimeric virus, SHIV(SF162P4). Although sterilizing immunity was not achieved, all vaccinated animals effectively controlled infection and remained free of disease for the duration of observation (over 3 years). In contrast, during the same period, the control animals progressed to disease. Both the vaccinees and the controls developed robust cell-mediated antiviral and neutralizing antibody responses following infection. A comparative analysis of these responses suggests that the more effective long-term control of infection by the vaccinated animals is due to the more rapid development of anti-HIV envelope antibodies. These studies suggest that priming by vaccination of B cell anti-HIV envelope responses maybe crucial for the long-term control of HIV infection. 相似文献
48.
The prognostic significance of tumor vascularity in intermediate-thickness (0.76-4.0 mm thick) skin melanoma. A quantitative histologic study. 总被引:12,自引:6,他引:12
下载免费PDF全文
![点击此处可从《The American journal of pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A. Srivastava P. Laidler R. P. Davies K. Horgan L. E. Hughes 《The American journal of pathology》1988,133(2):419-423
The vascularity of 20 primary skin melanomas was assessed histologically. These cases were selected from patients with intermediate thickness melanomas (0.76-4.0 mm thick) treated surgically to provide two groups of ten patients. One group had no evidence of recurrence with a minimum follow-up of 9 years. The second group of ten patients developed locoregional or systemic metastasis under follow-up, and seven of these patients died of disseminated melanoma. Age, sex, Breslow's tumor thickness, and Clark's level of invasion were similar in the two groups. Vascular quantitation was carried out by image analysis after vascular definition by Ulex europaeus-I agglutinin staining. The percentage vascular area at the tumor base in the recurrence group was more than twice that in the recurrence-free group. This study suggests that increased vascularity at the tumor base may have prognostic significance in intermediate thickness melanomas. 相似文献
49.
Rohini Srivastava Sonali Ray Meenakshi Sharma Nitin Sahai Ravi P. Tewari Basant Kumar 《Journal of medical engineering & technology》2020,44(7):423-430
Abstract This paper presents the hardware implementation of low delay, power-efficient, rate-adaptive dual-chamber pacemaker (RDPM) using a piezoelectric sensor. Rate adaptive pacemaker has the ability to sense the patient’s activity by means of some special sensors and it controls the pacing rate according to the patient’s activity. Ideally, there should be no delay between sensing and the subsequent pacing operation performed by the pacemaker. However, delay in the responses of various components in the circuitry produces an accumulative delay effect in any practical circuit. Physical activity and the physiological needs of the patient can be easily adapted by the rate-responsive pacemakers using a wide range of sensor information. The piezo-electric sensor recognises the pressure on human muscles because of physical activity and converts it to an electrical signal, which is received by the pulse generator of the pacemaker. When the patient is in the rest mode, the heart rate is the only parameter that is to be detected by the pacemaker. Thus, the heart rate and the physical activity both are the inevitable parameters for the design of RDPM. Performance analysis of the proposed RDPM shows a significant reduction in the delay between sensing and pacing. Device utility analysis shows that the proposed design not only requires lesser memory but also reduces the number of components on the chip. Therefore, it becomes very clear that the proposed pacemaker design will consume much lesser power. 相似文献
50.
Evoked potential changes in ischaemic myelopathy 总被引:2,自引:0,他引:2
Kalita J Srivastava AK Mittal P Sharma VP Misra UK 《Electromyography and clinical neurophysiology》2003,43(4):211-215
Somatosensory evoked potentials are employed in the intraoperative monitoring but there is paucity of information about the motor evoked potentials (MEP) in spinal cord ischaemia. Two patients aged 9 and 4 years developed paraplegia following surgery for coarctation of aorta. The aortic cross clamping time in these patients was 100 min and 30 min. respectively. The patient with longer clamping time had flaccid paraplegia and lower limb MEPs were not recordable; whereas the patient with shorter clamping time had spastic paraparesis and prolonged CMCT to right lower limb. The latter patient improved significantly. Tibial SEPs were normal in both the patients. Our results suggest that MEP may have a greater role than SEP in documenting and prognosticating ischaemic myelopathy. 相似文献