全文获取类型
收费全文 | 2060篇 |
免费 | 114篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 16篇 |
儿科学 | 113篇 |
妇产科学 | 34篇 |
基础医学 | 259篇 |
口腔科学 | 33篇 |
临床医学 | 154篇 |
内科学 | 366篇 |
皮肤病学 | 31篇 |
神经病学 | 131篇 |
特种医学 | 124篇 |
外科学 | 277篇 |
综合类 | 46篇 |
预防医学 | 110篇 |
眼科学 | 68篇 |
药学 | 240篇 |
中国医学 | 19篇 |
肿瘤学 | 164篇 |
出版年
2023年 | 14篇 |
2022年 | 29篇 |
2021年 | 61篇 |
2020年 | 29篇 |
2019年 | 31篇 |
2018年 | 48篇 |
2017年 | 29篇 |
2016年 | 40篇 |
2015年 | 58篇 |
2014年 | 51篇 |
2013年 | 117篇 |
2012年 | 142篇 |
2011年 | 124篇 |
2010年 | 110篇 |
2009年 | 82篇 |
2008年 | 145篇 |
2007年 | 115篇 |
2006年 | 107篇 |
2005年 | 116篇 |
2004年 | 91篇 |
2003年 | 94篇 |
2002年 | 78篇 |
2001年 | 21篇 |
2000年 | 25篇 |
1999年 | 25篇 |
1998年 | 34篇 |
1997年 | 31篇 |
1996年 | 30篇 |
1995年 | 22篇 |
1994年 | 20篇 |
1993年 | 18篇 |
1992年 | 13篇 |
1991年 | 16篇 |
1990年 | 16篇 |
1989年 | 24篇 |
1988年 | 17篇 |
1987年 | 8篇 |
1986年 | 14篇 |
1985年 | 9篇 |
1984年 | 11篇 |
1982年 | 8篇 |
1981年 | 15篇 |
1980年 | 12篇 |
1979年 | 5篇 |
1978年 | 10篇 |
1977年 | 6篇 |
1976年 | 10篇 |
1975年 | 9篇 |
1968年 | 5篇 |
1954年 | 4篇 |
排序方式: 共有2185条查询结果,搜索用时 13 毫秒
51.
Nagui S. T. Gendi Ken I. Welsh Walther J. Van Venrooij Rama Vancheeswaran Jill Gilroy Carol M. Black 《Arthritis \u0026amp; Rheumatology》1995,38(2):259-266
Objective. To determine any clinical or genetic markers of differentiation and outcome in a previously described cohort of 46 patients with mixed connective tissue disease (MCTD). Methods. Patients were clinically evaluated, chart notes reviewed, and HLA subtyping and immunology profiles performed where possible. Eleven had died and 7 were lost to followup. Results. MCTD had differentiated into systemic lupus erythematosus in 12 patients and into systemic sclerosis in 13. The latter was associated with HLA-DR5 (P = 0.038), and nondifferentiation was associated with HLA-DR2 or DR4 (P = 0.007). Three HLA-DR4 positive patients had MCTD that evolved into rheumatoid arthritis. Erosive and/or deforming arthritis was associated with HLA-DR1 or DR4 (P = 0.015). HLA-DR3 was associated with interstitial lung fibrosis (P = 0.044) and keratoconjunctivitis sicca (0.001 < P < 0.01). Severe Raynaud's phenomenon predicted higher mortality (0.01 < P < 0.05). Conclusion. We suggest that MCTD is, for most patients, an intermediate stage in a genetically determined progression to a recognized connective tissue disease. Those whose disease remains undifferentiated might be considered a distinct subset. 相似文献
52.
Xu Shi-Wen Manvinder Panesar Rama Vancheeswaran Justin Mason Dorian Haskard Carol Black Irwin Olsen David Abraham 《Arthritis \u0026amp; Rheumatology》1994,37(11):1689-1697
Objective. To examine intercellular adhesion molecule 1 (ICAM-1) and lymphocyte function-associated antigen 3 (LFA-3) in cultures of normal and systemic sclerosis (SSc) dermal fibroblasts. Methods. The surface and soluble forms of ICAM-1 and LFA-3 were measured by flow cytometry and capture enzyme-linked immunosorbent assay, respectively. Results. Surface ICAM-1 was significantly higher on SSc fibroblasts compared with normal controls. β-estradiol did not directly enhance ICAM-1 or LFA-3 expression in either normal or SSc cells, but significantly augmented the cytokine-induced increase in ICAM-1. Soluble ICAM-1 (sICAM-1) and sLFA-3 were detected in fibroblast cultures. While no difference was found in the level of sLFA-3, the shedding of sICAM-1 was significantly increased (P < 0.001) in cells from SSc patients. Conclusion. SSc fibroblasts express intrinsically elevated levels of surface ICAM-1 and release higher levels of sICAM-1 in vitro. Increased expression of ICAM-1 by interferon-γ and tumor necrosis factor α alone, and the further induction in combination with β-estradiol may underlie an aspect of fibroblast dysfunction in SSc and the female predisposition to the disease. 相似文献
53.
Sripal Reddy Mada Mallikarjuna Reddy Metukuri Laxminarayana Burugula Pallu Reddanna Devarakonda Rama Krishna 《Phytotherapy research : PTR》2009,23(6):878-884
In the present study the antiinflammatory and antinociceptive activities of a few selected flavonoids were investigated. Procumbentin, gossypin, chrysin and methylhespiridin were studied for antiinflammatory and antinociceptive activities using in vitro enzymatic assays and in animal models utilizing acetic acid‐induced writhing in mice and hind paw edema in rats. In vitro studies were performed using TMPD (NNN′N′‐tetramethyl‐p‐phenylene diamine) and oxygraphic methods for COX‐1 (cyclooxygenase‐1), COX‐2, 5‐LOX (5‐lipoxygenase) and 15‐LOX. Gossypin and procumbentin showed COX‐2 inhibitory activity and exhibited IC50 (COX‐2/COX‐1) ratios of 0.14 and 0.11, respectively. None of the flavonoids tested in this study showed LOX inhibitory activity. Four groups were studied for each test compound following intraperitoneal (i.p.) administration of doses of 10, 30 and 100 mg/kg. Antiinflammatory activity was measured by the carrageenin‐induced rat hind paw edema model and antinociceptive activity by acetic acid‐induced writhing. Procumbentin and gossypin showed antinociceptive activity at the 100 mg/kg dose. Gossypin showed antiinflammatory activity at doses of 10, 30, 100 mg/kg. Procumbentin and gossypin exhibited COX‐2 inhibitory activity when tested by in vitro methods. Procumbentin and gossypin showed antinociceptive, and gossypin showed antiinflammatory, activities. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
54.
Henny KD Crepaz N Lyles CM Marshall KJ Aupont LW Jacobs ED Liau A Rama S Kay LS Willis LA Charania MR 《AIDS and behavior》2012,16(5):1092-1114
This meta-analysis estimates the overall efficacy of HIV prevention interventions to reduce HIV sexual risk behaviors and sexually transmitted infections (STIs) among heterosexual African American men. A comprehensive search of the literature published during 1988-2008 yielded 44 relevant studies. Interventions significantly reduced HIV sexual risk behaviors and STIs. The stratified analysis for HIV sexual risk behaviors indicated that interventions were efficacious for studies specifically targeting African American men and men with incarceration history. In addition, interventions that had provision/referral of medical services, male facilitators, shorter follow-up periods, or emphasized the importance of protecting family and significant others were associated with reductions in HIV sexual risk behaviors. Meta-regression analyses indicated that the most robust intervention component is the provision/referral of medical services. Findings indicate that HIV interventions for heterosexual African American men might be more efficacious if they incorporated a range of health care services rather than HIV/STI-related services alone. 相似文献
55.
Aspergillus fumigatus isolates were tested with three antifungals by flow cytometry (FC) and fluorescence-activated cell sorting. FC results after 4 h correlated well with MICs obtained by the NCCLS M38-A method; voriconazole exhibited fungicidal activity, albeit to a lesser extent than amphotericin B, but to a greater extent than itraconazole. 相似文献
56.
Zhang XF Zhu CZ Thimmapaya R Choi WS Honore P Scott VE Kroeger PE Sullivan JP Faltynek CR Gopalakrishnan M Shieh CC 《Brain research》2004,1009(1-2):147-158
The profile of tetrodotoxin sensitive (TTX-S) and resistant (TTX-R) Na(+) channels and their contribution to action potentials and firing patterns were studied in isolated small dorsal root ganglion (DRG) neurons after L5/L6 spinal nerve ligation (SNL). Total TTX-R Na(+) currents and Na(v) 1.8 mRNA were reduced in injured L5 DRG neurons 14 days after SNL. In contrast, TTX-R Na(+)currents and Na(v) 1.8 mRNA were upregulated in uninjured L4 DRG neurons after SNL. Voltage-dependent inactivation of TTX-R Na(+) channels in these neurons was shifted to hyperpolarized potentials by 4 mV. Two types of neurons were identified in injured L5 DRG neurons after SNL. Type I neurons (57%) had significantly lower threshold but exhibited normal resting membrane potential (RMP) and action potential amplitude. Type II neurons (43%) had significantly smaller action potential amplitude but retained similar RMP and threshold to those from sham rats. None of the injured neurons could generate repetitive firing. In the presence of TTX, only 26% of injured neurons could generate action potentials that had smaller amplitude, higher threshold, and higher rheobase compared with sham rats. In contrast, action potentials and firing patterns in uninjured L4 DRG neurons after SNL, in the presence or absence of TTX, were not affected. These results suggest that TTX-R Na(+) channels play important roles in regulating action potentials and firing patterns in small DRG neurons and that downregulation in injured neurons and upregulation in uninjured neurons confer differential roles in shaping electrogenesis, and perhaps pain transmission, in these neurons. 相似文献
57.
Rama Pulicharla Francois Proulx Sonja Behmel Jean-B. Srodes Manuel J. Rodriguez 《RSC advances》2022,12(32):20876
The spatial–temporal behaviour of contaminants of emerging concern (CECs) are not well-documented in drinking water sources, including in Quebec, Canada. In this study, a set of seven contaminants, which are more frequently reported in water sources, were monitored from May 2016 to August 2017 at ten locations within an urbanized watershed (lakes and rivers) in Quebec, Canada. Samples were collected between a wastewater plant discharge (upstream) and the intake of a drinking water plant (downstream). The results showed that three (acetaminophen, salicylic acid, caffeine) out of seven CECs were consistently detected at a range of up to a few hundred ng L−1 at all sampling stations throughout the sampling period with a detection frequency between 51% and 94%. Upstream of two wastewater plant discharge locations, six CECs were measured above the detection limit compared to other locations where only three CECs (acetaminophen, salicylic acid, caffeine) were detected. Most of the CEC concentrations were higher (a few ng L−1) during late winter in comparison with the summer, in both years 2016 and 2017. The results highlight that the wastewater effluents and septic system effluents are significant sources of CECs that are released into the surface water. Moreover, the results help to identify the spatio-temporal patterns, which is a crucial element to understand the fate of CECs in water sources submitted to extreme weather conditions during the year. This research also provides baseline data for CEC occurrence at different points across lakes, rivers, and tributaries which will be useful for future ecotoxicological studies.The spatial–temporal behaviour of contaminants of emerging concern (CECs) are not well-documented in drinking water sources, including in Quebec, Canada. 相似文献
58.
59.
Cloning, expression, and immunological characterization of the P30 protein of Mycoplasma pneumoniae 总被引:2,自引:0,他引:2 下载免费PDF全文
Varshney AK Chaudhry R Kabra SK Malhotra P 《Clinical and Vaccine Immunology : CVI》2008,15(2):215-220
Mycoplasma pneumoniae, a self-replicating cell wall-deficient prokaryote, has a differentiated terminal organelle that is essential for cytadherence and gliding motility. P30, an important protein associated with the terminal organelle, is required for the cytadherence and virulence of M. pneumoniae. P30 is a transmembrane protein with an intracytoplasmic N terminus and an exposed C terminus. In the present study, we amplified and sequenced the full-length p30 gene of Mycoplasma pneumoniae directly from 18 Indian asthmatic patients. Sequence diversity was observed in the p30 genes from 16 clinical samples when the sequences were compared with the sequence of strain M-129. We also successfully expressed a fragment of the p30 gene (P30B) that includes the complete C-terminal proline-rich amino acid sequences in different Escherichia coli expression systems. The maltose binding protein (MBP)-P30B fusion protein was recognized by M. pneumoniae-infected patient sera in immunoblots, and the protein was immunogenic in mice. We further analyzed the reactivity of the MBP-P30B fusion protein with patient sera in an enzyme-linked immunosorbent assay (ELISA) and compared it with the reactivity obtained with a commercial kit (the Serion ELISA Classic kit). The sensitivity and the specificity of the in-house ELISA were 78.57% and 89.47%, respectively. This study suggests that the P30 protein can be used as an antigen along with other adhesin proteins for the immunodiagnosis of M. pneumoniae infection. 相似文献
60.