全文获取类型
收费全文 | 1830篇 |
免费 | 109篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 43篇 |
妇产科学 | 66篇 |
基础医学 | 185篇 |
口腔科学 | 22篇 |
临床医学 | 151篇 |
内科学 | 391篇 |
皮肤病学 | 45篇 |
神经病学 | 152篇 |
特种医学 | 127篇 |
外科学 | 138篇 |
综合类 | 83篇 |
预防医学 | 93篇 |
眼科学 | 23篇 |
药学 | 130篇 |
中国医学 | 1篇 |
肿瘤学 | 313篇 |
出版年
2021年 | 12篇 |
2020年 | 14篇 |
2019年 | 10篇 |
2018年 | 16篇 |
2017年 | 10篇 |
2016年 | 17篇 |
2015年 | 20篇 |
2014年 | 30篇 |
2013年 | 81篇 |
2012年 | 41篇 |
2011年 | 47篇 |
2010年 | 46篇 |
2009年 | 50篇 |
2008年 | 47篇 |
2007年 | 72篇 |
2006年 | 58篇 |
2005年 | 57篇 |
2004年 | 59篇 |
2003年 | 64篇 |
2002年 | 56篇 |
2001年 | 45篇 |
2000年 | 46篇 |
1999年 | 57篇 |
1998年 | 60篇 |
1997年 | 58篇 |
1996年 | 55篇 |
1995年 | 30篇 |
1994年 | 38篇 |
1993年 | 40篇 |
1992年 | 44篇 |
1991年 | 41篇 |
1990年 | 47篇 |
1989年 | 71篇 |
1988年 | 54篇 |
1987年 | 56篇 |
1986年 | 42篇 |
1985年 | 32篇 |
1984年 | 37篇 |
1983年 | 22篇 |
1982年 | 16篇 |
1981年 | 19篇 |
1980年 | 21篇 |
1979年 | 18篇 |
1978年 | 15篇 |
1977年 | 10篇 |
1976年 | 10篇 |
1975年 | 13篇 |
1972年 | 12篇 |
1965年 | 9篇 |
1941年 | 11篇 |
排序方式: 共有1966条查询结果,搜索用时 359 毫秒
11.
Prognostic accuracy of preoperative and postoperative scintimetry after femoral neck fracture 总被引:4,自引:0,他引:4
K A Alberts 《Clinical orthopaedics and related research》1990,(250):221-225
Forty patients with fresh femoral neck fractures treated with closed reduction and internal fixation were included in a prospective study of nonunion and osteonecrosis by preoperative and postoperative scintimetry. Correlated roentgenographic follow-up studies were continued for two years postoperatively. The aim of the study was to determine the relative prognostic accuracy of preoperative versus postoperative scintimetry. A ratio between the radionuclide uptake over the femoral head on the fracture side and the contralateral side exceeding 1.9 at the preoperative scintimetry and 1.2 at the postoperative scintimetry was associated with a high incidence of union, whereas a lower ratio often predicted subsequent complications (redisplacement, nonunion, or late segmental collapse). Prognostic accuracy was higher for scintimetry of fractures treated with closed reduction and internal fixation (0.70) than for untreated fractures (0.53). These results suggest that scintimetry is useful postoperatively to complement roentgenographic examination in assessing the prognosis of femoral neck fractures. 相似文献
12.
Anderson RA; Evans LW; Irvine DS; McIntyre MA; Groome NP; Riley SC 《Human reproduction (Oxford, England)》1998,13(12):3319-3325
Follistatin is a binding protein for the activin and inhibin family of
hormones, regulating their biological activity. In the male reproductive
tract, the interaction of these factors is likely to be involved in the
regulation of the proliferation of several cell types. We have investigated
the presence of follistatin and activin A in seminal plasma using specific
immunoassays and have localized follistatin and activin/inhibin subunits in
the adult human testis, prostate and seminal vesicle to establish their
likely sources. High concentrations of immunoreactive follistatin were
present in seminal plasma in normal men (mean 97.9 ng/ml; 1.43 ng/ml in
peripheral plasma) and were similar in men with oligo/azoospermia and
following vasectomy. Follistatin immunoreactivity was localized to both
Leydig and Sertoli cells of the testis, and to epithelial cells of the
prostate gland and seminal vesicle, which are likely to be the predominant
sources of the hormone in seminal plasma. Activin A was also present in
seminal plasma in normal men but was undetectable following vasectomy, thus
deriving from the testis. Consistent with this finding, the betaA-subunit
was immunolocalized in Sertoli and Leydig cells but was not present in
seminal vesicle or prostate gland. The functional significance of the high
concentrations of follistatin secreted into seminal plasma by the prostate
gland and/or seminal vesicle is uncertain, but they may regulate the
biological activity of testis-derived activin A and inhibin B.
相似文献
13.
14.
This study describes our experience using a percutaneously placed small-bore catheter for drainage of malignant pleural effusions and subsequent instillation of a sclerosing agent to obliterate the pleural space. We treated 15 consecutive patients with known metastatic cancer and a symptomatic pleural effusion. Twelve patients survived for more than four weeks after the procedure; 11 of these 12 patients had a successful objective clinical response. The procedure was well tolerated, with little or no discomfort during catheter placement and the maintenance period. No serious complications were encountered. We conclude that the use of a small-bore percutaneously placed "pneumothorax" catheter in the management of malignant pleural effusions is an effective and more comfortable alternative to large-bore closed-tube thoracostomy. 相似文献
15.
Antonio C. Buzaid David S. Alberts Janine Eispahr Kurt Mosley Yei-Mei Peng Kendra Tutsch Collin P. Spears Harinder S. Garewal 《Cancer chemotherapy and pharmacology》1989,25(2):124-130
Summary Dipyridamole (DP) has previously been studied both in vitro and in vivo in combination with various antimetabolites, including methotrexate and 5-fluorouracil (5FU). We evaluated in vitro and clinically the effects of adding DP to fluorodeoxyuridine (FUDR) in colorectal cancer. Using a human colony-forming assay, we observed that 0.05 M DP increased the cytotoxicity of FUDR by a median of 33.5-fold vs 1.5-fold for 5FU against human colon-cancer cell lines. The mechanism of the DP-enhanced antitumor activity of FUDR is not completely understood but appears to be related to a profound inhibition by DP of thymidine accumulation in and FUDR efflux from colon-cancer cell lines. On the basis of these in vitro results, 28 patients with metastatic colon cancer were entered in a clinical trial of monthly courses of 0.1 mg/kg FUDR daily for 14 days and 75 mg oral DP 5 times daily for 14 days starting on the 3rd day of continuous i.v. FUDR infusion. The pharmacokinetics of DP was studied in three patients; the results showed that 98% of total serum DP was protein-bound and that free DP levels were significantly lower than the concentrations necessary for the expected in vitro DP/FUDR modulation. Treatment was well tolerated, with only 12 patients developing mild to moderate toxicity. Of 27 evaluable patients, 4 achieved a partial response that lasted 2, 3, 5, and 6+ months. This relatively low response rate (15%), which is similar to that achieved with FUDR alone, may be explained by the low steady-state plasma concentrations of free DP achieved in our patients. Other means of DP administration, such as i.v., i.a., and i.p. injection, may be required to achieve free DP concentrations necessary for successful biochemical modulation of FUDR in patients.Supported in part by grants CA17094, CA23074, and CA39629 from the National Institutes of Health, Bethesda, Md 20205, and a grant from the Arizona Chronic Disease Commission. HSG is a recipient of an American Cancer Society Career Development Award 相似文献
16.
17.
The CTLA-4 gene region of chromosome 2q33 is linked to, and associated with, type 1 diabetes. Belgian Diabetes Registry 总被引:8,自引:1,他引:8
Nistico L; Buzzetti R; Pritchard LE; Van der Auwera B; Giovannini C; Bosi E; Larrad MT; Rios MS; Chow CC; Cockram CS; Jacobs K; Mijovic C; Bain SC; Barnett AH; Vandewalle CL; Schuit F; Gorus FK; Tosi R; Pozzilli P; Todd JA 《Human molecular genetics》1996,5(7):1075-1080
Susceptibility to autoimmune insulin-dependent (type 1) diabetes mellitus
is determined by a combination of environmental and genetic factors, which
include variation in MHC genes on chromosome 6p21 (IDDM1) and the insulin
gene on chromosome 11p15 (IDDM2). However, linkage to IDDM1 and IDDM2
cannot explain the clustering of type 1 diabetes in families, and a role
for other genes is inferred. In the present report we describe linkage and
association of type 1 diabetes to the CTLA-4 gene (cytotoxic T lymphocyte
associated-4) on chromosome 2q33 (designated IDDM12). CTLA-4 is a strong
candidate gene for T cell- mediated autoimmune disease because it encodes a
T cell receptor that mediates T cell apoptosis and is a vital negative
regulator of T cell activation. In addition, we provide supporting evidence
that CTLA-4 is associated with susceptibility to Graves' disease, another
organ- specific autoimmune disease.
相似文献
18.
19.
M Eneroth N Mandahl S Heim H Willén A Rydholm K A Alberts F Mitelman 《Cancer Genetics and Cytogenetics》1990,48(1):101-107
Short-term cultures of two myxoid liposarcomas and two mixed-type (myxoid and round cell) liposarcomas were cytogenetically analyzed. A t(12;16)(q13;p11) was present in three tumors, whereas the fourth had an unbalanced 12;16-translocation with breaks in 12q13 and 12q22, with loss of the 12q13-q22 segment, and in 16p11. In the two mixed liposarcomas, the breakpoints could be determined at subband level to 12q13.3 and 16p11.2. 相似文献
20.
Y chromosome microdeletions, in azoospermic or near-azoospermic subjects, are located in the AZFc (DAZ) subregion 总被引:9,自引:2,他引:9
Submicroscopic deletions of the Y chromosome and polymorphisms of the
androgen receptor (AR) gene in the X chromosome have been observed in men
with defective spermatogenesis. To further define the subregions/genes in
the Y chromosome causing male infertility and its relationship to
polymorphisms of the AR polyglutamine tract, we screened the genomic DNA of
202 subfertile males and 101 healthy fertile controls of predominantly
Chinese ethnic origin. Y microdeletions were examined with 16
sequence-tagged site (STS) probes, including the RBM and DAZ genes,
spanning the AZFb and AZFc subregions of Yq11, and related to the size of
trinucleotide repeat encoding the AR polyglutamine tract. Y microdeletions
were detected and confirmed in three out of 44 (6.8%) of azoospermic and
three out of 86 (3.5%) severely oligozoospermic patients. No deletions were
detected in any of the patients with sperm counts of >0.5 x 10(6)/ml,
nor in any of the 101 fertile controls. All six affected patients had
almost contiguous Y microdeletions spanning the entire AZFc region
including the DAZ gene. The AZFb region, containing the RBM1 gene, was
intact in five of the six subjects. Y deletions were not found in those
with long AR polyglutamine tracts. Our study, the first in a Chinese
population, suggest a cause and effect relationship between Y
microdeletions in the AZFc region (possibly DAZ), and azoospermia or
near-azoospermia. Y microdeletions and long AR polyglutamine tracts appear
to be independent contributors to male infertility.
相似文献