全文获取类型
收费全文 | 10362篇 |
免费 | 1193篇 |
国内免费 | 48篇 |
专业分类
耳鼻咽喉 | 106篇 |
儿科学 | 374篇 |
妇产科学 | 264篇 |
基础医学 | 1487篇 |
口腔科学 | 225篇 |
临床医学 | 1138篇 |
内科学 | 2046篇 |
皮肤病学 | 143篇 |
神经病学 | 777篇 |
特种医学 | 727篇 |
外国民族医学 | 10篇 |
外科学 | 1368篇 |
综合类 | 278篇 |
一般理论 | 5篇 |
预防医学 | 877篇 |
眼科学 | 222篇 |
药学 | 715篇 |
1篇 | |
中国医学 | 10篇 |
肿瘤学 | 830篇 |
出版年
2022年 | 82篇 |
2021年 | 168篇 |
2020年 | 99篇 |
2019年 | 174篇 |
2018年 | 216篇 |
2017年 | 164篇 |
2016年 | 155篇 |
2015年 | 203篇 |
2014年 | 233篇 |
2013年 | 333篇 |
2012年 | 401篇 |
2011年 | 470篇 |
2010年 | 260篇 |
2009年 | 294篇 |
2008年 | 404篇 |
2007年 | 420篇 |
2006年 | 412篇 |
2005年 | 379篇 |
2004年 | 341篇 |
2003年 | 340篇 |
2002年 | 342篇 |
2001年 | 313篇 |
2000年 | 312篇 |
1999年 | 279篇 |
1998年 | 220篇 |
1997年 | 204篇 |
1996年 | 209篇 |
1995年 | 164篇 |
1994年 | 159篇 |
1993年 | 163篇 |
1992年 | 236篇 |
1991年 | 204篇 |
1990年 | 182篇 |
1989年 | 204篇 |
1988年 | 199篇 |
1987年 | 188篇 |
1986年 | 206篇 |
1985年 | 205篇 |
1984年 | 120篇 |
1983年 | 126篇 |
1982年 | 94篇 |
1981年 | 95篇 |
1980年 | 87篇 |
1979年 | 130篇 |
1978年 | 108篇 |
1977年 | 94篇 |
1976年 | 114篇 |
1974年 | 99篇 |
1973年 | 117篇 |
1972年 | 86篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Cisplatin and its analogs have become important components of chemotherapeutic regimens for the treatment of solid tumors, however, their overall effectiveness is limited by the emergence of drug-resistant tumor cells. Resistance to the platinum drugs is multifactorial consisting of mechanisms that prevent the formation of lethal platinum-DNA adducts and mechanisms that operate downstream of the drug/target interaction to promote cell survival. Continued progress in the study of the drug resistance phenotype as well as the development of new platinum analogs may eventually lead to improved therapies and increased survival rates. 相似文献
72.
73.
The traditional method of establishing a pneumoperitoneum before laparoscopic surgery is via a Verres needle inserted in the midline below the umbilicus while tenting the abdominal wall with the hand. A new approach is described in which preliminary surgical exposure and tenting of the linea alba immediately above the umbilicus is achieved before needle insertion through the superior margin of the umbilical ring. The advantages of this new technique over the conventional method are discussed. Further technical features important in the safe formation of the pneumoperitoneum are emphasized. 相似文献
74.
75.
76.
New Latex Bead Agglutination Assay for Differential Diagnosis of Cattle Infected with Mycobacterium bovis and Mycobacterium avium subsp. paratuberculosis 下载免费PDF全文
Hye Cheong Koo Yong Ho Park Jongsam Ahn W. Ray Waters Mary Jo Hamilton George Barrington Abdelaziz A. Mosaad Mitch V. Palmer Sang Shin William C. Davis 《Clinical and Vaccine Immunology : CVI》2004,11(6):1070-1074
Extensive studies have shown that the current assays used to identify cattle infected with Mycobacterium bovis or Mycobacterium avium subsp. paratuberculosis are not sufficiently sensitive and specific to detect all infected animals, especially animals recently infected with the pathogens. In the present report we show that these limitations might be overcome with a latex bead agglutination assay (LBAA). With the specific immunodominant epitope (ESAT6-p) of M. bovis, we developed an LBAA and enzyme immunoassay (EIA) for that purpose and compared them with the “gold standard” culture method and skin test for their efficacy in detecting bovine tuberculosis. When sera from control healthy cows (n = 10), M. avium subsp. paratuberculosis-positive cattle (naturally infected, n = 16; experimentally infected, n = 8), and M. bovis-positive cattle (naturally infected, n = 49;experimentally infected, n = 20) were applied to an EIA and an LBAA developed with ESAT6-p, the two tests showed similar sensitivity (97.1% by EIA, 95.7% by LBAA), high specificity (94.2% by EIA, 100% by LBAA), and a positive correlation (kappa value, 0.85; correlation rate, 93.2%; correlation coefficient, 0.64). Receiver operating characteristic analysis of EIA results and comparison with the culture method determined a suitable cutoff value at 0.469, with an area under the curve of 0.991 (95% confidence interval, 0.977 to 1.0). As LBAA didn't show any positive reactions with sera from uninfected control cows or M. avium subsp. paratuberculosis-infected cattle, which were confirmed to be free of M. bovis by culture or PCR, LBAA using the ESAT6-p can be a rapid and useful M. bovis diagnostic assay. The data suggest that rapid, sensitive, and specific assays can be developed with peptides containing immunodominant epitopes present in proteins uniquely expressed in M. bovis or M. avium subsp. paratuberculosis for differential diagnosis of cattle infected with M. bovis or M. avium subsp. paratuberculosis. 相似文献
77.
Mark A. Beilke Debra Riding In Rebecca Hamilton Gary A. Stone Elaine K. Jordan Gene Brashears Wayne Nusbaum David Huddleston Clarence J. Gibbs Jr. Maneth Gravell 《Journal of neuroimmunology》1991,33(2):129-143
HLA-DR expression in neuroendothelial cells (NEC) was studied during the course of SIV encephalitis in rhesus monkeys. HLA-DR determinants were detected on NEC in monkeys with SIV encephalitis, but not in control animals. In situ hybridization with an SIV probe indicated that HLA-DR expression was not a consequence of SIV replication within NEC. Cultured rhesus NEC stimulated with gamma interferon expressed HLA-DR to a higher degree than cultured brain fibroblasts or astrocytes. These data support the contention that NEC participate in retrovirus-induced inflammation and autoimmunity within the central nervous system. 相似文献
78.
Feng-Chun Tsai Daniel Marelli Jessica Bresson David Gjertson Reza Kermani Abbas Ardehali Fardad Esmailian Michele Hamilton Gregg C Fonarow Jaime Moriguchi Mark Plunkett Antoine Hage Julie Tran Jon A Kobashigawa Hillel Laks 《American journal of transplantation》2002,2(6):539-545
Older age, prior transplantation, pulmonary hypertension, and mechanical support are commonly seen in current potential cardiac transplant recipients. Transplants in 436 consecutive adult patients from 1994 to 1999 were reviewed. There were 251 using standard donors in 243 patients (age range 18-69 years). To emphasize recipient risk, 185 patients who received a nonstandard donor were excluded from analysis. The indications for transplant were ischemic heart disease (n = 123, 47%), dilated cardiomyopathy (n = 82, 32%), and others (n=56, 21%). One hundred and forty-nine (57%) recipients were listed as status I; 5 and 6% were supported with an intra-aortic balloon and an assist device, respectively. The 30-d survival and survival to discharge were 94.7 and 92.7%, respectively; 1-year survival was 89.1%. Causes of early death were graft failure (n = 6), infection (n = 4), stroke (n = 4), multiorgan failure (n = 3) and rejection (n = 2). Predictors were balloon pump use alone (OR= 11.4, p =0.002), pulmonary vascular resistance > 4 Wood units (OR = 5.7, p = 0.007), pretransplant creatinine > 2.0 mg/dL (OR = 6.9, p = 0.004) and female donor (OR = 8.3, p = 0.002). Recipient age and previous surgery did not affect short-term survival. Heart transplantation in the current era consistently offers excellent early and 1-year survival for well-selected recipients receiving standard donors. Early mortality tends to reflect graft failure while hospital mortality may be more indicative of recipient selection. 相似文献
79.
Traditionally, penicillin binding to serum proteins was believed to be a passive chemical process; however, it appears to be facilitated by serum factors. The objectives of this in vitro investigation were to examine facilitated penicillin haptenation, to study the kinetics of haptenation, and to determine the nature of haptenation-facilitating factors. The model involved addition of [3H]benzylpenicillin to serum or albumin solutions (at pH 7.3 to 7.4) and incubation at 37 degrees C for up to 72 h. The extent of penicillin binding to proteins in serum was found to be four- to fivefold higher than with solutions having comparable concentrations of purified albumin, total protein, or total immunoglobulin. Ultrafiltration of serum reduced penicillin binding to serum proteins substantially. An ultrafiltrable haptenation-facilitating factor(s) was found to be less than 0.5 kDa but was not calcium or magnesium. Finally, the extent of penicillin binding was related to albumin purity, as binding substantially increased with albumin purity. These findings suggest that there is a factor(s) in serum that facilitates covalent binding of penicillin to serum proteins. The factor(s) can be removed and then restored to increase penicillin binding to albumin. It appears that at least one component of the facilitation factor is less than 0.5 kDa, which suggests that it is not a peptide and that it is some simple serum component other than calcium or magnesium. 相似文献
80.
A few hours after servicing illuminated lamps inside a whole body ultraviolet radiation B (UVB) phototherapy cabin, a technician developed erythema to the anterior neck with subsequent peeling, despite wearing a UV-opaque face shield. Measurements using polysulphone film badges attached to various sites on the head and neck of a mannikin were carried out to explore the spatial distribution of UVB exposure. It was found that the lower face and neck can receive sufficient exposure to result in erythema, the reason being that the fluorescent lamps will extend to about 1.5 m inferior to the head of an upright person and so result in irradiation from below. It is important, therefore, that if operators or service personnel need to be in an illuminated UVB cabin for several minutes or more, adequate protection should be provided to the chin and neck, in addition to a UV-opaque face shield. 相似文献